SYNCHRONIZED ROBOTIC BONE MILLING

Abstract

Described herein are robotically coordinated systems and methods for safe and efficient spinal decompression and bone milling. In various embodiments, a robotic spinal surgery system is provided with at least three robotic arms co-located on a single mobile base wherein the movement of the robotic arms is coordinated by a central control unit on the base. The system further comprises tools for spinal decompression, elements for protection of nervous tissue and navigation cameras. The nerve protection elements are placed between bony anatomy structures and nervous structures to prevent contact of the spinal decompression tools with the nervous structures. The nerve protection elements further include safety components that can optionally close electrical circuits with the decompression tools and sense or stimulate the nervous structures. Methods of deploying the inventive system in surgery are also provided.

Claims

1. A system for safe surgery comprising: a robotic surgery apparatus comprising at least three robotic arms disposed on a single cart and a central control unit disposed in the cart; a bone milling tool held by one of the at least three robotic arms; a sensitive organ protection tool held by another of the at least three robotic arms; and a camera or sensor held by a third of the at least three robotic arms; wherein the movement of the robotic arms is coordinated by the central control unit such that the protection tool is positioned to provide protection to a critical sensitive structure.

2. The system of claim 1, wherein the single cart is mobile.

3. The system of claim 1, wherein at least one of the at least three robotic arms is deployed on each side of the patient.

4. The system of claim 1, wherein the critical sensitive structure is a critical nervous system structure.

5. The system of claim 4, wherein the sensitive organ protection tool comprises: a portion configured to close an electric circuit when it makes contact with the bone milling tool; and a second portion configured to protect the critical nervous system structure.

6. The system of claim 5, wherein the second portion is additionally configured to sense or stimulate the critical nervous system structure.

7. The system of claim 1, wherein the camera or sensor is selected from the group consisting of a navigation system, a tracking system, x-ray and MRI.

8. The system of claim 1, wherein at least one small active or passive marker is placed on the bony anatomy of a vertebra of a patient as part of a spinal decompression procedure.

9. The system of claim 8, wherein at least two small active or passive small markers are placed on the bony anatomy of a vertebra of a patient.

10. The system of claim 9, wherein the camera or sensor is held close to the bony anatomy of the vertebra of the patient.

11. The system of claim 10, wherein the small markers are less than 1 cm in size and the camera or sensor is held less than 1 meter from the bony anatomy of the vertebra of the patient.

12. The system of claim 1, wherein additional cameras or sensors are placed on the robotic arm holding the bone milling tool and on the robotic arm holding the sensitive organ protection tool.

13. The system of claim 1, wherein the robotic arm holding the bone milling tool and the robotic arm holding the sensitive organ protection tool are equipped with torque sensing capabilities.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIGS. 1a, 1b and 1c show various views of the spinal anatomy with portions of bone that may require milling adjacent to nerve or spinal cord structures.

[0021] FIG. 2 is a close-up view of a portion of a vertebra that may require milling directly adjacent to a nerve structure.

[0022] FIG. 3 shows a robotic system according to a representative embodiment of the present invention wherein multiple centrally coordinated robotic arms hold milling and protective tools.

[0023] FIG. 4 shows a protective end effector according to a representative embodiment of the present invention comprising conductive and sensing elements.

DETAILED DESCRIPTION OF THE INVENTION

[0024] With reference now to the figures and several representative embodiments of the invention, the following detailed description is provided.

[0025] In a working example of the invention exemplified by FIG. 1, several views of spinal bony anatomy are shown. In each of the three views, a vertebra 104 is shown. In each case, a portion 101 of the vertebra 104 requires milling, for example because it is pressing on an adjacent nerve structure. In various of the views, a nerve root 102 and/or the spinal cord 103 are shown. Use of the inventive system with, for example, 3 coordinated robotic arms with, for example, a milling tool, a nerve protection tool and a camera being deployed by the 3 arms, allows for precise milling of the portion 101 of bone while greatly minimizing the risk of catastrophic damage to the nerve root 102 or spinal cord 103 or other nerve structure.

[0026] FIG. 2 shows a close up view of a portion of bony anatomy 201 immediately adjacent to a nerve root 202 or other nerve structure. With this arrangement of bone and nerve structures, milling of the bone (or decompression) will often be required as an appropriate surgical treatment due to the portion of bony anatomy 201 pressing or impinging on the nerve root 202 or other nerve structure. This problem requiring surgery is often caused by stenosis or other compression which can be caused by various reasons such as age degeneration, congenital and non-congenital deformation, trauma etc.

