Patent Application
20080269596
The present invention relates generally to systems and methods for use in carrying out surgical procedures, and in particular to an integrated orthopaedic surgery system and methods of use thereof, and implants, instruments, computer program code and computer programs for use therein.
Computer aided surgery typically provides for the display of images of body parts and the positions of navigated tools so that the surgeon can use the images to guide them while carrying out the surgical procedure. However, it is typically required to register the image of the patients body part with the actual position of the body part.
Markers detectable by a tracking system can be attached to a body part so that the position of the body part can be tracked, e.g. during a surgical procedure. Such markers are sometime referred to as fiducial markers. A variety of marker types can be used depending on the nature of the tracking system and how signals are generated by the marker and communicated to the tracking system. However, markers are typically provided on some kind of support structure by which the marker is mounted on the body part, such as on the skin, or anchored to bone or another subcutaneous body part or anatomical structure.
For example a surgical sensor is described in U.S. Pat. No. 6,499,488 (Hunter et al.) in which a sensor, which sends signals to a surgical guidance system, is provided in a housing mounted on a surgical screw, or in a hollow part of the screw in lieu of the housing. The surgical screw can be screwed into a bony anatomical structure. Hence, the sensor is attached to a bony anatomical structure by the screw. However, the sensor is still supported by the screw and the sensor is not itself located in the bony structure. Further, an incision is still required in order to attach the sensor to the body part
As indicated above, various methods and systems can be used to track the position of a medical probe or implant inside the body of a subject.
For example, U.S. Pat. Nos. 5,391,199 and 5,443,489 to Ben-Haim, whose disclosures are incorporated herein by reference, describe systems wherein the coordinates of an intrabody probe are determined using one or more field sensors, such as a Hall effect device, coils, or other antennae carried on the probe. Such systems are used for generating three-dimensional location information regarding a medical probe or catheter.
PCT Patent Publication WO 96/05768, and the corresponding U.S. patent application Ser. No. 09/414,875, to Ben-Haim et al. (also published as U.S. Patent Application Publication US 2002/0065455 A1, whose disclosures are incorporated herein by reference, describe a system that generates six-dimensional position and orientation information regarding the tip of a catheter. This system uses a plurality of sensor coils adjacent to a locatable site in the catheter, for example near its distal end, and a plurality of radiator coils fixed in an external reference frame. These coils generate signals in response to magnetic fields generated by the radiator coils, which signals allow for the computation of six location and orientation coordinates.
U.S. Pat. No. 6,239,724 to Doron et al., whose disclosure is incorporated herein by reference, describes a telemetry system for providing spatial positioning information from within a patient's body. The system includes an implantable telemetry unit having (a) a first transducer, for converting a power signal received from outside the body into electrical power for powering the telemetry unit; (b) a second transducer, for receiving a positioning field signal that is received from outside the body; and (c) a third transducer, for transmitting a locating signal to a site outside the body, in response to the positioning field signal.
U.S. patent application Ser. No. 10/029,473 to Govari, published as U.S. Patent Application Publication 2003/0120150, describes apparatus for tracking an object. The apparatus includes a plurality of field generators, which generate electromagnetic fields at different, respective frequencies in a vicinity of the object, and a radio frequency (RF) driver, which radiates a RF driving field toward the object. A wireless transponder is fixed to the object. The transponder includes at least one sensor coil, in which a signal current flows responsive to the electromagnetic fields, and a power coil, which receives the RF driving field and conveys electrical energy from the driving field to power the transponder. The power coil also transmits an output signal responsive to the signal current to a signal receiver, which processes the signal to determine coordinates of the object.
Registration procedures typically require images of the patient to have been acquired previously and so multiple medical procedure at multiple sites are required in order to allow the surgical procedure to be carried out.
Also, different practitioners may be involved in capturing the images and/or carrying out the surgical procedure. Therefore, some of the images that the surgeon would want may not actually have been captured and therefore would not be available to the surgeon. Also the images may be capture some time before the surgery and so may not accurately reflect the current status of the patient.
Further, the surgical practitioner may have little or no control over the information that can be used during the surgical procedure and that information although existing may not be instantly available to the surgeon in the form most useful at any time during the surgical procedure.
Therefore, the present invention addresses deficiencies in surgical systems and method for allowing computer aided surgery to be carried out.
According to a first aspect of the invention, there is provided an integrated surgical system. The integrated surgical system can be used in an orthopaedic operating room to enable a surgeon to carry out a computer aided surgical procedure on a subject or patient.
The integrated surgical system can include a subject support and/or a wireless magnetic tracking system and/or a registration system configured to register the position of the body part of the subject with an image of the body part of the subject and/or a display device and/or a control system which integrates the functionalities of parts of the surgical system and/or a surgeon interface operable by the surgeon to control operation of the integrated surgical system.
The tracking system can generating a magnetic field defining a working volume of the tracking system. The subject support can be located at least partially within the working volume. The tracking system can include a tracking control system configured to track the position of a marker detectable by the tracking system within the working volume and generate a signal indicative of the position of the marker within a reference frame of the tracking system.
The display device can be configured to display a registered image of the body part, or bone, of the subject and/or an image representative of a trackable implant during a computer aided surgical procedure.
The system can comprise a further wireless tracking system. The further wireless tracking system can be an infrared wireless tracking system. The further tracking system can be in communication with the control system and can be configured to generate a signal indicative of the position of a tracked element in the reference frame of the further wireless tracking system.
The display device can be a part of a tracking system control system. The display device can be a touch sensitive display. The display device can be a part of the surgeon interface. A plurality of such display devices can be provided. A separate display device can be provided for each tracking system. Preferably a single display device is provided as a part of the control system for a plurality of tracking systems.
The surgeon interface can include an orientation sensitive device operable by a surgeon to enter control commands. The orientation sensitive device can be a wireless device. The device can be a gyromouse.
The surgeon interface can include a heads up display. The heads up display can be wearable by the surgeon. The heads up display can be configured to display at least a one of the images selected from the group comprising: a captured image of the body part; an image of a model of the body part; a registered image of the body part; a video image of the body part; a representation of an implant; a representation of an instrument; an indication of the planned position of an implant, instrument or incision; and any combination or overlay of the preceding.
The system can further comprise a wall display unit. The wall display unit can be configured to provide a plurality of image regions and/or a single image region. The or each image region can be capable of displaying a different image and/or the image can be a combination of images.
The different images can be selected from the group comprising: a captured image of the body part; an image of a model of the body part; a registered image of the body part; a video image of the body part; a representation of an implant; a representation of an instrument; an indication of the planned position of an implant, instrument or incision; and any combination or overlay of the preceding.
The system can further comprises a surgical site display device. The surgical site display device can be movable. The surgical site display device can include an image display portion and a support. The image display portion can be positionable over the surgical site of the patient in use. The surgical site display device can include an image capturing device having a field of view including the surgical site. The device can generating a surgical site image and the surgical site image can be displayed in the image display portion in registration with the surgical site. The image capturing device can be a video camera. The surgical site image can be, or include, a real time video, or still, image of the surgical site. A further image can be overlayed on the surgical site image. The further image and the surgical site image can be displayed in the image display portion at the same time. The further image can be in registration with the surgical site. The further image can be selected from the group comprising: a captured image of the body part; an image of a model of the body part; a registered image of the body part; a video image of the body part; a representation of an implant; a representation of an instrument; an indication of the planned position of an implant, instrument or incision; and any combination of the preceding.
The system can further comprise an image capturing device which captures real time video, or still, images. The real time video, or still, images can be displayed in real time on at least one display device of the system. Preferably the images are displayed in real time in a one of the image regions of an image wall.
The system can further comprise a surgical light. The surgical light can be suspended and be movable to different positions and orientations with respect to the operating table. An image capturing device can be provided as a part of the surgical light.
A one or a plurality of the parts of the system can be suspended. This reduces the amount of floor space taken up by parts of the system, thereby providing easier and freer access to the patient by the surgeon and other surgical staff.
The system can further comprising an image storage device storing a plurality of captured images of the body part of the subject. The images of the body part can be selected from the group comprising: X-ray images; CT scan images; and X-ray fluoro images. The storage device can be remote or local. A remote storage device can be in communication with the system over a network.
The system can include a model body part storage device. A plurality of generic 3-d models of different body parts, virtual body parts or representations of body parts can be stored. The body parts can be bones. The bones can be selected from the group comprising: a femur; a part of a femur; a femoral head; a pelvis; a part of a pelvis; an acetabulum of a pelvis; a tibia; a part of a tibia; a knee joint; a hip joint; a vertebra; an ankle; fibula; a part of a fibula; a shoulder; a wrist; and an elbow. The storage device can be local or remote. The storage device can be in communication with the system over a network.
An implant image storage device can be provided. The storage device can store 3d images, virtual implants or representations of a plurality of implants useable in the computer aided surgical procedure. The implants can be selected from the group comprising; femoral implants; tibial implants; pelvic implants; spinal implants; prosthetic ankles; prosthetic knees; prosthetic hips; prosthetic shoulders; prosthetic elbows; prosthetic wrists.
An instrument image storage device can be provided. The instrument storage device can store 3d images, virtual instruments or representations of a plurality of instruments useable in the computer aided surgical procedure.
The registration system can include an X-ray or X-ray fluoroscopy registration system. A first and/or second x-ray source can be provided and respective first and/or second detectors associated with the sources can be provided. A source or sources and/or a detector or detectors can be moveable. The source(s) and/or detector(s) can be movable so as to capture images from at least two different directions.
The registration system can be configured to capture at least a first image and a second image of the body part from different directions with the patient on the operating table.
The registration system can includes a first x-ray source and a second x-ray source, a first detector positioned to capture the first image of the body part resulting from the first x-ray source and a second detector positioned to capture the second image of the body part resulting from the second x-ray source. The detectors can be x-ray detectors which generate a digital image or x-ray fluoroscopy detectors.
The first detector and the second detector can be positioned above the subject support the first and second detectors can be suspended. The first x-ray source and the second x-ray source can be positioned below the subject support. The x-ray sources can be located within a floor.
The control system can include a registration control part. The control system can include computer program instructions executable to generate a 3d image of the body part from the first image and second image, to determine the position of the body part in the reference frame of the tracking system and to register the 3d image of the body part with the position of the body part in the reference frame of the tracking system.
The tracking system can include a magnetic field generating subsystem. The position of the magnetic field generating subsystem and/or subject support can be movable so as to change the position and/or orientation of the working volume relative to the subject support. Hence the surgical site can more easily be located within the working volume. A part of the subject support can be movable and/or a part of the magnetic field generating subsystem can be movable. A reference frame on which magnetic field generating coils are mounted can be moved relative to the patient support. The patient support can be moved relative to a reference frame on which magnetic field generating coils are mounted.
The first x-ray source and the second x-ray source can be provided on, in, within or under a floor on which the subject support is located.
The system can include an image handling sub-system. The system can include a video mixing and control subsystem which controls the format, type and display of images on a plurality of different image display parts of the system and/or which receives images from a plurality of different image sources. The image sources can include an endoscope, a video camera, a still camera, a digital camera, an image store, a surgical planning application, a surgical workflow application, an IGS application, and a tracking system or systems. The display devices can include a tracking control system display or displays, an image wall, a heads up display, a surgical site display.
The control system can include computer program instructions providing an orthopaedic surgery workflow program and/or an orthopaedic planning program and/or an image guided surgery program. The image guided surgery program can be configured to implement an orthopaedic procedure at least partially planned by the orthopaedic planning program.
