Patent Description:
Instruments for use in spinal or musculoskeletal surgery that include a sensor for detecting specific conditions are known in the art. For example, <CIT> describes a cannulated bone anchor with an elongate instrument in the form of a sensor with a sensor element at the tip that extends through the channel of the bone anchor and that is configured to sense respective characteristics as, for example the density of the bone, or which is configured to perform neuro-monitoring. Another instrument that is configured to detect the relative position of a first member to a second member of the instrument is known from <CIT>.

Lumbar or thoracic interbody fusion surgery is one of the most commonly performed spinal fusion surgeries using an instrument. Some known surgical approaches for interbody fusion of the lumbar spine include posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), anterior lumbar interbody fusion (ALIF) antero-lateral ALIF, and lateral interbody fusion. The transforaminal lumbar interbody fusion technique involves approaching the spine from the side of the spinal canal through a midline incision in the patient's back. The implant is inserted between adjacent vertebra along a curved trajectory. This is enabled by the intervertebral implant being pivotable or rotatable around an axis of rotation relative to a longitudinal axis of the instrument for inserting the intervertebral implant. Intervertebral implants suitable therefore are described, for example, in <CIT> and <CIT>.

Monitoring of surgical steps in a patient's body during surgery has become an important aid for facilitating and improving surgery. Meanwhile, there also exist methods and arrangements for simulating orthopedic spinal column surgery. <CIT> describes a method using model structures which form anatomical structures and which are optically, haptically and functionally modeled on organs or organ parts to be surgically treated. By means of the model structures simulated surgical operations are carried out.

<CIT> discloses an articulating inserter and instrument system including a base instrument pivotally connected to an implant or trial implant by an articulating joint. Means to measure the angulation during articulation are provided. This angle is determined by assessing the difference between the angle following insertion and the angle following articulation. Such means may be radiofrequency (RF) triangulation means. The handle contains an RF emitter or reader and three or more passive markers are contained at known locations with the implant/trial(s). Based upon RF tracking of markers, the handle provides a graphic display of trial orientation in both superior/inferior and right/left lateral planes relative to a known reference flat on the handle.

However, monitoring of surgical steps that include non-axial movements of a component are difficult.

It is an object of the invention to provide an improved or alternative surgical device, in particular for spinal or musculoskeletal surgery or for simulated surgery, and a method of using the same as well as a surgical implant and a system of such a surgical implant and an instrument for inserting the surgical implant that are suitable for monitoring, in particular computer-based monitoring, of the surgical insertion steps. Moreover, it is the object to provide a method for simulating the implant insertion.

The object is solved by a system of a surgical implant and an instrument according to claim <NUM> and a method according to claim <NUM>. Further developments are given in the dependent claims. The further developments described below that relate to the surgical implant can also be applied to the surgical device, the methods and the system and vice versa.

A device for use in spinal or musculoskeletal surgery or in simulated surgery comprises a first component, a second component that is configured to assume various positions relative to the first component, and a detection device configured to detect a position of the second component relative to the first component, wherein the detection device is configured to deliver position data corresponding to detected positions of the second component to an evaluation unit for monitoring a change of the position of the second component relative to the first component. The surgical implant and the system is particularly suitable for navigated surgery. In navigated surgery, the position of the implant to be inserted and/or the instrument for inserting the implant is tracked via optical or electromagnetic methods and shown on images of the patient, such as conventional X-ray images or computer tomography (CT). In particular, the surgical device and the method permit real-time visualization of the insertion process of the implant or of a manipulation process during the surgery by means of computer-aided navigation.

The term surgical implant or implant as described hereinafter includes not only a surgical implant that is intended to be inserted and to remain in a patient's body but also includes trial implants that are used for testing and that do not remain in the patient's body or are not implanted in a live body at all, or it further includes instruments or portions thereof that are temporarily inserted and removed afterwards, such as an awl or a drill.

In the case that the surgical implant is an intervertebral implant, it is possible to track a curved insertion trajectory, in particular in transforaminal lumbar interbody fusion techniques. However, the intervertebral implant can also be used for other fusion techniques.