[0027] FIG. 3 shows a robotic system for bone milling according to an embodiment of the present invention. The robotic arms of the inventive system are mounted on a single mobile rigid chassis that comprises a centralized control unit, allowing for synchronized movement and control of the robotic arms. In the context of spinal decompression procedures, this synchronized control allows for precise bone milling at optimal angles and orientation.

[0028] The system's structure and morphology enable optimal deployment of the multiple robotic arms from both sides of the patient bilaterally. This special deployment of the robotic arms keeps its main mass at the sides of the patient so the surgical field is clear for surgery and imaging/sensing by the third arm and/or the surgeon. Moreover, the said method of deployment and positioning of the robotic arms enables the arms to approach the surgical area and specifically the milled bone most of the times while being in a partial folded position. It is well known in the art that robots are more rigid, hence more accurate, when they are partially folded, meaning not in a fully extended position. Standard robotic systems known in the art today, unlike the current inventive system, are positioning the arms relatively far from each other and from the patient which requires the arm to reach far often in a fully extended configuration and thus lose accuracy.

[0029] In FIG. 3, robotic arms 307, 308 and 309 are shown mounted to a rigid chassis 301 that may optionally be mobile. The robotic arm 307 holds a milling tool 311. The robotic arm 308 holds a nerve protective tool 312. The robotic arm 309 holds a camera 310. In this embodiment navigation camera is used as a main method for the robots/tools/patient tracking while it can be comprised of several alternative technologies such as visual light imaging, X-ray, MRI, magnetic tracking, laser sensing and more. Also shown in FIG. 3 is a surgical table 302 that the robotic system fits under (and, if mobile, may optionally be deployed under the table and/or removed before, during and after the surgical procedure) and a patient body 303. In the patient body a nerve structure 304 and a portion of bony anatomy 305 that requires milling are shown. The protective tool 312 is placed between the nerve structure 304 and the portion of bony anatomy 305 so that the milling tool 311 can carry out precise milling without fear of damage to the nerve structure 304. The camera 310 helps to bring the robotic arms 307, 308 and 309 to the appropriate position with respect to the surgical field with the assistance of a miniature marker 306 that is placed at the beginning of the surgical procedure. The camera 310 can then monitor the progress of the surgical procedure from an optimal angle.

[0030] Today the common way to track the operated organ e.g. boney anatomy and/or more specifically vertebral body is to place a marker on it while the marker must stand high above the open wound e.g. 5-25 cm due to the basic reason that it needs to be visible to the camera/sensor that is passively placed 1-3 meter away. This way the ability of this long, light weight marker to keep its position relative to the bony anatomy is limited and therefore its accuracy is very low. From this reason up until today this tracking technology is seldomly used for delicate accurate tasks such as spinal decompression. In the present invention, thanks to the active close range and maneuvering robotic arm that holds the camera/sensor and is able to bring it within close proximity to the open wound, the markers can be very small (e.g., 1 cm and less) and by that being rigidly connected to the milled bone and stay highly accurate. The markers can be passive or active markers and can support several tracking/sensing technologies e.g., visible light different colors combination and contrast, infra-red reflection, magnetic resonance, laser and more. Moreover, thanks to its miniature size i.e., small size and several grams weight, they be directly screwed to the bone (e.g., 3-6 mm threads) and stay secured and by that provide unprecedented accuracy. One of skill in the art will understand that, with markers of this small size, and the navigation camera being held close to the surgical field to achieve optimal angles, multiple, small, active or passive markers can be placed on several aspects of a single vertebra for optimal visualization.

[0031] In alternate embodiments of the present invention, additional navigation cameras can be placed on the robotic arms holding the milling tools. In another alternative, additional navigation cameras can be placed on end effectors held by the robotic arms also holding the milling tools. The placement of additional cameras on the operating/surgical arms can further enhance the view of the surgical field and provide additional information for providing the small markers. The skilled artisan will understand that each of the cameras can be placed with great precision and provide an enhanced view of the surgical field due to the coordinated movement of the robotic arms that are mounted on a single mobile chassis with a central control unit.

