SURGICAL KIT FOR MINIMALLY INVASIVE SPINE SURGERY

Abstract

The invention relates to a surgical kit, for performing minimally invasive spine surgery. The surgical kit comprises a position detection system, configured for detecting position and orientation of localizers from received sensor signals in the position detection system's coordinate system. The surgical kit also comprises a sensor carrier, configured to be removably arranged in a lumen of a medical instrument, the sensor carrier having at least two localizers, the localizers each being configured for providing a sensor signal representing position and orientation of the respective localizer. Furthermore, the surgical kit comprises a plurality of medical instruments having a lumen in which the sensor carrier can be removably arranged for connecting the respective medical instrument to the position detection system.

Claims

1-18. (canceled)

19. A surgical kit, for performing minimally invasive spine surgery, the surgical kit comprising: a position detection system configured for detecting a position and an orientation of localizers from received sensor signals in a coordinate system; a sensor carrier configured to be removably arranged in a lumen of a medical instrument, the sensor carrier having at least two localizers, each of the two localizers being configured for providing a sensor signal representing the position and the orientation of the respective localizer; and a plurality of different medical instruments having a lumen in which the sensor carrier can be removably arranged for connecting the respective medical instrument to the position detection system.

20. The surgical kit of claim 19, wherein one of the plurality of medical instruments comprises an access needle having a lumen extending from a distal end of the access needle to a proximal end of the access needle, and wherein the access needle is configured for being guided to a target location in a body of a patient.

21. The surgical kit of claim 20, wherein the plurality of medical instruments comprises at least one of: a guidewire configured for being inserted into the lumen of the access needle; a guiding rod having a lumen and being configured to be advanced over the guidewire; at least one dilation tube configured for being advanced over the guiding rod and for dilating an access path to a target location; a working tube configured to be advanced over the at least one dilation tube and for providing a working channel for medical instruments, wherein at its distal end, the working tube is shaped such that it can be anchored to a patient's bone; a reamer having a lumen in which an endoscope can be arranged and being configured to be arranged inside the working channel of the working tube for creating a posterior-lateral access to the central nervous system; an endoscope having at least one endoscope working channel for inserting another medical instrument, the endoscope being configured for medical imaging inside a patient's body; and a medical instrument configured to be arranged inside the working channel of the endoscope and for removing at least a part of an intervertebral disc or a surrounding body tissue.

22. The surgical kit of claim 19, wherein the plurality of medical instruments comprises at least one of: a spine cage configured for restoring disc space between two vertebrae when being arranged between the respective vertebrae; a lamina screwdriver with lamina screw, the screwdriver having a lumen extending from a proximal end of the screwdriver to a distal end of the lamina screw, the screwdriver being configured for anchoring the lamina screw into a lamina of a vertebra; a tap for tapping a hole into the vertebra for anchoring a bone screw; and a pedicle screwdriver with a pedicle screw, the screwdriver having a lumen extending from a proximal end of the screwdriver to a distal end of the pedicle screw, the screwdriver being configured for anchoring the pedicle screw into a pedicle of the vertebra.

23. The surgical kit of claim 19, wherein a first one of the localizers is arranged at a distal end of the sensor carrier and a second one of the localizers is arranged at a distance from the first localizer towards a proximal end of the sensor carrier, the sensor carrier further comprising a hypo tube extending from the distal end to the proximal end of the sensor carrier and enclosing the at least two localizers.

24. The surgical kit of claim 23, further comprising a third localizer configured for providing a sensor signal representing a position and an orientation of the third localizer, the third localizer being arranged at a distance from the first and second localizers towards the proximal end of the sensor carrier.

25. The surgical kit of claim 19, further comprising a medical instrument identification setup, the medical instrument identification setup comprising: a calibration device configured such that its position and orientation in the position detection system's coordinate system can be determined by the position detection system; a calibration unit configured for calibrating a medical instrument with the sensor carrier arranged in its lumen by calculating a distance between the medical instrument's tip and at least one of the two localizers based on the position and orientation of the calibration device and the position and orientation of at least one of the two localizers determined by the position detection system; and a medical instrument identification unit configured for determining a length of the medical instrument's lumen at least from the calculated distance and for using the determined length of the lumen for identifying the medical instrument.

26. The surgical kit of claim 25, wherein the calibration unit is configured for determining a medical instrument's virtual longitudinal axis based on the positions of the at least two localizers.

27. A method comprising the steps of: providing a sensor carrier configured to be removably arranged in a lumen of a medical instrument, the sensor carrier having at least two localizers, each of the at least two localizers being configured for providing a sensor signal representing a position and an orientation of the respective localizer; inserting the sensor carrier into a lumen of an access needle; calibrating the access needle with sensor carrier; navigating the access needle with the sensor carrier inside a body of a patient to a vertebra, and, at the same time, determining the position and the orientation of the at least two localizers from sensor signals and indicating the position of at least a tip of the access needle in a patient model visualized on a monitor using the determined position and orientation of the localizers; removing the sensor carrier from the lumen of the access needle; inserting a guidewire into the lumen of the access needle; and removing the access needle from the guidewire such that only the guidewire stays inside the body of the patient.

