DE202004014119U1 - Surgical instrument to determine the size and/or height of a spinal disk implant, between neighboring vertebra in a human/animal spine, has test implant laying units at angles on holders for use with a variety of disks - Google Patents

Abstract

The surgical instrument (10) determines the size and/or height of an implant in a human or animal spine (22), in the space (12) between two vertebra (18,20). The implant has a section to be laid on a joint surface (24) of one vertebra with a second section directly or indirectly at the first section to be laid on the joint surface (26) of the neighboring vertebra. The instrument has a holding unit (28) defining the longitudinal direction (44), and at least one test implant (76) with its laying unit (78). The first and/or second test implant laying units are linked to the laying unit holders (56,58) by release mountings, and are at two defined and different angles at the holders in relation to the longitudinal direction.

Description

The The present invention relates to a surgical instrument for Size and / or height determination one in an intervertebral space between two adjacent vertebral bodies of two Vertebrae of a human or animal spine can be used Intervertebral implant, the intervertebral implant first contact element for contacting an articular surface of one of the two neighboring ones vertebra and one directly or indirectly mounted on the first contact element second contact element for contact with an articular surface of the has another of the two adjacent vertebral bodies, the instrument a a longitudinal direction defining holding part and at least one trial implant, which a first and a second, at least one contact surface each Facing one of the articular surfaces comprising trial implant plant element, being on a distal End of the holding part at least one contact element holding element releasable Connect to the at least one trial implant is provided.

to Treatment of degenerative diseases in the spine very often intervertebral disc tissue surgically removed. Subsequently neighboring segments of movement, i.e. neighboring vertebrae, become Example using a bone chip and / or artificial intervertebral implants merged. An alternative to the fusion of adjacent vertebral bodies the implantation of intervertebral disc prostheses with which mobility adjacent vertebral body can be obtained at least partially relative to each other.

A Intervertebral disc prosthesis serves, among other things, the original To restore intervertebral disc height and the spine stabilize again.

to Determination of the required size respectively Amount of Intervertebral implants are different instruments or trial implants known which are introduced into the cleared intervertebral space for determining size and height. Dependent on the one determined with the instrument or with the trial implant Implant size and height the actual intervertebral implant selected and then implanted.

It is the object of the present invention, an instrument of the beginning described type to improve so that a size and / or height determination an intervertebral implant on simple and different Way possible is.

This The task is described in the case of a surgical instrument Kind according to the invention solved, that this first and / or the second trial implant contact element based on the longitudinal direction in at least two defined, different angular positions relative to the at least one contact element holding element with this solvable is connectable.

The Design according to the invention allows it, the trial implant system elements in at least two different To connect angular positions with the contact element holding element. This allows the trial implant to be viewed at different angles to introduce into the intervertebral space. In other words, it is possible the trial implant not only by, for example, an anterior one Introduce access but also through a lateral approach. So there can be access to Intervertebral space can be chosen freely and the trial implant system elements are for this purpose with the holding part either in a first or in another angular position connected to the contact element holding element. So there are no compromises more natural or optimal angular position is required when inserting the trial implant. A patient can be optimally positioned. The instrument according to the invention can be then adjust according to the operational circumstances. It also allows the detachable Connection of the trial implant system elements to the at least one Contact element holding element, different trial implants with different heights and / or lordosis angles, that is to say enclosed between the contact surfaces Angles to connect with the holding part. So it's just a holding part required with appropriate trial implant system elements to achieve a To reproduce a large number of trial implants and different ones Additions to introduce into the intervertebral space.

Advantageous it is when the first or the second trial implant plant element in the at least two defined, different angular positions is each arranged in a common plane and that the two Levels are identical. In other words, it means that the first or the second trial implant system element quasi by a pure geometric rotation from the first angular position to the second Angular position is convertible. However, it must Instrument should not be designed so that the transition from the first angular position in the second angular position is possible directly by rotation. A translational-rotational-translational movement may also be required.

