DE29614920U1 - Surgical device for aligning and temporarily fixing a segment of a calotte - Google Patents

Description

Surgical device for aligning and temporarily fixing a skull segment

The present invention relates to a surgical device for aligning and temporarily fixing a skull segment removed from a skull capsule to the remaining skull cap.

During cranio-surgical interventions, it is necessary to provide the surgeon with access to the surgical area by removing a skull segment from the patient's skull cap. To do this, several trepanation holes are usually drilled into the skull cap, which are then connected to one another using craniotome cuts to form an incision gap. The incision gap thus created surrounds the skull segment so that it can be removed from the skull cap and the surgeon has access to the brain underneath. After the operation, the skull segment must be reinserted into the skull cap and fixed to the remaining skull cap.

To fix the calotte segment to the remaining skull cap, wire loops, threads or metal micro-plates are usually used. To use the wire loops and threads, through-holes are made in the edge areas of the calotte segment and, adjacent to it, on the remaining skull cap, through which the wire loops or threads are passed. If, as an alternative or in addition to the wire loops and threads, the

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If micro-plates are used to bridge the incision gap, it is necessary to screw these ends to the skull segment on the one hand and to the remaining skull cap on the other.

Both screwing and the creation of additional through holes involve mechanical stress on the calotte segment. This means that in many cases the calotte segment shifts when it is fixed to the remaining skull cap in such a way that an unevenly wide cutting gap is created along its circumference. Furthermore, when fixing the calotte segment, there is a risk that the level of the calotte segment will not match that of the remaining skull cap.

The object of the present invention is to provide an easy-to-use surgical device with the aid of which the skull segment can be aligned relative to the remaining skull cap and temporarily fixed during the attachment of a permanent connecting element.

This object is achieved according to the invention in a surgical device of the type mentioned at the outset in that the device comprises a pulling element and a holding element that can be braced with it, wherein the pulling element is essentially T-shaped, comprises a shaft and two pulling arms protruding from it and is rotatable about its longitudinal axis and wherein the holding element is held on the shaft so as to be adjustable in its longitudinal direction.

Due to its T-shaped design, the traction element can be inserted distally directly into the incision gap between the calvarial segment and the remaining skull cap.

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To do this, it is only necessary to align the tension arms protruding from the shaft in the longitudinal direction of the cutting gap. The width of the tension arms and the diameter of the shaft are selected so that they are smaller than the width of the cutting gap. After insertion, the tension element is rotated by approx. 90° around its longitudinal axis so that the tension arms protruding from the shaft grip the bone tissue of the calotte segment and the remaining skull cap adjacent to the cutting gap. The device also includes a holding element that is adjustably held on the shaft of the tension element. The cutting gap can be covered by the holding element so that the holding element on the outside of the skull capsule comes to rest on the calotte segment and the remaining skull cap. The tension element and holding element can be clamped together, i.e. the bone areas of the calotte segment and the remaining skull cap adjacent to the cutting gap can be clamped between the tension element and the holding element. This results in the calotte segment being aligned with the remaining skull cap. In addition, the tensioning of the tension and holding element also results in the calotte segment being fixed to the remaining skull cap.

If several surgical devices according to the invention are introduced into the incision gap distributed over the circumference of the skull segment and the tension and holding elements are clamped together, this results in the level of the skull segment adapting to that of the remaining skull cap and the incision gap taking up essentially the same width over the entire circumference of the skull segment. Permanent connecting elements, for example the wire loops or threads mentioned at the beginning, can now be attached to the skull segment aligned and temporarily fixed in this way.

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If permanent fixation is ensured, the tension between the pulling and holding element is released and the pulling element is rotated again by about 90° so that the pulling arms are again aligned parallel to the longitudinal direction of the cutting gap and the pulling element can be removed from the cutting gap. The surgical device according to the invention is therefore easy to handle and enables alignment and temporary fixation of the calotte segment in a simple manner and with little expenditure of time.

In order to facilitate the insertion of the traction element into the gap between the calotte segment and the remaining skullcap, it is advantageous if the shaft tapers conically in its distal end area. For example, it can be provided that the shaft is chamfered on the sides facing the calotte segment or the skullcap during insertion and thus has a larger diameter in relation to the longitudinal axis of the traction arms than transversely to it.

It can also be provided that the distal end region of the shaft is frustoconical and has a smaller diameter at its distal end, at which the pulling arms are held, than at a distance from it.

It is particularly advantageous to pivot the traction arms at the distal end of the shaft with the pivot axis aligned transversely to the longitudinal axis of the traction arms. This makes it possible to align the traction arms at an angle to the longitudinal axis of the shaft to compensate for any irregularities in the skull.

