SURGICAL INSTRUMENT AND METHOD FOR DETECTING THE POSITION OF A SURGICAL INSTRUMENT

Abstract

The invention relates to a surgical instrument with an instrument handle, an instrument shank connected to the instrument handle, an instrument tip with a work point, which instrument tip is connected to the instrument shank, and a first locator arranged on the instrument handle or the instrument shank. During a use of the surgical instrument, the instrument shank can be deflected, e.g. on account of transverse forces, at least between the first locator and the work point. A second locator is arranged at a distance from the first locator and, by comparison with the latter, closer to the work point, wherein the second locator is designed to detect five degrees of freedom.

Claims

1-18. (canceled)

19. A position detection system for establishing the position of surgical instruments, comprising: one or more surgical instruments, wherein each of the one or more surgical instruments comprises: an elongate instrument handle having a proximal end and a distal end; an elongate straight instrument shaft connected to the distal end of the instrument handle and defining an instrument axis, the instrument shaft having a proximal end and a distal end, the proximal end of the instrument shaft being connected to the instrument handle; a first locator arranged at the instrument handle, wherein the first locator comprises a position sensor having two coils and configured to detect six degrees of freedom; and a second locator arranged at the distal end of the straight instrument shaft adjacent to the instrument tip, wherein the second locator comprises a position sensor having one coil, has smaller dimensions than the first locator, and is configured to detect five degrees of freedom, wherein the first locator is arranged closer to the proximal end of the handle than the second locator, wherein the second locator is arranged at a distance from the first locator closer to the work point; and an electromagnetic field generator, correlated to a reference coordinate system; an evaluation unit for establishing the position of locators arranged in the position detection system, wherein the evaluation unit is configured to determine an instrument-specific calibration vector from the second locator to the work point in a coordinate system of the first locator where the instrument shaft is straight relative to the instrument axis, and wherein the evaluation unit is further configured to determine a location and direction of the work point in the reference coordinate system by transforming a coordinate of the second locator in the reference coordinate system, displaced by the calibration vector, into the coordinate system of the first locator; and a display unit for displaying at least one of the one or more surgical instruments in its true position.

20. The position detection system of claim 19, wherein the position detection system is configured to identify the type of surgical instrument on the basis of characteristic values relating to surgical instruments and the respective arrangement of the first locator and the second locator on the one or more surgical instruments.

21. The position detection system of claim 19, wherein the determination of the instrument-specific calibration vector is performed prior to elastic deformation of the instrument shaft, and wherein the transformation for determination of the location and direction of the work point is performed at each measurement cycle.

22. The position detection system of claim 19, wherein the second locator supplies a location and the first locator supplies a direction for the transformation of the work point.

23. The position detection system of claim 19, wherein the first locator is a patient locator, which is arranged separately from the surgical instrument and securely on a patient.

24. The position detection system of claim 19, wherein the first locator is a drill sleeve, which is arranged separately from the surgical instrument and securely on the patient, wherein the surgical instrument is insertable into the drill sleeve, and wherein the evaluation unit is further configured to establishing the location of the work point of the surgical instrument by measurement of an insertion depth of the instrument into the drill sleeve.

25. The position detection system of claim 19, wherein the evaluation unit is further configured to store the instrument-specific calibration vector in an instrument memory unit, and to determine the location and alignment of the work point in the reference coordinate system after reading out the calibration vector from the instrument memory unit.

26. The position detection system of claim 19, wherein the second locator for each of the surgical instruments has a diameter of less than 0.5 mm.

27. The position detection system of claim 19, wherein for at least one of the one or more surgical instruments, said surgical instrument has a memory unit for storing relative location data of the second locator relative to the first locator, for storing relative location data of the work point relative to the second locator, for storing relative location data of the work point relative to the first locator, or a combination thereof.

28. The position detection system of claim 19, wherein for at least one of the one or more surgical instruments, the instrument shaft is bendable in response to a force component acting perpendicular to the instrument axis.