It is expedient if the first and / or the second trial implant contact element and the at least one contact element holding element are detachable Ren connect can be brought into engagement with each other by a relative movement towards each other in a transverse to the longitudinal direction of connection. This configuration avoids that when the trial implant is inserted into the intervertebral space, shear and tensile forces typically acting in the longitudinal direction can lead to the trial implant becoming detached from the holding part.

advantageously, is the at least one contact element holding element with the first and / or connectable to the second trial implant contact element in a non-positive and / or positive manner. It can be so a simple connection between the contact element holding element and form the at least one trial implant contact element.

The Building the instrument becomes particularly easy when a first and a second connecting element is provided for connecting the at least one a contact element holding element with the first and / or with the second trial implant plant element and if one of the trial implant plant elements and the at least one contact element holding element each one of the two fasteners. For example, by merging or Engaging the two fasteners can be a safe one Connection between the at least one contact element holding element and the first and / or the second trial implant contact element getting produced.

The Structure of the instrument becomes particularly simple when the first connecting element a receptacle and the second connecting element for receptacle corresponding and insertable projection is.

Is cheap it when the protrusion is on the Trial Implant Facing Element cylindrical pin protruding onto the contact element holding element and if the receptacle corresponds to the pin in diameter Hole or blind hole is. This simplifies the construction of the instrument, its manufacture and also the exchange of the Trial implant system elements.

Around an unintentional loosening the trial implant contact elements from the at least one contact element holding element due to pushing and pulling forces longitudinal to avoid the holding part, it is advantageous if the projection in a direction transverse to the longitudinal direction insertable into the recording is.

conveniently, a locking connection is provided to secure a connection of the at least one contact element holding element with the first and / or the second trial implant contact element in one of the angular positions. The locking connection can inadvertently loosen the trial implant contact element connected to the at least one contact element holding element can be prevented in a connection position.

at a preferred embodiment According to the invention, a clamping direction can be provided for the clamping Securing a connection of the at least one contact element holding element with the first and / or the second trial implant system element in one of the angular positions. Through the clamping device can unintentional loosening of the Trial implant contact element from the at least one contact element holding element be prevented.

Advantageous it is when the clamping device is at least one of the connecting elements at least partially encompassing clamping element, which into a gap between the at least one contact element holding element and the first and / or the second trial implant contact element can be used and before connecting the at least one contact element holding element and the first and / or the second trial implant contact element at least on one side protrudes the gap. Preferably, a deformable, in particular an elastic clamping element can be used so that clamping forces from Clamping element in the connecting position in the opposite direction the contact element holding element and the trial implant contact element Act.

On The instrument is particularly simple if the Gap includes a circumferential annular groove on the projection and if the clamping element is an elastic ring, the diameter of which is larger than is a depth of the ring groove. For example, a connecting pin with of the annular groove, so that when inserting the pin into a corresponding one Not only a connection, but also a clamp can be reached between the two parts.

conveniently, a tensioning device is provided for securing an exciting Connection of the at least one contact element holding element with the first and / or the second trial implant system element in one of the angular positions.

It is advantageous if a plurality of trial implants are provided and if the plurality of trial implants have different distances between the contact surfaces and / or different lordosis angles between the devices have areas. Due to the plurality of trial implants, different implant sizes and heights can be determined with a single holding part and a required lordosis angle between the contact surfaces can be determined. As soon as the sizes to be determined are known, the intervertebral implant to be permanently implanted can be selected and inserted into the intervertebral space.

According to one preferred embodiment of the Invention can be provided that an angle adjustment device is provided for specifying and setting the different Angular positions of the first and / or the second trial implant contact element relative to the at least one contact element holding element, that the angle adjusting device at least two with each other in the different angle settings engaging adjustable elements and that the first and / or the second Trial implant system element, a first setting element and the at least one a contact element holding element have a second setting element. The correspondingly arranged setting elements allow Defined angle settings of the trial implant system element and the contact element holding element in the desired manner.

Especially Cheap it is when at least one of the at least two setting elements in the form of a shot and if at least one more of the at least two setting elements in the form of one in the setting holder insertable Adjustment projection is formed. An angle setting can can then be easily specified by the adjustment projection inserted into the setting holder becomes. This results in a defined angular position of the contact element holding element relative to the trial implant system element.

