SMART DRILL, JIG, AND METHOD OF ORTHOPEDIC SURGERY

Abstract

The present invention provides a MEMS sensor guidance system mounted on a surgical instrument and uses the MEMS sensor to determine Inertial Measurement Units to track rotation and acceleration in all three spatial directions. Further the invention provides a method of surgery in which a reference axis, a loci, and a depth are defined and the instrument including the sensor cluster of the invention is placed in relation to the y-axis and x-axis and following the working end is aligned and the orientation and depth data display is observed to aid in maintaining the desired instrument.

Claims

1. A surgical guidance system for use with a work piece in a surgical field and comprising a MEMS sensor and a microprocessor having memory loaded with software that enables the interpretation of real-time data gathered by the MEMS sensor wherein the MEMS sensor tracks the orientation and movement over time of the work piece in the surgical field using a locally defined coordinate system.

2. A surgical guidance system as set forth in claim 1 further comprising a display or audio command mechanism.

3. A surgical guidance system as set forth in claim 2 wherein the display displays one or multiple graphical user interfaces.

4. A surgical guidance system as set forth in claim 3 wherein the graphical user interface recommends an orientation or vector of the work piece over time.

5. A surgical guidance system as set forth in claim 4 wherein the graphical user interface includes a two dimensional matrix and a marker responding to the location of the work piece over time, and the graphical user interface recommends the orientation through the display by tracking the marker on the two dimensional matrix and indicating a desirable location of the marker corresponding to a desirable location of the work piece.

6. A surgical guidance system as set forth in claim 5 wherein the two dimensional matrix is a circle, square, or rectangle and the marker is a spot.

7. A surgical guidance system as set forth in claim 1 wherein the graphical user interface can be used to guide a change in orientation of the work piece.

8. A surgical guidance system as set forth in claim 7 wherein the work piece is used for cutting and the change of orientation of the work piece dictates an angle of cutting.

9. A surgical guidance system as set forth in claim 1 including a display where the display includes graphical user interface which indicates the depth of the work piece over time.

10. A surgical guidance system as set forth in claim 9 wherein the graphical user interface is a bar graph which acts as a surgical depth guide.

12. A surgical guidance system as set forth in claim 10 wherein the graphical user interface further includes a two dimensional matrix with a marker.

13. A surgical guidance system as set forth in claim 1 wherein the system includes a memory including data as to the desired location of multiple fasteners and the memory records a local coordinate system which is determined by a user during surgery.

14. A surgical guidance system as set forth in claim 13 wherein the memory includes information as to the anatomy of a specific patient.

15. A surgical guidance system as set forth in claim 13 wherein the memory includes information as to the anatomy of a specific surgical procedure.

16. A surgical instrument comprising an instrument having a work piece and an integrated surgical guidance system which tracks the work piece in a surgical field and the surgical guidance system comprising a MEMS sensor which is carried on the instrument and a microprocessor having memory loaded with software that enables the interpretation of real-time data gathered by the MEMS sensor wherein the MEMS sensor tracks the orientation and movement over time of the work piece in the surgical field using a locally defined coordinate system.

17. A surgical instrument as set forth in claim 16 wherein the sensor is a six or nine degree of freedom sensor.

18. A surgical instrument as set forth in claim 16 wherein the work piece is one of a screw driver, a blade, a burr or an ablation piece.

19. A surgical guidance system as set forth in claim 18 further including display having a graphical user interface which recommends an orientation of the work piece over time.

20. A method of surgery comprising the steps of prepping the surgical area; setting a reference axis and registering the reference axis in a surgical guidance system comprising a sensor, a microprocessor having a memory and a display; defining a loci and a value dy of the loci to establish a reference coordinate system; introducing a work piece into the reference coordinate system and monitoring the action of the work piece using the surgical guidance system in order to perform a surgical procedure.