The tracking system can pass or provide data indicating the identity of a marker, or of each of a plurality of markers, being tracked by the tracking system to the control system.
The control system can determine the nature of the element with which the marker is associated. The or each marker can be associated with a bone, an implant, an instrument, or a part of the surgical system, e.g. a part of the registration system or the surgical site display.
The system can further comprise a marker, or a plurality of markers, wirelessly trackable by the tracking system. The marker or markers can be attached to an implant or implants. The marker or markers can be attached to an instrument or instruments. The marker or markers can be attached to a bone or bones. The marker or markers can be attached to a part of the surgical system.
The or each marker can have a housing including a bone anchor for retaining the marker within the bone of the subject. The marker can be hermetically sealed in the housing. The housing can be configured to be percutaneously implantable within the bone of a subject. The or each marker can have a housing and the marker can be hermetically sealed in the housing. The housing can be configured to be secured within or to an implant or part of an implant.
The system can further include a prosthetic joint, or part of a prosthetic joint. The prosthetic joint can comprise a first orthopaedic implant bearing a first marker wirelessly trackable by the tracking system and/or a second orthopaedic implant bearing a second marker wirelessly trackable by the tracking system. A marker can be provided in a wall, stem, pin, peg or bone anchoring part of the orthopaedic implant.
The prosthetic joint can be a knee joint, an ankle joint, a hip joint, an elbow joint, a wrist joint, a hip joint, a shoulder joint, or a spinal joint.
The prosthetic joint can be a prosthetic knee joint, and the first orthopaedic implant can be a femoral component and the second orthopaedic component can be a tibial component. The femoral component can includes a locating pin and the first marker can be located at least partially within the locating pin. The tibial component can includes a keel or anchor and the second marker can be located at least partially within the keel or anchor.
The prosthetic joint can be a prosthetic hip joint, the first orthopaedic implant can be an acetabular component and the second orthopaedic component can be a femoral component. The acetabular component can be a cup and the first marker can be located within a wall of the cup. The marker can be at an apex of the cup. The femoral component can have a body and the second marker can be located at least partially within the body. The second marker can be located at a shoulder of the body or at the tail or stem of the body.
The system can include a plurality of markers wirelessly trackable by the wireless magnetic tracking system. A first of the markers can be configured to be powered by RF induction. The first marker can be implantable in the bone of the subject. A second marker can be configured to be powered by RF induction. The second marker can be attachable to an orthopaedic implant. A third marker can be battery powered. The third is marker can be attachable to an instrument. The instrument can be configured for use in the surgical procedure to prepare for implanting the orthopaedic implant, or for implanting the orthopaedic implant in the body of the subject.
According to a second aspect of the invention, there is provided a dummy or virtual body part for use in training a surgeon to carry out an orthopaedic surgical procedure on a surgical site. The dummy body can comprising an outer layer, an inner volume and a three dimensional formation surrounded by the inner volume. The an outer layer can be of a first material which mimics skin. The inner volume can be of a second material within the outer layer. The second material can mimics interior body tissues, and in particular tissues or structures associated with a joint. The three dimensional formation can be of a third material which mimics bone. The outer layer, inner volume and formation are can be arranged to correspond to a joint of a human body.
The dummy body part can have a first three dimensional formation corresponding to a knee joint and a second three dimensional formation corresponding to a hip joint.
The first material can be a polyurethane elastomer and/or the second material can be a polyurethane elastomer and/or the third material can be a solid foam.
According to a third aspect of the invention, there is provided a method for operating an integrated surgical system to enable a surgeon to carry out a computer aided surgical procedure. The method can include determining the position of at least a first marker being wirelessly tracked by a wireless magnetic tracking system. The position of the body part of the subject can be registered with an image of the body part of the subject. A registered image of the body part of the subject can be displayed on a display device. An image representative of an implant at a current position of the implant relative to the body part can also be displayed on the display device. The images can be displayed during the computer aided surgical procedure. A command can be received from a surgeon interface. Operation of a part of the integrated surgical system can be controlled responsive to the command.
The wireless magnetic tracking system can generates a magnetic field defining a working volume of the tracking system within which the subject support is at least partially located. The position of the marker can be within a reference frame of the tracking system.
The body part and image of the body part can be registered within the reference frame of the tracking system.
The method can further comprise determining the position of a second marker being wirelessly tracked by an infrared wireless tracking system. The position of the second marker can be within a reference frame of the infrared wireless tracking system. The method can further comprising determining the position of the second marker in the reference frame of the wireless magnetic tracking system.
The method can further comprise determining the position of an element to which the marker is attached in the reference frame of the magnetic wireless tracking system. The element can be an instrument, a bone, an implant or a part of the surgical system, such as a part of a registration system or a surgical site display.
The method can further comprise generating an image for display on a heads up display. The image can be supplied to the heads up display. The image can be selected from the group comprising: a captured image of the body part; an image of a model of the body part; a registered image of the body part; a video image of the body part; a representation of an implant; a representation of an instrument; an indication of the planned position of an implant, instrument or incision; and any combination and/or overlay of the preceding.
The method can further comprise generating a plurality of different images for display on a wall display unit. A one of the plurality of images can be supplied for display in an image region of the wall display unit. A different one of the plurality of images can be displayed in each of a plurality of image regions.
The different images can be selected from the group comprising: a captured image of the body part; an image of a model of the body part; a registered image of the body part; a video image of the body part; a representation of an implant; a representation of an instrument; an indication of the planned position of an implant, instrument or incision; and any combination and/or overlay of the preceding.
The method can further comprise capturing a surgical site image of a surgical site. The surgical site image can be supplied to a display device. The display device can be positionable over the surgical site of the patient in use. The surgical site image can be displayed in registration with the surgical site. The surgical site image can be a real time video or still image of the surgical site.
The method can further comprise registering a further image with the position of the surgical site. The further image can be overlayed on the surgical site image. The further image is selected from the group comprising: a captured image of the body part; an image of a model of the body part; a registered image of the body part; a video image of the body part; a representation of an implant; a representation of an instrument; an indication of the planned position of an implant, instrument or incision; and any combination of the preceding.
The method can further comprising capturing real time video images of a surgical site. The real time video images can be supplied for display in real time on at least one display device of the system.
The method can further comprise retrieving and/or receiving an image from an image storage device. The an image can be a one of a plurality of captured images of the body part of the subject. The images of the body part can be selected from the group comprising: X-ray images; CT scan images; ultrasound; and X-ray fluoroscopy images.
The method can further comprise selecting a one of a plurality of generic 3d models of different body parts stored in a storage device. Selecting the 3-d model can be based on a measure of the patient's body part derived from a captured image of the body part. The selected one of the plurality of generic 3d models can be morphed to more closely match the body part of the subject. An image derived from the morphed generic 3d model, or the morphed generic 3d model, can be displayed.
The method can further comprise selecting and/or retrieving a one of a plurality of stored 3d images of a plurality of implants useable in the computer aided surgical procedure. The current orientation and/or position of an implant corresponding to the selected implant can be determined. Selecting the implant image can be based on determining the identity of a marker attached to the implant corresponding to the selected implant image. An image can be generated from the selected 3d image of the implant. The image can correspond to a surgeon's view of the implant for the current orientation of the implant. The image can be displayed at the current position of the implant. The displayed implant image can be registered with a displayed registered image of the body part.
The method can further comprise selecting a one of a plurality of stored 3d images or representations of a plurality of instruments useable in the computer aided surgical procedure. Selecting the instrument image can be based on determining the identity of a marker attached to the instrument corresponding to the selected instrument image. The current orientation and/or position of an instrument corresponding to the selected implant can be determined. An image can be generated from the selected 3d image of the instrument. The image can corresponding to a surgeon's view of the instrument for the current orientation of the instrument. The image can be displayed at the current position of the instrument. The displayed instrument image can be registered with a displayed registered image of the body part.
The method can further comprising capturing a first x-ray or x-ray fluoroscopy image of the body part for a first direction and a second x-ray or x-ray fluoroscopy image of the body part for a second direction, different to the first direction. A 3d image of the body part can be generated from the first image and second image. The position of the body part in the reference frame of the tracking system can be determined. The 3d image of the body part can be registered with the position of the body part in the reference frame of the tracking system.
The position and/or orientation of a captured image of the body part in the reference frame of the tracking system can be used to register the 3d image of the body part and the position of the body part. The position and/or orientation of a captured image can be determined by detecting the position of an image capturing device in the reference frame of the tracking system. The position and/or orientation of a captured image can be determined from a fixed positional and/or orientational relationship of the image capturing device with the reference frame of the tracking system.
The method can further comprise controlling images from different sources and displaying images from different sources on different image display parts of the system.
The method can further comprise displaying a user interface for an orthopaedic surgery workflow program and receiving and processing commands entered via the user interface.
The method can further comprised displaying a user interface for an orthopaedic planning program and receiving and processing orthopaedic planning commands entered via the user interface. At least a part of a surgical plan can be saved. Implant type, implant size and/or implant position selection commands can be received and/or processed.
The method can further comprise displaying a user interface for an orthopaedic image guided surgery program. Commands entered via the user interface can be received and processed to control the image guided surgery procedure.
The method can further comprise generating and displaying images to guide the surgeon to carry out surgical steps. A, some or all of the surgical steps can have been planned by the orthopaedic planning program. The steps can be planned pre-operatively or intra-operatively. Pre-operative planning can be entirely virtual.
The method can further comprising determining the identity of each of a plurality of markers being tracked by the tracking system. The nature of an element with which the marker is associated can be determined for each or all of the plurality of markers.
The nature of the element can be selected from the group comprising: a bone; an implant; an instrument; a tool; and a part of the surgical system.
The method can further comprising determining the current position of a trackable instrument, or all trackable instruments, in the reference frame of the tracking system. Only the current position of an instrument or instruments located within the working volume can be determined.
The method can further comprise determining the current position of a bone, or all bones, in the reference frame of the tracking system. Only the current position of a bone or bones located within the working volume can be determined. The or each bone can have a marker implanted therein.
The method can further comprise determining the position in the reference frame of the tracking system of a first orthopaedic implant bearing a first marker wirelessly trackable by the tracking system. The position in the reference frame of the tracking system of a second orthopaedic implant bearing a second marker wirelessly trackable by the tracking system can be determined. The position in the reference frame of the tracking system of all marked orthopaedic implants can be determined. Only the current position of an implant or implants located within the working volume can be determined
The first orthopaedic implant can be a femoral component of a prosthetic knee joint and/or the second orthopaedic component can be a tibial component of a prosthetic knee joint. The first orthopaedic implant can be an acetabular component of a hip joint and/or the second orthopaedic component can be a femoral component of a hip joint.
According to a fourth aspect of the invention, there is provided computer program code executable by a data processing device to provide the method of the third aspect of the invention. There is also provided a computer readable medium bearing computer program code according to the fourth aspect of the invention.
According to a fifth aspect of the invention, there is provided a wirelessly trackable prosthetic joint. The prosthetic joint can comprise a first component bearing a first wirelessly trackable marker and/or a second component bearing a second wirelessly trackable marker. The first wirelessly trackable marker and/or the second wirelessly trackable marker can each be hermetically sealed.
The first and/or second wirelessly trackable marker can be configured to be powered by RF induction.
The first wirelessly trackable marker and/or the second wirelessly trackable marker can each be hermetically sealed in an encapsulant and/or in a housing. The housing can include at least a ceramic part.
The first and/or second wirelessly trackable marker can be magnetically wirelessly trackable.
