DE10353700A1 - Intelligent, automatically controlled tool for milling bones - Google Patents

Abstract

The invention relates to a device and a method for controlling the path of a medical instrument relative to a tissue on the human or animal body with edges 4 for supporting the device to the body to be treated and actuators for influencing the movement of the device operated by a surgeon becomes. The trajectory of the device is registered by an internal or external localization system 9 and compared with a predetermined trajectory. Based on this comparison, a control unit 8 sends corresponding signals for path correction to the actuators, which are designed as brakes 3a, 3b and / or as motors. Thus, a very accurate path can be traversed with an easy-to-use device.

Description

The The present invention relates to a method and apparatus for material removing machining tissue on the human or animal body, such as on the milling or Drilling on bones.

In In many surgical disciplines, it is necessary to precisely perform a bone incision. To can different methods are applied.

The Problem of detachment of bone covers comes in the maxillofacial and neurosurgery at different Surgery, such as in the treatment of tumors, infections, Injury etc. before. To date, different methods have been used for application, which is essentially in the conventional (manual) Have surgery and computer-aided surgery divided.

In the conventional surgical method, to open bone lids initially, as in 3 is shown, with the "trepan" several holes laid, and then through these holes with differently curved "raspatories" the dura mater (brain skin) are released from the bone. Now, with the craniotome (with attached dura protection) along a previously recorded line, the bone cover is milled out.

there can Problems such as adhesions occur, which does not cause dura injuries are always avoidable. Also can Bone cuts not previously planned and transferred to the skull as is possible with navigation and robotic interventions.

Similar to The GPS, when navigated, is operated by two external cameras measure the position of a surgical instrument, and with the Triangulation methods relate the exact coordinates to the patient. The "medical workstation" also calculates the correlation between the instruments, the patient and the medical image data (Computed tomography and / or magnetic resonance imaging, by special image processing a spatial, three-dimensional Reproduce an image of the patient). Intraoperatively, the image data and the real patient in the operating room by means of some anatomical or artificial Landmarks correlates (= "registered") Points visited both in the image material, as well as in reality and measure their coordinates. Then be these points are correlated by means of mathematical optimization methods and with the calculated transformation, the entire patient becomes registered with the image data. A similar process (in which using surface scans registered) was also presented by the own working group. However, the surgeon has his eyes between monitor and surgical site constantly the accuracy is lower than with robotic interventions.

Therefore The so-called "navigated control" was developed at it possible is the router in "forbidden Zones "automatically shut down or the milling speed the way down. This allows It allows the surgeon to focus on the surgical site. At "Navigated Control "gets away assumed that it (although undesirable but still possible) is, the planned route, e.g. due to patient movement or Manual deviation of the surgeon to "leave." However, this would be displayed on the monitor, acoustically output and the router would possibly off. The disadvantage of this method is that Deviations from the nominal line are possible and need to be corrected manually.

A similar Project is funded by a working group of the University of Mannheim pursued under the name "Intelligent Tool Drive "(ITD) is known. The goal of the project is a small 5-DOF manipulator based on a parallel kinematic, the automatic alignment and stabilization of a drill in medical applications (Pedikelverschraubung) allows. It should be external disturbances such as involuntary transient movements of the operator and the hand tremor balanced and the drill bit to be stabilized. The hand-held operation robot ITD seeks the possibilities of Robotics (high precision) with those of navigation (simplified orientation on the patient) and combine the experience of the surgeon. In addition, the tremor of Hand a dithering motion individually at about 4-5 and 8-12 Hz lies, compensate, keep the drill or instrument tip steady respectively. The However, due to its kinematics, the system has a limited working space. Fields of application exist in the predrilling of pedicle screws in The spine. It can with the system can not be easily milled trajectories.

Furthermore, robots in bone surgery surgery have hitherto been most commonly used for drilling wells or milling out shanks for hip prosthesis placement. For this purpose, former industrial robots for surgery were usually upgraded to comply with safety regulations. Commercially known robots include Robodoc (Davies, USA), Caspar (Schwerin, DE), Neuromate (Davies, USA), Otto (Berlin, DE) and Path The inventors have developed a robotic system for milling trajectories, in which the use of a robot suffers from the disadvantage that it requires a large logistical and technical effort in sterilizing and in ensuring the required safety.