21. A method of surgery as set forth in claim 20 wherein the surgery is a minimally invasive surgery.

22. A method of surgery as set forth in claim 20 wherein the reference axis is set by drilling a pilot hole and inserting a pin along the axis which is coincident with the reference axis and recording that in the memory of the guidance system.

23. A method of surgery as set forth in claim 22 wherein two points on the pin at a pre-determined spaced distance are registered in the memory of the guidance system in order to register the reference axis.

24. A method of surgery as set forth in claim 23 wherein the loci is, an entry point for a fastener; and a depth is determined by measuring a boundary distance.

25. A method of surgery as set forth in claim 24 wherein the boundary distance is a depth.

26. A method of surgery as set forth in claim 25 wherein the depth is based on the thickness of a bone.

27. A method of surgery as set forth in claim 26 wherein the depth is recorded in a memory of the microprocessor as a value, dy.

28. A method of surgery as set forth in claim 27 wherein a value is determined along an axis, x which is orthogonal to the direction of the depth.

29. A method of surgery as set forth in claim 28 wherein the axis x is determined using a horizontal jig.

30. A method of surgery as set forth in claim 29 wherein the jig is a virtual jig.

31. A method of surgery as set forth in claim 30 wherein the jig includes an indication for one or more fastener holes in an implant.

32. A method of surgery as set forth in claim 31 wherein the jig uses a reflected light beam and is provided in the microprocessor.

33. A method of surgery as set forth in claim 20 further including the step of calibrating the guidance system by assuring that the axes are properly aligned and recording the calibration in the memory of the system.

34. A method of surgery as set forth in claim 33 wherein the work piece is aligned to the fastener entry location and the orientation data is displayed on the display screen.

35. A method of surgery as set forth in claim 34 wherein a graphical user interface is provided which includes a marker and a two dimensional matrix and the marker is aligned in the two dimensional matrix during the surgery.

36. A method of surgery as set forth in claim 35 wherein the surgery involves the placement of a fastener having an orientation, and the fastener orientation is determined and maintained by aligning them in the two dimensional matrix.

37. A method of surgery as set forth in claim 36 further including a secondary work monitor including the step of a degree of work on the secondary work monitor.

38. A method of surgery as set forth in claim 37 wherein the secondary work monitor indicates the depth of penetration of the work piece in the Y-axis.

39. A method of surgery as set forth in claim 20 wherein the surgical guidance system further includes an audio indication of the orientation of the work piece.

40. A method of surgery as set forth in claim 20 wherein the work piece is a fastener driver, and is used to insert a locking screw in an implant.

41. A method of surgery as set forth in claim 20 wherein the surgical guidance system includes a communication receiver which can receive and convert to memory data.

42. A method of surgery as set forth in claim 41 wherein the data is one of more of data regarding the placement of multiple fasteners, data as to specific surgical procedures and patient specific data.

43. A method of surgery as set forth in claim 20 wherein the memory includes a plurality of defining means of defining the reference coordinate system and the means for the user to select one or more of the defining means for a surgery.

44. A method of surgery as set forth in claim 20 further including the step of using a visual image in conjunction with the surgical guidance system.

45. A method of surgery as set forth in claim 44 wherein the visual image is captured using fluoroscopy.

46. A method of surgery as set forth in claim 45 wherein the visual image is used to verify the coordinate system or the scale.

47. A method of surgery as set forth in claim 20 wherein the surgical guidance system can be sterilized.

48. A method of surgery as set forth in claim 20 wherein the depth of the implant is determined digitally so as to preclude the use of less precise mechanical measuring means.

49. A surgical guidance system as set forth in claim 9 wherein the display is mounted to one or more of a guide, a driver and a cutting tool.

50. A surgical guidance system as set forth in claim 9 wherein the display is mounted to a cutting tool and the cutting tool includes a template with a defined entry or exit site.

51. A surgical guidance system as set forth in claim 1 wherein the system includes one or more safety parameters.

52. A surgical guidance system as set forth in claim 1 wherein the system is optimized for a specific surgical procedure.