The first and/or second wirelessly trackable marker can be located within a wall, stem, locating formation, pin, keel or anchor part of an implant component. The marker can be enclosed within any of the preceding parts of the implant component.
The first and/or second wirelessly trackable marker can be wirelessly trackable with the first component and/or the second component implanted subcutaneously in the body of a subject. That is the makers can be trackable through the patient's skin after the surgical wound has been closed and without the marker being exposed by the skin.
The joint can be a prosthetic knee, a prosthetic hip, a prosthetic ankle, a prosthetic wrist, a prosthetic elbow, a prosthetic shoulder or a prosthetic spinal part or joint.
The joint can be a prosthetic knee. The joint can be a uni-condylar prosthetic knee. The first component can be a femoral component. The femoral component can have a femur engaging surface and a bearing surface corresponding to a single condyle of the femur. The second component can be a tibial component. The tibial component can have a tibia engaging surface and a bearing on an opposed side. The bearing can be configured to engage with a single condyle bearing surface only of the femoral component as the prosthetic knee is articulated.
The femoral component can includes a location pin. The location pin can extend from the femur engaging surface. The location pin can have a cavity therein in which the marker is partially located or wholly located. The marker can be enclosed within the location pin.
The femoral component can be configured with at least a first sensor coil of the marker aligned or parallel with a principal axis of the body part. The principal axis can be the longitudinal axis of the femur.
The tibial component can include a keel or anchor part for engaging in the tibia in use. The marker can be located at least partially in the keel or anchor part.
The tibial component can be configured with at least a first sensor coil of the marker aligned with a principal axis of the body part. The principal axis can be an anterior-posterior axis or direction of the tibia.
The joint can be a hip joint. The first component can be an acetabular component. The second component can be a femoral component. The femoral component can be or include a stem part.
The first marker can comprise a housing defining a cavity and a marker located within the cavity. The cavity can have three parts. A first part can receive a sensor coil. A second part can receive control circuitry. A third part can receive an RF power induction coil.
The acetabular component can have a wall and the acetabular marker can be located within the wall of the acetabular component.
The housing can have a convex outer surface and a concave inner surface. The acetabular component can have a convex outer surface and a concave inner surface. The outer surface of the housing can smoothly continues the outer surface of the acetabular component. The inner surface of the housing can smoothly continue the inner surface of the acetabular component. The inner surfaces of the housing and/or acetabular component can be highly polished to provide an articulate surface.
The femoral component can defines a cavity therein and the second marker can be located partially or wholly in the cavity. The marker can be enclosed in the cavity.
According to a sixth aspect of the invention, there is provided a kit of parts for use in a computer aided orthopaedic surgical procedure. The kit includes a first percutaneously implantable marker for implanting in a first bone associated with a joint to be replaced and a prosthetic joint according to the fifth aspect of the invention. A second percutaneously implantable marker for implanting in a second bone associated with the joint to be replaced can also be provided.
The kit can further comprise an instrument or instrument assembly for injecting the first and/or second markers through the skin of the patient so as to implant the markers in the bone or bones of the patient.
According to a seventh aspect of the invention, there is provided a computer implemented method for carrying out an orthopaedic surgical procedure. The procedure can include implanting a first orthopaedic implant bearing a first marker magnetically wirelessly trackable by a tracking system and/or a second orthopaedic implant bearing a second marker magnetically wirelessly trackable by the tracking system in a body of a subject. The method can include creating a surgical plan defining the intended implantation positions for the first and/or second orthopaedic implants. An image of a part of the body of the subject can be registered with the position of the part of the body of the subject in the reference frame of the tracking system. The surgical plan can be registered with the tracking system. The current positions of the first and/or second orthopaedic implants are determined. A first image representing the part of the body of the patient, a second image representing the current position of the first orthopaedic implant and/or a third image representing the current position of the second orthopaedic implant can be displayed. An indication of the planned positions of the first and/or second orthopaedic implants derived from the surgical plan can also be displayed.
According to a eighth aspect of the invention, there is provided a method for carrying out an orthopaedic computer aided surgery procedure on a body of a subject in an operating room. The method can include planning the intended position of a first orthopaedic implant wirelessly magnetically trackable by a tracking system having a reference frame. A part of the body of the subject in the operating room can be registered. An image guided surgery system can be used to determine an implantation position of the first orthopaedic implant in the part of the body. The orthopaedic implant can be implanted at the implantation position.
The method can further comprise percutaneously implanting at least a first sensor wirelessly magnetically trackable by the tracking system in a bone of the part of the body.
The first sensor can be implanted prior to locating the body in the operating room.
The first sensor can be implanted with the body in the operating room.
The first sensor can be implanted prior to planning the intended position of the first orthopaedic implant.
Registering a part of the body can occur before planning the intended position of the first orthopaedic implant. Registering a part of the body can occur after planning the intended position of the first orthopaedic implant.
Planning the intended position can be carried out virtually.
The method can further comprising taking first and second x-ray, or x-ray fluoroscopic, images of the part in the operating room from different directions. The intended position of the first orthopaedic implant can be planned using a 3d model of the body part derived from the first and second images. Preferably the first and second images are from directions approximately 90E apart.
The first and second x-ray, or x-ray fluoroscopic, images of the part can be taken without moving the patient in the operating room. The method can include moving an x-ray source and/or an x-ray, or x-ray fluoroscopy, detector.
The method can further comprise visually assessing the performance of the implanted first orthopaedic implant in the operating room by viewing a real time representation of the position of the implant or implants and/or the part of the body immediately after implantation and before or after closing the surgical wound.
The method can further comprise percutaneously removing a marker wirelessly magnetically trackable by the tracking system from within a bone of the body part.
Preferred features of a one of the aspects of the invention can also be counterpart preferred features of other aspects of the invention mutatis mutandis.
The present invention will be more fully understood from the following detailed description of the embodiments thereof, taken together with the drawings in which:
Similar items in different Figures generally have common reference numerals unless indicated other wise.
With reference to
The orthopaedic operating system 1 includes an operating table 2 which acts as a patient support and on which a patient, or subject, on which an orthopaedic procedure is to be carried out can be located. Various embodiments of patient support 2 will be described in greater detail below with particular reference to
The system 1 also includes a first tracking system 3 and in other embodiments can also include a second tracking system 4. In one embodiment, the first tracking system 3 is a wireless, magnetic tracking system which can track the positions of sensors and provide an indication of the position and orientation of the magnetic sensors, also referred to herein as markers, within a working volume of the tracking system 3. The tracking system 3 has a reference frame, or co-ordinate frame, associated with it and which is also associated with the overall orthopaedic surgery system 1. The tracking system and markers will be described in greater detail below also.
A second tracking system 4 can also be provided and can be a wireless or wire line based tracking system. In one embodiment, the second tracking system can be based on detecting reflected or transmitted infrared radiation. A suitable infrared based tracking system is a suitably configured Vector Vision or Vector Vision 2 system as provided by BrainLab AG of Heimstetten, Germany. The infrared tracking system can include IR camera parts provided by Northern Digital Inc of Canada under the trade name Polaris. This system can also uses active tools or instruments which omit infrared radiation rather than merely reflecting infrared radiation.
The provision of two separate tracking systems allows greater flexibility in the surgeon's work procedures and allows differently marked tools, instruments, implants and reference arrays to be used in order to allow the position of various elements within the system to be determined. It will be appreciated that the infrared based tracking systems require a line of sight to be maintained between the tracked element and infrared detectors and therefore the magnetic field based tracking technology can be preferred as the surgeon does not need to be as mindful of maintaining the line of sight.
The orthopaedic operating system 1 also includes an X-ray or X-ray fluoroscopy based imaging sub-system 5 which can be used to capture images of the patient on the operating table 2 to either pre, intra or post-operatively. In one embodiment, the X-ray imaging system provides a part of an auto-registration feature of the orthopaedic operating system 1 as will be described in greater detail below. The X-ray imaging system can be an X-ray system or can be an X-ray fluoroscopy system.
A real time video imaging system 6 is also provided in the form of a surgical light with an integrated video camera 6. This system can be used to provide illumination of the surgical site and to provide wide filed of view or close up video images.
A surgical site display device 7 is also provided which can be used by the surgeon to display a real time image of the surgical site and on to which other images can be displayed and/or overlayed on the surgical site image. For example, an indication of the location of an incision, cut, an implant, a planned position or an instrument can be displayed as part of an image guided surgical process which will be described in greater detail below.
A large scale display 8 is also provided in the form of a video or image wall. The image display wall has a plurality of imaging regions on which various different images from various different image sources can be displayed in order to provide an immersive environment in which the surgeon can operate and to provide various sources of information to the surgeon in different formats on which to base his surgical activities and decisions. A suitable display wall is available from Barco N.V., based in Belgium.
A control system 9 is also provided which controls and integrates the overall functionality of the various parts and sub-systems of the orthopaedic operating system 1 so that the functionalities are integrated together rather than being disparate parts. The surgeon can control the operation of the operating room via a surgeon interface 10. The surgeon interface 10 can comprise a variety of input and output devices for entering instructions and commands and displaying information to the surgeon. The control system 9 is illustrated schematically by a single suitably programmed general purpose computer device. However in practice, the control system can be implemented by a number of devices so that the control function is distributed throughout the orthopaedic operating system 1. The invention should therefore not be considered to be limited to an implementation involving a single computer and indeed, as will be apparent from the following description, a number of interacting computing devices can be provided.
The surgeon interface 10 can include a gyromouse 11 which is an orientation sensitive input device whereby the surgeon can enter commands to the control system by moving the gyromouse 11 and/or changing its orientation and/or pressing buttons. In this way, the surgeon can control menus and move cursors in order to make selections and enter commands via a graphical user interface displayed on control system display unit 12. A suitable gyromouse is provided by Gyration, Inc of the USA.
Display unit 12 provides a user interface to the surgeon and also displays any number of a plurality of images to the surgeon and is a primary source of information and images available to the surgeon. Display unit 12 has a touch sensitive screen so that the surgeon can enter commands and select options via the screen of display device 12. A plurality of display devices like display 12 can be provided, one for each of the tracking systems, or alternatively a single display device can be used to control and display images from both the tracking systems. The latter option is preferred so as to minimise the number of components in the system.
The surgeon interface 10 can also include a heads up display unit 13 wearable by the surgeon and on which various images, combinations of images and overlays of images can be provided so as to further enhance the surgeon's immersion in the orthopaedic operating environment. A suitable heads up display is provided under the name MOSIS. Another suitable heads up display is the MD-06 as provided by MicroOptical Corporation.
As schematically illustrated in
As also illustrated in
As also illustrated in
With reference to
The video mixing and control system 191 receives images of various tracked elements of the system from the magnetic tracking system 3 and/or the infrared tracking system 4. A video camera part 18 of the surgical lighting and camera system 6 provides a real time video input. Data store 14 can provide stored patient scan images and images of models of bones, instruments, implants and virtual representations of other parts of the orthopaedic operating system. An endoscope 193 can also be provided which acts as a further source of images which can be displayed. Any other sources of video 194 can also be supplied to the video mixing and control system. An image capturing part of the surgical site display device 7 can also provide an input to the video mixing and control system and can also receive images to overlay on a surgical site image, displayed to the surgeon.
The video mixing and control system also outputs images for display on the heads up display unit 13, for display on the different regions of the image wall 8 and also for display on the control system monitor 12. Control system monitor 12 is a touch screen device as indicated previously via which the surgeon can enter commands which are processed by video control system 195 in order to control or vary the sources of images to be displayed, the nature of the images to be displayed and the display devices on which the images are to be displayed. Examples of the types of images that can be displayed will become apparent from the following description.