The The object of the invention is therefore to provide a device and a Method for the material-removing processing of a fabric on human or animal body, which can precisely comply with a given machining path, thereby easy to operate and avoids the disadvantages of the prior art.

These Task is with a device for the path control of a medical instrument with the features according to claim 1 and 15 and with a method with the features solved according to claim 8. Advantageous developments of the invention are set forth in the dependent claims.

The The object is achieved by a Device for Path control of a medical instrument solved, the path relative to a tissue on the human or animal body is regulated and that the following components: one or more wheels or sliding or rolling members for support of the device on the body to be treated; and one or more actuators for moving the device or Influencing the movement of the device along a given or predetermined path based on fed into the device Movement signals, the trajectory of the device in particular by an attachable localization system for detecting the Position of the device ascertainable is.

So far it is not known the principle of "mobile robotics", i.e. robots with wheels and without kinematics, to use in surgery on humans. The Coupling with the navigation allows local, precise control, the execution with Brakes or motors as actuators allows the compact, simple (also sterilizable) construction.

According to one preferred embodiment of Invention can the actuators be designed as brakes, the predetermined Trajectory of the device by a corresponding signal from the control unit for braking at least one of the wheels influence. By deliberately braking at least one of the Wheels can do that Hand of the surgeon be corrected so that the predetermined path is achieved substantially.

Consequently can the device a preoperative Implement predetermined orbit very accurately, without a great deal of effort to require in preparation and sterilization. Furthermore the surgeon has the option to depart from the given path within certain limits, and he can concentrate fully on the surgical site without to turn his eyes away.

The Wheels, however, can Alternatively, be powered and a drive signal from the Control unit can be issued so that the movement of the device is affected becomes. It is in place of the deceleration of a wheel or in addition to this the opposite Wheel driven to perform the previously described path correction. It become the same with this construction (the so-called active variant) Benefits achieved as with the previously described construction with the Brakes as actuators (the so-called passive construction).

It but it is also possible to combine the active and the passive construction, i. either braked wheels as well as powered wheels use. It can about that In addition, free-wheeling wheels to be ordered.

For example is at a cranial surgery the device by a sliding shoe on the fabric part to be processed, i. on the skull clamped or guided, so the device on one side through the wheels supported and on the other side through the shoe. This will a safe support or leadership of the device scored, leaving an unintentional injury to neighboring Tissue parts, such as the brain skin advantageously can be avoided.

The Device can about that with a deviation control device for preoperative setting from admissible Be provided deviations from the given path of movement. With help This deviation control device can be used by the surgeon preoperatively the permissible Deviations depending on determine the type of planned intervention.

In addition, the object is achieved according to the invention by a method for regulating the path of a medical device relative to a tissue on the human or animal body with the following steps: determining a predetermined trajectory of the device; Supporting the web control device on the body to be treated by means of one or more wheels; Detecting the trajectory of the device; and controlling actuators of the apparatus to affect the trajectory of the apparatus based on a comparison of the predetermined trajectory with the sensed trajectory Trajectory.

The individual elements such as wheels for support on the fabric part to be processed, sliding shoe or sliding shoes, Brakes and / or drive motors can in any number be combined. Furthermore can also other support devices be used as the sliding shoe described here.

The System thus forms a middle ground between conventional Navigation and Surgery Robotics. This allows a precise execution of Cuts with simultaneous ergonomic and economic benefits. A similar System is also for the guiding suitable for other instruments (endoscope, etc.).

there the system is not just in oral and maxillofacial surgery (MKG) and neurosurgery, but also in other bone surgery applications used.

These and other objects, features and advantages of the invention easier to understand when Read the following description in conjunction with the accompanying drawings:

1 shows an inventive device for material-removing processing of tissue on the human body.

2 shows an exploitation drawing of the device 1 ,

3 shows the use of the device as Kraniotom for sawing out a bone cover.