53. A surgical guidance system as set forth in claim 52 wherein the surgical procedure is a spinal surgery.

54. A surgical guidance system as set forth in claim 1 wherein the system includes a simulated visual representation of a simulated anatomy.

55. A method of surgery as set forth in claim 20 wherein the surgery is a biopsy.

56. A surgical guidance system as set forth in claim 1 further comprising one or more linear potentiometer.

57. A surgical instrument as set forth in claim 16 further comprising one or more linear potentiometer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is side perspective view of a first representation of the surgical guide in accordance with a first embodiment of the present invention;

[0017] FIG. 2 is a detail of the surgical guide of FIG. 1 showing the display and graphical user interface;

[0018] FIG. 3 is a schematic representation of the guidance system in accordance with the invention illustrating the sensor array, which is in communication with the microprocessor, which is in reciprocal communication with the display;

[0019] FIG. 4 is a illustration of a set-up for an orthopedic surgery illustrating the use of k-wires or pins to define the reference coordinate system;

[0020] FIG. 5 is a radiograph from the front and the back illustrating the reference locations for a set of screws used in the assembly of a construct for the repair or fusion of an ankle including a distal fibula plate and screws and compression screws angled upward through the medial malleoli into the tibia.

[0021] FIG. 6 is a side view illustrating a first distal metatarsal following a chevron cut and re-alignment for repair of Hallus Valgus and prior to the placement of hardware illustrating a step of the method of bunion surgery in accordance with the present invention;

[0022] FIG. 7 is a view following the drilling of a hole and insertion of a k-wire along the axis that a fusion screw will intersect of the method of bunion surgery of the present invention;

[0023] FIG. 8 is an orthographic view of the k-wire in the bone from FIG. 6;

[0024] FIG. 9 is an illustration of the location of the fusion screw entry location (the smaller dot and the larger dot represents the K-wire location);

[0025] FIG. 10 illustrates the measurement along the axis of the k-wire of the thickness of the metatarsal, which value is recorded as dy;

[0026] FIG. 11 illustrates a tangible alignment jig (which could be replaced by a virtual version of the jig) placed over the k-wire for measurement of the marked screw entry point along the length of the alignment jig, which value is recorded as the value dx; and wherein the sensor prompts the values of dx and dy for entry into the sensor cluster interface using the display or a remote interface, such as a mobile phone;

[0027] FIG. 12 illustrates the placement of a second embodiment of the instrument in accordance with the invention, in this case, a drill with the attached sensor cluster over the k-wire/alignment jig, and after assuring that the alignment jig is parallel to the line made with the marked screw entry location and the centroid axis of the k-wire, the system is calibrated by pressing the “calibrate alignment” button on the sensor interface;

[0028] FIG. 13 illustrates the method of the invention in which the instrument with a drill bit in place is aligned to the screw entry location and in which the orientation is displayed on the display screen, in particular by a green circle;

[0029] FIG. 14 illustrates the display screen user interface in which the orientation is shown in one GUI, and the depth of work is shown on a second GUI; and

[0030] FIG. 15 illustrates a further embodiment of a jig that can be used to help define the local coordinate system of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0031] The guidance system 10 of the present invention as illustrated in FIG. 3 provides an integrated sensor cluster 12 and integral or separate microprocessor 14 including hardware and software that can aid in the proper targeting for example, for fasteners in general or more specifically for a work piece or a screw, wires or pins, relative to a surgical work area, or for a particular procedure for example for performing an osteotomy. The guidance system 10 is used with a surgical instrument 20, and can be provided separately for attachment to the instrument, or can be built into the instrument. Alternatively, as is convenient, it can be provided as components, such as the display which can be integrated into various surgical tools, or into a separate display, such as glasses or even a mobile device. Since the system is used in surgery, it needs to be able to be sterile so that it can be provided sterile as a sterilized disposable device for a single use, which is attached to a re-usable instrument or it could also be sterilizable, in which case, it could be integrated into the instrument.