With reference to
Also during the pre-operative phase 602, markers detectable and trackable by the wireless magnetic tracking system 3 can be percutaneously implanted in the bones of the patient. The positions of the patient's bones can then be tracked so as to aid in the assessment of the orthopaedic performance of the patient. Also during the pre-operative phase 602, the planning of the orthopaedic surgical procedure can be carried out using a surgical planning software application. In some embodiments of the method, patient registration is carried out pre-operatively. A number of these operations can be carried out in the operating room or alternatively prior to the patient entering the operating room.
A second phase 604 corresponds to intra-operative preparations, that is, generally, operations between the beginning of surgery, i.e. the initial incision, and the end of surgery, i.e. closing the surgical wound. Intra-operative procedures can include the registration of the patient's body parts, in some embodiments, intra-operative surgical planning of the positions of implants, navigated and image guided surgical steps, including the preparation of bones and placement of implants, and immediate assessment of the orthopaedic performance of the implanted orthopaedic implants. It is also possible to capture images of the patient's body parts intra-operatively and use those images in the image guided or navigated surgical steps.
A third phase of the overall method 600 includes post-operative procedures, which can include an assessment of the orthopaedic performance of the patient, including viewing images of the kinematic performance of implanted orthopaedic implants, capturing images of the patient's body parts and implants and removing implanted bone markers. Some or all of these operations can be carried out in the operating room or subsequently in other medical facilities.
With reference to
As illustrated in
A general workflow module 618 provides a definition of the various steps to be carried out by the surgeon in planning and executing a particular surgical operation e.g. the steps involved in a hip replacement or knee replacement operation, and generally controls the overall process of registering the patient, planning the procedure and executing the procedure, as schematically illustrated by arrow 620.
A patient registration module 620 provides various routines and procedures allowing images of patient body parts and virtual images of various elements used in the orthopaedic operating room, e.g. body parts, instruments and implants, to be registered with the actual position of the elements in the reference frame of the orthopaedic operating room system. Various registration procedures can be used depending on the nature of the registration procedure to be used, e.g. captured patient image based or captured patient image free, and whether it is a pre-operative or intra-operative registration procedure. For example registration information may be required by the planning module 614 and/or by the computer aided surgery module 616 if an intra-operative registration procedure is used.
An image processing and handling module 622 is also provided and interacts with the planning and orthopaedic surgery modules to provide image handling, processing and display services. The image processing module has access to the data store 14 which includes patient body scan image data 624 and stored images 626 of various elements, and models of the elements, used and tracked in the orthopaedic operating room, such as generic bone shapes, instruments and implants. Using the stored image data, real time 3D representations of the patient's body parts, implants and instruments can be displayed in real time both during the planning and computer aided surgery stages of the overall method.
With reference to
Further the position of the X-ray sources and detectors are known to the tracking and navigation systems. Bone markers implanted in the patient that also show on the X-rays, can provide one mechanism by which the patient anatomy can automatically be registered by the navigation system. The X-ray system can be controlled by the surgeon via the surgeon interface and the acquired image can be displayed on the image wall 8 screens.
In one embodiment no preoperative scan or X-ray is taken of the patient and instead 2D fluoroscopy images are captured using the X-ray based imaging system and from these a 3D model of the patient's bones is built. Orthogonal X-ray shots are taken and the X-ray image data is used to morph a generic 3D model of the bone to customise the model for that specific patient. With this digital model all aspects of the optimal implant position can be planned virtually, e.g. component size, leg length, offset, stem anteversion and cup position for a hip implant. There are a number of advantages to this approach. This technique is particularly useful in revision arthroplasty when a CT scan would not be possible but when an accurate 3 dimensional model will enable restoring joint anatomy even when significant bone erosion has occurred and landmarks have been destroyed. The technique can also be used for trauma and spinal applications.
With reference to
In use, the surgical site display device is positioned with the field of view 632 covering the surgical site of the patient, e.g. the knee or hip. The current image of the image capturing device 630 is displayed in the display part 636 so that the surgeon can see the patient's body immediately below the surgical site display device and in registration with the surgical site.
The surgeon can then select to display in place of the image of the patient's body, or overlay on the display of the patient's body, visual representations of useful information, such as the planned position of an initial incision, the planned or navigated positions of instruments or tools, such as drill guides, and the planned positions of implants, and three dimensional images of the implants and body parts, e.g. the patient's bones. Also, scan images or images derived from patient's scans can also be displayed in the display screen 636, such as X-ray images, CT scan images or ultrasound images. Hence, the surgeon can concurrently display various visual forms of information concurrent with a current display of the surgical site of the patient.
There will now be described an embodiment of the wireless, magnetic based tracking system 3, various embodiments of operating room table 2, and various embodiments of wirelessly magnetically detectable and trackable markers for implanting in the bones of patients, for use with orthopaedic implants and for use with instruments and tools.
Unless the context indicates otherwise, in the following the terms “marker” and “sensor” or “position sensor” will be used interchangeably to refer to a device trackable by the tracking system, the position and/or orientation of which can be determined. An “implantable marker” will generally be used to refer to a marker that has been adapted so as to be implanted within the bone of a patient. The terms “implant”, “orthopaedic implant”, “prosthesis” or “prosthetic implant”, or variations thereof will generally be used to refer to a prosthetic orthopaedic implant for implanting in a body to replace a part of a joint or bone. Such an implant can bear or otherwise have a marker or sensor attached thereto, or therein, so as to provide a marked implant trackable by the tracking system.
Additionally or alternatively, position sensors or markers may be fixed to implants, such as a prosthetic joint or intramedullary insert, in order to permit the position of the implant to be monitored, as well. For example, the use of such position sensors in a hip implant is shown U.S. patent application Ser. No. 10/029,473.
Field generator coils 32 are driven by driver circuits 34 to generate electromagnetic fields at different, respective sets of frequencies {T1}, {T2} and {T3}. Typically, the sets comprise frequencies in the approximate range of 100 Hz-30 kHz, although higher and lower frequencies may also be used. The sets of frequencies at which the coils radiate are set by a computer 36, which serves as the system controller for system 20. The respective sets of frequencies may all include the same frequencies, or they may include different frequencies. In any case, computer 36 controls circuits 34 according to a known multiplexing pattern, which provides that at any point in time, no more than one field generator coil is radiating at any given frequency. Typically, each driver circuit is controlled to scan cyclically over time through the frequencies in its respective set. Alternatively, each driver circuit may drive the respective coil 32 to radiate at multiple frequencies simultaneously.
For the purposes of tracking system 3, coils 32 may be arranged in any convenient position and orientation, so long as they are fixed in respect to some reference frame, and so long as they are non-overlapping, that is, there are no two field generator coils with the exact, identical location and orientation. Typically, for surgical applications such as that shown in the figures, coils 32 comprise wound annular coils about 15-20 cm in outer diameter (O.D.) and about 1-2 cm thick, in a triangular arrangement, wherein the centers of the coils are about 80-100 cm apart. The coil axes may be parallel, as shown in this figure, or they may alternatively be inclined, as shown, for example, in
In orthopaedic and other surgical applications, it is desirable that coils 32 be positioned away from the surgical field, so as not to interfere with the surgeon's freedom of movement. On the other hand, the coils should be positioned so that the working volume of the tracking system includes the entire area in which the surgeon is operating. At the same time, the locations and orientations of coils 32 should be known relative to a given reference frame in order to permit the coordinates of tool 28 and implantable marker 30 to be determined in that reference frame.
In order to meet these potentially-conflicting requirements, coils 32 are mounted on a reference structure 40. In the embodiment of
Alternatively or additionally, an image registration procedure may be used to calibrate the positions of coils 32 relative to patient 26. An exemplary registration procedure, based on X-ray imaging, is described in U.S. Pat. No. 6,314,310 whose disclosure is incorporated herein by reference. Further alternatively or additionally, a reference sensor, fixed to patient 26 or to the operating table in a known location, may be used for calibration. The use of reference sensors for this purpose is described, for example, in U.S. Pat. No. 5,391,199.
The position sensors in implantable marker 30 and tool 28 typically comprise sensor coils, in which electrical currents are induced to flow in response to the magnetic fields produced by field generator coils 32. An exemplary arrangement of the sensor coils is shown in
At any instant in time, the currents induced in the sensor coils comprise components at the specific frequencies in sets {T1}, {T2} and {T3} generated by field generator coils 32. The respective amplitudes of these currents (or alternatively, of time-varying voltages that may be measured across the sensor coils) are dependent on the location and orientation of the position sensor relative to the locations and orientations of the field generator coils. In response to the induced currents or voltages, signal processing and transmitter circuits in each position sensor generate and transmit signals that are indicative of the location and orientation of the sensor. These signals are received by a receiving antenna (shown, for example, in
Circuitry 78 also stores a unique identifier for marker 70 and the unique identifier is also transmitted to the tracking system, so that the tracking system can determine the identity of the marker from which positional data is being received. Hence the tracking system can discriminate between different markers when multiple markers are present in the working volume of the tracking system.
Although in
Alternatively, if only a single sensor coil is used, computer 36 can still determine five position and orientation coordinates (X, Y, Z directions and pitch and yaw orientations). Specific features and functions of a single coil system (also referred to as a single axis system) are described in U.S. Pat. No. 6,484,118, whose disclosure is incorporated herein by reference.
When a metal or other magnetically-responsive article is brought into the vicinity of an object being tracked, such as implantable marker 30 or tool 28, the magnetic fields in this vicinity are distorted. In the surgical environment shown in
In order to alleviate this problem, the elements of tracking system 3 and other articles used in the vicinity of the tracking system are typically made of non-metallic materials when possible, or of metallic materials with low permeability and conductivity. For example, reference structure 40 may be constructed using plastic or non-magnetic composite materials, as may other articles in this vicinity, such as the operating table. In addition, computer 36 may be programmed to detect and compensate for the effects of metal objects in the vicinity of the surgical site. Exemplary methods for such detection and compensation are described in U.S. Pat. Nos. 6,147,480 and 6,373,240, as well as in U.S. patent application Ser. Nos. 10/448,289, filed May 29, 2003 and 10/632,217, filed Jul. 31, 2003, all of whose disclosures are incorporated herein by reference.
Although for simplicity,
In operation, power coils 74 serve as a power source for sensor 70. The power coils receive energy by inductive coupling from an external driving antenna (shown, for example, in
In another embodiment, not shown in the figures, sensor coils 72 are non-concentric. In this embodiment, each of the sensor coils typically has an inner diameter of about 0.5-1.3 mm and comprises about 2000-3000 turns of 11:m diameter wire, giving an overall coil diameter of 9 mm. The effective capture area of the coil is then about 400 mm2. It will be understood that these dimensions are given by way of example only and the actual dimensions may vary over a considerable range. In particular, the size of the sensor coils can be as small as 0.3 mm (with some loss of sensitivity) or as large as 2 mm or more. The wire size of the sensor coils can range from 10-31:m, and the number of turns between 300 and more than 3000, depending on the maximum allowable size and the wire diameter. The effective capture area of the sensor coils is typically made as large as feasible, consistent with the overall size requirements. The sensor coils are typically cylindrical, but other shapes can also be used. For example, barrel-shaped or square coils may be useful, depending on the geometry of the screw housing.