28. The method of claim 27, further comprising: inserting the sensor carrier into a lumen of a guiding rod and calibrating the guiding rod; removing the sensor carrier from the guiding rod and advancing the guiding rod over the guidewire up to the vertebra; removing the guidewire from the guiding rod and inserting the sensor carrier into the guiding rod; and navigating the guiding rod with arranged sensor carrier to a facet joint of the vertebra and, at the same time, determining the position and the orientation of the at least two localizers and indicating the position of at least the distal tip of the guiding rod in a patient model visualized on a monitor using the determined position and orientation of the localizers.

29. The method of claim 28, further comprising: removing the sensor carrier from the guiding rod; advancing at least one dilation tube over the guiding rod, wherein the dilation tube is configured for dilating an access path to the vertebra; inserting the sensor carrier into a lumen of a working tube, wherein at its distal end the working tube is shaped such that at its distal end the working tube can be anchored to a bone of the patient, calibrating the working tube; removing the sensor carrier from the working tube; advancing the working tube over the dilation tube towards the facet joint; removing the guiding rod and the dilation tube; inserting the sensor carrier into the working tube and anchoring the working tube with its distal end to the vertebra, and, at the same time, determining the position and the orientation of the at least two localizers and indicating the position of at least of the distal tip of the working tube in a patient model visualized on a monitor using the determined position and orientation of the localizers; removing the sensor carrier from the working tube; inserting the sensor carrier together with an endoscope into a lumen of a reamer, afterwards, inserting the reamer with sensor carrier and endoscope into the working channel of the working tube and using the reamer for creating a posterior-lateral access to the central nervous system, and, at the same time, determining position and orientation of the at least two localizers and indicating the position at least a distal tip of the reamer in a patient model visualized on a monitor using the determined position and orientation of the localizers; and removing at least a part of an intervertebral disc or a surrounding body tissue through an endoscope working channel of the endoscope.

30. The method of claim 29, wherein while removing an intervertebral disc through a channel of the endoscope, the position and the orientation of the at least two localizers are determined and used for indicating the position of at least a distal tip of the endoscope in a patient model visualized on a monitor.

31. The method of claim 29, wherein after inserting the sensor carrier into the lumen of at least one of the access needle, the guiding rod, the working tube, the reamer, or the endoscope, automatically identifying the medical instrument having the sensor carrier arranged in its lumen by determining a distance between the distal tip of the medical instrument and the position of at least one of the two localizers, and determining a length of the lumen of the respective medical instrument based on the determined distance.

32. The method of claim 29, further comprising displaying on a monitor a visualisation of a patient model with the position of at least one of the access needle, the guiding rod, the working tube, the reamer, and the endoscope indicated in the model, or an endoscope image captured by the endoscope.

33. A method of fusing at least two vertebrae comprising: providing a sensor carrier configured to be removably arranged in a lumen of a medical instrument, the sensor carrier having at least two localizers, each of the at least two localizers being configured for providing a sensor signal representing a position and an orientation of the respective localizer; providing a working tube with a working channel, the working tube being arranged inside a body of a patient to provide a posterior-lateral access to a disc space between two vertebrae, wherein at least a part of an intervertebral disc or surrounding body tissue has been removed from the disc space; using the working channel for implanting a spine cage into a spine of the patient for restoring the disc space between the two respective vertebrae; inserting the sensor carrier into an access needle and navigating the access needle with arranged sensor carrier to a lamina of one of the two vertebra, and, at the same time, determining the position and the orientation of the at least two localizers and indicating the position of at least a distal tip of the access needle in a patient model visualized on a monitor using the determined position and orientation of the localizers; and drilling the lamina with the access needle, and, at the same time, determining the position and the orientation of the at least two localizers and indicating the position of at least of the distal tip of the access needle in the patient model visualized on a monitor using the determined position and orientation of the localizers.

34. The method of claim 33, further comprising: removing the sensor carrier from the access needle; inserting the sensor carrier into a lumen of a lamina screwdriver having a lamina screw attached such that at least one of the localizers is located at a distal tip of the lamina screw; and implanting the lamina screw in the lamina with the sensor carrier being arranged in the lamina screwdriver and the lamina screw, and, at the same time, determining the position and the orientation of the at least two localizers and indicating the position of at least of a distal tip of the lamina screw in a patient model visualized on a monitor using the determined position and orientation of the localizers.

35. The method of claim 34, further comprising: removing the sensor carrier from the lamina screwdriver; inserting the sensor carrier into a lumen of an access needle and navigating the access needle and sensor carrier to a pedicles of the vertebra, and, at the same time, determining the position and the orientation of the at least two localizers and indicating the position of at least a distal tip of the access needle in a patient model visualized on a monitor using the determined position and orientation of the localizers; removing the sensor carrier from the access needle; and inserting the sensor carrier into a lumen of a tap and tapping a tapped hole into the pedicle, and, at least while tapping, determining the position and the orientation of the at least two localizers and indicating the position of at least of a distal tip of the tap in a patient model visualized on a monitor using the determined position and orientation of the localizers.