4 shows a block diagram of the individual components of the control or regulation of the device.

following The invention will be explained in detail with reference to the drawings.

The apparatus comprises a drive and drive system for traversing a predetermined path, which consists essentially of a frame 2 and one or more wheels or sliding or rolling members 4 consists.

The device shall leave a predetermined path on the body of a human or animal to be treated. For example, this pathway is determined preoperatively from computer tomographic data. For this purpose, the device with the wheels 4 in a first embodiment of the invention by means of a handle or handpiece 1 placed on the patient's body.

This will be the position of a tool 6 (For example, a cutter or laser or laser, ultrasound, X-ray and the like) by a localization system attachable to the device 9 and / or by a separate location system 9 (eg with one or more cameras) to the patient. Such localization systems 9 are well known in the art and therefore will not be described here. These systems are based on mechanical, optical, electromagnetic or other principles or a combination of the same.

The localization system 9 sends a signal in accordance with the respective position of the tool 6 or from corresponding reference points thereof to a control or regulation unit 8th which has access to the image or planning data of the operation. The control unit 8th is now able to get from the received position data regarding the position of the tool 6 to determine the actual path of processing and to compare this with the preoperatively set or definable target path.

On the basis of this target / actual comparison, the control unit 8th determine a path correction and a corresponding signal to one or more actuators 10 of the device sending one or more brakes 3a . 3b (in the "passive variant") or one or more motors or drives (in the "active variant") have.

The surgeon preferably moves the device manually using the handle 1 along the predetermined path, with the brakes 3a . 3b through the control unit 8th be controlled with signals that the device complies with the predetermined path. In other words, while the device is being advanced and guided manually by the surgeon, the device will correct the surgeon's hand so that the predetermined path is substantially met, or that the device substantially follows that predetermined path.

Consequently be the cons, for example, a robot in the clinical Application has avoided. The surgeon is still the surgeon, while his hand is supported by this smart device. That is, the device is very simple is in the handling and still allows precise editing.

The brake 3a . 3b are preferably electrically controlled and act mechanically via a brake pad 3c on the wheels 4 , The brakes may have an electromagnetic design or an electrostrictive design. Furthermore, the brakes can 3a . 3b by traction, Positive or magnetic, for example by eddy current act. Thus materials of components of brakes 3a . 3b as well as the wheels 4 Selected so that abrasion is minimal and at the same time a fast and reliable consistent response of the brakes 3a . 3b is guaranteed. In addition, their sterilization is easy and inexpensive to perform.

suitable Materials are, for example, plastics, in particular based on carbon, Metals, in particular titanium or aluminum alloys, ceramics, Composites and the like. But they are all the others as well suitable materials can be used.

In a second embodiment, the device becomes active through the wheels 4 driven, ie the wheels 4 are equipped with motors (not shown) with encoders, which due to the signals of the control unit 8th move the device substantially along the predetermined path. It can either be on the brakes 3a . 3b Alternatively, the device can also be used with the brakes 3a . 3b be equipped. The encoders allow redundant monitoring and control in addition to the localization system 9 , In addition, it is possible in this embodiment that the drive of the wheels 4 by a slight pressure of the surgeon on the handle 1 is triggered. In other words, the device only starts when the surgeon exerts a slight pressure on the device in the direction of the predetermined path. The device can be stopped at any time by slight pressure against the direction of movement.

The control or regulation of the brakes 3a . 3b or the motors is designed so that certain deviations from the predetermined path are allowed. These deviations are less than about 0.6 mm, preferably less than about 0.3 mm for plan test specimens and regular orbits, such as straight lines and circular arcs. With frequent changes of direction, the deviation from the planned path should be less than about 1 mm, preferably less than about 0.5 mm.

at millings on plastic skulls, where the bone thickness varies, and regular lanes, such as straight lines and arcs is the deviation from the planned lane is less than about 1 mm, preferably less than about 0.5 mm. For anatomical preparations, the cutting defect lies below about 1.5 mm, preferably below about 1 mm.

ever according to the purpose of the device However, this can also be designed so that higher or lower Deviations are described as previously described.