Tool marker or sensor 104 may be permanently housed inside tool 28, or the sensor may alternatively be removable (to replace battery 108, for example). Because the geometry of tool 28 is known, the location and orientation of handle 100, as indicated by sensor 104, indicates precisely the location and orientation of the distal tip of shaft 102. Alternatively, the tool sensor may be miniaturized and may thus be contained inside shaft 102. Optionally, the tool sensor may be calibrated before use in order to enhance the precision with which the shaft position is measured.
Location pad 110 is also seen in
Communication coil 116 is coupled by wires (not shown) to computer 36. The computer processes the signals received from communication coil 116 in order to determine the locations and orientations of the sensors. Coils 114 and 116 may be printed on the surface of pad 110, as shown in
Structure 160 may be mounted on a cart 166 with wheels, enabling it to be positioned either at the foot (
Although the embodiments described hereinabove relate specifically to tracking systems that use time-varying magnetic fields, the principles of the present invention may also be applied, mutatis mutandis, in other sorts of tracking systems, such as ultrasonic tracking systems and tracking systems based on DC magnetic fields.
As illustrated in
With reference to
The distal end 204 has a generally tapered shape and includes a tip 210 for self-locating the implantable marker in a hole in a bone in use as will be described in greater detail below.
The proximal end 206 of the housing has a substantially square shaped formation 212 which provides a connector for releasably engaging with an insertion tool as will be described in greater detail below. The proximal end 206 has a bore 214 passing there through for receiving a thread or suture which can assist in removal of the implantable marker as will also be described in greater detail below. It will be appreciated that the connector formation 212 can have other shapes which allow an instrument to be releasably connected thereto so as to impart rotational drive to the implantable marker.
For example the connector can have any polygonal shape, such as triangular or star shaped, and can also have a curve shape, such as an oval or elliptical shape. In alternate embodiments, the connector can also be in the form of a slot, rib or lip for engaging with a matching connector formation on the end of insertion tool. As illustrated in
The self-locating tip 210 can be provided as an integral part of housing 200 or can be provided as a separate part which is subsequently attached to housing 200. For example tip 210 can be moulded on to the distal end 214 of housing 200, mechanically fixed thereto or attached using an adhesive or any other suitable techniques, depending on the materials of the tip 210 and distal end 204 of housing 200. Tip 210 can be made of a resorbable material so that the tip is resorbed into the bone of a patient over time. In one embodiment, the resorbable material is polylactic acid although other resorbable materials can be used. In some embodiments, the tip can be made of a biodegradable material.
Housing 200 has an outer surface 216. A screw thread 218 is provided on the outer surface and extends along substantially the entire length of the housing body. Screw thread 218 interacts with surrounding bone in use to anchor the implantable marker in the bone material so as to retain the implantable marker securely in place when implanted.
In one embodiment, the profile of the thread is selected so as to be not too sharp and not too blunt. It has been found that too sharp a thread profile, while providing a good cutting action into the bone, can cause the bone to retreat from the thread thereby reducing the retention of the implant in the bone. A blunter thread profile does not provide as good a cutting action as a sharper profile, but provides improved retention of the implant in the bone, as the surrounding bone has a reduced tendency to resorb from the more rounded thread. As best illustrated in
The housing 200 can be made of a variety of materials and can be constructed in a variety of ways. In one embodiment, the housing is made of an X-ray opaque material so that the implantable marker will be easily identifiable in X-ray images. It is also preferred if the material of the housing is easily visualisable in CT and/or MRI scan images. The housing can be made of ceramic materials, e.g. zirconium, alumina or quartz. The housing can be made of metals, e.g. titanium and other bio-compatible metals. The housing can be made of alloys, e.g. Ti6Al4V. The housing can be made of plastics materials, e.g. epoxy resins, PEEKs, polyurethanes and similar. Also, the housing can be made of combinations of the above materials and the housing can be made of component parts made of different types of materials, selected from the above mentioned materials at least. The component parts can be joined together using any suitable technique, such as brazing, welding or by using suitable glues or adhesives.
In one preferred construction, the housing is assembled from three elements, in which the distal end 204 is in the form of a titanium cap, a portion of the body 202 is in the form of a titanium collar and the proximal end 206 is in the form of a ceramic end cap. The titanium collar is joined to the ceramic proximal end portion by brazing, the encapsulated marker is inserted within the body and finally the distal end cap is assembled over the end of the marker and laser welded to the titanium collar. The marker is positioned with the RF power antenna toward the proximal end and the sensor coils toward the distal end of the housing.
In another embodiment, the housing is made from two ceramic parts which are then laser welded together along a joint extending along the longitudinal axis of the housing. In other embodiments, the housing can be provided by moulding the housing around the encapsulated marker for example by moulding a plastics material around the marker. The internal shape of the mould can be used to define the outer shape of the housing. Alternatively, the outer shape of the housing can be defined by subsequently machining the material moulded around the marker.
Housing 200 wholly encloses the marker and further hermetically seals the encapsulated marker. It is preferred if a small volume, e.g. approximately 1 mm3 of air is provided as free space in the hermetically sealed housing so as to allow for expansion owing to changes in temperature. It is also preferred to include a small amount, e.g. 1 mm3 of hygroscopic material to absorb moisture from the internal atmosphere of the housing. Suitable materials include MgS and silica gel.
The housing can have a length in the range of approximately 10 to 16 mm and a diameter in the range of approximately 3 to 6 mm. In one embodiment the housing 200 (without tip 210) has a length of approximately 14 mm and an outer diameter of approximately 3.6 mm (4.5 mm from the thread tips).
In the embodiment illustrated in
In other embodiments, a rough outer surface can provide a bone anchor and a rough outer surface can be realised by using a mould having a roughened inner surface so that the outer surface of the moulded housing is roughened. In other embodiments, the surface finish of the housing can be used to provide a bone anchor e.g. by blasting the surface with titanium to provide approximately 12 micron roughness. The material with which the surface of the housing is blasted can vary and is typically the same material as the material of which the housing is made. For example a ceramics housing can be blasted with ceramics materials to provide enhanced roughness to promote or otherwise facilitate bone on growth.
In another embodiment, the surface of the housing can be treated to promote bone on growth by sintering small balls or particles of material on to the outer surface of the housing. For example, balls of approximately 250 micron diameter metal particles can be sintered to the outer surface of the housing. Such a surface coating is provided under the trade name Porocoat by DePuy International Limited of Leeds, the United Kingdom. In other embodiments, a mesh can be provided on the outer surface of the housing to promote bone on growth. In other embodiments, a hydroxy apatite coating can be provided on the outer surface of the housing. Other forms of coating can also be provided so as to promote or otherwise facilitate bone on growth.
A further embodiment of the marker includes a transducer or other sensor for detecting a property in the region or area around where the marker has been implanted. Transducer or sensor generates an electrical signal representative of the local property of the body and the signal is processed by circuitry 78 for transmission back to the tracking system using antenna 76. In other embodiments, the signal from the transducer can be transmitted back to the tracking system using a wire line system, e.g. a electrical conductor or optical conductor, such as a fibre optic cable.
The transducer or sensor can be of many types, depending on the property to be measured. For example the body transducer 380 can be a pressure transducer, a stress transducer, a temperature sensor, which provides a measure of the local temperature, a biological activity sensor, which provides an indication of a biological activity (e.g. osteoblast activity) or a chemical sensor, which provides an indication of a local chemical property (e.g. pH). Other types of sensors for different kinds of properties can of course be used also.
The marker can be wholly encapsulated by encapsulant material and/or a housing, or apertures may be provided in the encapsulant and/or housing in appropriate places to allow any sensor or detector parts of the transducer to have access to the local region of the body that it is intended to measure.
With reference to
The encapsulated marker is not wholly enclosed in this embodiment and a part of the marker, including the power coil and antenna is exposed. The sensor coil part of the marker is located within the cavity of the housing. This way, when the implantable marker is implanted within a bone, the sensing coils are located within the bone and surrounded by bone so that the position indicated by the sensing coils corresponds to a position within the bone adjacent to the surface of the bone.
Implantable marker 230 has a bone anchor in the form of a plurality of barbs 240 located around the periphery of the housing 232. Each barb is in the form of a rigid member 242 mounted by a pivot 244 to the body of the housing. Pivot 244 includes a spring, or other resilient biasing device, which biases the member 242 away from the stowed state illustrated in
The implantable marker 230 is particularly suited for use in a “push fit” insertion method as will be briefly described below.
With reference to
With reference to
Instrument assembly 280 includes a guide instrument 282 having a housing 284 and an elongate guide tube 286 having a guide channel extending along a longitudinal axis thereof. There is also provided a drill instrument having an elongate body with a circular cross-section and having a drill bit 288 at a distal end having a skin piercing tip 290 with a trochar form.
At step 262, the instrument assembly 280 is pushed through the skin 300 of the patient by a user pushing on the instrument assembly in the direction indicated by arrow 302. The skin piercing tip 290 of the drill bit penetrates the outer surface of the skin and allows the drill and guide tube 286 to be inserted through the patient's skin. The drill can move in the guide channel relative to the guide tube 296 and the guide tube is pushed towards the bone until the distal end 292 of the guide tube engages with the outer surface of the bone 304 of the patient. The distal end of the guide tube 292 bears teeth or other serrated formations which can be pushed into the bone so as to pliably position the guide tube and so as to prevent rotation of the guide tube 286.
Then at step 264, as illustrated in
Irrespective of whether a separate insertion tool is provided or whether the adapter and drill provide the insertion tool, at step 268, the end of the insertion tool/adapter is engaged with a one of the implantable markers in housing 284.
At step 272, the instrument assembly is withdrawn from the patient's skin. At 274, the user can then percutaneously implant a further implantable marker if required, in the same manner, as indicated by line 276. For example, a first implantable marker may be implanted in the tibia and a second implantable marker may be implanted in the femur, so as to allow the positions of the tibia and fibula to be tracked during a computer aided surgical procedure. If it is determined at step 274 that no further implantable markers are required in the patient's bones, then the method ceases at step 278.
With reference to
Method 310 begins at step 312 and initially a user of the method locates the approximate position of the implantable bone marker at step 314. The stitches are undone 332 and the ends of the suture 330 are obtained.
As illustrated in
After the suture 330 has been engaged with the end of the insertion tool at step 316, then at step 318, the insertion tool assembly is pushed through the skin of the patient while applying tension to the free ends of the suture 330 so as to guide the instrument assembly toward the connector 214 on the proximal end of the implantable marker 200. At step 320, the distal end of the insertion tool is attached to the implantable marker and switch 296 can be operated so as to unscrew the implantable marker from the bone 304. The sutures 330 are kept under tension so as to keep the implantable marker connected to the distal end of the insertion tool. In an alternate embodiment, the implantable marker can be removed manually using a tool similar to tool 28 inserted through guide tube 286. At step 322, once the implantable marker has been unscrewed from the bone 304, the instrument assembly and implantable marker are withdrawn through the patient's skin 300. The user can then determine whether there are any further implantable markers to be removed at step 324, and if so, the further implantable markers can be removed using the same method, as indicated by line 326. When it has been determined that all the implantable markers have been percutaneously removed, then at step 328, the method of removal 310 ends.
The implantable markers described above are trackable by the tracking system and therefore once they have been percutaneously implanted in the patient's bones, the position of the patient's bones can be tracked and displayed during a computer aided surgical procedure. It will be appreciated that no invasive surgical steps are required in order to implant the markers and therefore the implantable markers can be implanted before a surgical procedure and so can be carried out as a clinical, or out-patient procedure. For example, the implantable markers can be percutaneously implanted in the patient's bones several days or weeks before the surgical procedure. IN other embodiments of the method, the markers are percutaneously implanted with the patient in the operating room but before any incision related to the orthopaedic surgical procedure has taken place.