Around a desired one Angular position of the trial implant system element relative to the at least to secure a contact element holding element, it is advantageous when the adjustment projection is in a direction transverse to the longitudinal direction insertable into the setting holder is. Will the holding part in the longitudinal direction moves, so can exerted by this and tensile forces not cause that the Can be moved relative to the setting holder especially inadvertently emerge from it.

The The structure of the instrument is further simplified if the trial implant system element is at least carries an adjustment projection and if the contact element holding element has at least two setting receptacles having. This allows the at least one adjustment projection of the trial implant system element in one or the other of the at least to introduce two setting shots and so different angular positions of the trial implant system element to specify relative to the at least one contact element holding element.

Is cheap it if the at least one contact element holding element is cylindrical is shaped and if a longitudinal axis of the at least one contact element holding element extends transversely to the longitudinal direction. The System element holding element can be so particularly easy to manufacture and in a simple manner with a large number of trial implant system elements.

Further it may be advantageous if the trial implant system elements one recess for each have the at least one contact element holding element and if the at least one contact element holding element in a form-fitting manner or essentially positive insertable into the recess is. This can be an additional Stop or a support of the trial implant contact element relative to the contact element holding element can be achieved.

Around the trial implant through different, desired approaches in the human body to introduce the intervertebral space, is it convenient when the first and / or the second trial implant element in the second angular position relative to the at least one contact element holding element rotated by an angle of incidence relative to the first angular position can be arranged. The setting angle can be selected in each case that this trial implant held on the holding part can be inserted in the desired manner can, for example, through a lateral or anterior approach.

conveniently, the setting angle has a value in a range from 10 ° to 30 °.

According to one preferred embodiment of the Invention can be provided that at the distal end of the instrument a first and a second contact element holding element are provided is and that that first contact element holding element with the first trial implant contact element and the second contact element holding element with the second trial implant contact element solvable is connectable. This allows the two contact element holding elements individually for connection to the trial implant system elements train. In particular, they can be shaped differently. Furthermore, it is possible to Contact element holding elements inclined relative to each other on the holding part train so that a Lumbar angle already through the contact element holding elements themselves can be specified.

In order to be able to distract adjacent vertebral bodies with the instrument at the same time it is advantageous if the first contact element holding element and the second contact element holding element are mounted such that they can be moved towards and / or away from one another transversely or substantially transversely to the contact surfaces. On the one hand, this allows the size of the intervertebral implant to be used and the lordosis angle to be determined, as well as a distance between the contact surfaces.

Advantageous it may be when the distal end of the holding part has two expanding jaws has when the expanding jaws comprise the contact element holding elements or wear and if the spreading jaws by one arranged on the holding part Drive device, which is at the proximal end of the holding part arranged actuator includes, from each other can be moved away and / or towards each other. The holding part can according to this Design in the form of egg nes spreading instrument, which Has expanding jaws for connecting to the trial implant system elements are trained.

Preferably the expanding jaws are mounted parallel to each other.

Around with a variation in the distance between the two trial implant system elements to be able to determine this it is advantageous if the holding part is a displacement measuring device has for measuring and displaying a distance between the contact surfaces or a path of movement of the contact element holding elements relative to one another. For example, if the distance between the contact surfaces is known, then can with the position measuring device a change of the distance determined and added to the known distance become. In this way reduce the number of trial implant system elements required, because different heights adjusted and determined by spreading the contact element holding elements can be.

The The following description of a preferred embodiment of the invention is used in connection with the drawing of the detailed explanation. Show it:

1 : a distal end of an instrument according to the invention with trial implant plates inserted between adjacent vertebral bodies;

2 : an enlarged view of the distal end of the instrument with trial implant plates held in a first angular position at the distal end of the instrument;

3 : a view similar 2 , but with the trial implant plates held in a second angle setting at the distal end of the instrument; and

4 : an exploded view of the distal end of the instrument.