36. The method of claim 35, further comprising: removing the sensor carrier from the tap; inserting the sensor carrier into a lumen of a pedicle screwdriver with a pedicle screw and placing the pedicle screw into the pedicle, and, at least while placing the screw, determining the position and the orientation of the at least two localizers and indicating the position of at least a distal tip of the pedicle screw in a patient model visualized on a monitor using the determined position and orientation of the localizers; and using a sensor carrier, an access needle, a tap, and a pedicle screwdriver with another pedicle screw for placing the other pedicle screw in one of the neighbouring vertebrae and connecting the at least two pedicle screws placed in the vertebrae with a rod in order to fuse the two neighbouring vertebrae.

37. The method of claim 33, wherein the position of the spine cage is tracked relative to the position and the orientation of the at least two localizers of the sensor carrier and indicated in a patient model visualized on the monitor.

38. The method of claim 36, further comprising the step of automatically detecting at least a lamina screw length, or a pedicle screw length by: arranging the sensor carrier in the lumen of the screwdriver with the attached lamina or pedicale screw such that the at least two localizers are arranged at a distance to each other along a longitudinal axis of the screwdriver; determining a distance between a distal tip of the lamina or the pedicle screw and the positions of at least one of the two localizers based on the position and the orientation of the at least two localizers; and automatically detecting the length of the lamina screw or the pedicle screw based on the determined distance.

39. The method of claim 33, wherein the at least two localizers of the sensor carrier are arranged close to the distal tip of the sensor carrier, the sensor carrier further comprising a third localizer that is arranged at a distance to the at least two localizers towards a proximal end of the sensor carrier, the method comprising the step of calculating a bending of the access needle with the sensor carrier arranged in its lumen by calculating a bending angle enclosed between at least one of the at least to localizers and the third localizer based on determined positions and orientations the localizers.

40. The method of claim 39, further comprising visualizing a digital representation of at least part of the access needle on the monitor in a bended state according to the detected bending angle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0184] In the following, preferred embodiments of the invention are described with reference to the figures. In the figures:

[0185] FIG. 1: schematically shows a sensor carrier for connecting a medical instrument to a position detection system,

[0186] FIG. 2: schematically shows a medical instrument identification setup, comprising a sensor carrier and a calibration device;

[0187] FIG. 3: schematically shows a medical instrument with sensor carrier, the medical instrument contacting a calibration device,

[0188] FIG. 4: refers to the geometrical arrangement of the sensor carrier's localizers, medical instrument and the calibration device as schematically depicted in FIG. 3,

[0189] FIG. 5: schematically shows a screwdriver with an attached pedicle screw and a sensor carrier being arranged in the screwdriver's and the pedicle screw's lumen, the pedicle screw being in contact with a calibration device,

[0190] FIG. 6: refers to the geometrical arrangement of the sensor carrier's localizers, the screwdriver and the calibration device as schematically depicted in FIG. 5,

[0191] FIG. 7: shows a flow diagram representing a method for automatically identifying a medical instrument,

[0192] FIG. 8: shows schematically a surgical kit for performing minimally invasive spine surgery,

[0193] FIG. 9: shows a flow diagram representing a method of removing at least a part of an intervertebral disc and/or surrounding body tissue,

[0194] FIG. 10: shows a flow diagram representing a method of fusing at least two vertebrae.

DETAILED DESCRIPTION

[0195] FIG. 1 schematically shows a sensor carrier 100 for connecting a medical instrument to a position detection system. For connecting a medical instrument to a position detection system, the sensor carrier 100 can be inserted into a medical instrument's lumen. With the sensor carrier 100 being arranged in a medical instrument's lumen, a navigated procedure can be performed and the position of the medical instrument, e.g., inside a patient's body, can be tracked and displayed on a monitor. After having accomplished a navigated procedure, the sensor carrier can be removed from the medical instrument's lumen and inserted into the lumen of another medical instrument for connecting the other medical instrument to the position detection system.

[0196] The sensor carrier 100 has a distal end 102 and a proximal end 104. The sensor carrier 100 comprises three localizers 106, 108, 110 that are arranged along the length of the sensor carrier 100. The localizers 106, 108, 110 each are configured for providing a sensor signal representing position and orientation of the respective localizer 106, 108, 110. For example, each of the localizers 106, 108, 110 can comprise at least one sensor coil, for connecting a medical instrument with arranged sensor carrier 100 to an electromagnetic position detection system.

[0197] Close to the sensor carrier's proximal end 102, a first localizer 106 of the three localizers is arranged. A second localizer 108 of the three localizers is arranged at a distance from the first localizer 106 towards the proximal end 104 of the sensor carrier 100. The sensor carrier 100 further comprises a third localizer 110 that is arranged at a distance from the first and second localizers 106, 108 towards the sensor carrier's proximal end 104. The third localizer 110 of the three localizers is optional and is not present in alternative embodiments of the sensor carrier 100.

[0198] The sensor carrier 100 having three localizers 106, 108, 110 is particularly suitable for identifying a medical instrument having an angle that is characteristic for the medical instrument. Preferably, for calculating an angle of a medical instrument, the sensor carrier 100 is arranged in the medical instrument's lumen such that the medial instrument's angle is located between the third localizer 110 and the first and second localizers 106, 108. From position and orientation determined for the localizers 106, 108, 110, respectively, the angle of the medical instrument can be calculated, e.g., with a calibration unit of a medical instrument identification setup, and used by a medical instrument identification setup's medical instrument identification unit for identifying the medical instrument with the sensor carrier 100 arranged in its lumen.