With reference to
At step 656, any pre-operative imaging of the patient can be carried out, such as CT scan, X-ray, ultrasound or X-ray fluoroscopy imaging. The patient image data 624 is stored in storage device 14 so as to be accessible subsequently. It will be appreciated that in some embodiments, pre-operative imaging 656 is not required and therefore in some embodiments, step 656 is optional.
At step 658, the surgeon can carry out pre-operative planning of the surgical procedure using a surgical planning software application. The surgical planning application allows the surgeon to determine the appropriate size of implant to use and the appropriate positions and orientations at which to fix the implant in order to provide appropriate orthopaedic performance of a patient. The results of the planning are saved as a surgical plan for subsequent use during the computer aided surgical procedure. In other embodiments, no pre-operative planning is carried out and instead an intra-operative plan is created and therefore 658, in some embodiments, is optional.
All or some of the above steps can be carried out outside the operating room in some embodiments. At step 662, the patient is registered with the reference frame of the orthopaedic operating room using a suitable registration procedure. A variety of different registration procedures can be used in order to register the position of the patient's body parts in the operating room with images of the patient's body parts. Various methods for registering the patient will be described in greater detail below. After the position of the patient has been registered, then at step 666 the stored surgical plan is merged with the registered patient position so that the surgical plan is now registered in the reference frame of the operating room.
In an alternate embodiment in which the pre-operative planning is not carried out, then at step 664, after the patient has been registered, surgical planning is carried out using the registered patient body position and so a registered surgical plan is provided at step 666.
Some registration methods can require access to the patient's bones and therefore in some embodiments, step 662 corresponds to an intra-operative procedure whereas in other embodiments, registration step 662 can be considered a pre-surgical operation procedure. At step 668, the surgical procedure is either begun or continued and, using the surgical plan, the surgeon carries out the surgical operation using various marked instruments, tools and implants with reference to the various display screens which provide a real time indication of the positions of the instruments, implants and body parts so as to provide an image guided surgical environment for carrying out the method.
While carrying out the computer aided surgical procedure, the surgeon can select to view various images on various of the display units provided throughout the operating room by the orthopaedic operating system 1 so as to access as much useful information in visualisable form as required in order to carry out the procedure. Navigation of the tools, instruments and implants can be carried out using the wireless magnetic tracking system and/or the infrared tracking system.
At step 670, immediately after completion of the implantation part of the surgical procedure, the surgeon can assess the success of the surgical procedure e.g., by comparing an actual image of the surgical site with an indication of the planned position of the implants, or by articulating the joint and comparing the behaviour of the patient's joint with a theoretic, planned or pre-operative joint behaviour. This post-operative assessment can be carried out either before or after the surgical wound has been closed.
In some embodiments, the bone markers can be left in the patient's bones to allow for future assessment of the orthopaedic performance of the patient's body. In other embodiments, at step 672, the implanted bone markers can be removed while the surgical wound is still open or alternatively percutaneously, using the instruments and methods previously described. The bone markers can be removed in the operating room, or alternatively, after the patient has been removed from the operating room in a clinical out patient procedure. The overall method 650 then ends at step 674.
Before describing a particular computer aided surgical procedure which can take advantage of the implantable bone markers described above, a number of trackable instruments and tools will be described. These instruments or tools bear on, or in, them a marker, similar to marker 90. Alternatively, they may include an inductively RF powered marker such as marker 70. The markers can be encapsulated in a specific encapsulant material or can be encapsulated, e.g. by being moulded into, a part of the instrument or tool. Alternatively, the marker is attached to the tool and located within a cavity of the tool, in a manner similar to that of tool 28 as illustrated in
With reference to
Pointer 360 can be used so as to digitise the surface of a body part, e.g. a part of a bone as part of registering that bone with the coordinate frame of the tracking system. In one embodiment, the marker is positioned in the handle 362 with a set of sensor coils concentric with the longitudinal axis of the pointer element 364. In this way, the orientation of that set of sensor coils substantially corresponds to the orientation of the longitudinal axis of the pointer. The positional relationship between the free end of tip 366 and the position of the marker in the pointer 360 is stored in the tracking system. Therefore when the tracking system identifies the marker, using the transmitted marker ID information, the tracking system can automatically determine the position of the tip of the pointer 366 in the reference frame of the tracking system.
With reference to
With reference to
In use, tool 380 can be used to form a bone surface to a preferred shape or profile or to otherwise remove unwanted bone material. By operating switch 384, the cutting surface 392 is driven and can be played across the bone surface so as to cut the bone surface to the desired shape or profile. The tracking system identifies the marker within the tool using the transmitted marker ID data and the tracking system is pre-programmed with the positional and orientational relationship between the marker and the cutting surface 392. Using planning software, a preferred shape or form of a bone surface can be identified pre or intra-operatively. Then in order to generate that bone surface, the tool can be moved over the bone and the tracking system can detect the position of the tool and allow the tool to cut away the bone surface until the tracking system determines that the position of the cutting element 392 corresponds to the desired position of the bone surface at which time the shutter can be actuated so that the tool 380 no longer cuts the bone surface.
Hence, in this way, the tool can be used to allow the surgeon to easily cut the bone to a preferred shape or profile merely by running the tip of the tool 390 over the bone with the tracking system and computer aided surgical system starting or stopping the cutting action of the tool as appropriate. In another embodiment, no shutter or closure mechanism is provided and instead, driving power is no longer supplied to the cutting element 392 so as to provide the same effect.
With reference to
The arm 406 links the top and bottom plates in such a way as to allow the top and bottom plates to separate relative to each other to a predetermined maximum distance. A single spring is fitted between the plates and engages interior surfaces of the plates. The spring provides a biasing mechanism to controllably force the tensor plates toward an open or expanded configuration in which the device is extended along the longitudinal axis of the knee joint when in flexion. A spring force in the range of from substantially 6 kg to 12 kg can be used.
The device is used is to distract the femur from the tibia to establish the correct mechanical loading across the knee joint. The device can be used in an image guided surgery uni-condylar knee replacement as will be described below. The device is introduced into the knee joint after the tibia has been cut and before the femur is cut using an introducer tool which closes or compresses the tensor, and which is then slowly released to contact both the tibia and the femur. The tensor device 400 is placed on a resected part of the tibia and is oriented with its longer dimension in an anterior-posterior direction and its shorter dimension in a lateral-medial direction and with the straight edge of the plates toward the middle of the knee. The bottom plate is placed in the same position as the tibial component will be positioned. The device provides a known force to gap relationship. The tensor device opens and closes with the force of the ligaments of the knee during flexion and extension. When in place, the tibia is flexed and extended and the femur to tibia distances are recorded using the image guided surgery software. From this information the surgeon can decide on and plan the femur cut height to restore the correct joint gap. Hence the device allows the knee joint to be restored having a more correct tension and femur to tibia rotation.
With reference to
The first handle part 432 and second handle part 436 are made from a suitable surgical material, such as aluminium 7075. The pivot 434 is also made of a suitable surgical material, such as silver steel. The upper nose 438 and lower nose 440 are also made from a suitable surgical material, such as an alloy, such as Ti6Al4V.
In use, the handles 432, 436 of compression tool 430 are displaced apart opening the mouth of the tool which is engaged about the tensor device 400 with ridge 442 engaging in channel 444. The handles 432, 436 are then closed by the surgeon and the mechanical advantage provided by the leveraged effect of the handles allows a significant compressive force to be applied to tensor device 400 so as to compress the tensor device 400 into a compressed configuration. The tensor device can then be inserted between the femur and resected tibial surface and positioned therein. The handles 432, 436 are then opened and the compression tool is slid away from the tensor device 400 at a direction generally along the axis of channel 444 leaving the tensor device 400 in situ between the femur and resected tibia.
With reference to
The prosthetic implant 450 includes a femoral component 452 and a tibial component 454. Tibial component 454 includes a tibial tray part 456 and a bearing part 458 fixedly attached to the tibial tray 456 by retaining formations.
Femoral component 452 has a continuous smooth outer bearing surface 460. A keel 462 extends along the middle of the femoral component between a toe end 464 and a heel end 466. A hollow locating pin or peg 468 extends away from the heel 462 at a generally centrally location. Peg 468 has a cavity within it which receives a marker 70 so that the position and orientation of the femoral component can be tracked by the tracking system.
An inner bone contacting side of the femoral component has four segments 472, 474, 476, 478 each presenting a substantially flat surface to a suitably prepared femur. Peg 468 is received in a hole or cavity in the prepared femoral head and keel 462 is received in a anterior-posterior groove in the femur. Peg 468 helps to locate the femoral component and groove 462 helps to resist twisting of the femoral component relative to the femur.
As illustrated, uni-condylar implant 450 is for a lateral condyle of a right leg or medial condyle of a left leg and a mirror image implant is also provided for use in replacing the medial and lateral condyles of left and right legs respectively. As illustrated, the marker 470 is aligned with a one of its sensor coils aligned with the longitudinal axis of the femur. The marker can be encapsulated in an encapsulant material and/or partially or wholly enclosed in an outer housing before being secured within the cavity of peg 468. Preferably the marker is an RF induction powered marker to ensure that power can be supplied to the marker throughout the lifetime of the prosthetic implant.
Tibial tray 456 has a lower tibia engaging surface 480 with a keel member 482 extending downwardly there from and along the anterior posterior direction. Keel 482 has a cavity in which a further marker 484 is located. Marker 484 is similar to marker 470. At least a one of the sensor coils of marker 484 is aligned with the anterior/posterior axis of the tibial component 454.
Bearing 458 has an upper curved bearing surface 486 which substantially reproduces the shape of the top of the tibia of a normal knee joint. Bearing surface 486 has a generally slightly concave shape. In use, the outer surface 460 of femoral component 452 bears against bearing surface 486 as the knee joint is articulated.
The femoral component 452 and the tibial tray 456 can be made of any suitable bio-compatible materials. Typically, they are made of bio-compatible metals, including titanium and titanium based alloys, steels and cobalt-chromium based alloys. The tibial tray 458 can be made of plastics materials, such as polymeric materials and in particular ultra-high molecular weight polyethylene (UHMWPE).
As best illustrated in
With reference to
At step 684, the surgeon uses the surgeon interface 10 to load patient data and any pre-operative data and/or patient scan data and/or images from the data storage device 14. At step 686, the surgeon can select various data items and patient images to be displayed on the wall display unit 8 and/or on the control system screen 12.
At step 688, an auto-registration procedure is carried out by the surgeon selecting this option and entering a command via surgeon interface 10. The auto-registration procedure will be described with reference to
Previously, a plurality of CT scans of a plurality of different bones is carried out and a plurality of generic models of bones of different sizes are created and stored in the database. In this embodiment, a plurality of generic femurs and tibias is created from CT scans of real femurs and tibias and saved in the database. Using the measure or metric indicative of the size of the patient's actual bone, a generic bone model most closely matching the patient's bone is selected from the database at step 744. Then at step 746, the selected generic bone model is morphed, i.e. its size and/or shape is scaled so as to more accurately correspond to the patient's actual bone shape and size. The customised three dimensional model is then used in the rest of the procedure to provide a more accurate model of the patient's bone.