In the 1 to 4 is a whole with the reference symbol 10 provided surgical instrument for determining the size and / or height of an intervertebral space 12 between two adjacent vertebrae 14 and 16 two vertebrae 18 and 20 a spine 22 usable intervertebral implant. The intervertebral implant is not shown in the figures, but typically comprises a first contact element for contact with a first articular surface 24 of the vertebral body 14 and a directly or indirectly mounted, in particular movably mounted, second contact element on the first contact element for contacting a second, in the direction of the first joint surface 24 pointing second articular surface 26 of the vertebral body 16 ,

The instrument 10 comprises an instrument part designed as a holding part 28 , at the distal end of which a spreading device 30 is arranged. The spreader 30 comprises two parallel spreading jaws 32 and 34 the over a scissor link 36 are interconnected. The scissor link 36 includes two handlebars 38 and 40 , the handlebar 38 with a bearing pin 42 whose longitudinal axis is transverse to a longitudinal axis 44 of the instrument part 28 is oriented with the expanding jaw 32 is pivotally connected. The handlebar is the same 40 at a distal end of the expanding jaw 34 using a parallel to the bearing pin 42 oriented bearing pin 46 pivoted. Each of the two expanding jaws 32 and 34 is parallel to the longitudinal axis 44 trending elongated hole 48 respectively 50 provided, in which one at the free ends of the handlebars 38 and 40 Guide pin protruding transversely to the longitudinal axis 52 respectively 54 dive in and be guided. Through the scissor link 36 there is a parallel movement of the two expanding jaws 32 and 34 enforced. The spreader 30 forms a parallel spreader.

On the distal side is on the expanding jaws 32 and 34 one retaining ring each 56 and 58 arranged, the contact element holding elements and each form a central bore 60 respectively 62 have that serve as recordings. An axis of symmetry 64 the retaining rings 56 and 58 runs across the longitudinal axis 44 , Furthermore, the retaining rings 56 and 58 pierced twice, parallel to the axis of symmetry 64 , There are therefore two adjustment holes each 66 and 68 such as 70 and 72 in each retaining ring 56 and 58 educated. Longitudinal axes of the bore 60 and the adjustment hole 66 both intersect the longitudinal axis 44 , as well as the longitudinal axes of the bore 62 and the adjustment hole 70 , The adjustment holes 68 and 72 are relative to the adjustment holes 66 and 70 by a pitch angle 74 arranged offset in the circumferential direction, which is 22 ° in the present embodiment.

Part of the instrument 10 is also a trial implant 76 which is two identical plates 78 includes. The plate 78 is essentially cuboid and has one for abutting one of the articular surfaces 24 respectively 26 contact surface that can be created 80 on. On a substantially parallel to the contact surface 80 in the opposite direction facing bottom 82 is a cylindrical ring holder 84 incorporated, which is essentially laterally open pointing in the proximal direction. The diameter of the ring holder 84 corresponds to an outer diameter of the retaining rings 56 and 58 , The ring intake 84 is coaxial to the axis of symmetry 64 arranged. A retaining pin is also coaxial with the same 86 from the plate 78 whose outer diameter is the inner diameter of the holes 60 and 62 equivalent. The holding pin 86 is circumferential with an annular groove 88 provided, in which an O-ring 90 is inserted, the diameter of which is somewhat larger than a depth of the annular groove 88 in the radial direction. The ring groove 88 with the O-ring inserted in it 90 form a clamping device with which a connection of the plate 78 with one of the two retaining rings 56 and 58 can be secured. The O-ring is elastically deformed 90 after inserting the retaining pin 86 in one of the two holes 60 or 62 , Parallel to the holding pin 86 there is an adjustment pin 92 whose outer diameter corresponds to the inner diameter of the adjustment holes 66 to 72 equivalent.

