BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:
FIG. 1 is a schematic illustration of the whole of a subject's spine, showing two reference bridges, constructed and operative according to various preferred embodiments of the present invention, namely, a full-spine bridge assembly covering the whole length of the spine, and a short bridge covering several vertebrae of the lumbar section of the spine;
FIG. 2 illustrates schematically a close-up view of a lumbar section of a subject's spine, showing the short bridge of FIG. 1 connecting a number of lumbar vertebrae together;
FIG. 3 is a schematic illustration of a lumbar section of subject's spine, showing a bridge, similar in function to that of the embodiment of FIG. 2, but constructed and operative according to another preferred embodiment of the present invention;
FIG. 4 is a schematic illustration of a lumbar section bridge, showing the component parts for anchoring the lumbar section to the subject's pelvis;
FIG. 5 is an alternative preferred embodiment of a lumbar section bridge, similar to that shown in FIG. 4; and
FIGS. 6 and 7 schematically show preferred embodiments of the whole spine bridge assembly described in the embodiments of FIGS. 4 and 5, but with a miniature surgical robot attached thereto; FIG. 6 shows the robot mounted on the thoracic section of the bridge, while FIG. 7 shows the robot mounted on the lumbar section of the bridge.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Reference is now made to FIG. 1, which is a schematic illustration of a model of the whole of a subject's spine, showing two reference bridges, constructed and operative according to various preferred embodiments of the present invention, for facilitating the performance of surgical procedures on the spine 10 of the subject. The illustration shows a first reference bridge 12 connecting a number of lumbar vertebrae 14 for enabling treatment of several vertebrae in a single procedure, as mentioned in application (i) hereinabove, and a second reference bridge assembly 16, composed of several bridge sections, preferably connected to a number of vertebrae 18 along the entire length of the spine, as well as to the skull 20 and the pelvis 22, as mentioned in application (ii) hereinabove. It is to be understood that the two bridges shown can generally be used either as one connected system with no mutual relative motion, or separately and independently. Each of these embodiments is now described in more detail in the drawings to follow.
Reference is now made to FIG. 2, which illustrates schematically a view of a lumbar section of a subject's spine, showing a bridge, constructed and operative according to a first preferred embodiment of the present invention, connecting a number of lumbar vertebrae together. Though this embodiment is illustrated in connection with the lumbar vertebrae, it is to be understood that it is applicable to groups of vertebrae at any level of the back. In the preferred embodiment illustrated, the bridge 12, comprising a cross member 30 with referencing holes 32, and two vertical support arms 34, is connected to the spinous processes of four adjacent vertebrae 14. When applied to a real subject, the attachment is preferably performed minimally invasively, through small incisions in the subject's skin and back tissue (not shown in any of the drawings). Though the cross members 30 are shown as simple flat elements in most of the illustrated embodiments of the present application, it is to be understand that they could also be of any other preferred form, such as rails, or angled profiles, or even a double strips, and the term cross member as claimed in the present application, is thuswise to be understood. Two preferred methods of attachment are shown in FIG. 2, the support arms 34 being preferably attached by means of clamps 36 onto the spinous processes of the outer pair of vertebrae, while the inner vertebrae are preferably connected to the cross member 30 by means of 1.5-2 mm K-wires 38 attached to their corresponding spinous processes.
Once the bridge has been mounted onto the vertebrae to be treated, the cross member 30 constitutes a platform disposed close to and above the spine, and which has a fixed position relative to each of the vertebrae connected thereto, and moves in absolute space together with the vertebrae. As described hereinabove, a preliminary registration procedure, as known in the art, can be performed to define the relative position and orientation of each of the vertebra relative to the frame itself, by means of dynamic referencing sensors, or a passive measuring arm operating as a mechanical digitizer. Once this has been done, the position of each of the vertebrae is known relative to the bridge, and if suitable pre-registration fiducials have been used, the position also of the bridge itself relative to the operation planning environment, whether a preoperative CT or MRI image, or an intra-operative X-ray fluoroscopic image, or any other image. According to one preferred method of use of the bridge of this embodiment, a miniature surgical robot, such as that described in allowed U.S. patent application Ser. No. 09/912,687, to one of the inventors of the present application, and herein incorporated by reference in its entirety, may be attached to one or more of the referencing holes 32. Such a miniature robot is then able to utilize the registration information to perform accurately positioned procedures, such as screw hole drilling, on each of the vertebrae in succession, regardless of whether the subject moves between the procedures on the successive vertebrae. This thus enables such procedures to be performed more conveniently and comfortably than by means of prior art methods, where either each vertebra is registered and operated on independently, or alternatively, if they are connected preoperatively, the subject is fixed relative to the operating table to render the connected vertebrae immobile.
According to another preferred procedure, the operation may be performed by a surgeon using hand-held tools, and an external tracking system used to relate the position of these tools to the position of the bridge and each of the vertebrae, and to the operation environment, whether predetermined by preliminary imaging, or determined intra-operatively.