[0032] The guidance system 10 has a senor cluster or sensor array 12 that includes at least (and possibly only) a 9 degree of freedom (DOF) three axis accelerometer 32, gyroscope 34, and magnetometer 36 sensor that could be used to track such motion and orientation. This sensor cluster 12 is further integrated into a system that contains a microcontroller 38 and a visual display 40 (preferably both integrated into a single unit, but where the microcontroller 38 or display 40 could be accessed remotely by the senor cluster, including, for example, on a mobile device, such as a cell phone). The required capabilities of the microprocessor are comparable to the capabilities of the Arduino Mega 2560 microcontroller with a ATmega 2560 microprocessor with 256 KB flash memory, 8 KB of SRAM, 4 KB EEPROM, and a clocking speed of 16 Mhz. Thus, the guidance system is advantageously integrated into or attached to the surgeon's instrument, 20 such as a drill or saw to provide feedback to the surgeon with respect to orientation relative to a defined axis (i.e. “attitude”) as well as positional guidance (meaning the ability of the system to direct the surgeon to maintain a desired position during surgery. The guidance system 10 defines a reference 100 along with a relative reference position 102, to provide the information required to know the dynamics of the system (i.e. surgical instrument orientation and position relative to the reference position and direction determined from the surgery site.) In order to obtain the real time position, the microprocessor 38 uses the data from the acceleration and mathematically integrates it twice. Since this integration can compound bias error and begin to accumulate position drift, the error signal is compensated for using a defined offset or a specific algorithm in a software component of the invention. Orientation is obtained from integrating the time rate change of angular position (angular velocity) once to obtain the real time angular position and these outputs, the difference in the initial angular position and reference special position can be shown on the display 40 in order to allow the surgeon to perform the orientation and positional corrections needed In order to match the directional output of the GUI 42 on the display 40 of the guidance system10.

[0033] The display 40 of the present invention provides a GUI 42 (graphical user interface) which for example, includes a targeting or guidance mechanism 46 such as a spot 47 on a plot 48 (which is advantageously circular) where the surgeon has the goal of centering the spot 47 in the plot 48 to cause the instrument (10 such as a drill or screw driver) to work on axis 104 relative to the defined reference 100. A second GUI provides a bar graph 110, which displays a relative depth (for example for the distal end of a drill tip or a fastener) to provide visual assistance as to the desired amount of penetration of the drill bit or fastener.

[0034] As an alternative to, or in addition to the display, the guidance system can include an audio alert system, for example, a series of beeps or buzzing that can either increase or decrease volume, temp of frequency in order to present information to the guidance user, for example by increasing the tempo as the work piece comes to it's desired location. In addition, the guidance system can include safety means, such as stops to avoid drilling too deep or in the wrong location.

[0035] In further embodiment, the mechanical jig 210 that is illustrated in FIG. 15 has an opening or bore 212 which captures a guide wire to define a first axis extending along the axis of the opening 212 and defined by the interior side walls of the opening. A first arm 214 extends at a first right angle to the opening, and includes a level, such as the bubble level 216 to ensure that the jig is level. An orthogonal sliding arm 218 is provided and is provided with hatch marks to provide a visual indication of a defined length along the second arm 218. Optionally arm 214 can be provided with a mechanism for translating the arm along the axis of arm 218 without changing the angle between the two arms in order to provide an optimal geometry for associated sensors, such as linear potentionmeters. The jig is provided with one, two or more 100 mm 10 kOhm linear potentiometers 220, and is connected, such as by a wired 222 or a wireless connection to the microprocessor of the system. Ideally, the potentiometers are located on different arms of the jig to verify the relative location of the coordinate system, and the k-wire may also include a potentiometer (i.e. a third one) here to mark that distance as well. The jig may include an offset from the bone to accommodate the anatomy as desired.