The plate 78 is designed such that it is one of the retaining rings 56 or 58 can accommodate, the holding pin 86 in the hole 60 respectively 62 and the adjustment pin 92 in one of the adjustment holes 66 and 68 respectively 70 and 72 can be introduced. The plate 78 can thus easily parallel to the axis of symmetry 64 , i.e. across the longitudinal axis 44 , with one of the retaining rings 56 and 58 be engaged. Are the two plates 78 with the retaining rings 56 and 58 connected such that the adjusting pin 92 into the adjustment holes 66 and 70 immerse, then there is an alignment of the plates 78 symmetrical to the instrument part 28 or to the longitudinal axis 44 , With such a, in the 1 and 2 shown angular adjustment of the plates 78 relative to the retaining rings 56 and 58 the instrument can be used for this, the trial implant 76 through an anterior approach into a human or animal body and into the intervertebral space 12 introduce.

The insertion of the trial implant 76 Lateral access is facilitated when the plates 78 with the retaining rings 56 and 58 be connected so that the adjusting pin 92 into the adjustment holes 68 and 72 plunge. The plates 78 are one of them 3 shown second angular position with the retaining rings 56 and 58 connected, and take a compared to that in the 1 and 2 shown angular position a position rotated by 22 °.

In the in the 1 to 4 illustrated embodiment are the wide retaining rings 56 and 58 aligned parallel to each other. It would also be conceivable to have ring surfaces pointing away from one another 94 and 96 the retaining rings 56 and 58 to tend towards each other. In this way, a certain lordosis angle can be achieved 98 the articular surfaces 24 and 26 specify, adjust relative to each other.

The instrument 10 not only includes those in the 1 to 4 illustrated plates 78 , but also other plates, not shown 78 different sizes and different inclinations of the contact surfaces 80 relative to each other. Due to the different inclined contact surfaces 80 can also be caused by the articular surfaces 24 and 26 predetermined lordosis angle 98 be replicated. The plates also differ 78 also in height, so that intervertebral spaces of different heights 12 can be measured in the desired manner.

The instrument 10 is used intraoperatively as follows. First, a patient is positioned in the desired manner. This can be done, for example, with a frontal access lying on your back. Relief of the spine can already be achieved through the special positioning of the patient.

In a next step, an access is created in the patient's body, to the desired intervertebral space 12 out. The damaged intervertebral disc tissue is then removed. After that, the instrument 10 prepared accordingly. This means that different trial implants based on the anatomical conditions 76 about the right size, with the appropriate height and natural lordosis angle 98 , Depending on the chosen approach, anterior or lateral, the plates are 78 the trial implant 76 on the respective retaining rings 56 and 58 plugged on, either with the adjusting pins 92 into the adjustment holes 66 and 70 or 68 and 72 , After that, the instrument 10 inserted into the patient's body in such a way that the trial implant 76 in the intervertebral space 12 dips. With a drive device, not shown, the expanding jaws are, if necessary 32 and 34 moved apart until the contact surfaces 80 on the articular surfaces 24 and 26 issue. If necessary, you can use the instrument 10 the neighboring vertebrae 14 and 16 to be spread even further. On the instrument part 28 is a display device, not shown, is formed, which comprises a scale on which certain implant sizes are identified. With appropriate selection of the plates 78 the implant to be selected can then be read directly from the scale. Alternatively, the scale can also be a length scale, so that, based on the displayed value, a distance between the two joint surfaces 24 and 26 determined from each other and the intervertebral implant to be used can be selected accordingly.

In a next step, the two expanding jaws 32 and 34 moved towards each other again and the trial implant 76 from the intervertebral space 12 away.

Claims (27)