[0199] The sensor carrier 100 further comprises a hypo tube 112 extending from the distal end 102 to the proximal end 104 of the sensor carrier 100 and enclosing the three localizers 106, 108, 110. The hypo tube 112 is configured to give mechanical stability to the sensor carrier 100 and to protect the localizers 106, 108, 110 from external influences.

[0200] FIG. 2 schematically shows a medical instrument identification setup 200 comprising a sensor carrier 202, a calibration device 204, a position detection system 206, a calibration unit 208, and a medical instrument identification unit 210.

[0201] The sensor carrier 202 can be configured the same way as the sensor carrier described with reference to FIG. 1. In particular, the sensor carrier 202 has at least two localizers (not shown) and can optionally have at least a third localizer that, preferably, is arranged close to the sensor carrier's proximal end. The localizers each are configured for providing a sensor signal representing position and orientation of the respective localizer. The sensor carrier 202 is configured to be removably arranged in a lumen of a medical instrument for connecting the medical instrument to the position detection system 206.

[0202] The sensor carrier 202 is connected to the position detection system 206 via a cable 203. In some embodiments of the medical instrument identification setup 200 provision is made of a sensor carrier that can be wirelessly connected to the position detection system 206. Via the cable 203, sensor signals provided by the localizers of the sensor carrier 202 can be transmitted to the position detection system 206. The position detection system 206 is configured for determining position and orientation of the localizers of the sensor carrier 202 in the position detection system's coordinate system 212 from received sensor signals.

[0203] For example, the position detection system 206 can be an electrometric position detection system having a field generator for generating an alternating electromagnetic field. For determining position and orientation of the sensor carrier's localizers, the localizers, preferably, comprise one or more sensor coils. When exposed to an alternating electromagnetic field, a voltage is induced in each of the coils that depends on position and orientation of the respective sensor coils in the alternating electromagnetic field. A sensor signal representing the induced voltage can be tapped from each of the sensor coils and transmitted to the position detection system for determining position and orientation of the sensor coils, respectively.

[0204] The calibration device 204 of the medical instrument identification setup 200 is configured such that its position and orientation in the position detection system's coordinate system 212 can be determined by the position detection system 206. For example, the calibration device 204 can be arranged at a position whose coordinate is known in the position detection system's coordinate system 212. It is also possible that the calibration device 204 is equipped with one or more localizers, the position and orientation of which can be directly determined with the position detection system 206. The calibration device 204, preferably, is connected to the position detection system 206 for transmitting sensor signals representing position and orientation of the calibration device to the position detection system.

[0205] The position detection system 206 is connected to the calibration unit 208 for providing determined positions and orientations of localizers. The calibration unit 208 is configured for calibrating a medical instrument with the sensor carrier 202 arranged in its lumen by calculating a distance between the medical instrument's tip and at least one of the sensor carrier's localizers. The calibration unit 208 is configured for using the position and orientation of the calibration device 204 known in the position detection system's coordinate system 212 and position and orientation of at least one of the sensor carrier's localizers as determined by the position detection system 206. Preferably, the calibration unit is configured for determining whether or not the medical instrument's tip is in contact with the calibration device 204. Preferably, the calibration unit is configured for using position and/or orientation of at least one of the sensor carrier's localizers which have been determined with the position detection system 206 at a moment of contact between the medical instrument's tip and the calibration device 204.

[0206] Since the distance between the medical instrument's tip and at least one of the sensor carrier's localizers is characteristic for the length of the lumen of a medical instrument, from a calculated distance the length of a lumen can be derived. Furthermore, since the length of a medical instrument's lumen is characteristic for the medical instrument itself, the determined length of a medical instrument's lumen can be used for automatically identifying the medical instrument having the sensor carrier 202 arranged in its lumen.

[0207] For identifying a medical instrument having the sensor carrier 202 arranged in its lumen, the medical instrument identification setup 200 comprises the medical instrument identification unit 210 that is connected to the calibration unit 208 for obtaining a calculated distance between a medical instrument's tip and at least one of the sensor carrier's localizers. The medical instrument identification unit 210 is configured for determining a length of the medical instrument's lumen at least from a distance between a medical instrument's tip and at least one of the sensor carrier's localizers as calculated by the calibration unit 208. The medical instrument identification unit 210 is configured for using the determined length of the medical instrument's lumen for identifying the medical instrument. The medical instrument identification unit 210 can be configured to alternatively or additionally to the lumen's length use a medical instrument's angle that has been calculated by the calibration unit 208 from position and orientation of at least two localizers between which the medical instrument's angle is located when the sensor carrier is arranged in the medical instrument's lumen. For identifying the medical instrument, the medical instrument identification unit 210 can be configured to compare the distance calculated by the calibration unit 208 and also the medical instrument's angle to various lengths and/or angles of a plurality of medical instruments contained in a database that can be accessed by or that is part of the medical instrument identification unit 210.