It is advantageous if the pulling arms are positioned from a central position that is aligned transversely to the longitudinal axis of the shaft.

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can be swivelled by approximately 30° clockwise and anti-clockwise.

It is advantageous if the holding element surrounds the shaft of the pulling element in a ring shape. Such a design has the advantage that no special orientation is required for the holding element in relation to the pulling arms in the circumferential direction. Rather, the holding element comes into contact with the outside of the calotte segment and the remaining skull cap regardless of the orientation of the pulling arms.

In an advantageous embodiment, it is provided that the shaft has an external thread and the holding element can be screwed onto the shaft. The holding element can, for example, be designed as a lock nut, so that the bone areas of the calotte segment adjacent to the cutting gap and the remaining skull cap can be clamped between the tension arms and the lock nut.

In a particularly preferred embodiment of the surgical device according to the invention, the holding element is held displaceably on the shaft. This enables particularly simple handling, as the holding element can be moved directly along the shaft to attach the surgical device.

In an advantageous embodiment, the tensioning of the tension and holding element is achieved by the holding element being displaceable in the proximal direction of the shaft against the effect of an elastic restoring force. For example, it can be provided that the holding element, in the unloaded state, rests directly on the tension arms protruding from the shaft and for inserting the tension element into the

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Cutting gap comes into contact with the upper side of the cutting gap and is moved along the shaft in a proximal direction. The movement takes place against the effect of an elastic restoring force, so that the holding element is subjected to a clamping force directed at the pulling arms.

The elastic restoring force can be achieved in an advantageous manner in that the holding element can be subjected to a spring force directed at the tension arms by a spring element supported on a projection of the shaft. For example, it can be provided that the shaft carries a support flange at a distance from the tension arms, for example at its end facing away from the tension arms, on which the spring element is supported with its proximal end, while the distal end of the spring element comes to rest on the upper side of the holding element facing away from the tension arms. If the holding element is displaced in the proximal direction in such a design, it experiences a spring force directed at the tension arms due to the spring element.

The spring element can advantageously be designed as a helical spring surrounding the shaft.

In an advantageous embodiment, it is provided that the holding element has a sleeve surrounding the shaft, which has a projection protruding from the outside at its proximal end to lift the sleeve against the effect of the elastic restoring force. The projection can, for example, be designed as an end flange surrounding the sleeve along its entire outer circumference, the underside of which facing the pulling arms forms a contact surface for the surgeon, who can grip the end flange with his index and middle fingers and thus

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can easily move the sleeve in the proximal direction.

It is particularly advantageous if the shaft has a handle at the end facing away from the pulling arms.

The handle can be designed as a crossbar, for example. In particular in combination with a sleeve with a projection at the end, this results in particularly simple handling of the surgical device according to the invention, in that the crossbar forms a handle for the surgeon from which he can move the sleeve against the effect of the elastic restoring force by gripping under the projection and lifting it in the direction of the crossbar arranged at the end. In the raised state, the sleeve is at a distance from the pulling arms so that the pulling element can be inserted directly into the incision gap and rotated, and the surgeon then releases the sleeve so that it rests against the outside of the dome segment and the remaining skull dome and, due to the tension force between the sleeve and the pulling arms caused by the restoring force, the dome segment and the remaining skull dome are mutually aligned.

The following description of preferred embodiments of the invention serves to explain it in more detail in conjunction with the drawing. They show:

Figure 1: a schematic representation of a human skull with a skull segment aligned and temporarily fixed by means of the surgical device according to the invention;

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Figure 2:

a schematic, perspective representation of a first embodiment of the surgical device according to the invention during the insertion of a pulling element into an incision gap;

Figure 3:

a schematic representation according to Figure 2 after twisting of the tension element;

Figure 4:

a schematic, perspective view of a second embodiment of the surgical device according to the invention and

Figure 5:

a schematic, perspective representation of a third embodiment of the surgical device according to the invention.

Figure 1 shows a human skull 10 with a skull capsule 12 into which three trepanation holes 13, 14, 15 have been made, which are then connected to one another via craniotome cuts 16, 17 and 18. The craniotome cuts form an incision gap 20 that surrounds a skull segment 22 that can be removed from the skull capsule 12 to give a surgeon access to the brain underneath. After the operation, the skull segment 22 is reinserted into the skull capsule 12 and fixed to the remaining skull cap 24 surrounding the skull segment 22, so that the skull segment 22 can grow back together with the skull capsule 12.