Generally, intervertebral implants according to <CIT> and <CIT>, may be used for the surgical implant that is provided with the detection device.

In a further embodiment, the instrument may be provided with a navigation device for optical or electrical detection of a position of the instrument relative to a reference position. Hence, with the surgical implant and the instrument it is possible to monitor the surgical step from the beginning of the insertion until the final placement of the implant in a patient's body.

An embodiment of a method of a surgical procedure using a surgical device as described above includes a step of detecting the positions of the second component relative to the first component and using the position data corresponding to the detected positions for computer-aided navigation.

The method can be carried out using a model of a patient's body part in which the surgery is intended to be carried out and which may have similar properties compared to a live body. In this case, the method is a simulation method of a surgical procedure. Alternatively, the method can be carried out on cadaver as well as, in variants not falling under the scope of the claimed invention, on a live body.

Further features and advantages of the invention will become apparent from the description of embodiments by means of the accompanying drawings. Embodiments according to the invention are those that fall within the scope of the claims. Embodiments that do not fall within the scope of the claims are described here for a better understanding of the invention, and features of these embodiments can be used for a further development of the invention.

Referring to <FIG>, an embodiment of a surgical implant for use in spinal or musculoskeletal surgery or in simulated surgery in the form of an intervertebral implant <NUM> and an instrument <NUM> for insertion of the surgical implant is shown. The intervertebral implant <NUM> includes a detection device <NUM> that is provided with a sensor <NUM> and a transmission portion <NUM> for transmitting data detected by the sensor <NUM> to an evaluation unit. The detection device <NUM> is configured to extend through the instrument such that the sensor <NUM> can be accommodated in the intervertebral implant <NUM>.

The intervertebral implant <NUM> is formed as a body with a top wall 10a and an opposite bottom wall 10b that are configured to engage the end plates of adjacent vertebrae when the intervertebral implant <NUM> is placed into an intervertebral space. A sidewall 10c connects the top wall 10a and the bottom wall 10b. The body has an outer contour adapted to fit into the intervertebral space, for example, the outer contour can have a banana shape or a kidney shape. However, any other suitable shape may also be realized. In view of its path of insertion, the intervertebral implant <NUM> has a first or leading end <NUM> and an opposite second or trailing end <NUM>. At the trailing end <NUM>, a recess <NUM> is formed that permits engagement with the instrument <NUM> in such a manner that the implant <NUM> can be pivoted relative to the instrument in a predefined angular range. In greater detail, the recess <NUM> defines an circumferentially extending opening for inserting an engagement portion <NUM> of the instrument <NUM>. Inside, the recess <NUM> comprises a spherical portion 13a (also shown in <FIG>) that is configured to accommodate a spherical portion of the engagement portion <NUM> of the instrument <NUM>. Sidewalls 13b that limit the recess <NUM> form an angle with each other and thereby limit the pivoting of the intervertebral implant <NUM> relative to the instrument <NUM>. An axis R extending through the spherical portion 13a of the recess and substantially perpendicular to a longitudinal axis S of the instrument <NUM> forms an axis of rotation or a pivot axis of the intervertebral implant <NUM> relative to the instrument <NUM>. A virtual line extending from the leading end <NUM> to the trailing end <NUM> and intersecting the axis R of rotation defines a longitudinal axis L of the intervertebral implant <NUM>. The pivot or rotation angle of the intervertebral implant <NUM> relative to the instrument <NUM> is defined as the angle that the longitudinal axis L of the intervertebral implant <NUM> forms with the longitudinal axis S or shaft axis of the instrument.

From the recess <NUM> an elongate recess <NUM> extends inside the intervertebral implant <NUM> up to a distance from the leading end <NUM>. The recess <NUM> is configured to accommodate the sensor <NUM> and a portion of a connection line <NUM> that connects the sensor <NUM> with the transmission portion <NUM>. For example, the recess <NUM> may have an elongate, rectangular contour that has a width only slightly greater than that of the sensor <NUM> so that the sensor <NUM> is guided therein when it is inserted into the intervertebral implant <NUM>. A plurality of additional openings and/or recesses 15a, 15b, 15c may be formed in the body for various purposes, among others to allow ingrowth of tissue and vessels, for saving weight or for cleaning.