Furthermore can the device Alternatively, be designed so that the allowable deviation over a Input unit of a computer or the like preoperatively can be determined.

The Device becomes preferably in the oral or maxillofacial surgery or for cranial operations uses. However, it can also be used in orthopedics, for example for screwing used by pedicle screws.

For additional guidance of the device this can also with a sliding shoe 7 be equipped, as in 1 and 2 is shown formed substantially in an L-shape. This shoe 7 essentially has a parallel to a tool extending web 7a and a thereto inclined, preferably substantially perpendicularly extending guide plate or element 7b on. The body tissue to be processed, such as a bone, is doing between the guide plate 7b on one side and the wheels 4 clamped on the other side at least temporarily or arranged. Thickness compensation of body tissue is preferred by a spring 5 allows for a longitudinal displacement of the shoe 7 preferably substantially along the longitudinal extension of the web 7a allowed.

The sliding shoe 7 allows for example in a cranial surgery that the device is clamped to the skull by the guide plate 7b of the sliding shoe 7 along the inside of the skullcap slides while the wheels 4 Roll on the outside of the same. Thus, too deep penetration of the tool into the skull of the patient is avoided.

following Now the operation of the device is based on an exemplary skull operation described.

After the area to be processed is present, for example, by means of computer tomography in the form of image data in a computer or a database, a cutting path on the skull is determined preoperatively. After that, as in 3 is shown with a so-called trepan 26 several holes 21 shaped. Subsequently, through these holes 21 the dura mater (brain tissue) with differently bent detachment elements (so-called raspatories) 22 . 23 detached from the bone.

The tool clamped in the device 6 can now through one of the holes 21 be introduced into the skull and the given or pre calculated milling path 25 essentially be worn down to the bone lid 24 to cut or to mill out. In doing so, injury to the brain is avoided by reducing the depth of penetration of the tool 6 into the skull through the previously described shoe 7 is advantageously limited.

For milling the given path 25 now the wheels 4 placed on the outside of the skull and the device is by means of the handle 1 in the direction of the given path 25 emotional. Deviations from the given path are now provided by the actuators 10 corrected.

In the so-called "passive variant", this is done by deliberately braking a wheel 4 to move the device in the direction to the braked wheel 4 to steer. In the "active variant", this correction can be done by driving the opposite wheel 4 respectively. However, it is also possible to combine both variants so that the wheels both with brakes 3a . 3b are equipped as well as with engines.

In the active variant, the feed force of the device can also completely or partially by the drive of the wheels 4 be applied by means of the motors. For this purpose, the feed is switched by the motors either by a separate switch or by "pushing" of the device, ie by pushing the patch on the patient's body device are the wheels 4 put in a rotation. As a result, a signal is generated in the engine or a separate (not shown) Drehwinkel- or speed sensor, which is connected to the control unit 8th is sent. The control unit 8th The drive of the wheels starts in response to this signal input 4 ,

On the other hand, stopping of the device can again be triggered either by a separate switch or by slowing down the device by passing over the handle 1 one of the direction of movement of the device at least partially opposite force is initiated. The speed sensors or the motors now in turn direct a corresponding signal to the control unit 8th , which then shuts off the engines and the brakes 3a . 3b activated.

such Speed sensors are well known and should therefore here not described in detail become. Furthermore It is also a well-known principle, the deceleration of an electric motor to be determined by means of the load torque and accordingly on the absorbed current. This should also not be described here. The However, invention is not limited to these principles, but it is any other Method can be used, with which a manual braking of the engines can be determined by the surgeon.

The Device is but not limited to the construction described here and both embodiments can can be combined arbitrarily. For example, the device can also work with more than two wheels equipped with both braked wheels and driven wheels as well as freewheeling Wheels to Use can come.

In addition, other than the shoe described here 7 or several sliding shoes are used simultaneously. The sliding shoe 7 may also be provided at its top with small wheels so that it rolls on the part of the tissue to be supported or on a part of the tissue to be protected from the machining tool, such as the dura mater, instead of sliding.