29. The position detection system of claim 19, wherein for at least one of the one or more surgical instruments, the instrument shaft is bendable between the first locator and the distal end of the instrument shaft, during use of the surgical instrument.

30. The position detection system of claim 19, wherein for at least one of the one or more surgical instruments, said surgical instrument further comprises a narrow-angled instrument tip integrally connected to the distal end of the straight instrument shaft, the angled instrument tip having a work point which is configured to elastically deform away from the instrument axis.

31. The position detection system of claim 30, wherein the part of the narrow-angled instrument tip between the second locator and the work point is less flexible than the remaining part of the narrow-angled instrument tip.

32. The position detection system of claim 19, wherein for at least one of the one or more surgical instruments, the elongate instrument handle is cylindrical, the elongate straight instrument shaft is in the form of a stepped cone, and the angled instrument tip is smaller than the distal end of the instrument shaft.

33. The position detection system of claim 19, wherein for at least one of the one or more surgical instruments, the instrument shaft is detachably connected to the distal end of the instrument handle.

34. The position detection system of claim 19, wherein for at least one of the one or more surgical instruments, wherein the first locator has at least one reflector for light waves, or sound waves.

35. The position detection system of claim 19, wherein for at least one of the one or more surgical instruments, the second locator is arranged within an external contour of the surgical instrument.

36. The position detection system of claim 19, wherein for at least one of the one or more surgical instruments, the second locator is arranged in the distal end of the instrument shaft so as to be at a distance of less than 2 cm from the work point.

37. The position detection system of claim 19, wherein for at least one of the one or more surgical instruments, wherein the instrument shaft has greater flexibility than the instrument handle.

38. The position detection system of claim 19, wherein the display unit is configured to superimpose preoperative image data of a patient, intraoperative image data of a patient, or a combination thereof, concurrently with displaying at least one of the one or more surgical instruments in its true position.

39. The position detection system of claim 19, wherein the display unit is configured to highlight the work points of the one or more surgical instruments, anatomical structures of a patient, or a combination thereof, with colored markings and/or labels.

Description

[0069] Below, invention is intended to be explained in more detail on the basis of an exemplary embodiment, with reference being made to the figures. In detail:

[0070] FIG. 1 shows a schematic side view of an integral embodiment of a surgical instrument according to the invention;

[0071] FIG. 2 shows a schematic side view of a two-part embodiment of a surgical instrument according to the invention;

[0072] FIG. 3 shows a schematic view of a position detection system according to the invention for establishing the position of surgical instruments; and

[0073] FIG. 4 shows a schematic side view of a surgical instrument according to the invention, comprising optical reflectors as a first locator for optical position detection.

[0074] FIG. 5 shows a schematic illustration of a method according to the invention for detecting the position of a surgical instrument.

[0075] The surgical instrument 10 shown in FIG. 1 has an instrument axis A, an elongate, substantially cylindrical instrument handle 12, an elongate, cylindrical instrument shaft 14 arranged coaxially at the distal end of the instrument handle 12 and an angled instrument tip 16 arranged at a distal end of the instrument shaft 14. Instead of the cylindrical form, the surgical instrument 10 can also be embodied in a substantially cuboid manner or have an oval cross section. At the distal end, the instrument tip 16 has a work point 18 which is not arranged on the instrument axis A in this embodiment. In alternative embodiments, the work point 18 can also be arranged on the instrument axis A.

[0076] The instrument shaft 14 has a smaller diameter than the instrument handle 12 and the instrument tip 16 has a smaller diameter than the instrument shaft 14. In this embodiment, the instrument shaft 14 is many times longer than the instrument tip. A force component acting perpendicularly to the instrument axis on the work point 18 causes bending of the surgical instrument 10, substantially in the region of the instrument shaft 14.

[0077] A second locator 20 is arranged in a region of the instrument shaft 14 adjacent to the instrument tip 16. The second locator 20 is preferably arranged in a cavity of the instrument shaft 14. A locator cable (not identifiable in this illustration) extends, within the interior of the surgical instrument 10 from the second locator 22 to a proximal end 25 of the surgical instrument 10. The second locator 20 is arranged as close as possible to the work point 18 of the instrument tip 16. The locator 20 can also be arranged in the instrument tip 16. The second locator 20 is preferably a position sensor with a single coil for an electromagnetic position detection system.