It shall be noted that the intervertebral implant can also be realized as a porous body or a body consisting of a grid-like structure that exhibits an open cell structure.

The instrument <NUM> comprises the engagement portion <NUM> forming an end portion of a shaft <NUM> that is guided in a sleeve or tube <NUM>. The shaft <NUM> is advanceable and retractable relative to the tube <NUM> such that for engaging the intervertebral implant <NUM> the shaft <NUM> can be advanced, and for fixing the intervertebral implant <NUM>, the shaft <NUM> can be retracted. A longitudinal channel 22a extends through the shaft <NUM> and the engagement portion <NUM> for passing through the detection device <NUM>. The length of the shaft <NUM> is such that an end portion <NUM> opposite to the engagement portion <NUM> extends out of the tube <NUM> to permit attachment of further parts and to permit the insertion of the sensor device <NUM>. For insertion of the sensor device <NUM>, the longitudinal channel 22a comprises an insertion window <NUM> through which the detection device can be inserted.

The engagement portion <NUM> may be spherical segment-shaped with flat sidewalls 21a. In addition, the shaft <NUM> is at least partially rotatable relative to the tube <NUM>. A size of the engagement portion <NUM> relative to the recess <NUM> is such, that the engagement portion <NUM> can be inserted into the recess <NUM> only in a first orientation in which the flat sidewalls 21a face substantially towards the top face 10a and the bottom face 10b of the intervertebral implant <NUM>, respectively. Moreover, the size of the engagement portion <NUM> is such that the engagement portion <NUM> is prohibited from removal in a second orientation in which the flat sidewalls 21a are in a substantially upright position in which they may be substantially perpendicular to the top wall 10a and the bottom wall 10b.

The shaft <NUM> also may have a marking 22b close to the engagement portion <NUM> that indicates the second orientation, that is the upright position of the engagement portion <NUM>. When the marking 22b is aligned with a marking 23a on the outer surface of the tube <NUM> the upright position of the engagement portion <NUM> is indicated. Once inserted, when the engagement portion <NUM> engages the spherical portion 13a of the recess <NUM>, the intervertebral implant <NUM> is pivotable relative to the instrument <NUM>. The tube comprises projections 23b at its front end which serve for guiding the shaft <NUM> therebetween. Moreover the projections 23b serve for orienting the intervertebral implant <NUM> such that the engagement portion <NUM> is insertable into the recess <NUM> of the intervertebral implant <NUM> only in the first orientation of the engagement portion <NUM>. In addition, the projections 23b are configured to inhibit tilting of the intervertebral implant <NUM> relative to the axis of rotation R in the second configuration of the engagement portion <NUM>. The sensor <NUM> of the sensor device <NUM> is insertable into the intervertebral implant only in the second configuration of the engagement portion <NUM>. To fixedly connect the intervertebral implant <NUM> to the instrument the shaft can be retracted so that tube <NUM> presses on the implant and firmly clamps the engagement portion <NUM> within the recess <NUM>. Furthermore, the tube <NUM> may have a holding portion <NUM> at its end opposite to the engagement portion <NUM>. Also on the holding portion <NUM>, an axially extending elongate indication mark 24a may be provided that is configured to indicate the fixed or locked configuration of the instrument <NUM> relative to the intervertebral implant <NUM>.

A cover member <NUM> is connectable to the shaft <NUM>. The cover member <NUM> may be sleeve-shaped and may comprise a circumferential window <NUM> that exposes the transmission portion <NUM> of the detection device <NUM>. For example, the window <NUM> permits to provide access to a plug-in connector, for example an USB connector, and/or to guide out a data cable <NUM> or facilitates wireless data transmission. Lastly, a nut <NUM> may be mounted to the shaft <NUM>, for example screwed thereto on a thread 220a provided at the end portion <NUM> of the shaft <NUM>. The nut <NUM> serves for hitting thereon to drive the intervertebral implant <NUM> into the intervertebral space. At the free end of the nut <NUM>, a cylindrical peg or hook <NUM> may be provided that can be engaged for example by a claw, so that the instrument <NUM> can be withdrawn once the intervertebral implant <NUM> has been placed.