[0208] FIG. 3 schematically shows a medical instrument 300 with sensor carrier 302. The medical instrument's tip 304 is in contact with a calibration device 306. The medical instrument 300 has a lumen 308 extending from the medical instrument's proximal end to its distal end. In the lumen 308 the sensor carrier 302 is arranged. The sensor carrier 302 comprises two localizers 310, 312, a first localizer 310 of the two localizers being arranged at the distal end 314 of the sensor carrier 302 and a second localizer 312 being arranged at a distance from the first localizer 310 towards the sensor carrier's proximal end 316.

[0209] Having two localizers arranged in the distal end region of the sensor carrier is of advantage since it facilitates determining the trueness of the medical instrument's virtual longitudinal axis to the physical instrument's longitudinal axis. The virtual longitudinal axis can be extrapolated from the distal end of the sensor carrier to the distal end of the medical instrument to thus determine the position of the medical instrument's distal end. The medical instrument's virtual longitudinal axis can also be displayed in sectional images on a monitor. Displaying the virtual longitudinal axis in sectional images on a monitor is of importance, e.g., when aiming with a medical instrument at an anatomical target from a large distance, e.g., from 5 to 15 cm. With an accurately displayed virtual longitudinal axis, e.g., of an access needle, a surgeon can assess position and orientation of the needle to reliably navigate the needle to a target location.

[0210] The virtual longitudinal axis can also be determined by the position detection system and/or the calibration unit in case one localizer implements a 5 DOF sensor. However, using one 5 DOF sensor to determine the medical instrument's virtual longitudinal axis typically is subject to an angle error of the coil, an error introduced by the physical alignment inside the sensor carrier and an error introduced by the physical alignment of the sensor carrier inside the instrument. This can lead to angle errors between 4° and 5°.

[0211] Advantageously, when using two localizers each implementing a 5 DOF sensor, e.g., by using sensor coils, it is possible to reduce the angle error to only the position error of both sensor coils. Spacing the sensor coils 100 mm apart from each other, and having position errors of less than 1 mm, it is possible to reduce the angle error to less than 1° (tan( 1/100)).

[0212] The length of the sensor carrier 302 is shorter than the length of the medical instrument 300 such that there exists a non-zero distance between the sensor carrier's distal end 314 and the medical instrument's tip 304. The distance is characteristic for the medical instrument and can be used for determining the length of the medical instrument's lumen 308. Since the length of the medical instrument's lumen 308 is characteristic for the medical instrument 300 itself, by means of the length of the medical instrument's lumen 308 the medical instrument 300 with arranged sensor carrier 302 can be identified.

[0213] The medical instrument 300 can be a medical instrument that has a lumen 308 provided, e.g., for advancing the medical instrument 300 over a guidewire. For example, the medical instrument 300 can be an access needle, a guiding rod, a working tube, tap, a balloon dilation device, or a screwdriver.

[0214] The sensor carrier 302 can be configured the same way as the sensor carrier described with reference to FIG. 1 or as the sensor carrier described with reference to FIG. 2. In particular, the sensor carrier 302 and the calibration device 306 can be elements of a medical instrument identification setup, e.g., of a medical instrument identification setup as described with reference to FIG. 2.

[0215] FIG. 4 refers to the geometrical arrangement of the sensor carrier's localizers 310, 316, medical instrument and the calibration device 306 as described with reference to FIG. 3.

[0216] The two localizers 310, 316 are arranged at a distance to each other along the longitudinal axis 400 of the medical instrument 300.

[0217] For automatically identifying the medical instrument 300, the distance 402 between the calibration device 306 and the localizer 310 that is arranged close to the sensor carrier's distal end is calculated, e.g., by means of a calibration unit as described with reference to FIG. 2. For calculating the distance 402, preferably, position and orientation of the calibration device 306 and position and orientation of the localizer 310 as determined by a position detection system, e.g., of a medical instrument identification setup, can be used.

[0218] In particular, position and orientation of the localizer 310 can be determined when the medical instrument's tip is in contact with the calibration device 306 and used for calculating the distance 402. Advantageously, if the medical instrument's tip is in contact with the calibration device 306, the position of the medical instrument's tip can directly be determined from position and orientation of the calibration device 306.

[0219] Position and orientation of the second localizer 312 can be used as a reference for performing a plausibility check on the calculated distance 402. Position and orientation of the first localizer 310 and the second localizer 312 can also be used for calculating a centering error and/or a positioning error and/or an angle error. The calculated centering error and/or positioning error and/or angle error can be compensated by the calibration unit when calculating the distance 402 between the calibration device and the localizer 310. Thereby it is possible to calculate the distance 402 between the calibration device 306 and the localizer 310 with improved accuracy with the calibration unit.

[0220] Having calculated the distance 402 between the calibration device 306 and the localizer 310, the distance 402 can be used for determining the length of the medical instrument's lumen 308 based on which the medical instrument 300 itself can be identified.

[0221] As shown in FIG. 3, in FIG. 5, a medical instrument with arranged sensor carrier is shown schematically, the medical instrument contacting a calibration device.