[0032] FIG. 4 provides a close-up view of a nerve protective tool 400 according to an embodiment of the present invention. The protective tool 400 has a metallic portion 401 and a sensing portion 402. The tool can have several sizes and shapes to fit the various decompression and bone milling techniques. Some in the form of small spoon shape, starting from 1-2 mm wide to long, curved or flat spatula. Also, today there are common in the market hundreds of bone milling high speed burs and dozens of tools which are used manually by surgeons as a protective tool. The specific design of the milling bure and the protective tool are application dependent but also dependent on the specific surgeon personal taste, preference, surgical philosophy, training etc. The robotic arms can adjust its robotic motion and milling technique according to the surgeon planning and chosen technique and tools.

[0033] The metallic portion 401 sits adjacent to the bony anatomy 404 and can interact with the milling tool during the procedure. In one embodiment, when the milling tool contacts the metallic portion, a circuit is closed and a signal is sent to the control unit in the rigid chassis of the robotic system that can then send feedback to stop the milling tool, reverse the milling tool, or take some other action to ensure precision and safety in the surgical procedure. There could be several material combinations that can facilitate this requirement and it is not limited to one specific material. An electric closed circuit between the milling tool and the protective tool can be achieved almost by any bio-compatible metallic substance (e.g., steel, Titanium, Aluminum etc.). Additional relevant technologies can be comprised of the use of magnetic induction, capacitive sensing and more. All are based on the close proximity of the milling tool and the protective tool which are centrally governed. The sensing portion 402 of the protective tool 400 can either sense or stimulate the nerve structure 403 during the surgical procedure, again to ensure precision and safety in carrying out the procedure.

[0034] The protective tool serves as a barrier between the milling tool and the sensitive organ which requires positive, active, dynamic continuously changing protection. This tool has several functions. On the one hand it physically separates the sensitive organ from the soon to be milled bone (sometimes this organ is pressed against and physically stuck to the bone). This tool may be comprised from at least two different materials with at least two different functionalities. The upper part that is facing the bone and the milling tool is comprised of the material that fit the technology chosen to close the circuit with the milling tool. The lower part which touches the sensitive organ e.g., nerve can also be comprised of several materials. It can be passive from a soft material e.g., plastic, silicon etc. it can be made of nonconductive isolating material to prevent any electrical flow to the nerve e.g., plastic, ceramic etc. and it also can be made from a sensing/electrode substance that has the ability to one way sense chemical and/or electrical signals from the nerve (nervous system). It can also be active by having the ability to transmit low electrical current e.g., 10ma and also sense the nerve reaction. This sensing technology is well established in the art but not in conjunction with a multi arm robotic system. This system, tools and technique can provide multiple tools and methods for milling bone, protecting sensitive organs and sensing passively or actively at any given step of the procedure. This sensing can be done by surgeon choice, by robotic algorithm or randomly per specific period or action. This combination of robotic, sensing and intelligent tools can enable a multilayer system with several safety layers.

[0035] All of the embodiments shown in FIGS. 1 through 4 can be used in inventive methods of carrying out spinal decompression procedures. In one such example, the robotic system shown in FIG. 3 can deploy a milling tool 311 on a robotic arm 307, a protective tool 312 on a robotic arm 308 and a camera 310 on a robotic arm 309. The camera 310 and end effectors are deployed to the optimal position for the procedure partially by navigation enabled by the placement of a marker 306. Once the robotic arms 307, 308 and 309 are in the optimal location and angulation, the protective tool 312 can be deployed between a portion of bony anatomy 305 that requires milling and a nerve structure 304 that requires protecting and milling can proceed. Use of the inventive system and method allows for precise, safe milling to take place with appropriate safeguards for stopping or reversing the milling as required.

[0036] In alternate embodiments of the present invention, the operating/surgical robotic arms (those holding the surgical tools for decompression/milling or other tasks) are also equipped with torque sensing capabilities. The bony anatomy of the spine is known to move during spinal surgical procedures due to movement of the patient and also forces applied during the surgery. Accordingly, if the robotic arms are capable of sensing torque feedback, this can help in tracking of the bony anatomy (along with information provided by the navigation cameras tracking the markers placed on the bony anatomy). Again, since the robotic arms are robotically coordinated by the central control unit on the single, mobile chassis, torque information can be taken into account by the central control unit (along with, for example, navigation information) in order to more accurately track the anatomy and the robotic arms. This, in turn, produces more accurate results in delicate procedures such as bone milling.

[0037] One of skill in the art will realize that several variations on the disclosed embodiments are possible while staying within the bounds of the current invention. Solely by way of example, different variations in the number of navigation cameras, robotic arms, markers and end effectors can be used without departing from the invention. As another example, markers of varying sizes can be used. The embodiments provided are representative in nature.