Reference is now made to FIG. 3, which is a schematic illustration of a lumbar section of subject's spine, showing a bridge, similar in function to that of the embodiment of FIG. 2, but constructed and operative according to another preferred embodiment of the present invention. Features common to those of FIG. 2 are labeled with the same reference characters. The bridge shown in FIG. 3 differs from that shown in FIG. 2 in that the cross member 40 of the bridge has a series of flat surfaces 42, with mounting holes 44 which are located to match the mounting holes of the base 48 of a miniature surgical robot 46, of the type shown below in FIGS. 6 and 7. The robot is shown in FIG. 3 ready for mounting onto the center position of the bridge. Such a preferred mounting method makes it particularly simple to move the robot from position to position when needed, while maintaining the accuracy of the registration. Though the robot in FIG. 3 is shown without any operating tools attached to its working platform 50, it is to be understood that any such tools may preferably be attached thereto, such as is described in the above mentioned allowed U.S. patent application Ser. No. 09/912,687.
The bridge of FIG. 3 also shows another preferred method of attachment to the vertebrae, whereby the center of the bridge is attached by means of a clamp, and the outer ends by means of K-wires attached to the spinous processes of the pouter vertebrae.
Reference is now made back to FIG. 1, in order to describe details of the construction and operation of the whole-spine bridge, according to another preferred embodiment of the present invention. The bridge, according to this embodiment, can preferably be divided into three separate joined component sections—a lumbar section, a thoracic section and a cervical section. It is to be understood however, that this division is only one convenient manner of constructing such a bridge, and the present invention is not meant to be limited thereby. Other preferred constructions can also be envisaged, and even partial spine bridges, where not all three sections of the spine are included, such as a lower back bridge covering from the thoracic section down to the pelvis, or an upper back bridge, covering from the thoracic section up to the skull.
The thoracic section 76 of the bridge is connected at its lower end to the lumbar section 60, and at its upper end by means of one or more clamps 78 to the spinous processes of one or more chosen vertebrae from the thoracic spine region. Alternatively and preferably, though not shown specifically in FIG. 1, one or more 1.5-2 mm K-wires are drilled into one or more chosen vertebrae from the thoracic spine region, in the same manner as K-wires are shown in FIG. 2 for use with the lumbar vertebrae. As will be described in more detail below, a sliding carriage is preferably attached to the bridge, and can be moved to any desired position along the thoracic section of the bridge, and rigidly locked preferably by means of a thumbscrew above the region of interest. A robotic system or a dynamic referencing probe can be attached to the sliding carriage, and positioned at any of several defined locations down the thoracic spine, in order to reach any desired point along the thoracic spinal region. The miniature surgical robot can preferably be mounted on the platform of the carriage, in a manner similar to that shown in FIGS. 6 and 7 hereinbelow.
At the top end of the spine, the cervical section of the bridge 80 is shown. A halo ring 81 or another commonly used fixing device, is rigidly attached on the subject's skull 20. It is to be understood that this aspect of the invention is applicable whether the fixing device is attached directly to the skull bones, such as by screws penetrating into the bone structure, or whether the fixing device is attached to the skull by means of a clamping mechanism which holds the fixing device rigidly relative to the skull by applying pressure to the skull through the skin, but without penetrating the skin. In this application, both of these types of devices are described and claimed as being “attached” on the subject's skull. The upper end of the cervical section 80 of the bridge is preferably supported by attachment to the halo ring 81. The lower end is supported either by attachment to the upper end of the thoracic section 76 of the bridge, or by means of a clamp or one or more K-wires to spinous processes suitably located near the lower cervical region. As with the lumbar 60 and thoracic bridge 76 sections, a sliding carriage is preferably attached to the bridge, and can be moved to any desired position along the thoracic section of the bridge, and rigidly locked above the region of interest. A robotic system or a dynamic referencing probe can be attached to the sliding carriage, and can thus be positioned at any of several defined locations in order to reach any desired point in the cervical spinal region. The miniature surgical robot can preferably be mounted on the platform of the carriage, in a manner similar to that shown in FIGS. 6 and 7 hereinbelow.
The cervical section of the bridge is preferably profiled to have the same approximate shape 83 as the cervical lordosis, such that the operating point of the robot mounted on the carriage remains close to the point of operation on the subject's spine.
Although in the preferred embodiment of the spinal bridge shown in FIG. 1, the thoracic section 76 of the bridge is shown anchored to the ends of the cervical 80 and lumbar 60 sections, it is to be understood that the invention is not meant to be limited thereby, but that any suitable connection scheme may be used, whereby the ends of each section of the bridge are firmly connected to their neighboring section's ends, Where applicable, such that all of the sections of the bridge form one rigid structure generally parallel to the line of the spine, and are also firmly disposed relative to the vertebrae of the spine. Thus, for example, according to another preferred embodiment of the present invention, either or both ends of the thoracic section could preferably be connected directly to vertebrae, and the cervical and lumbar sections attached to the thoracic section. Furthermore, although the invention has been described using three sections of the whole-spine bridge, it is to be understood that the invention is not meant to be limited thereby, but that embodiments using two adjacent sections of the three described are also understood to be included as preferred embodiments of the present invention.