In order to promote the healing process, it is advantageous if the cutting gap 20 extends along the entire circumference of the calotte

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segments 22 has essentially the same width. It is also desirable if the level of the calotte segment 22 corresponds to the level of the remaining calotte 24. The final fixation of the calotte segment 22 to the remaining calotte 24 can be carried out, for example, by means of metal micro-plates or by means of wire loops and threads. In order to ensure that the calotte segment 22 maintains an optimal orientation with respect to the remaining calotte 24 during their application, the calotte segment 22 is temporarily fixed using the surgical device described below, with the calotte segment 22 simultaneously being aligned relative to the remaining calotte 24.

A first embodiment of the surgical device according to the invention is shown in Figures 2 and 3. Figure 2 shows a surgical connecting element 26 with a cylindrical shaft 28 that can be inserted into the incision gap 20 between the calotte segment 22 and the remaining skull cap 24, the distal end of which is T-shaped and has two tension arms 30 and 31 that protrude perpendicularly to the shaft. At the proximal end facing away from the tension arms 30, 31, a support flange 32 is held on the shaft 28 that surrounds it in the circumferential direction, as well as a crossbar 34 that is aligned perpendicularly to the shaft 28 and that is fixed centrally to the proximal end face of the shaft 28 with respect to its longitudinal direction.

The shaft 28 is surrounded along its entire length in the circumferential direction by a helical spring 36, the proximal end of which rests against the support flange 32 and which carries a retaining ring 38 at its distal end, through which the shaft 28 passes and

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is subjected to a spring force by the coil spring 36 directed onto the tension arms 30 and 31.

The diameter of the shaft 28 and the width of the pulling arms 30 and 31 are selected such that the shaft 28 and the pulling arms 30 and 31, provided they are aligned parallel to the longitudinal direction of the cutting gap 20 - as shown in Figure 2 - can be introduced into the cutting gap 20, while the diameter of the retaining ring 38 exceeds the width of the cutting gap 20 so that it covers the cutting gap 20. The crossbar 34 is aligned parallel to the pulling arms 30 and 31 so that the surgeon can orient himself on the alignment of the crossbar 34 when he introduces the pulling arms 30 and 31 and the distal end region of the shaft 28 into the cutting gap 20. Since the diameter of the retaining ring 38 is larger than the width of the cutting gap 20, the retaining ring 38 comes to rest on the upper side of the calotte segment 22 and the remaining skull cap 24 when the pulling arms 30 and 31 enter the cutting gap 20.

The shaft 28 is inserted into the cutting gap 20 until the pulling arms 30 and 31 assume a position below the calotte segment 20 and the remaining skull cap 24. After reaching this position, the shaft 28 is rotated by approximately 90° around its longitudinal axis, as shown in Figure 3. The pulling arms 30 and 31 now grip under the calotte segment 22 or the remaining skull cap 24 in the areas adjacent to the cutting gap 20. The retaining ring 38 is mechanically connected to the shaft 28 via the helical spring 36 and the support flange 32, and the lowering of the distal end region of the shaft 28 results in the retaining ring 38 and the pulling arms 30 and 31 being clamped together due to the spring force of the helical spring 36.

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This in turn causes the tension arms 30 and 31 to rise until the level of the dome segment 22 matches the level of the remaining skull dome 24, with the retaining ring 38 serving as a counter ring and ensuring level compensation. The distal end area of the shaft 28, which extends through the cutting gap 20, also serves as a spacer between the dome segment 22 and the remaining skull dome 24. If several connecting elements 26 are applied in this way distributed over the circumference of the dome segment 22, the result is that, on the one hand, the level of the dome segment is aligned with the level of the remaining skull dome and, on the other hand, that the cutting gap 20 takes up approximately the same width along the entire circumference of the dome segment 22. In addition, the dome segment and the remaining skull dome 24 are mutually fixed. After the application of several connecting elements 26, the skull segment 22 can thus be permanently fixed in the remaining skull cap 24 by means of known fastening elements, without the risk of the skull segment 22 assuming a misorientation.

A second embodiment of the surgical device according to the invention is shown in Figure 4. This shows a surgical connecting element 40 which essentially corresponds to the connecting element 26 described above and in which identical parts are designated with the same reference numerals as in Figures 1 to 3.

The connecting element 40 shown in Figure 4 comprises, in addition to the retaining ring 38, which is subjected to an elastic restoring force in the distal direction by means of the helical spring 36, a sleeve 42 which is connected in one piece to the retaining ring and surrounds the helical spring 36, at the proximal

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An end flange 44 aligned parallel to the retaining ring 38 is held on the front face. With the help of the end flange 44, which is mechanically connected to the retaining ring 38 via the sleeve 42, the handling of the connecting element 40 is simplified, since the surgeon can grip the end flange 44 and thereby lift the sleeve 42 and the retaining ring 38 against the effect of the coil spring 36, so that the distal end region of the shaft 28 and the two pulling arms 30 and 31 are spaced apart from the retaining ring 38. The free-standing T-shaped end region of the connecting element 40 can thus be introduced unhindered into the cutting gap 20 and then rotated by 90°.