The sensor <NUM> is configured to detect a change of an angle between the the intervertebral implant <NUM> and the instrument <NUM>. More specifically, the sensor <NUM> detects the angle change between the longitudinal axis L of the intervertebral implant <NUM> and the shaft axis S of the instrument <NUM>. The sensor <NUM> may be, for example, an acceleration sensor that detects an acceleration of a mass through a change in capacity of a capacitor or a piezoelectric acceleration sensor that detects a change in pressure by acceleration of a mass. Alternatively, the sensor <NUM> may be realized by a gyroscope that detects the displacement of a resonance mass and its hanging following a Coriolis acceleration. Also gravitational sensors may be applied. In particular, the acceleration sensor, the gravitational sensor or the gyroscope may be realized with micro-electromechanical systems (MEMS). Such MEMS are well-known and comprise spring-mass systems wherein the springs and the mass are formed by miniaturized silicon structures for example by means of photolithography. The resolution of the sensor <NUM> used in the detection device <NUM> may be preferably between about <NUM>° to <NUM>°, more preferably about <NUM>°.

An overall length of the detection device <NUM> may be such, that the transmission portion <NUM> projects out of the holding portion <NUM> of the tube <NUM> when the sensor <NUM> is placed in the recess <NUM> of the intervertebral implant <NUM>. The main part of the connection line <NUM> that extends through the shaft <NUM> may be a substantially stiff line, for example a printed circuit board. In the region of the engagement of the engagement portion <NUM> with the intervertebral implant <NUM>, the connection line comprises a flexible portion <NUM> that allows the rotational movement between the intervertebral implant <NUM> and the instrument <NUM>. The flexible portion <NUM> may be realized as a substantially flat cable, such as a ribbon cable. Also the transmission portion <NUM> may include a printed circuit board on which a data-processing unit for pre-processing the measured data and a transmission unit for transmitting the data to an external evaluation unit are provided. Alternatively, the data-processing unit may be already included in the sensor <NUM>. The transmission unit <NUM> may be configured to transmit the data via the cable <NUM> and/or to transmit the data in a wireless manner.

Referring to <FIG>, the instrument <NUM> may be equipped with a navigation device <NUM> that enables detection of the position of the instrument relative to a reference position. In the embodiment, the navigation device is an optical navigation device. Such a navigation device is well-known in the art and may comprises an arm <NUM> that extends substantially transverse to the shaft axis S and can be mounted via a mounting portion <NUM> that permits to adjust the axial position along the shaft axis and the circumferential position of the arm <NUM>. This can be realized, for example, via a clamping screw <NUM> that is actuated by a knob <NUM>. From the end of the arm <NUM> a plurality of transverse branches <NUM> extend, usually in a cross-arrangement, that may be oriented substantially parallel to the shaft axis S and which may have various lengths. At the free ends of the branches <NUM> balls <NUM> are provided, respectively, that are oriented away from the shaft axis S. The balls <NUM> are configured to be detected optically via an optical detection unit, such as a camera.

Turning now to <FIG>, a system or equipment for real-time visualization of the insertion of the intervertebral implant <NUM> is shown. A vertebra <NUM> is provided with a second navigation device <NUM>' that may of the same type as the navigation device <NUM> attached to the instrument <NUM> and that may be mounted, for example, to the spinal process. The second navigation device <NUM>' is detectable and delivers the position of the vertebra <NUM>. The position of the instrument <NUM> is detectable via the navigation device <NUM> attached to the instrument <NUM>. In addition, the equipment includes one or more cameras <NUM> to optically detect the position of the navigation device <NUM> on the instrument <NUM> and of the second navigation device <NUM>' attached to the vertebra <NUM> so that the position of the instrument <NUM> relative to the vertebra <NUM> can be determined. The position of the intervertebral implant <NUM> relative to the instrument <NUM>, more specifically the angle of rotation around the axis of rotation R, is detectable by the sensor <NUM>. Thus the position of the intervertebral implant <NUM> relative to the vertebra <NUM> can be determined from the data obtained through the navigation device <NUM> and the data obtained by the sensor <NUM>. The corresponding data are transmitted to a processing unit <NUM>, such as a computer, that calculates image data that can be visualized on a screen <NUM>. Hence, with this equipment, it is possible to display the procedure of placement of the intervertebral implant into the intervertebral space in a real-time manner.

