Tracking Device, Surgical Instrument Including Same, And Surgical Navigation System With The Surgical Instrument

Abstract

A tracking device for use in a surgical navigation system. The device includes an electromagnetic sensor configured to generate a sensor signal that depends on an external electromagnetic field. The device also includes at least one line element electrically connected to the sensor. The line element includes a first line section, a second line section, and a third line section arranged between the first and second line sections. A strain relieve unit includes a core, an outer surface, and at least one recess which extends in the outer surface circumferentially around a longitudinal axis of the core. The first line section extends into the strain relieve unit on a first side of the strain relieve unit, the second line section extends into the strain relieve unit on a second side of the strain relieve unit opposite the first side, and the third line section extends within the recess.

Claims

1. A tracking device for use in a surgical navigation system, the tracking device comprising: an electromagnetic sensor configured to generate a sensor signal that depends on an external electromagnetic field; at least one line element electrically connected to the electromagnetic sensor, wherein the line element comprises a first line section, a second line section, and a third line section arranged between the first line section and the second line section; and a strain relieve unit comprising a core, wherein the core comprises a longitudinal axis, an outer surface and at least one recess which extends in the outer surface circumferentially around the longitudinal axis, wherein the first line section extends into the strain relieve unit on a first side of the strain relieve unit, the second line section extends into the strain relieve unit on a second side of the strain relieve unit, and the third line section extends within the recess.

2. The tracking device of claim 1, wherein the recess extends around the core several times.

3. The tracking device of claim 1, wherein the recess extends along a circle when viewed along the longitudinal axis.

4. The tracking device of claim 1, wherein the recess comprises at least two adjacent grooves that extend around the core in a direction substantially perpendicular to the longitudinal axis of the core.

5. The tracking device of claim 1, wherein the recess is part of a thread formed in the outer surface of the core.

6. The tracking device of claim 1, wherein the strain relieve unit guides the line element in a guiding direction, wherein the guiding direction is at least one of radially inward direction and a radially outward direction with respect to the longitudinal axis.

7. The tracking device of claim 1, wherein, with respect to the longitudinal axis, the first line section is arranged at a first radial position and/or the second line section is arranged at a second radial position, and the third line section is arranged at a third radial position, wherein at least one of the first radial position and the second radial position is radially inward of the third radial position when viewed along the longitudinal axis.

8. The tracking device of claim 1, wherein the line element comprises at least one of a line section arranged between the first line section and the third line section and a line section arranged between the second line section and the third line section, wherein said line section extends radially outward with respect to the longitudinal axis when viewed along the longitudinal axis.

9. The tracking device of claim 1, wherein at least one opening is formed in the outer surface of the core, wherein the line element extends through the opening.

10. The tracking device of claim 9, wherein the at least one opening comprises at least one slit, wherein the slit is formed in the core, extends along the longitudinal axis of the core and overlaps the recess in an overlap region, wherein the at least one recess comprises one or more turns relative to the longitudinal axis, and wherein in the overlap region each turn of the recess around the core is interrupted by the slit.

11. The tracking device of claim 10, wherein the slit comprises a base, and wherein the first line section extends at the base of the slit.

12. The tracking device of claim 1, wherein the strain relieve unit further comprises a sleeve, wherein the core is arranged at least partly inside the sleeve.

13. The tracking device of claim 12, wherein the core is threaded into the sleeve.

14. The tracking device of claim 12, wherein the core is glued to the sleeve such that the line element is not glued to at least one of the core and the sleeve.

15. The tracking device of claim 1, wherein the core comprises a cylindrical basic shape.

16. The tracking device of claim 1, wherein the core is a one-piece unit.

17. A surgical instrument comprising: a tracking device comprising: an electromagnetic sensor configured to generate a sensor signal that depends on an external electromagnetic field; at least one line element electrically connected to the electromagnetic sensor, wherein the line element comprises a first line section, a second line section, and a third line section arranged between the first line section and the second line section; and a strain relieve unit comprising a core, wherein the core comprises a longitudinal axis, an outer surface and at least one recess which extends in the outer surface circumferentially around the longitudinal axis, wherein the first line section extends into the strain relieve unit on a first side of the strain relieve unit, the second line section extends into the strain relieve unit on a second side of the strain relieve unit, and the third line section extends within the recess.

18. The surgical instrument of claim 17, further comprising a surgical tool head with a first end and a second end, wherein the electromagnetic sensor is arranged at the first end, the strain relieve unit is arranged at the second end, and the line element extends along the surgical tool head.