[0222] In FIG. 5, the medial instrument is a screwdriver 500 with an attached medical screw 502, e.g., a bone screw, preferably, a pedicle screw.

[0223] A lumen 504 extends from the screwdriver's proximal end 506 to the medical screw's distal end 508. In the lumen 508, the sensor carrier 510 is arranged. The sensor carrier 510 comprises two localizers 512, 514 wherein a first localizer 512 is arranged close to the sensor carrier's distal end 516 and the second localizer is arranged at a distance from the first localizer 516 towards the sensor carrier's proximal end 518. The sensor carrier 510 can be configured the same way as the sensor carrier as described with reference to FIG. 1 or with reference to FIG. 2.

[0224] The medical screw 502 has a length 520 that is characteristic for the medical screw 502. Thus, by determining the length of the screw, on the basis of the screw length the medical screw 502 itself can be identified.

[0225] With its distal end 506, the medical screw 502 is in contact with the calibration device 522 for calibrating the screwdriver 500, e.g., with a calibration unit of a medical instrument identification setup, e.g., as described with reference to FIG. 2. Calibrating the screwdriver comprises determining a distance 600 between the calibration device 522 and the first localizer 512 as depicted in FIG. 6.

[0226] FIG. 6 refers to the geometrical arrangement of the sensor carrier's localizers 512, 514, the screwdriver and the calibration device 522 as schematically depicted in FIG. 5. The localizers 512, 514 are arranged along the screwdriver's longitudinal axis 602. In particular, position and orientation of the first localizer 512 are used for calculating the distance 600 to the calibration device which corresponds to the distance between the first localizer 512 and the medical screw's distal end 506.

[0227] The distance 600 is characteristic for the length of the medical screw 502. Therefore, the determined distance 600 can be used for automatically identifying the medical screw 502. For example, for identifying the medical screw 502 based on the determined distance 600, the length of the screwdriver 500 and the length of the sensor carrier 510 can be used. It can also be exploited that the positions of the localizers relative to each other are fixed. Preferably, the first localizer 512 is arranged close to the sensor carrier's distal end such that by determining the first localizer's position and orientation, position and orientation of the sensor carrier's distal end can be obtained.

[0228] The calibration device 522 and the sensor carrier 510 can be elements of a medical instrument identification setup, in particular, of a medical instrument identification setup as described with reference to FIG. 2.

[0229] FIG. 7 shows a flow diagram representing a method for automatically identifying a medical instrument.

[0230] Initially, a sensor carrier is provided (step S1) which is configured to be removably arranged in a lumen of a medical instrument. The sensor carrier has at least two localizers. The localizers each are configured for providing a sensor signal representing position and orientation of the respective localizer. The sensor carrier can be a sensor carrier as described with reference to FIG. 1, or with reference to FIG. 2, or a sensor carrier as described with reference to FIG. 3 or 5.

[0231] A calibration device is provided (step S2), the position and orientation of which is known in the coordinate system of a position detection system. For example, the calibration device can be arranged at a position whose coordinate is known in the position detection system's coordinate system. It is also possible that the calibration device comprises one or more localizers that are configured for providing a sensor signal representing position and orientation of the calibration device.

[0232] The sensor carrier is inserted into a lumen of a medical instrument (step S3). The medical instrument having a lumen can, e.g. be a catheter, a Jamshidi needle, a tap, a screwdriver with an attached bone screw, e.g., a pedicle screw, that can be placed with the screwdriver into a patient's bone, or another cannulated medical instrument. After insertion, the sensor carrier is removably arranged in the medical instrument's lumen and can, thus, be removed after having accomplished a task with the medical instrument and used for connecting another medical instrument to a position detection system.

[0233] Position and orientation of the at least two localizers are determined from provided sensor signals (step S4). For example, the localizers can comprise one or more sensor coils the position of which can be determined with an electromagnetic position detection system having a field generator for generating an alternating electromagnetic field. When exposed to a generated electromagnetic field, a voltage is induced representing position and orientation of the sensor coils. From a tapped sensor signal representing the induced voltage, position and orientation of the sensor coils can be determined by the position detection system in the position detection system's coordinate system.

[0234] A distance between the calibration device and at least one of the two localizers is calculated (step S5) based on the determined position and orientation of the localizers to calibrate the medical instrument. Preferably, the distance is calculated based on position and orientation of the localizers determined when the medical instrument's tip is contacting a calibration device.

[0235] Afterwards, in step S6, the length of the medical instrument's lumen is determined at least from the calculated distance. In particular, the distance between the calibration device and at least one of the two localizers is characteristic for the length of the medical instrument's lumen and, thus, for the medical instrument itself.

[0236] Subsequently, in step S7, at least the determined length of the lumen is used for automatically identifying the medical instrument with the sensor carrier being arranged in its lumen. Additionally, also a medical instrument's angle and/or a length of that section of the sensor carrier that extends beyond the medical instrument's proximal end can be used for identifying the medical instrument. For identifying the medical instrument, the determined length of the lumen can be compared with entries of a database representing lengths of lumens of different medical instruments, e.g., of medical instruments of a surgical kit that is used during surgery.