Surgical instrument ( 10 ) to determine the size and / or height of an intervertebral space ( 12 ) between two adjacent vertebrae ( 14 . 16 ) two vertebrae ( 18 . 20 ) a human or animal spine ( 22 ) usable intervertebral implant, the intervertebral implant being a first contact element for contacting an articular surface ( 24 ) of the one ( 14 ) of the two adjacent vertebrae ( 14 . 16 ) and a second contact element, directly or indirectly mounted on the first contact element, for contact with an articular surface ( 26 ) of the other ( 16 ) of the two adjacent vertebrae ( 14 . 16 ), the instrument ( 10 ) a longitudinal direction ( 44 ) defining holding part ( 28 ) and at least one trial implant ( 76 ) which comprises a first and a second, in each case at least one contact surface ( 80 ) for contact with one of the articular surfaces ( 24 . 26 ) having a trial implant plant element ( 78 ) comprises, at a distal end of the holding part ( 28 ) at least one contact element holding element ( 56 . 58 ) for detachable connection to the at least one trial implant ( 78 ) is provided, characterized in that the first and / or the second trial implant contact element ( 78 ) related to the longitudinal direction ( 44 ) in at least two defined, different angular positions relative to the at least one contact element holding element ( 56 . 58 ) can be releasably connected to it. Instrument according to claim 1, characterized in that the first or the second trial implant contact element ( 78 ) is arranged lying in one plane in the at least two defined, different angular positions and that the two planes are identical. Instrument according to one of the preceding claims, characterized in that the first and / or the second trial implant contact element ( 78 ) and the at least one contact element holding element ( 56 . 58 ) can be brought into engagement for releasable connection by a relative movement towards one another in a direction transverse to the longitudinal direction ( 44 ) running connection direction ( 64 ). Instrument according to one of the preceding claims, characterized in that the at least one contact element holding element ( 56 . 58 ) with the first and / or the second trial implant contact element ( 78 ) is non-positively and / or positively connectable. Instrument according to one of the preceding claims, characterized in that a first and a second connecting element ( 60 . 62 . 86 ) are provided for connecting the at least one contact element holding element ( 56 . 58 ) with the first and / or the second trial implant contact element ( 78 ) and that one of the trial implant system elements ( 78 ) and the at least one contact element holding element ( 56 . 58 ) one of the two connecting elements ( 60 . 62 . 86 ) wear. Instrument according to claim 5, characterized in that the first connecting element has a receptacle ( 60 . 62 ) and the second connecting element for receiving ( 60 . 62 ) corresponding and insertable projection ( 86 ) is. Instrument according to claim 6, characterized in that the projection on the trial implant contact element in the direction of the contact element holding element ( 56 . 58 ) protruding cylindrical pin ( 86 ) and that the receptacle is one for tapping ( 86 ) corresponding bore diameter ( 60 . 62 ) or in-hole drilling. Instrument according to one of claims 5 or 6, characterized in that the projection ( 86 ) in one direction ( 64 ) transverse to the longitudinal direction ( 44 ) in the recording ( 60 . 62 ) can be introduced. Instrument according to one of the preceding claims, characterized in that a latching connection is provided for securing a connection of the at least one contact element holding element ( 56 . 58 ) with the first and / or the second trial implant contact element ( 78 ) in one of the angular positions. Instrument according to one of the preceding claims, characterized in that a clamping device ( 88 . 90 ) is provided for the clamping securing of a connection of the at least one contact element holding element ( 56 . 58 ) with the first and / or the second trial implant system element ( 78 ) in one of the angular positions. Instrument according to claim 10, characterized in that the clamping device comprises at least one of the connecting elements ( 60 . 62 . 86 ) at least partially encompassing clamping element ( 90 ), which in a gap ( 88 ) between the at least one contact element holding element ( 56 . 58 ) and the first and / or the second trial implant system element ( 78 ) can be used and before connecting the at least one contact element holding element ( 56 . 58 ) and the first and / or the second trial implant system element ( 78 ) at least on one side over the gap ( 88 ) protrudes. Instrument according to claim 11, characterized in that the gap on the projection ( 86 ) circumferential annular groove ( 88 ) and that the clamping element has an elastic ring ( 90 ) whose diameter is greater than a depth of the ring groove ( 88 ) is. Instrument according to one of the preceding claims, characterized in that a tensioning device is provided for securely securing a connection of the at least one contact element holding element ( 56 . 