19. The surgical instrument of claim 18, wherein the surgical tool head is a stylet.

20. A surgical navigation system for tracking a position of a surgical instrument, the surgical navigation system comprising: a tracking device comprising: an electromagnetic sensor configured to generate a sensor signal that depends on an external electromagnetic field; at least one line element electrically connected to the electromagnetic sensor, wherein the line element comprises a first line section, a second line section, and a third line section arranged between the first line section and the second line section; a strain relieve unit comprising a core, wherein the core comprises a longitudinal axis, an outer surface and at least one recess which extends in the outer surface circumferentially around the longitudinal axis, wherein the first line section extends into the strain relieve unit on a first side of the strain relieve unit, the second line section extends into the strain relieve unit on a second side of the strain relieve unit, and the third line section extends within the recess; a field generator for generating the external electromagnetic field; and a localizer connected to the electromagnetic sensor of the tracking device of the surgical instrument for determining a position of the surgical instrument based on the sensor signal received from the electromagnetic sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Further details, advantages and aspects of the present disclosure will become apparent from the following embodiments taken in conjunction with the drawings, wherein:

[0033] FIG. 1 shows a schematic view of a surgical navigation system with a surgical instrument;

[0034] FIG. 2 shows a schematic perspective view of a part of the surgical instrument with a tracking device according to a first embodiment;

[0035] FIG. 3 shows a schematic perspective view of an interior of a part of the surgical instrument including a strain relieve unit of the tracking device;

[0036] FIG. 4 shows a schematic perspective view of a core of the strain relieve unit;

[0037] FIG. 5 shows a schematic perspective cross-sectional view of the strain relieve unit;

[0038] FIG. 6 shows a schematic perspective view of a surgical instrument with a tracking device according to a second embodiment;

[0039] FIG. 7 shows a schematic perspective view of an interior of a part of the surgical instrument according to the second embodiment including a strain relieve unit of the tracking device;

[0040] FIG. 8 shows a schematic perspective view of a core of the strain relieve unit of the second embodiment; and

[0041] FIG. 9 shows a schematic perspective cross-sectional view of the strain relieve unit of the second embodiment.

DETAILED DESCRIPTION

[0042] In the following description, exemplary embodiments of a tracking device, a surgical instrument and a surgical navigation system will be explained with reference to the drawings. The same reference numerals will be used to denote the same or similar structural features.

[0043] FIG. 1 shows a schematic view of a surgical navigation system 12 with a surgical instrument 54 according to an embodiment of this disclosure. The surgical navigation system 12 comprises a field generator 62 for generating an external electromagnetic field 16, which is represented by a number of exemplary field lines. During navigation, for instance during a surgical procedure, a patient (not shown) is located within the external electromagnetic field 16. Hence, the surgical instrument 54 is moved within the external electromagnetic field 16 when being applied to the patient.

[0044] The surgical instrument 54 comprises a handle 66 and a surgical tool head 56. In the shown embodiment, the surgical tool head 56 is a stylet. The surgical tool head 56 comprises a first end 58 which is a distal end and a second end 60 which is a proximal end. An electromagnetic sensor 14 is arranged at the first end 58. The electromagnetic sensor 14 is part of a tracking device 10 which will be described below with reference to FIGS. 2 to 5.

[0045] Furthermore, the surgical navigation system 12 comprises a localizer 64 connected to the electromagnetic sensor 14 for determining a position of the surgical instrument 54 based on a sensor signal received from the electromagnetic sensor 14. The tracking device 10 comprises a line element 18 which extends through the handle 66 and the surgical tool head 56, thus connecting the electromagnetic sensor 14 to a connector 68. The connector 68 is removably connected to the localizer 64. In the shown embodiment, the localizer 64 may therefore be used with different types of surgical instruments 54.

[0046] The electromagnetic sensor 14 may comprise a coil and/or may be a coil. The external electromagnetic field 16 may be a constant electromagnetic field or a time-varying electromagnetic field, for example depending upon an operation mode of the surgical navigation system 12. The electromagnetic sensor 14 is configured to generate a sensor signal that depends on the external electromagnetic field 16. In the shown embodiment, the sensor signal is an analog signal, in particular an induced current and/or an induced voltage. Movement of the electromagnetic sensor 14 and/or the time variation of the external electromagnetic field 16 induces different currents and/or voltages in the electromagnetic sensor 14 leading to different sensor signals.