[0036] As a further aspect of the invention, a method of surgery is provided which relates generally to surgery in which a MEMS sensor guidance system 10 is mounted on an instrument 20 and with uses the MEMS sensor 12 to determine Inertial Measurement Units to track rotation and acceleration in all three spatial directions. One such method of surgery is illustrated as a chevron cut bunionectomy, although it is understood that it can be used for other surgeries, for example, for fusion such as for the placement of a compression screw, or for any small or long bone or spinal or maxofacial surgery, for example using a plate or implant that is fixed relative to a bone or bones, by a fastener, such as a screw, or many other surgical procedures.

[0037] In accordance with this method, the surgical area is prepped, such as for example by excision to allow access to the area for surgical intervention (or in the case of minimally invasive surgery to allow an implant to be placed without a fully opened incision). Next, a reference axis is set, for example by drilling a pilot hole, in the bone 310 (having a chevron incision 311) and inserting a k-wire 312 such as along an axis which a fastener will intersect and defining a reference axis by registering two points on the k-wire at a known spaced distance, in the memory of the microprocessor. Next, a loci is defined, for example, an entry point 314 for a fastener 316; and a depth is determined by measuring a boundary distance for the intervention (e.g., when a fastener will be inserted into a bone segment, the thickness of the bone is measured which represents the depth beyond which the surgeon does not wish to penetrate in order to avoid disturbing the soft tissue beyond the cortical surface on the back side of the bone segment). This depth is recorded in a memory of the microprocessor of the instrument in accordance with the invention as a value, dy. Next, a value is determined along an orthogonal axis, x, which can be determined using an actual horizontal jig 318 that includes an indication for a fastener entry hole, or by a virtual version of the jig for example utilizing a reflected light beam instead of the metal jig and wherein the virtual jig is provided in the microprocessor of the instrument. Then, the instrument preferably including the sensor cluster of the invention is placed in relation to the y-axis and x-axis and the device is calibrated using the button marked “calibrate alignment” on this sensor interface display, after assuring that the axes are properly aligned, for example by checking to be sure that the alignment jig is parallel to the line made with the marked fastener entry location and the centroid axis of the k-wire. Then, with the instrument in place, the working end is aligned to the area of intervention, for example, for a drill, the distal end of the drill bit in the drill is aligned to the fastener entry location and the orientation data is displayed on the display screen such as by a green circle, and the fastener orientation is determined and maintained by aligning a fastener icon displayed on the instrument sensor cluster screen in the proper positioning on the alignment marker and by monitoring the degree of work on the secondary work monitor, for example on a graphical representation of the depth or degree of penetration in the Y-axis. This procedure helps to ensure the optimal placement for surgical intervention, for example, for the placement of a pilot hole in order to assure the subsequent alignment and full seating of a fastener, such as a screw having a threaded locking head in relation to a projected internally threaded locking screw hole in an orthopedic implant. As final steps of the method in accordance with the invention, the alignment is repeated as necessary for the placement of all fasteners, and the surgical access or incision is closed.

[0038] The method of the present invention is particularly advantageous for use in minimally invasive procedures, and procedures in which fasteners are introduced percutaneously, or through the skin.

[0039] In accordance with the present invention, various procedures can be performed with the assistance of the instrument guidance system, including for example, inserting fasteners including with up-loaded specific information as to the relative location of a plurality of fasteners or of the relative location of bone fragments for typical fracture patterns, or in the case of reconstruction, the angle of incision for example by maneuvering the desired axis over time, since the present system has the advantage of allowing a rate change of orientation to be monitored. Likewise, the device can be used to access patient specific information, which might be gathered on the basis of pre-surgical imaging including for example, fluoroscopy, MRI, tomography and x-ray imaging.

[0040] While in accordance with the patent statutes the best mode and preferred embodiment have been set forth, the scope of the invention is not limited thereto, but rather by the scope of the attached claims.