58 ) with the first and / or the second trial implant contact element ( 78 ) in one of the angular positions. Instrument according to one of the preceding claims, characterized in that a plurality of trial implants ( 76 ) is provided and that the majority of trial implants ( 78 ) different distances between the contact surfaces ( 80 ) from each other and / or different lordosis angles ( 98 ) between the contact surfaces ( 80 ) exhibit. Instrument according to one of the preceding claims, characterized in that an angle adjusting device ( 66 . 68 . 70 . 72 . 92 ) is provided for specifying and setting the different angular positions of the first and / or the second trial implant system element ( 78 ) relative to the at least one contact element holding element ( 56 . 58 ) that the angle adjustment device ( 66 . 68 . 70 . 72 . 92 ) at least two adjustment elements which can be brought into engagement with one another in the different angular positions ( 66 . 68 . 70 . 72 . 92 ) and that the first and / or the second trial implant element ( 78 ) a first setting element ( 92 ) and the at least one contact element holding element ( 56 . 58 ) a second setting element ( 66 . 68 . 70 . 72 ) exhibit. Instrument according to claim 15, characterized in that at least one of the at least two adjusting elements ( 66 . 68 . 70 . 72 . 92 ) in the form of a setting holder ( 66 . 68 . 70 . 72 ) and that at least one further of the at least two setting elements ( 66 . 68 . 70 . 72 . 92 ) in the form of a 66 . 68 . 70 . 72 ) insertable projection ( 92 ) is trained. Instrument according to claim 16, characterized in that the adjustment projection ( 92 ) in one direction ( 64 ) transverse to the longitudinal direction ( 44 ) in the setting holder ( 66 . 68 . 70 . 72 ) can be introduced. Instrument according to one of claims 16 or 17, characterized in that the trial implant contact element ( 78 ) at least one adjustment projection ( 92 ) and that the contact element holding element ( 56 . 58 ) at least two shots ( 66 . 68 . 70 . 72 ) having. Instrument according to one of the preceding claims, characterized in that the at least one contact element holding element ( 56 . 58 ) is cylindrical and that a longitudinal axis ( 64 ) of the at least one contact element holding element ( 56 . 58 ) transverse to the longitudinal direction ( 44 ) runs. Instrument according to one of the preceding claims, characterized in that the trial implant system elements ( 78 ) each have a recess for the at least one contact element holding element ( 56 . 58 ) and that the at least one contact element holding element ( 56 . 58 ) positively or essentially positively in the recess ( 84 ) can be introduced. Instrument according to one of the preceding claims, characterized in that the first and / or the second trial implant contact element ( 78 ) in the second angular position relative to the at least one contact element holding element ( 56 . 58 ) relative to the first angular position by an angle ( 74 ) can be arranged twisted. Instrument according to claim 21, characterized in that the setting angle ( 74 ) has a value in a range from 10 ° to 30 °. Instrument according to one of the preceding claims, characterized in that at the distal end of the instrument ( 10 ) a first and a second contact element holding element ( 56 . 58 ) is provided and that the first contact element holding element ( 56 ) with the first trial implant system element ( 78 ) and the second contact element holding element ( 58 ) with the second trial implant system element ( 78 ) is releasably connectable. Instrument according to claim 23, characterized in that the first contact element holding element ( 56 ) and the second contact element holding element ( 58 ) transversely or essentially transversely to their contact surfaces ( 80 ) are mounted movably towards and / or away from each other. Instrument according to one of claims 23 or 24, characterized in that the distal end of the holding part ( 28 ) two expanding jaws ( 32 . 34 ) has that the expanding jaws ( 32 . 34 ) the contact element holding elements ( 56 . 58 ) embrace or carry and that the expanding jaws ( 32 . 34 ) by one on the holding part ( 28 ) arranged drive device, which a at the proximal end of the holding part ( 28 ) arranged actuating element comprises, are movable away from each other and / or towards each other. Instrument according to claim 25, characterized in that the expanding jaws ( 32 . 34 ) are spread apart parallel to each other. Instrument according to one of claims 24 to 26, characterized in that the holding part ( 28 ) has a path measuring device for measuring and displaying a distance between the contact surfaces ( 80 ) from each other or a travel path of the contact element holding elements ( 56 . 58 ) relative to each other.