[0047] In other embodiments, the electromagnetic sensor 14 may comprise a processing unit for generating a digital sensor signal based on the detected external electromagnetic field 16. The line element 18 may then be used for transmitting said digital sensor signal.

[0048] The localizer 64 comprises a processing unit which is configured to determine a current position of the electromagnetic sensor 14 within the external electromagnetic field 16 depending on the sensor signal and at least one parameter describing the external electromagnetic field 16, such as a field strength, a field gradient, a time evolution of the field etc.

[0049] In the present exemplary embodiment, the line element 18 is a twisted pair cable. Both cables of the cable pair may be connected to opposite contacts of the electromagnetic sensor 14 (e.g., to the two ends of a coil thereof).

[0050] FIG. 2 shows a schematic perspective view of a part of the surgical instrument 54 with the tracking device 10. FIG. 3 shows a schematic perspective view of an interior of a part of the surgical instrument 54 including a strain relieve unit 26 of the tracking device 10. The strain relieve unit 26 is configured for providing a strain relieve for the line element 18 and will be described below in greater detail. The strain relieve unit 26 comprises a core 28 and a sleeve 52 fitted over the core 28.

[0051] In this embodiment, the connector 68 is implemented as releasable quick connector which allows for tool-free connection to and de-connection from the localizer 64. In other embodiments, there may be no connector 68, but the line element 18 may instead be directly connected to the localizer 64.

[0052] FIG. 4 shows a schematic perspective view of the core 28 of the strain relieve unit 26.

[0053] The core 28 comprises a longitudinal axis 30. Furthermore, the core 28 comprises an outer surface 32 and a recess 34 which extends in the outer surface 32 circumferentially around the longitudinal axis 30.

[0054] The core 28 may at least partly be made of plastic. In some embodiments, a core may at least partly be made of metal. In some embodiments, a core may at least partly be made of ceramics. Furthermore, a combination of different materials, in particular of the mentioned materials, may be used. The recess 34 extends around the core 28 several times. When viewed along the longitudinal axis 30, the recess 34 extends along a circle.

[0055] The recess 34 is part of a thread 44 formed in the outer surface 32 of the core 28. The recess 34 is arranged on a distal side of the thread 44. The recess 34 thus describes a helical path around the outer surface 32 of the core 28. The recess 34 is a helical groove.

[0056] The line element 18 comprises a first line section 20 which extends into the strain relieve unit 26 from a first side. In the shown embodiment, the first side is a proximal side of the strain relieve unit 26, in particular with respect to the connector 68 and/or the localizer 64. In addition, the line element 18 comprises a second line section 22 which extends into the strain relieve unit 26 from a second side opposite the first side. In the shown embodiment, the second side is a distal side of the strain relieve unit 26, in particular with respect to the connector 68 and/or the localizer 64.

[0057] The line element 18 further comprises a third line section 24 arranged between the first line section 20 and the second line section 22. The third line section 24 extends within the recess 34. The third line section 24 follows the helical path described by the recess 36. The third line section 24 is arranged within the thread 44.

[0058] The recess 34 has a V-shaped or a U-shaped cross-section, suitable for receiving the third line section 24. The recess 34 has a depth which assures that the third line section 24 is at least flush with the outer surface 32 of the core 28, i.e., the third line section 24 is flush with the outer surface 32 or recessed with respect to the outer surface 32.

[0059] In the following, reference is also made to FIG. 5, which shows a schematic perspective cross-sectional view of the strain relieve unit 26. The core 28 is a one-piece structure. The core 28 is made of plastic. The core 28 is a hollow structure with a cylindrical basic shape. The first line section 20 extends into an interior of the core 28.

[0060] The strain relieve unit 26 guides the line element 18 radially inwardly and radially outwardly with respect to the longitudinal axis 30. Specifically, with respect to the longitudinal axis 30 the first line section 20 is arranged at a first radial position, the second line section 22 is arranged at a second radial position, and the third line section 24 is arranged at a third radial position, wherein the first radial position and the second radial position are radially inward of the third radial position when viewed along the longitudinal axis 30.

[0061] In the present embodiment, the first line section 20 and the second line section 22 extend coaxially with respect to each other and coaxially with respect to the longitudinal axis 30. Hence, the first radial position and the second radial position are identical.

[0062] In other embodiments, all three radial positions may be different. Furthermore, in some embodiments the first line section 20 and/or the second line section 22 may extend coaxially with at least a portion of the third line section 24.