Referring to <FIG> steps of assembling the instrument <NUM>, the intervertebral implant <NUM> and the detection device <NUM> will be explained. As shown in <FIG>, the intervertebral implant <NUM> is attached to the instrument <NUM> in the configuration in which the shaft is advanced and the engagement portion <NUM> is oriented such that the flat top and bottom surfaces 21a are substantially parallel to the top and bottom surface 10a, 10b of the intervertebral implant. In this configuration the engagement portion <NUM> can be introduced into the recess <NUM>. Then, the engagement portion <NUM> or the intervertebral implant <NUM> is rotated by <NUM>° so that the engagement portion <NUM> is seated with its spherical outer surface in the spherical recess portion 13a and no longer removable.

As shown in <FIG>, the shaft <NUM> of the instrument may be at the outermost position of the recess <NUM>. Then the shaft <NUM> is retracted so that the tube <NUM> is pressed against the intervertebral implant <NUM> to fixedly connect the intervertebral implant <NUM> to the instrument <NUM>. The angle that the longitudinal axis L of the intervertebral implant <NUM> and the shaft axis S form is designated as a starting or initial angle.

Next, as shown in <FIG>, the detection device <NUM> is mounted to the assembly of the intervertebral implant <NUM> and the instrument <NUM>. The detection device is guided through the shaft <NUM> until the sensor <NUM> and the flexible portion <NUM> rest in the recess <NUM> in the intervertebral implant <NUM>. The transmission portion <NUM> projects out of the shaft <NUM>.

Then, as depicted in <FIG>, the cover member <NUM> is placed onto the holding portion <NUM> of the instrument so that only the transmission portion <NUM> is accessible through the window <NUM> and the rest of the detection device <NUM> is protected.

Finally, as shown in <FIG>, the nut <NUM> is mounted to the end portion <NUM> of the shaft <NUM>. In this condition, the assembly is ready for insertion into a patient's body.

Referring to <FIG>, steps of insertion of the intervertebral implant <NUM> into the intervertebral space and the real-time visualization of the insertion are shown. It should be mentioned that instead of the second navigation device <NUM>' attached to a vertebra, any other reference position that may be outside the patient's body may be used for calculating the real-time position of the instrument <NUM>.

As shown in <FIG>, the intervertebral implant is at the entrance of the intervertebral space while still being fixedly connected to the instrument <NUM>. The angle between the intervertebral implant <NUM> and the instrument <NUM> in this condition is the starting angle. The absolute position of the intervertebral implant is calculated on the basis of geometrical data of the instrument <NUM>, of the intervertebral implant <NUM> and of the vertebra <NUM>. The position of the instrument is detected via the navigation device <NUM> and displayed in real-time on the screen <NUM>.

Next, as shown in <FIG>, the fixation of the intervertebral implant <NUM> to the instrument <NUM> is released, for example by retracting the tube portion <NUM> to such an extent that the implant is rotatable but the engagement portion <NUM> cannot be withdrawn from a recess <NUM>. In this condition, the intervertebral implant <NUM> can rotate or pivot relative to the instrument around the axis of rotation R a pivot plane. Next, the intervertebral implant <NUM> is pushed into the intervertebral space with the instrument <NUM> and thereby rotates around the axis of rotation R. During this, the angle of rotation of the implant relative to the instrument is, preferably constantly, detected and the data are transmitted via the transmission portion <NUM> to the processing unit <NUM>. The software calculates on the basis of the angular data and the absolute position data the position of the intervertebral implant <NUM> relative to the vertebra <NUM>. Thereby, the starting angle is used as an offset to the actually measured angle data. The insertion process can be displayed in real time on the screen <NUM>. An image of the implantation site that may be obtained pre-operatively may be used to visualize the position of the instrument and the implant.