Various methods for creating a 3D model of a patient's bone from 2D images can also be used. For example, methods are described in U.S. Pat. No. 5,951,475 and international patent application publication number WO 01/22368, which are incorporated herein by reference in their entirety for all purposes.
After method 740 has completed, process flow returns to step 728 at which the position of the X-ray system in the reference frame of the operating room is determined. This can be achieved in a number of ways. For example there can be a fixed positional relationship between the X-ray system and the operating room, in which case a calibration of the X-ray system can be carried out which results in a determination of the position of the imaging plane of the X-ray system in the reference frame of the operating room. Alternatively, a marker trackable by the tracking system 3 can be attached to each of the X-ray detectors. There is a known positional relationship between the imaging plane of the X-ray detectors and the markers.
The tracking system can therefore determine the position and orientation of the imaging plane in the reference frame of the tracking system. Therefore the position of the image of the patient's bone in the reference frame of the tracking system can be determined. Hence the position of the 3D image relative to the reference frame of the tracking system can be determined from the positions of the 2D images in the reference frame of the tracking system.
At step 730, the position of the patient's bones in the reference frame of the tracking system is determined. This is simply a matter of determining the current position of the bone markers 708, 712 in the patient's bones.
At step 732, the 3d representation of the patient's bone is then mapped, in the reference frame of the tracking system, on to the actual detected position of the patient's bone as graphically illustrated by 754 in
In an alternate embodiment, the implantable bone markers are provided in an X-ray opaque form so that an image of the bone marker or markers is present in the captured X-ray images. Hence the position of the image in the reference frame of the tracking system is known and so an appropriate mapping can be determined and carried out so as to map the 3d bone model derived from the X-ray images on to the position of the patient's bones.
After the auto-registration procedure 720 has completed at step 734, the method returns to step 690 at which a registered surgical plan is generated. In an embodiment in which a pre-operative plan was created, then the pre-operated surgical plan is merged with the registered model of the body part so as to provide a registered surgical plan. In another embodiment, an intra-operative surgical plan is created on the already registered model of the body part.
A pre-operative assessment of the patient's joint is conducted by extending and flexing the joint and recording the relative locations of the bones using the implanted markers and the tracking system. Having recorded the bone positions, the surgeon then uses the planning application to choose the implants that best the fits the patient's bones. This typically requires balancing anterior/posterior sizing and medial/lateral sizing. The best implant location is then a compromise of size versus best functional position according to the implant design characteristics. The surgeon can then view a virtual model of the flexion and extension positions (kinematic) of the bones versus external/internal rotation of the tibia to femur and select the best compromise for the patient.
As illustrated in
At step 928, the sizes of the tibial and femoral implants are selected and their positions are planned.
One embodiment of the planning process can include the following. Initially, the position of the centre of the femoral head is defined together with the position of the midpoint of the maleolar axis, which between them define the leg mechanical axis. Then the following positions are defined: (i) the epicondylar axis on the femur, (ii) the local distal anatomical femur axis direction, (iii) the distal point of the femur mechanical axis, (iv) the highest and lowest distal points on the femur, (v) the posterior condyle point, (vi) the anterior femur cortex, (vii) the true anterior-posterior direction, (viii) the lowest condylar position on the tibia, (ix) the true anterior posterior direction, and (x) the anterior cruciate ligament point. The mid point of the maleolar axis at the ankle and (ix) define the tibial mechanical axis.
The position of the tibial component can be determined based on: height in relation to the lowest condyle point; anterior/posterior position in relation to (x); anterior/posterior rotation in relation to (ix); medial-lateral position in relation to (ix); and posterior and medial/lateral tilt in relation to the tibia mechanical axis.
The position of the femoral component can be determined based on: height in relation to the highest distal condyle point; anterior/posterior position in relation to the anterior cortex; anterior/posterior rotation in relation to the epicondylar axis, (vi) and in relation to the location of the tibia plan cut; medial-lateral position in relation to (iii); medial-lateral tilt in relation to tibia cut plan and (ii); and posterior tilt in relation to (ii).
When the knee implant sizes have been selected and their positions determined, then at step 930, a virtual range of motion analysis is carried out for the models of the patients bones and using the planned implant sizes and positions. Then at step 932, the virtual range of motion of the patient is compared with the actual range of motion captured previously and at step 934, the surgeon can determine whether the implant sizes and/or positions are appropriate. If not, and further planning is required the processing returns to step 928 as indicated by line 936 and the size and/or positions of the implants can be changed. Steps 928, 930, 932, 934 and 936 can be repeated as often as necessary until the surgeon is satisfied with the surgical plan. Then at step 938, the surgical plan can be saved if surgery is to be carried out later on, or alternatively surgery can be commenced.
After the orthopaedic plan has been completed in step 690, then at step 692, the surgeon carries out an initial incision. In one embodiment, the initial incision is carried out in a navigated manner. The surgical site display device 7 is positioned over the patient's knee and displays an image of the patient's knee to the surgeon. The surgical planning software can then overlay a graphical indication of the position and form of the incision required in order to execute the planned orthopaedic procedure. After having viewed the planned incision position and shape overlayed over the patient's knee, the surgeon can then remove the surgical site display device and make the incision. Using only a single incision helps to make the procedure a minimally invasive one. In one embodiment, the scalpel or incision device bears a trackable marker and the position of the scalpel is displayed on the control screen 12 together with the position of the incision and an image of the patient's knee and these images are used to guide the surgeon to make the appropriate incision.
After having made the navigated incision, at step 694, the surgical site display can be repositioned over the opened surgical site and/or the surgical camera system 6 can be used to capture real time images of the surgical site which the surgeon can select to display on wall display unit 8 and/or on the control unit display 12. The surgeon can also select to display previously captured images of the patient's knee, e.g. CT scan, X-ray, ultrasound or X-ray fluoroscopy images. The surgeon can also display surgical planning information, such as the preferred or planned location of the implants and can overlay and combine these and other images mentioned previously as appropriate for the surgeon's purposes.
Then at step 696, the surgeon begins the implantation procedure during which the positions of instruments, implants and other elements used by the surgeon are tracked by the tracking system and graphical representations of the implants, instruments and other elements are displayed so as to provide a visual guide to the surgeon. The surgeon can select what images and/or combinations of images to display on whichever of the display devices he finds most convenient as indicated by step 698. At step 700, if the surgical procedure has not been completed, then as schematically indicated by line 702, the tracking system continues to track the positions of the instruments, implants and bones at step 696 and the displays are continuously updated to provide a real time display of the elements within the tracking system.
Then at step 774, a generic 3D model appropriate for the size of the patient's bone is selected based on the captured points. The model is then aligned with the patient's bone using the captured points which define a characteristic anatomical feature by which the model and bone can be aligned so as to provide a registered 3D model representing of the patient's bone. As the points on the patient's bone have been captured by the tracking system, the position of the patient's bone in the reference frame of the tracking system are known and the image of the patient's bone is automatically registered in the reference frame of the tracking system. Then at step 776, the implant planning application is used to plan the surgical procedure using the registered model of the patient's bone so as to provide the registered surgical plan. The remaining steps are similar to those described previously with reference to
With reference to
The surgical procedure begins at step 492 and at step 494 the navigated incision is made in the skin surrounding the patient's knee so as to expose the surgical site. At step 496, the patient's knee joint is opened and the knee is subluxed or otherwise distracted so as to allow access to the top of the tibia. At step 498, a cutting guide 516, bearing a marker, is navigated into position and attached to the tibia at a position to allow a part of the tibia 514 to be resected in accordance with the position determined by the planning software. A cutting tool 518 is then used with guide 516 so as to make the tibial cut and resect a part of the surface of the tibia as illustrated in
At step 500, as illustrated in
The femur is then positioned with the knee joint in flexion and at step 502 marked 522 guide is navigated on to the resected part of the femur and attached to the resected part of the condyle by pins 524. Cutting tool 518 is then used to make three femoral angle cuts to remove a posterior part of the condyle 526, a bone part 528 between the resected surface and a posterior surface and an anterior part 530 as illustrated in
After the femoral angle cuts have been made at step 502, at step 504, the tibial and femoral implants are fitted. Using navigated guides and/or marked drills, reamers, broaches and other surgical tools, a channel in the anterior-posterior direction is created in the resected parts of the femur to receive keel 462. The hole is drilled in the resected part of the femur to accept location pin 468. A cavity is created in the resected surface of tibia 514 to accept tibial keel part 482. The tibial and femoral orthopaedic parts are then fitted to the prepared femur and tibia respectively and secured in place, e.g. using bone cement.
Various conventional surgical steps can then be carried out in order to complete the knee reconstruction and to close the incision and then the method is completed at step 506. After the surgical procedure completes at step 506, at step 704 of methods 680 or 770, the surgeon can evaluate the success of the procedure for example by comparing the actual positions of the implants with the planned implant positions and/or articulating the joint and comparing the actual movement of the patient's limbs with a planned or theoretical movement or pre-operative range of motion of the patient's limbs. This can be carried out with the surgical wound still open or with the surgical wound closed. After the surgical wound has been closed, then at step 706 the computer aided surgical procedure ends and then the bone markers can be removed as illustrated in
With reference to
The pelvic component 544 has a generally concave or cup shape. The pelvic component 544 has a body part 546 with an outer shell part 458 generally in the shape of a part of a sphere and treated to encourage bone ongrowth. A substantially circular aperture 550 is provided in an outer part at the apex of cup 544 for receiving a marker including at least a sensor coil, RF induction power coil, antenna and associated circuitry so that the marker can receive power and transmit its identifier, and position and orientation data to the tracking system. The marker is described in greater detail with reference to
The femoral component 542 includes a body part 552 generally in the form of a shoulder having a stem or tail part 554 toward an inferior part of the body and a neck part 556 toward a superior part of the body. A marker 558, similar to marker 470, is provided in a cavity toward a superior part of the shoulder of body 552. Neck 556 tapers slightly toward a free end. A head part 560 is attached to neck 556 by a collar or sleeve member 562. Sleeve 562 has a generally annular shape and provides an adapter by which head 560 is secured to body 552 in a tight push fit manner.
Head 560 has a highly polished surface 562 generally corresponding to a part of the surface of a sphere. An annular channel 564 extends around a longitudinal axis of head 560 and an inner wall 566 defines a cavity 568 within which sleeve 562 and neck 556 are received. Body 552 has an outer surface or shell part 570 extending there around which is configured to encourage bone on growth.
A cavity 572 having a substantially v-shape is provided in an upper part of the shoulder of body 552. Cavity 572 provides a connector by which an impactor tool can be engaged or otherwise attached to femoral component 542 to aid in fitting the implant.
With reference to
The housing 571 can be made from an assembly of a ceramic material and a metal or alloy material. Suitable ceramic materials included YTZP (Yttria partially toughened zirconia), Alumina or Zirconia toughened Alumina. Suitable alloys include titanium alloys, such as Ti6Al4V. The join between the ceramic and metal/alloy components can be provided by a combination of a high temperature braze (before assembly of the electronic components) and a laser or electron beam weld (with the electronics in situ). The ceramic parts allow for RF transmission therethrough.
A marker is 577 is provided in the housing. The housing 571 includes three cavities 574, 575, 576 in which the location coil 72, circuitry 78 and power coil 74 of the marker are located. The transmission antenna and connections between the electronics components are also provided in the housing. The electronic modules 72, 74, 78 are substantially the same as those described above for the implantable marker and provide the same functions but configured in a different geometry. Each or all of the marker electronic modules can be pre-encapsulated in an encapsulant material 578, such as an epoxy.