[0237] If a medical instrument is automatically identified, e.g., by a medical instrument identification setup, settings, e.g., the mode of displaying the medical instrument on a monitor can be adapted accordingly.

[0238] The method can be conducted with a medical instrument identification setup, in particular, with a medical instrument identification setup as described with reference to FIG. 2.

[0239] FIG. 8 schematically shows a surgical kit 800 for performing minimally invasive spine surgery.

[0240] The surgical kit 800 comprises a position detection system 802, a sensor carrier 804 that is operatively connected to the position detection system 802, and a plurality of medical instruments each having a lumen 806 in which the sensor carrier 804 can be arranged for connecting the respective medical instrument to the position detection system 802.

[0241] The sensor carrier 804 is configured to be removably arranged in a lumen of one medical instrument of the plurality of medical instruments 806. The sensor carrier 804 has at least two localizers, the localizers each being configured for providing a sensor signal representing position and orientation of the respective localizer. The sensor carrier 802 can be configured the same way as the sensor carrier described with reference to FIG. 1 or the sensor carrier des cribbed with reference to FIG. 3 or 5. In particular, the sensor carrier can have at least a third localizer that is arranged at or at least close to the sensor carrier's proximal end.

[0242] The position detection system 802 is configured for detecting position and orientation of localizers from respectively provided sensor signals in the position detection system's coordinate system. Preferably, an electromagnetic position detection system is used and the sensor carrier's localizers are equipped with sensor coils.

[0243] Advantageously, the surgical kit 800 can comprise or can be used in combination with a medical instrument identification setup, preferably, with the medical instrument identification setup as described with reference to FIG. 2. When using the surgical kit 800 in combination with medical instrument identification setup as described with reference to FIG. 2, the surgical kit's position detection system 802 and the sensor carrier 804 can also be the position detection system and the sensor carrier of the medical instrument identification setup, respectively.

[0244] A medical instrument of the plurality of medical instruments 806 having a lumen in which the sensor carrier 804 can be removably arranged for connecting the respective medical instrument to the position detection system 802 can, e.g., be an access needle, a guiding rod, a working tube, a reamer, an endoscope, a lamina screwdriver with lamina screw, a tap, or a pedicle screwdriver.

[0245] If the surgical kit 800 comprises an access needle, a guidewire, a guiding rod, at least one dilation tube, a working tube, a reamer, an endoscope, and a medical instrument that is configured to be arranged inside the endoscope's working channel and for removing at least a part of an intervertebral disc and/or surrounding body tissue, the surgical kit 800 is particularly suitable for conducting the method of removing at least a part of an intervertebral disc and/or surrounding body tissue as described with reference to FIG. 9.

[0246] A medical instrument of the plurality of medical instruments 806 having a lumen in which the sensor carrier 804 can be removably arranged for connecting the respective medical instrument to the position detection system can also be an access needle, a lamina screwdriver with lamina screw, a tap, and a pedicle screwdriver, is particularly suitable. If the surgical kit 800 comprises an access needle, a lamina screwdriver with lamina screw, a tap, and a pedicle screwdriver, and a spine cage, the surgical is particularly suitable for conducting the of fusing at least two vertebrae as described with reference to FIG. 10.

[0247] FIG. 9 shows a flow diagram representing a method of removing at least a part of an intervertebral disc and/or surrounding body tissue.

[0248] Initially, a sensor carrier is provided (step M1) that is configured to be removably arranged in a lumen of a medical instrument, the sensor carrier having at least two localizers, the localizers each being configured for providing a sensor signal representing position and orientation of the respective localizer.

[0249] The sensor carrier is inserted into a lumen of an access needle (step M2).

[0250] Subsequently, the access needle with arranged sensor carrier is calibrated on a calibration device (step M3),

[0251] Afterwards, the access needle with arranged sensor carrier is navigated inside a patient's body to a spine's vertebra, and, at the same time, position and orientation of the at least two localizers from sensor signals are determined (step M4). Additionally also the position at least of the tip of the access needle is indicated in a patient model visualized on a monitor using the determined position and orientation of the localizers.

[0252] Having reached a spine's vertebra, the sensor carrier is removed from the access needle's lumen and, subsequently, a guidewire is inserted into the access needle's lumen (step M5).

[0253] In a subsequent step (step M6), the access needle is removed from the guidewire such that only the guidewire stays inside the patient's body.

[0254] The sensor carrier is then inserted into a lumen of a guiding rod and the guiding rod is calibrated on the calibration device (step M7).

[0255] Afterwards, the sensor carrier is removed from the guiding rod and the guiding rod is advanced over the guidewire up to the facet joint of the vertebra (step M8).

[0256] Having reached the facet joint of the vertebra, the guidewire is removed from the guiding rod and the sensor carrier is inserted into the guiding rod, preferably, when getting close to the facet joint, indicated by increased resistance (step M9). At the same time, position and orientation of the at least two localizers are determined. The position at least of the distal tip of the guiding rod is indicated in a patient model visualized on a monitor using the determined position and orientation of the localizers.

[0257] Subsequently, the sensor carrier is removed from the guiding rod (step M10).

[0258] After removing the sensor carrier from the guiding rod, at least one dilation tube is advanced over the guiding rod, wherein the dilation tube is configured for dilating an access path to the vertebra (step M11).

