Patent Application
20090048610
With the proliferation of minimally invasive percutaneous medical procedures, there increasingly arises a need for placement of medical probes inside the human body at a high level of accuracy. This need is particularly, although not exclusively, apparent in neuro-diagnostic and neuro-therapeutic procedures, such as electrical neurostimulation, brain biopsy, brain tissue ablation, local drug delivery, and more. In some of these procedures, the requirement for high accuracy applies not only to the X, Y, and Z coordinates of the probe's distal tip inside the target tissue, but also to the angle of rotation of the probe relative to the tissue. Examples of such procedures include, but are not limited to the following types of medical probes and procedures:
1) A cannula that houses an internal elongated element whose distal tip is pre-bent sideways, where the pre-bent tip assumes a straight shape while it passes through the cannula and re-assumes its pre-bent shape when it emerges out of the cannula's distal tip, for delivery of a diagnostic or therapeutic procedure, such as electrical stimulation or local drug delivery or biopsy or ablation or brachytherapy or tissue monitoring with a sensor, to a tissue location that is off the cannula's longitudinal axis.
2) An optical fiber for delivery of photodynamic therapy, which is the light-based activation of light-sensitive chemotherapeutic drugs delivered to malignant tumors in order to kill the cancerous cells. Photo-dynamic therapy can be delivered to the target tissue by way of directing an optical fiber carrying a laser beam. Such direction requires both axial and rotational control if the target tissue is located off the probe's longitudinal axis.
3) An optical fiber for delivery of optical neurostimulation, which is an emerging application in the field of neurostimulation. Optical neurostimulation, which may partially replace electrical neurostimulation, involves light-based activation and de-activation of proteins embedded in neurons, which, when activated, trigger on and off neuronal electrical flashing. This can be a highly accurate method of stimulating individual neurons, in contrast to electrical neurostimulation that has a more diffused effect. Optical neurostimulation is direction-dependent, as a light beam is directional in nature. Optical neurostimulation may be done by way of directing an optical fiber to a specific tissue target. If the target tissue is located off the probe's longitudinal axis, such direction requires both axial and rotational control, at a high level of accuracy. Optical stimulation can also be applied to other types of cells, in addition to neurons, in order to trigger on specific cell activity, e.g., insulin release by pancreatic cells.
4) An optical fiber for delivering light to excite fluorescent nanoparticles in order to image tumor tissue during biopsies and surgeries. This emerging imaging technique can be particularly useful for precisely spotting a brain tumor during a surgery to remove the tumor, where patient outcome depends on successful removal of the entire tumor. In this imaging procedure, nanoparticles that emit infrared light when they are excited by visible light are injected into the tumor area and attach to malignant cells. An optical fiber then delivers light to the tumor area. The infrared rays emitted by the nanoparticles can be picked up by a small camera and viewed by the surgeon. The direction of an optical fiber to the tumor requires both axial and rotational control, at a high level of accuracy, if the target tissue is located off the probe's longitudinal axis.
One challenge associated with the high accuracy associated with minimally invasive percutaneous medical procedures is that certain surgical devices associated with introducing probes are configured such that the probe's coordinates coincide with room coordinates and can therefore present accuracy issues with respect to placement of the probe in the body. Further, the increasing use of robotic devices to perform minimally invasive diagnostic and therapeutic procedures presents a need for precision placement of tools in-vivo when utilizing robotic mechanisms.
It would be desirable to provide a system and/or method that satisfies one or more of these needs or provides other advantageous features. Other features and advantages will be made apparent from the present specification. The teachings disclosed extend to those embodiments that fall within the scope of the claims, regardless of whether they accomplish one or more of the aforementioned needs.
One embodiment of the invention relates to a system for placement of a cannula and an internal shaft into a patient. The system includes a base having an attachment mechanism configured to be mechanically coupled to the patient to fix the spatial position of the base relative to the patient to maximize placement accuracy. The system further includes a linear drive mechanism coupled to the base, and a rotation mechanism coupled to the base. The system further includes a cannula coupled to the linear drive mechanism. The cannula has a longitudinal axis, a lumen, and a distal opening. The linear drive mechanism is configured to move the cannula in a linear direction along the longitudinal axis into the body and the rotation mechanism is configured to rotate the cannula about the longitudinal axis. The system further includes a shaft drive mechanism coupled to the linear drive mechanism and the rotation mechanism and a shaft slidably housed within the lumen of the cannula. The shaft drive mechanism is configured to move the shaft longitudinally but not rotationally within the lumen of the cannula to deploy a distal tip of the shaft out of the distal opening of the cannula.