[0078] In an alternative embodiment of the invention (not depicted here), the surgical instrument 10 has a plurality of second locators 20, which are arranged next to one another in the instrument shaft 14 or in the instrument tip 16 along the instrument axis A. This arrangement enables a reduction in the degrees of freedom establishable by the individual second locators 20 and therefore a reduction in the dimensions of the individual second locators 20. Here, it is important that this multiplicity of second locators 20, in the totality thereof, is embodied to establish the same number of degrees of freedom as a single second locator 20.

[0079] In the preferred embodiment of the invention shown in FIG. 1, a first locator 24 is arranged in the instrument handle 12 in the vicinity of the proximal end 25. The first locator 24 is preferably arranged in a cavity of the instrument handle 12. A locator cable (not depicted here) leads from the first locator 24 to the proximal end 25 of the surgical instrument 10 and preferably extends within the interior of the instrument handle 12. In an alternative embodiment, the first locator 24 is arranged in a different region of the instrument handle 12 or in the instrument shaft 14, wherein the first locator 24 is arranged closer to the proximal end 25 of the surgical instrument 10 than the second locator 20. The first locator 24 is preferably a position sensor with two coils for use in an electromagnetic position detection system such that the first locator 24 can detect all six degrees of freedom.

[0080] In an alternative embodiment (not depicted here), the surgical instrument 10 can have a plurality of first locators 24, which are arranged in the instrument handle 12 and/or the instrument shaft 14. The first locators 24 are preferably embodied to detect at least six degrees of freedom in the totality thereof. Preferably, the first locators 24 detect redundant signals such that, for example, the defect of a first locator 24 is easily establishable.

[0081] In the preferred embodiment of the invention shown in FIG. 1, a memory unit 22 is arranged in the instrument handle 12. A memory cable (not depicted here) is led from the memory unit to the proximal end of the surgical instrument 10 and it preferably extends within the interior of the instrument handle 12. Position data, e.g. relative positions of the work point 18 in relation to the first locator 24 and/or in relation to the second locator 20 and/or of the first locator 24 in relation to the second locator 20 are stored or storable in the memory unit 22. These position data are readable by the position detection system and a Surgical instrument 10 is therefore registrable in the position detection system.

[0082] The locator cable and the memory cable extend in an instrument cable 26 from the proximal end 25 of the surgical instrument 10 to an evaluation unit 28 depicted in FIG. 3.

[0083] The two-part surgical instrument 10, depicted schematically in FIG. 2, has an instrument handle 12, an instrument shaft 14 and an instrument tip 16 with a work point 18 arranged at a distal end of the instrument tip 16. A second locator 20 is arranged immediately adjacent to the work point 18 in the instrument tip 16. The position of the second locator 20 therefore substantially corresponds to the position of the work point 18. Furthermore, a transition region between the instrument tip 16 and the instrument shaft 14 has an offset embodiment. In alternative embodiments (not depicted here), the instrument shaft 14, instrument tip 16 and, transition region 15 can have virtually any form suitable for a surgical instrument.

[0084] In the embodiment depicted in FIG. 2, a first locator 24 is arranged in the instrument handle 12 adjacent to the proximal end 25. Alternatively, the first locator 24 can also be arranged in any other region of the instrument handle 12 or instrument shaft 14.

[0085] A proximal end of the instrument shaft 14 is held in the distal end of the instrument handle 12 and fixed in this position by way of a clamping screw 13. In the depicted exemplary embodiment, the regions of the instrument shaft 14 and instrument handle 12 engaging into one another have a round cross-sectional area. Preferably, these portions are flattened or have a polygonal, in particular triangular, square, pentagonal or star-shaped cross section and/or a guideway, e.g. according to the tongue and groove principle, in order to prevent relative twisting of instrument shaft 14 and instrument handle 12 by way of an interlock. Embodiments according to the invention are provided, in which these portions are embodied in such a way that the instrument handle 12 and the instrument shaft 14 can only be brought into engagement in a fixed mutual alignment.