[0063] The line element 18 comprises a fourth line section 45 arranged between the first line section 20 and the third line section 24. The fourth line section 45 extends radially outward with respect to the longitudinal axis 30 when viewed along the longitudinal axis 30. Furthermore, the line element 18 comprises a fifth line section 72 arranged between the second line section 22 and the third line section 24. The fifth line section 72 extends radially outward with respect to the longitudinal axis 30 when viewed along the longitudinal axis 30.

[0064] When viewed perpendicular to the longitudinal axis, the line element 18 describes a double step within the strain relieve unit 26, wherein coming from the first line section 20 the fourth line section 45 constitutes a step up from the first radial position to the third radial position, and the fifth line section 72 constitutes a step down from the third radial position to the second radial position.

[0065] The line element 18 may comprise a cable insulation, which may be at least partly removed and/or not present in any or all of the first through fifths line sections 20, 22, 24, 45, 72.

[0066] As can be seen in FIG. 4, at least one opening 47 is formed in the outer surface 32 of the core 28, wherein the line element 18 extends through the opening 47. The opening 47 comprises a slit 46, wherein the slit 46 is formed in the core 28, extends along the longitudinal axis 30 of the core 28 and overlaps the recess 36 in an overlap region 48. In the overlap region 48, each turn of the recess 34 around the core 28 is interrupted by the slit 46. The slit 46 connects the recess 36 to the interior of the core 28. The fourth line section 45 and the fifth line section 72 extend radially through the slit 46. Where it follows the recess 34, the third line section 24 extends across the slit 46 in the overlap region 48.

[0067] The third line section 24 is wound around the core 28 several times. A number of windings can be chosen as desired, for instance depending on an expected maximum strain.

[0068] The strain relieve unit 26 further comprises a sleeve 52. The sleeve 52 comprises a cylindrical interior with an internal thread 70. The core 28 is threaded into the sleeve 52 and partly arranged within the sleeve 52. Specifically, the thread 44 of the core 28 is threaded into the internal thread 70 of the sleeve 52. Threading the core 28 into the sleeve 52 assures a connection between the two components which withstands large pulling forces. Furthermore, the strain relieve unit 26 is easy to manufacture and easy to maintain, in particular since the strain relieve unit 26 can be repeatedly opened and closed.

[0069] The sleeve 52 covers the recess 34. The sleeve 52 and the core 28 together form channels in which the third line section 24 extends, which channels are constituted by the recess and a portion of the sleeve 52 covering the recess 34. The sleeve 52 prevents the third line section 24 from jumping out of the recess in a radially outward direction.

[0070] The third line section 24 is arranged in a section of the thread 44 which is not threaded into the internal thread 70 of the sleeve 52. The third line section 24 is loose with respect to the core 28, i.e. it is not glued to the core 28 or otherwise stationary fixated, but can slide at least over a small distance. Thus, when a pulling force acts upon the first line section 20 with respect to the second line section 22, the third line section 24 may slightly move within the strain relieve unit 26, wherein the pulling force is received by the recess 34, specifically by side walls defining the recess 34.

[0071] FIG. 6 shows a schematic perspective view of a surgical instrument 54′ with a tracking device 10′ according to a second embodiment. FIG. 7 shows a schematic perspective view of an interior of a part of the surgical instrument 54′ according to the second embodiment which contains a strain relieve unit 26′ of the tracking device 10′. Reference signs used in the context of the second embodiment are denoted with an apostrophe. The same numbers are used to identify the same or similar objects. In the following, mostly the differences with respect to the previous embodiment will be described. Where an object shown in FIGS. 6 through 9 is not described, reference is made to the respective object as shown in the context of the previous embodiment.

[0072] The tracking device 10′ comprises a strain relieve unit 26′ with a core 28′ and a sleeve 52′. A line element 18′ extends through the strain relieve unit 26′ and connects to an electromagnetic sensor 14′ of the tracking device 10′. The strain relieve unit 26′ provides strain relieve for the line element 18′

[0073] In the following, reference is made to FIGS. 8 and 9. FIG. 8 shows a schematic perspective view of the core 28′ of the strain relieve unit 26′ of the second embodiment. FIG. 9 shows a schematic perspective cross-sectional view of the strain relieve unit 26′ of the second embodiment.