Another embodiment of the invention relates to a method of diagnosing or providing a medical treatment to a target tissue of a patient using the probe introducer system described above. The method includes coupling the base of the system to the patient, creating an aperture in the patient sized to receive the cannula, advancing the cannula into the aperture with the linear drive mechanism until the distal opening of the cannula is located proximate the target tissue, rotating the cannula with the rotation mechanism to a desired angle, deploying the distal tip of the shaft out of the distal opening of the cannula with the shaft drive mechanism, and diagnosing or providing a medical treatment to the target tissue. The medical treatment may include delivering a therapeutic liquid, draining a liquid, performing electrical or optical stimulation of neurons and other cells, performing a biopsy, delivering a brachytherapy seed, performing photodynamic therapy, performing tissue ablation, or performing tissue diagnosis or monitoring. The base of the system may be coupled to the patient by way of direct fixation to the outside surface of the body or by fixation to an intermediate structure such as a stereotactic frame.
The invention is capable of other embodiments and of being practiced or being carried out in various ways. Alternative exemplary embodiments relate to other features and combinations of features as may be generally recited in the claims.
The invention will become more fully understood from the following detailed description, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like elements, in which:
Referring in general to the FIGURES, a medical probe introducer 10 is shown according to an exemplary embodiment. The medical probe introducer 10 is configured to allow a medical probe to be introduced into the body of a patient 5 such that the X-Y-Z position of the tip of the probe, as well as the rotational orientation of the probe, may be controlled with micrometer precision. Such precision is desirable to direct a medical probe to an objective tissue in the patient's body with minimal damage or disturbance to the surrounding tissue, especially in diagnostic and therapeutic procedures conducted in the central nervous system. The target tissue includes but is not limited to brain or other neural tissue that needs to be stimulated electrically or optically, or a malignant tumor to which a chemotherapeutic drug is to be locally delivered, or a suspected tumor that needs to be sampled by way of biopsy, or a malignant tumor that needs to be ablated or locally radiated, or pathological tissue such as ischemic tissue in the brain that needs to be monitored by a biochemical or physical sensor. The medical probe introducer 10 may be coupled directly to the patient as shown in
Referring now to
In an exemplary embodiment, the base 12 (e.g., static base) is a plate-like member to which the other components of the system are coupled. The base 12 includes a central opening that receives the rotation mechanism 20. The base 12 further includes an attachment mechanism, shown as multitude of openings 16 that receive fasteners to couple the base to the skull of a patient (e.g., with surgical screws). In another embodiment, the attachment mechanism is a stereotactic frame 6 coupled to the patient. The base may be coupled to the patient or to the stereotactic frame 6 with an adhesive or with another suitable mechanism. The base 12 is formed from a biocompatible solid material such as stainless steel (e.g., SST 303).
The rotation mechanism 20 (e.g., common dynamic base) is coupled to the base 12 and allows the cannula 60 and the shaft 70 to be rotated about the central longitudinal axis 62. According to one exemplary embodiment, the rotation mechanism 20 includes a main body with a generally L-shaped profile formed by a first wall 22 and a second wall 24. The main body of the rotation mechanism 20 further includes a circular end wall 26 that is perpendicular to the first wall 22 and the second wall 24. As shown best in
The rotation mechanism 20 is coupled to the base 12 with a bearing assembly including a bearing 30, a lock plate 32 and an inside bearing nut 34. In this way, the rotation mechanism 20 is linearly fixed to the base 12 but may still rotate relative to the base 12 about the axis 62. As shown best in
Referring now to
The linear drive mechanism 50 includes a linear scale 58. The linear scale 58 includes a multitude of indicators including a zero or datum indicator 59 to show the relative linear movement of the linear drive mechanism 50 relative to the rotation mechanism 20 and the base 12. According to an exemplary embodiment, the linear scale 58 includes indicators from 0-50 mm at 1 mm increments. According to other exemplary embodiments, the linear scale may have a different scale (e.g., inches, etc.) and may have more or fewer indicators. The movement of the linear drive mechanism 50 may be controlled manually, robotically through a gear system (e.g. by a robotic mechanism), by a screw, or by a micrometer.