Finally, as depicted in <FIG>, the implant has reached its place. This may be the case on the maximum angle between the intervertebral implant <NUM> and the instrument <NUM> is reached which is defined by the abutment of the shaft against the other sidewall 10b of the recess <NUM>. However, due to the real-time visualization, the surgeon can see whether the placement of the intervertebral implant is correct even if the maximum angle is not yet reached.

After placement of the intervertebral implant <NUM>, the connection between the intervertebral implant <NUM> and the instrument is released in that the engagement portion is rotated by <NUM>° and pulled out of the recess <NUM>. The instrument can be removed by attaching claws to the peg <NUM> of the nut <NUM> to withdraw the instrument. Finally, by detaching the nut <NUM> and the cover member <NUM>, the detection device <NUM> can be removed.

It shall be noted that in this embodiment a change of the angle of the intervertebral implant relative to the instrument is detected in the pivot plane only. Using more than one sensor may permit to add more degrees of freedom for the determination of the position. It shall also be noted that different sensors may be used for different purposes and different implants, depending on the location where the implant is intended to be used.

Referring to <FIG>, the same procedure as shown in <FIG> can also be carried out with the second navigation device <NUM>' attached to the vertebra <NUM>, for example to the spinal processus.

<FIG> shows a modification of the instrument. The detection device <NUM>' comprises a first sensor <NUM> which is identical or similar to the sensor <NUM> described before and which is configured to be placed in the intervertebral implant <NUM> and a second sensor <NUM>' that is configured to be placed in the instrument. Both sensors <NUM>, <NUM>' may be connected to the same transmission portion <NUM>. In this case, it is possible to permanently track the angular orientation of the implant <NUM> relative to the instrument <NUM> independently of whether the cage is fixedly connected to the instrument or is movable relative to the instrument.

<FIG> shows a still further modification in which instead of the sensor <NUM> placed in the accommodation space of the intervertebral implant <NUM>, a sensor <NUM>", such as for example a rotary encoder or a sensor as described above, is placed directly at the position of the in the rotational axis, for example in the engagement portion <NUM>. The sensor <NUM>" also detects rotation of the instrument relative to the intervertebral implant.

Referring to <FIG>, a further embodiment of a device for use in spinal or musculoskeletal surgery is shown. The device is in this case an instrument in the form of a screw or shank inserter <NUM>. The shank inserter <NUM> has a first component and a second component that is pivotable relative to the first component. This is realized, for example, via a cardanic hinge <NUM> by means of which an upper shank inserter portion <NUM> that forms the first component and a lower shank inserter portion <NUM> that forms the second component of the device are connected. The lower shank inserter portion <NUM> is configured to engage a head of a bone anchor <NUM> for inserting the bone anchor. On the upper shank inserter portion <NUM>, a navigation device <NUM> as described before is attached. The shank inserter <NUM> and the bone anchor <NUM> comprise a channel for guiding through a detection device <NUM>. The detection device comprises a sensor <NUM> that is placeable within a tip <NUM> of the bone anchor <NUM>. When the lower shank inserter portion <NUM> pivots relative to the upper shank inserter portion <NUM>, the change of the angular position of the bone anchor <NUM> relative to the upper shank inserter portion <NUM> is detectable and traceable via computer-aided navigation as described before. This embodiment may be useful in applications where the access to the location where the bone anchor shall be placed, is restricted and pivoting of the shank inserter could facilitate the insertion.

In <FIG> an embodiment of an instrument in the form of a shank inserter <NUM>' and an implant in the form of the bone anchor <NUM> is shown that differs from the embodiment of <FIG> in that the shank inserter <NUM>' does not have a pivotable portion. Instead, the shank inserter <NUM> is straight. The shank of the bone anchor <NUM> may assume during insertion, due to various reasons such as bending or specifically in the case of a bone anchor with flexible characteristic, an angle with respect to the longitudinal axis of the shank inserter <NUM>'. The detection device <NUM> with the sensor <NUM> in the tip of the bone anchor <NUM> permits to detect and track the position of the tip <NUM> relative to the longitudinal axis of the shank inserter <NUM>'.