Furthermore, it is also possible to perform the brakes not only mechanically in the manner described here, but also electrically, hydraulically, etc. The same applies to the wheels described here 4 integrated motors, which are preferably, but not limited to, electrically driven motors. These can also be separated from the wheels 4 be arranged and the wheels 4 drive via appropriate gear means.

Furthermore, the tool described here 6 not limited to a cutting tool such as a milling cutter or drill bit. It is also possible, for example, to clamp or insert a laser into the device according to the invention. In addition, it would also be conceivable to use a diagnostic device as the medical instrument, such as ultrasound, X-ray, computed tomography, in conjunction with the device according to the invention.

The device can be used in all those applications where a precise path control relative to a tissue on the human or animal body is important. Although the invention is described in terms of a hand-held device, it is not limited thereto. The device according to the invention can also be used (in the passive version) in connection with a robot, whereby it is held by a robot arm instead of by the hand of a surgeon and is operated by remote control. In such a case (equipped with a force torque sensor), the robot arm follows the specifications of the device according to the invention and monitors the movements redundantly. The robot can then in its capacity as a measuring system as a localization system 9 be used.

The device described here can except for the departure of predetermined paths 25 also be used for driving off open spaces. For this purpose, a permissible and an impermissible area is defined in the planning (which includes, for example, risk structures to be conserved). The brake 3a . 3b and / or actuators in conjunction with the localization system 9 restrict the movements to the permissible area.

1

handpiece

2

frame

3a, b

brakes

3c

brake pad

4

bikes

5

feather

6

Tool

7

shoe

7a

web

7b

guide plate

8th

control unit

9

Location system

10

actuator

21

well

22

Raspatorie

23

Raspatorie

24

bone flap

25

predetermined train

26

trepan

Claims (15)

Apparatus for controlling the path of a medical instrument relative to a tissue on the human or animal body comprising: one or more wheels ( 4 ) for supporting the device on the body to be treated; and one or more actuators ( 10 for moving the apparatus along a predetermined path based on motion signals input to the apparatus; the path of movement of the device being determined in particular by a localization system ( 9 ) for detecting the position of the device is detectable. Apparatus according to claim 1, wherein the actuators are used as brakes ( 3a . 3b ) are formed which limit the movement of the device by braking at least one of the wheels ( 4 ) influence. Apparatus according to claim 1 or 2, wherein the wheels ( 4 ) are driven and the movement of the device by driving at least one of the wheels ( 4 ) being affected. Device according to one of claims 1 to 3, with a sliding shoe ( 7 ) for clamping the device to the tissue part to be processed. Device according to one of claims 1 to 4 with a handle ( 1 ) for guiding the device by the surgeon. Control unit ( 8th ) which is connectable to a device according to claims 1 to 5 and can impart motion signals to the device on the basis of a comparison of a predetermined trajectory of the device with an actual trajectory of the device. Control unit ( 8th ) according to claim 6 with a deviation control device for the preoperative setting of allowable deviations from the predetermined trajectory. A method of controlling the path of a medical device relative to a tissue on the human or animal body comprising the steps of: determining a predetermined trajectory of the device; Supporting the device for path control on the body to be treated by means of one or more wheels ( 4 ); Detecting the trajectory of the device; and controlling or regulating actuators ( 10 ) of the device for influencing the path of the device on the basis of a comparison of the predetermined trajectory with the detected trajectory. A method of trajectory control according to claim 8, including the step of decelerating the wheels ( 4 ) for rail regulation. A web control method according to claim 8 or 9, comprising the step of driving the wheels ( 4 ) for rail regulation. A web control method according to any one of claims 8 to 10, comprising the step of clamping the device to the body part to be treated by means of a shoe (10 7 ). Method for web control according to one of Claims 8 to 11 with the step of preoperative setting from admissible Deviations of the device from the predetermined path. Computer program for performing a method one of the claims 8 to 12. disk with a computer program according to claim 13. System for path control of a medical instrument with a device according to one of claims 1 to 5 and a control unit ( 8th ) according to claim 6 or 7.