The body 52 is coupled to the cannula 60 (e.g., rigid needle, outside needle, insertion needle, etc.). The cannula 60 is an elongated tube-like member that is formed from a biocompatible solid material such as stainless steel (e.g., SST 303) and is configured to be inserted into the patient 5 as shown in
The shaft 70 is an elongated element that that is configured to be deployed from the cannula 60. The shaft 70 is at least partially nested within the cannula 60 and has a diameter smaller than the diameter of the lumen 64 of the cannula 60. As shown best in
According to some exemplary embodiments, distal segment 72 of the shaft 70 can be manufactured in such way that it is bent (e.g., in a 90 degree arc). In such exemplary embodiments, the distal segment 72 assumes a straight shape (e.g., aligned with the longitudinal axis 62) while it passes through the cannula 60 (as shown in
Referring especially to
The shaft drive mechanism 80 includes a linear scale 98. The linear scale 98 includes a multitude of indicators including a zero or datum indicator 99 to show the relative linear movement of the shaft drive mechanism 80 relative to the linear drive mechanism 50. According to an exemplary embodiment, the linear scale 98 includes indicators from 0-30 mm at 1 mm increments. According to other exemplary embodiments, the linear scale may have a different scale (e.g., inches, etc.) and may have more or fewer indicators.
The adaptor 92 is coupled to the shaft 70 with connectors 100. The connectors may be a commonly known connector such as a Luer connector. The medical probe introducer 10 may also include a Y-type connector 102 that allows a the connectors 100 and the shaft 70 to be in fluid communication with a liquid delivery device 110 shown in
The rotation mechanism 20, the linear drive mechanism 50, and the shaft drive mechanism 80 cooperate to allow a probe to be introduced into the patient with a high degree of axial and angular accuracy. The mechanisms 20, 50, and 80 may be used to control the axial position of the cannula 60, the axial position of the shaft 70, and the angular position of the cannula 60 and the shaft 70 at sub-millimeter or sub-degree accuracy. The mechanisms 20, 50, and 80 may be controlled either manually or robotically. The controller can exchange data with an imaging device, such as ultrasound or CT or MRI. If controlled robotically by a robotic mechanism, the mechanisms 20, 50, and 80 may be controlled via gears or other intermediate devices by a computerized controller and interface with the imaging device in real time, thus enabling image-guided placement of the shaft precisely at the desired tissue location. The medical probe introducer 10 may also be used in conjunction with a system for mapping the target tissue area, e.g., electrical mapping of brain tissue, to maximize accuracy of delivery.
Referring to
As can be appreciated by those skilled in the art, the medical probe introducer as described herein may have a wide variety of applications. According to one exemplary embodiment, the introducer may be used to direct an electrical or optical stimulation lead or fiber towards brain tissue to electrically or optically stimulate the brain tissue (e.g., to treat Parkinson's or Epilepsy, etc.). According to another exemplary embodiment, the introducer may be used to precisely install a medicine or contradiction fluid for medical imaging. According to another exemplary embodiment, the introducer may be used to locally burn cancerous tissue. According to another exemplary embodiment, the introducer may be used to remove a portion of tissue such as for a biopsy.
The described configuration of the medical probe introducer having an attachment mechanism permitting the introducer to be mechanically coupled to the patient addresses the accuracy challenge presented by minimally invasive percutaneous medical procedures. Because the introducer may be firmly attached (either directly or indirectly via an intermediate frame) to the treated patient body part (e.g. skull) thus having the probe's and the body part's spatial geometric coordinates coincide with no relative movement between them, a high degree of accuracy may be achieved, in contrast to devices in which the probe's coordinates coincide with room coordinates.
The construction and arrangement of the elements of the medical probe introducer as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited herein. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. It should be noted that the elements and/or assemblies of the system may be constructed from any of a wide variety of materials that provide sufficient strength, durability, or biocompatibility. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the preferred and other exemplary embodiments and medical procedures without departing from the scope of the present invention.