Whole spine bridges have been used previously for Halofemoral longitudinal and pelvic traction for the correction of spinal deformity. The spinal bridges of the present invention differ in that they are adapted for use in surgical procedures performed on the spine, generally to correct spinal deformities, such as scoliotic deformity. Use of the spinal bridge of the present invention improves the anatomical relationships between vertebrae on which procedures are being performed, such as by improving the accuracy with which screw insertion is made into the pedicles for attaching inserts for correcting such deformities. Additionally, the present invention may also be advantageous for providing increased accuracy in robotic screw insertion through reduction of mutual movement of adjacent vertebrae, since such mutual movement may result in degraded screw insertion accuracy. Furthermore, the use of the whole spine bridge of the present invention improves the accuracy of many surgical procedures performed using it, whether drilling, sawing, milling or even simple guidance of a surgical tool relative to the vertebrae of the whole spine, whether applied robotically or manually by the surgeon, such that the procedure is accurately performed relative to all of the vertebrae to be operated on.
Reference is now also made to FIGS. 4 and 5, which show further details of the lower end of the whole spine bridge, and which are to be viewed together with the details shown in FIG. 1. FIG. 4 is a schematic illustration of the lumbar section of the bridge, showing the component parts for anchoring this section to the subject's pelvis. FIG. 5 is a schematic illustration of an alternative embodiment to that shown in FIG. 4, of the lumbar section of the bridge. The lumbar bridge section 60 preferably comprises two nails 62 with screwed ends, inserted into the spina iliaca posterior superior on both right and left sides of the subject. A bar 66 is preferably attached to both screwed nails 62, in order to generate a rigid connection between the two nails, to serve as a base anchor for the lumbar section 60 of the spinal bridge. The upper end of the lumbar section of the bridge is preferably attached to a spinous process of one of the upper lumbar vertebrae, either by means of a clamp 68 as shown in FIG. 1, or by means of a K-wire 70, shown in FIG. 4, drilled into such a suitably located spinous process in the lumbar spine region. The lumbar bridge section and its component parts are preferably attached to each other by means of adjustable fittings, such that the disposition of the bridge relative to the spine can be performed with maximum flexibility to suit individual subjects.
Attached to the bridge is a sliding carriage 72, that can be moved to any desired position along the lumbar section of the bridge, and rigidly locked by means of a thumbscrew 74 above the lumbar spine region of interest. A robotic system or a dynamic referencing probe can be attached to the sliding carriage, and thus positioned at several defined orientations in order to reach any desired location along the lumbar spine. The miniature surgical robot or a dynamic referencing sensor can preferably be mounted on the platform of the carriage, in a manner similar to that shown in FIGS. 6 and 7 hereinbelow.
Reference is now made to FIG. 5, which schematically illustrates an alternative and preferable arrangement for the construction of the lumbar section of the bridge, and for anchoring this section to the subject's pelvis. Parts having the same function as those shown in the embodiment of FIG. 4, are labeled with the same reference characters, even though the structural form may be different. The sliding carriage 72 differs from that in FIG. 4 in that it has an offset table 75 on which a miniature robot is preferably mounted, such an offset table providing better lateral access to the vertebrae, such as is advantageous in the performance of translaminar or transfacet fusion procedures. Additionally, the bridge length adjustment is performed at the pelvic end and not at the upper end. The mounting block 71 at the top end can be adapted to be fixed to the spine either by means of a K-wire, as shown in FIG. 4, or by means of a spinal process clamp, as shown in FIG. 1.
Reference is now made to FIGS. 6 and 7, which schematically show preferred embodiments of the whole spine bridge described in the embodiment of FIG. 1, also showing attached thereto, a miniature surgical robot 82 of the type described in allowed U.S. patent application Ser. No. 09/912,687.
In FIG. 6, the robot 82 is shown attached by its base 84 to the adjustable platform 72 on the thoracic section 76 of the bridge. The top plate 86 of the preferred miniature robot shown is the surface whose motion is controlled by the robot actuators. To that surface is preferably attached a tool frame 88, which in the embodiment shown, carries a drill guide 90 for positioning the surgeon's drill accurately where required by the operation procedure. In FIG. 7, according to another preferred embodiment of the present invention, the robot 82 is shown attached by its base 84 to the adjustable platform 72 on the lumbar section 76 of the bridge. The top plate 86 of the robot shown is the surface whose motion is controlled by the robot actuators, and to that surface is preferably attached a tool frame 88, which in the embodiment shown, carries a drill guide 90 for positioning the surgeon's drill accurately when so required in the operation procedure.
It is appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described hereinabove as well as variations and modifications thereto which would occur to a person of skill in the art upon reading the above description and which are not in the prior art.
Patent Application
20080071272