[0259] Afterwards, the sensor carrier is inserted into a lumen of a working tube (step M12), wherein at its distal end the working tube is shaped such that at its distal end the working tube can be anchored to a patient's bone.

[0260] With the sensor carrier arranged in the working tube's lumen, the working tube is calibrated on the calibration device, and afterwards the sensor carrier is removed from the working tube (step M13).

[0261] The working tube with arranged sensor carrier is then advanced over the dilation tube up to the vertebra (step M14).

[0262] Subsequently, the guiding rod and the dilation tube are removed, preferably, when the working tube is close to the facet joint, indicated by increased resistance (step M15).

[0263] The sensor carrier is then inserted into the working tube and the working tube is anchored with its distal end to the vertebra (step M16). At the same time, position and orientation of the at least two localizers are determined and the position at least of the distal tip of the working tube is indicated in a patient model visualized on a monitor using the determined position and orientation of the localizers.

[0264] Having anchored the working tube to the vertebra, the sensor carrier is removed from the working tube's lumen to provide a working channel for insertion of a medical instrument (step M17).

[0265] Subsequently, the sensor carrier is inserted together with an endoscope into a reamer's lumen. Afterwards, the reamer with sensor carrier and endoscope is inserted into the working channel of the working tube. The reamer is used for creating a posterior-lateral access to the central nervous system (step M18). At the same time, position and orientation of the at least two localizers are determined and the position at least of the distal tip of the reamer is indicated in a patient model visualized on a monitor using the determined position and orientation of the localizers.

[0266] Having created the posterior-lateral access to the central nervous system, at least a part of an intervertebral disc and/or surrounding body tissue is removed through an endoscope working channel of the endoscope (step M19).

[0267] FIG. 10 shows a flow diagram representing a method of fusing at least two vertebrae.

[0268] Initially, a sensor carrier is provided (step P1) that is configured to be removably arranged in a lumen of a medical instrument. The sensor carrier has at least two localizers, the localizers each being configured for providing a sensor signal representing position and orientation of the respective localizer.

[0269] Also, a working tube with a working channel is provided (step P2), the working tube being arranged inside a patient's body to provide a posterior-lateral access to a disc space between two vertebrae, wherein at least a part of an intervertebral disc and/or surrounding body tissue has been removed from the disc space.

[0270] The working tube's working channel is used for implanting a spine cage into a patient's spine for restoring the disc space between the two respective vertebrae (step P3).

[0271] Afterwards, the sensor carrier is inserted into an access needle and the access needle with arranged sensor carrier is navigated to one of the vertebra's Lamina (step P4). At the same time, position and orientation of the at least two localizers are determined and the position at least of the distal tip of the access needle is indicated in a patient model visualized on a monitor using the determined position and orientation of the localizers.

[0272] A successive step (step P5) comprises drilling of a vertebras facet joint with the access needle, and, at the same time, determining position and orientation of the at least two localizers and indicating the position at least of the distal tip of the access needle in a patient model visualized on a monitor using the determined position and orientation of the localizers.

[0273] Afterwards, the sensor carrier is removed from the access needle and, subsequently, the sensor carrier is inserted into a lumen of a lamina screwdriver having a lamina screw attached such that at least one of the sensor carrier's localizers is located at least close to lamina screw's distal tip (step P6).

[0274] Then, the lamina screw is implanted in the vertebra's lamina with the sensor carrier being arranged in lamina screwdriver and lamina screw (step P7), and, at the same time, position and orientation of the at least two localizers are determined and the position at least of the distal tip of the lamina screw is indicated in a patient model visualized on a monitor using the determined position and orientation of the localizers.

[0275] Afterwards, the sensor carrier is removed from the screwdriver and after that, the sensor carrier is inserted into a lumen of an access needle and the access needle with arranged sensor carrier is navigated to one of the pedicles of the vertebra (step P8). At the same time, position and orientation of the at least two localizers are determined and the position at least of the distal tip of the access needle is indicated in a patient model visualized on a monitor using the determined position and orientation of the localizers.

[0276] The sensor carrier from is then removed the access needle and, afterwards, the sensor carrier is inserted into a lumen of a tap and a tapped hole is tapped into the vertebra's pedicle, and, at least while tapping, position and orientation of the at least two localizers are determined and the position at least of the distal tip of the tap is indicated in a patient model visualized on a monitor using the determined position and orientation of the localizers (step P9).

[0277] The sensor carrier is then removed from the tap and, subsequently, the sensor carrier is inserted into a lumen of a pedicle screwdriver with pedicle screw. The Pedicle screw is placed into the vertebra's pedicle, and, at least while placing the screw, position and orientation of the at least two localizers are determined and the position at least of the distal tip of the pedicle screw is indicated in a patient model visualized on a monitor using the determined position and orientation of the localizers (step P10).

[0278] Afterwards, the sensor carrier, an access needle, a tap and a pedicle screwdriver with another pedicel screw are used for placing the other pedicle screw in one of the neighbouring vertebrae and the at least two pedicle screws placed in the vertebrae are connected with a rod in order to fuse the two neighbouring vertebrae (step P11).