In <FIG> an embodiment of a surgical device is shown with a first instrument component in the form of an awl or drill <NUM> and a second instrument component in the form of an awl or drill holder <NUM>. The detection device comprises a sensor <NUM> as in the previous embodiment, that is positionable in the awl or drill <NUM>, preferably at the tip thereof. The navigation device <NUM> is provided at the awl or drill holder <NUM>. With this surgical device, it is possibly to detect and track any deviation of the position tip of the awl or drill <NUM> from the shaft axis of the awl or drill holder <NUM> during insertion. Such a deviation may result, for example, from a bending of the awl or drill <NUM>.

In <FIG> an embodiment of a surgical device is shown with a first instrument in the form of an awl or drill <NUM>' and a second instrument in the form of a shank inserter <NUM>' that is configured to hold and insert a cannulated bone anchor <NUM> while the awl or drill <NUM>' extends therethrough and is used for picking or pre-drilling a hole. The navigation device <NUM> is provided at the shank inserter <NUM>. The sensor device <NUM> in the tip of the awl or drill <NUM>' permits to detect and track the position of the awl or drill <NUM>' relative to the shank inserter <NUM>', in particular if the awl or drill <NUM>' advances in an inclined manner relative to the longitudinal axis of the shank inserter <NUM>'.

In <FIG> an embodiment of a surgical implant in the form of a spinal rod <NUM> and an instrument for insertion thereof in the form of a rod inserter <NUM> to insert the rod into receivers of bone anchors <NUM> is shown. The rod <NUM> is attachable to the rod inserter <NUM> at an attachment portion <NUM> that permits pivoting of the rod <NUM> relative to the rod inserter <NUM>. The navigation device <NUM> is provided at the rod inserter <NUM>. With the detection device comprising a first sensor <NUM> at the rod <NUM> and optionally a second sensor <NUM>' at the rod inserter <NUM>, it is possible to detect and track the position of the rod <NUM> relative to the rod inserter <NUM>, in particular when the rod is pivoted.

<FIG> show a still further embodiment of a surgical implant in the form of an expandable intervertebral implant <NUM> and an insertion and/or expansion instrument <NUM>. The intervertebral implant <NUM> can assume a first configuration as shown in <FIG> in which it is collapsed and has a smaller height and a second configuration as shown in <FIG> in which it is expanded and has a greater height than in the first configuration. In greater detail, the intervertebral implant <NUM> comprises a top wall 10a' and a bottom wall 10b' that are configured to engage the adjacent vertebral end plates, respectively, and may have diagonal bars or struts <NUM> that cross each other and that may be resilient or may otherwise assume a compressed and an elevated configuration. A detection device may include a first sensor <NUM> that is at the end of at least one of the struts <NUM> at or close to the top or bottom wall and a second sensor <NUM>' that may be at the crossing section of the struts. With the sensors, the change of the position of the top or bottom wall 10a', 10b', in particular the change in height of the intervertebral implant <NUM>, can be detected and tracked. In addition, the instrument may include a navigation device <NUM>.

Claim 1:
A system of a surgical implant, in particular for use in spinal or musculoskeletal surgery or in simulated surgery, and an instrument for inserting the surgical implant, the surgical implant including:
an implant body (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>', <NUM>, <NUM>) comprising an attachment portion configured to attach the implant to the instrument (<NUM>, <NUM>, <NUM>', <NUM>, <NUM>', <NUM>, <NUM>) for insertion of the implant and at least one accommodation portion configured to accommodate at least a portion of a detection device; and
a detection device (<NUM>, <NUM>', <NUM>) configured to detect a position of the implant relative to the instrument;
wherein the at least one portion of the detection device is removably positionable in the accommodation portion, and
wherein the implant body (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>', <NUM>, <NUM>) is configured to rotate relative to the instrument (<NUM>, <NUM>, <NUM>', <NUM>, <NUM>', <NUM>, <NUM>) around an axis of rotation and wherein the detection device (<NUM>, <NUM>', <NUM>) comprises an acceleration sensor configured to detect an angle of rotation around the axis of rotation of the implant body relative to the instrument, wherein the sensor is accommodated in the accommodation portion.