[0086] In the assembled state of the surgical instrument 10 depicted in FIG. 2, the instrument handle 12 and instrument shaft 14 are connected to one another both mechanically and electrically by way of electrical contacts not visible in this view. Sensor signals of the second locator 20 can be transferred to the instrument handle 12 by way of this electrical connection. Arranged at the proximal end 25 of the instrument handle 12 is an instrument cable 26 for transferring the locator data from the first locator 24 and from the second locator 20 to an evaluation unit 28 depicted in FIG. 3.

[0087] The example of an electromagnetic position detection system depicted in FIG. 3 has a surgical instrument 10 according to the invention, which is connected by way of the instrument cable 26 with the evaluation unit 28. The evaluation unit 28 is connected by way of a display cable 32 to a display unit 30 in order, for example, to depict an image of the surgical instrument 10, true to its position, in a reference coordinate system. Optionally, image data of a patient P, obtained preoperatively and/or intraoperatively, are displayable on the display unit 30 in a superposed manner and/or next to or over one another. Preferably, the display unit 30 is embodied to particularly highlight the work point 18 of the surgical instrument 10 and/or structures of the patient P, which are of particular interest to the surgeon, such as e.g. sensitive structures which may not be damaged, or tissue which needs to be treated or removed, graphically, for example by colored markings or appropriate labels.

[0088] The evaluation unit 28 is connected by way of a patient locator cable 34 to a patient locator 44, which is held on the forehead of the patient P by means of a fastening band 42. The patient P is registrable in the position detection system by means of the patient locator 44 in order to establish the position of the patient P in the reference coordinate system. A field generator cable 36 connects the evaluation unit 28 to a field generator 38, which is embodied as a headrest in this example. The field generator 38 emits an alternating electromagnetic field 40, which extends at least over the region of the patient P in which the operation is to be carried out. The position detection system depicted in FIG. 2 is therefore able to accurately determine the location of the work point 18 of the surgical instrument 10, even if the work point 18 of the surgical instrument 10 is deflected from the relative position thereof in relation to the instrument handle 12 or in relation to the first locator 24, for example due to pressure forces exerted on the surgical instrument 10 during the operation.

[0089] FIG. 4 schematically shows that an optical locator with a plurality of reflectors 46 can also be provided in place of, or in addition to, a first locator 24 in the form of a position sensor with sensor coils.

[0090] A schematic illustration of a method according to the invention for detecting the position of a surgical instrument, for example the instrument described with reference to FIG. 1, is shown in FIG. 5.

[0091] In a first step S1, an instrument-specific calibration vector from the second locator to the work point is initially determined in the coordinate system of the first locator in the case of a non-deflected instrument shaft.

[0092] In a second step S2, the calibration vector is stored in an instrument memory.

[0093] In a third step S3, the calibration vector is read from the memory.

[0094] In a fourth step S4, the location and direction of the work point is determined in the reference coordinate system by transforming a current coordinate of the second locator, displaced by the calibration vector, into the coordinate system of the first locator.

[0095] The transformation is carried out in each measurement cycle.

LIST OF REFERENCE SIGNS

[0096] 10 Surgical instrument

[0097] 12 Instrument handle

[0098] 13 Clamping screw

[0099] 14 instrument shaft

[0100] 15 Transition region

[0101] 16 Instrument tip

[0102] 18 Work point

[0103] 20 Second locator

[0104] 22 Memory unit

[0105] 24 First locator

[0106] 25 Proximal end

[0107] 26 Instrument cable

[0108] 28 Evaluation unit

[0109] 30 Display unit

[0110] 32 Display cable

[0111] 34 Patient locator cable

[0112] 36 Field generator cable

[0113] 38 Field generator

[0114] 40 Electromagnetic field

[0115] 42 Fastening band

[0116] 44 Patient locator

[0117] 46 Optical reflector

[0118] A Instrument axis

[0119] P Patient