The complete acetabular marker 571 is inserted into the acetabular cup. This can be carried out pre-operatively, during assembly of the acetabular cup, or intra-operatively just prior to, or after, implanting the acetabular cup.
With reference to
Based on the models of the patient's pelvis and femur, the surgeon determines the appropriate implant system to use. As will be indicated below, in some embodiments, other prosthetic hip implant parts, different to prosthetic hip 540, can be used. At step 788, the surgeon selects an initial size of cup implant and stem implant in order to start the planning procedure. At step 790, the surgeon can plan the position of a virtual model of the acetabular cup implant relative to the model of the patient's pelvis. An image of the model of the patient's pelvis and an image of the acetabular cup are displayed to the surgeon together with information indicating the orientation of the cup relative to the pelvis and other useful surgical planning information similar to that illustrated in
At step 792, the surgeon can consider whether the initially selected cup is appropriate and if not at step 794, the surgeon can select a different cup and plan the position of the differently sized cup at step 790. Steps 790, 792 and 794 can be repeated a number of times in an interactive process until the surgeon has settled on an appropriate cup size that best fits the patient's anatomy.
Planning the position of the cup can involve defining a rotation centre of the acetabulum and an outer diameter of the cup. This can be achieved by identifying multiple points inside the acetabulum of the model of the patient's pelvis and calculating the centre of rotation and outer diameter of the cup based on the acquired points. In an alternate embodiment, the surgeon can digitise the positions of the points on the acetabular cup of the actual patient's pelvis using a tracked pointer.
At step 796, the position of the stem component 542 is planned. The planning of the position of the stem component 542 is illustrated in
The position of the stem is calculated with its long axis co-axial with the longitudinal axis of the femur. A display of any angular difference between these axes can be provided. The stem is also positioned with the medial and lateral flares pressing against the femoral cortex and with the depth of the stem as required such that the leg length will be the same for both of the legs of the patient. The calculated stem antetorsion can be displayed. Step 798 includes planning the position of the stem relative to its depth in the femur in order to provide the required leg length.
Then at step 800, the leg length provided by the planned stem and acetabular cup position is calculated and compared with the pre-operative leg length and the leg length for the other leg of the patient at step 800. Also, the hip offset is calculated and again compared with the pre-operative hip offset of the patient and the hip offset for the patient's other hip. The calculation of the patient's leg length and calculation of the hip offset are illustrated schematically in
At step 806, the range of motion provided by the planned implants can be checked by moving the virtual representation of the patient's femur with respect to the pelvis using the planned implant sizes and positions. The separation between the implants, the separation between fixed points on the bones and the separation between a bone and an implant can be calculated. Any collisions can be looked for by varying the positions of the bones through a number of degrees of freedom, including flexion, abduction, adduction, extension, extrotation, introtation and introtFlexion. After a virtual range of motion analysis of the planned joint has been carried out, then at step 808 the plan can be saved if surgery is not immediately going to follow the planning procedure. In another embodiment, if surgery is to be carried out immediately, then the plan need not be saved and surgery can proceed.
Irrespective of how registration is carried out, at step 828, a reamer or drilling device bearing a marker trackable by the tracking system is used to drill the acetabulum in a navigated manner so as to provide a cavity for receiving the acetabular cup implant at the planned position. At step 830, a trackable trail impactor tool is used to place a trail cup in the acetabular cavity in order to check the actual position of the cup relative to the planned position. If it is determined that the acetabular cavity is suitable, then at step 832, a trackable impactor tool is used to position the acetabular cup implant in the acetabulum and to position and orient the cup in accordance with the planned position which is graphically displayed as part of a navigated cup positioning procedure. The position and orientation of the implanted cup is detected and used to display an indication of the position and orientation of the cup so that the implanted position and orientation of the cup can be compared with the planned position and orientation and its position verified.
At step 834, a guide bearing a marker is attached to the femur to allow a navigated neck resection of the femur to be carried out at step 834. At step 836 reaming of a cavity in the femur is begun and at step 838, a broach with a marker in its handle is used to broach the cavity in the femur in a navigated manner. After the cavity has been completed, at step 840, a stem inserter tool bearing a marker is used to implant the femoral component within the femoral cavity and impact the femoral component into position. The position and orientation of the stem component is displayed and in particular the varus/valgus position, the anterior/posterior tilt, the anteversion, the depth and any deviation from the planned axis of the implant in the femur. At step 842, the hip resulting from the actual positions of the implants can be checked and the surgical plan can be updated using the detected positions of the implants to verify that the leg length and offset requirements have been met.
Then at step 844, an immediate assessment of the performance of the hip can be carried out. The alignment of the implanted orthopaedic implants can be displayed and the influence of the positions of the implants on the leg length, the offset and the range of motion can be displayed to the surgeon. Immediate post-operative assessment of the orthopaedic performance of the patient can be carried out by articulating the limbs and hip joint and observing a graphical representation of the position of the bones and/or implant components. Also the movement of the bones and/or implant components can be compared with a theoretical or model performance, with a pre-operative performance or assessed based on the surgeon's skill and experience. The surgical procedure then ends at step 846.
With reference to
Acetabular cup 850 is particularly suited for use in an orthopaedic procedure in which only the articulate surfaces of the hip are replaced. The outer surface 852 of the cup is roughened to facilitate bone in growth. A preferred outer coating for the acetabular cup is that provided under the trade name Porocoat by DePuy International Ltd of the UK. The inner surface 854 of the acetabular cup, which provides the articulate surface of the hip joint, is highly polished. The cup 850 is made of a suitable bio-compatible material, such as a metal or alloy. In one embodiment, the cup is made of a cobalt chrome alloy.
In use, prosthetic femoral head 870 can be used to replace the articulate surface of a femur. Prosthetic head implant 870 can be made of any suitable bio-compatible material, such as a metal or alloy. In one embodiment, it is made of a cobalt chrome alloy.
Images of the implants 850, 860, 880 and details of their geometry, and the same for any associated implanting tools or instrument, are provided in the planning and IGS software so that the positions of the implants can be planned and so that they can be implanted using an IGS procedure.
With reference to
Method 880 relates to the navigated surgical steps carried out by the surgeon. A virtual model of the implant 860 is used during planning the position of the implant.
In use, implant 860 is attached to the femoral neck via stem locating pin 862. At step 882, a trackable guide is positioned on the femoral head with a guide drilling axis coincidental with an axis of the femoral head/neck along which the implant stem 862 is eventually to lie. After the guide has been positioned and fixed to the femoral head, at step 884, a pilot hole can be drilled using the guide. In an alternate embodiment, a hole for receiving the stem 862 can be drilled at step 884. At step 886, using the pilot hole in the femoral head, the femoral head is resected into a shape to engage in cavity 863 in the implant. An image of a desired resected head shape can be displayed to the surgeon to guide the surgeon during this step. At step 888, if not already done so, then a hole for receiving the stem 862 is drilled using a navigated instrument to ensure that the hole is drilled along the correct axis and to the correct depth.
Then at step 890, the head implant, or a trial head, can be attached to the resected femoral head. The position of the implant can be compared with a planned position and when it is determined that the position is acceptable, then the head implant can be cemented in place. Alternatively, a trial head can be used prior to attaching the actual implant head 860 to check the actual position of the head compared to the planned position.
With reference to
With reference to
Regions within the outer skin, not corresponding to joint regions are filled with a volume of material mimicking the performance of soft body tissue, e.g. volume 906 surrounding the femur. In a region surrounding a joint, e.g. the knee joint and the hip joint, a material which differs to the soft tissue material is used to mimic the behaviour and performance of a human joint. A volume of material is provided around and enclosing the joint. For example volume 908 surrounds the knee joint. A suitable material is a polyurethane elastomer. A further volume of joint material 910 is provided around the hip joint.
A synthetic or dummy ankle part 912 is also provided attached to the end of a synthetic tibia and/or fibula and enclosed within a volume of soft body tissue mimicking material. The dummy ankle part 912 can be made of a two part polyurethane resin. The dummy bones can be made of a solid foam which mimics the properties of dense cancellous bone. A suitable material is a solid foam, such as that provided by Synbone. A suitable material for the soft tissue mimicking material would be a two part expanding foam. A suitable polyurethane elastomer for the skin and joint enclosing parts would be the polyurethane elastomer provided under the trade name Smooth-On. A suitable two part polyurethane resin is that provided under the trade name Fast-Cast.
The particular materials used to provide the dummy body part 900 have been found to provide a particularly realistic dummy on which the orthopaedic procedures described herein, and other orthopaedic surgical procedures can be practised by a surgeon.
Generally, embodiments of the present invention employ various processes involving data stored in or transferred through one or more computer systems. Embodiments of the present invention also relate to an apparatus for performing these operations. This apparatus may be specially constructed for the required purposes, or it may be a general-purpose computer selectively activated or reconfigured by a computer program and/or data structure stored in the computer. The processes presented herein are not inherently related to any particular computer or other apparatus. In particular, various general-purpose machines may be used with programs written in accordance with the teachings herein, or it may be more convenient to construct a more specialized apparatus to perform the required method steps. A particular structure for a variety of these machines will appear from the description given below.
In addition, embodiments of the present invention relate to computer readable media or computer program products that include program instructions and/or data (including data structures) for performing various computer-implemented operations. Examples of computer-readable media include, but are not limited to, magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD-ROM disks; magneto-optical media; semiconductor memory devices, and hardware devices that are specially configured to store and perform program instructions, such as read-only memory devices (ROM) and random access memory (RAM). The data and program instructions of this invention may also be embodied on a carrier wave or other transport medium. Examples of program instructions include both machine code, such as produced by a compiler, and files containing higher level code that may be executed by the computer using an interpreter.
CPU 1002 is also coupled to an interface 1010 that connects to one or more input/output devices such as such as video monitors, track balls, mice, keyboards, microphones, touch-sensitive displays, transducer card readers, magnetic or paper tape readers, tablets, styluses, voice or handwriting recognizers, or other well-known input devices such as, of course, other computers. Finally, CPU 1002 optionally may be coupled to an external device such as a database or a computer or telecommunications network using an external connection as shown generally at 1012. With such a connection, it is contemplated that the CPU might receive information from the network, or might output information to the network in the course of performing the method steps described herein.
Although the above has generally described the present invention according to specific processes and apparatus, the present invention has a much broader range of applicability. In particular, aspects of the present invention is not limited to any particular kind of orthopaedic procedure and can be applied to virtually any joint or body structure. One of ordinary skill in the art would recognize other variants, modifications and alternatives in light of the foregoing discussion.
It will also be appreciated that the invention is not limited to the specific combinations of structural features, data processing operations, data structures or sequences of method steps described and that, unless the context requires otherwise, the foregoing can be altered, varied and modified. For example different combinations of structural features can be used and features described with reference to one embodiment can be combined with other features described with reference to other embodiments. Similarly the sequence of the methods step can be altered and various actions can be combined into a single method step and some methods steps can be carried out as a plurality of individual steps. Also some of the structures are schematically illustrated separately, or as comprising particular combinations of features, for the sake of clarity of explanation only and various of the structures can be combined or integrated together or different features assigned to other structures.
It will be appreciated that the specific embodiments described above are cited by way of example, and that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description.
| Number | Date | Country | Kind |
|---|---|---|---|
| 04251371.3 | Mar 2004 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/GB05/00933 | 3/10/2005 | WO | 00 | 10/23/2007 |
| Number | Date | Country | |
|---|---|---|---|
| 60575389 | Jun 2004 | US |