[0074] The core 28′ has a longitudinal axis 30′. Similar to the previous embodiment, the line element 18′ comprises a first line section 20′ extending into the strain relieve unit 26′ on a proximal side and a second line section 22′ extending into the strain relieve unit 26′ on a distal side. The first line section 20′ and the second line section 22′ extend at a first radial position and a second radial position, respectively, both coaxially with respect to the longitudinal axis 30′. A third line section 24′ of the line element 18 is arranged between the first line section 20′ and the second line section 22′ at a third axial position that is radially outward of the first and second radial positions. A fourth line section 45′ of the line element 18′ connects the first line section 20′ to the third line section 24′ and extends radially outward with respect to the longitudinal axis 30′. A fifth line section 72′ of the line element 18′ connects the second line section 22′ to the third line section 24′ and extends radially outward with respect to the longitudinal axis 30′.

[0075] The core 28′ comprises an outer surface 32′ and at least one recess 34′ which extends in the outer surface 32′ circumferentially around the longitudinal axis 30′, wherein the third line section 24′ extends within the recess 34′. The core 28′ comprises a cylindrical basic shape. The core 28′ is a plastic one-piece component. The basic structure of the core 28′ is a solid cylinder with different empty structures such as recesses, grooves, cavities etc. formed therein.

[0076] The recess 34′ comprises two adjacent grooves 40′, 42′ that extend around the core 28′ in a direction perpendicular to the longitudinal axis 30′ of the core 28. The grooves 40′, 42′ are parallel ring grooves.

[0077] In other embodiments, a single groove may be used. Furthermore, in some embodiments a larger number of grooves may be chosen, such as three, four, five or even more. The number of grooves can be adjusted depending on an expected maximum strain.

[0078] A slit 46′ is formed in the core 28′ that extends along the longitudinal axis 30′ and overlaps the two grooves 40, 42′ in an overlap region 48′. The grooves 40′, 42′ are connected via the slit 46′. The third line section 24′ extends along a first groove 40′ of the grooves 40′, 42′, through the slit 46′, and along a second groove 42′ of the grooves 40′, 42′.

[0079] The slit 46′ comprises a base 50′. The first line section 20′ extends at the base 50′ of the slit 46′. The base 50′ is located at a depth exceeding a radius of the core 28′. The base 50′ is concave, such that the slit 46′ has a U-shaped cross-section when viewed along the longitudinal axis 30′. The curvature of the base 50′ and the depth of the slit 46′ are chosen such that the first line section 20′ extends coaxially with respect to the longitudinal axis 30′.

[0080] A channel 74′ that extends coaxially with the longitudinal axis 30′ is formed in the core 28′. The second line section 22′ extends through the channel 74′. The channel may be connected to the slit 46′, wherein a lower wall of the channel 74′ may merge into the base 50′ of the slit 46′.

[0081] As can be seen from FIG. 9, the sleeve 52 comprises a cylindrical receiving space 76′ in which the core 28′ is received. A diameter of the receiving space 76′ essentially equals a diameter of the core 28′. The core 28′ is arranged within the sleeve 52′.

[0082] The core 28′ is glued to the sleeve 52′. In the shown embodiment, the core 28′ is glued to the sleeve such that the line element 18′ is not glued to the core 28′ or to the sleeve 52′. For instance, the region of the core 28′ comprising the recess 34′ and the slit 46′ may be free of glue. Gluing the core 28′ and the sleeve 52′ together allows for using a simple structure of the recess 34. Small inaccuracies regarding a rotational position of the sleeve 52′ with respect to the core 28′ do not affect the quality of the assembled strain relieve unit 26′. Furthermore, the resulting structure is robust and withstands large pulling forces.

[0083] As is apparent form the previous description, the surgical instrument 54′ of the second embodiment is generally of the same type as the surgical instrument 54 of the first embodiment. For both cases, the implementation with a stylet as surgical tool head 56, 56′ is to be understood merely exemplarily. Various other types of surgical instruments are conceivable according to this disclosure.

[0084] In addition, the tracking devices 10, 10′ may be implemented as tracking modules which can be connected to different types of surgical instruments. Such modules may for instance be implemented as screw-on caps, may click onto the respective surgical instrument, may be glued thereto or may otherwise be implemented to be permanently or removably attachable. In particular in this case an electromagnetic sensor may be located significantly closer to a strain relieve unit as in the illustrated embodiments, for instance directly adjacent to a strain relieve unit.

[0085] For both shown embodiments there may be a variant in which the line element 18, 18′ and in particular the third line section 24, 24′ is glued to the core 28, 28′ and/or the sleeve 52, 52′.

[0086] The features described in relation to the exemplary embodiments shown in the drawings can be readily combined to result in different embodiments. It is apparent, therefore, that the present disclosure may be varied in many ways. Such variations are not to be regarded as a departure from the scope of the invention which is defined by the claims appended hereto.