A third embodiment of the surgical device according to the invention is shown in Figure 5. This shows a connecting element 46 with a shaft 47, which has two pulling arms 48, 49 aligned transversely to the shaft 47 at its distal end and a crossbar 50 aligned parallel to the pulling arms 48, 49 at its proximal end. Aligned parallel to the longitudinal direction of the cutting gap 20, the pulling arms 48 and 49 as well as the distal end region of the shaft 47 can be inserted directly into the cutting gap 20 and then rotated by 90° about the longitudinal axis of the shaft 47, so that the pulling arms 48 and 49 grip under the calotte segment 22 or the remaining skull cap 24 in accordance with the embodiments described above. In contrast to the previously described connecting elements 26 and 40, the shaft 47 of the connecting element 46 has an external thread 52 onto which a lock nut 54 is screwed, which has a large number of longitudinal grooves 56 distributed over the circumference on its outside for better handling. The length of the external thread 52 is selected such that the lock nut 54 can be threaded along the external thread 52 as far into

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can be screwed in the proximal direction so that the distal end area of the shaft 47 can be inserted unhindered into the cutting gap 20 and rotated by approximately 90°. After rotating the shaft 47, the lock nut 54 is screwed in the distal direction until it comes to rest on the outside of the calotte segment 22 and the remaining skull cap 24 and the bone areas positioned between the tension arms 48 and 49 and the lock nut 54 are mutually aligned and clamped together.

In the embodiments shown in the drawing, the shaft 28 has the same diameter over its entire length. In order to facilitate the insertion of the distal end region of the shaft 28 into the cutting gap 20, it can be provided that the shaft 28 tapers conically in its distal end region. For this purpose, it can be designed in the shape of a truncated cone, for example. Since only the extension of the shaft transversely to the longitudinal axis of the pulling arms 30, 31 aligned parallel to the longitudinal direction of the cutting gap 20 is important during insertion, but not the extension of the shaft parallel to the longitudinal axis of the pulling arms 30, 31, it can also be provided that the shaft is conically chamfered on its sides facing the dome segment 22 or the remaining skull dome 24 during insertion and aligned transversely to the longitudinal axis of the pulling arms 30, 31.

It is also advantageous if the pulling arms 30 and 31 are pivotably mounted at the distal end of the shaft 28 with the pivot axis aligned transversely to the longitudinal axis of the pulling arms. This makes it possible to move the pulling arms 30 and 31 upwards and downwards, i.e. counterclockwise, from a central position aligned transversely to the longitudinal axis of the shaft 28 in order to compensate for any irregularities in the skull capsule 12.

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pointer direction and clockwise by up to 30°, for example.

Claims (11)

A 53 388 u 15 August 1996 - 15 - PROTECTION CLAIMS 1. Surgical device for aligning and temporarily fixing a skull segment removed from a skull cap to the remaining skull cap, characterized in that the device comprises a pulling element and a holding element (38; 54) that can be releasably clamped to it, wherein the pulling element is essentially T-shaped, comprises a shaft (28; 47) and two pulling arms (30, 31; 48, 49) projecting from it and is rotatable about its longitudinal axis and wherein the holding element (38; 54) is held on the shaft (28 or 47) so as to be adjustable in its longitudinal direction. 2. Surgical device according to claim 1, characterized in that the holding element (38; 54) surrounds the shaft (28; 47) of the pulling element in a ring shape. 3. Surgical device according to claim 1 or 2, characterized in that the shaft (47) has an external thread (52) and the holding element (54) can be screwed onto the shaft (47). 4. Surgical device according to claim 1 or 2, characterized in that the holding element (38) is slidably held on the shaft. 5. Surgical device according to claim 4, characterized in that the holding element (38) is displaceable against the action of an elastic restoring force in the proximal direction of the shaft (28). A 53 388 u 15 August 1996 - 16 - 6. Surgical device according to claim 5, characterized in that the holding element (38) can be acted upon by a spring element (36) supported on a projection (32) of the shaft (28) with a spring force directed onto the pulling arms (30, 31). 7. Surgical device according to claim 6, characterized in that the spring element is designed as a helical spring (36) surrounding the shaft (28), 8. Surgical device according to claim 5, 6 or 7, characterized in that the holding element has a sleeve (42) surrounding the shaft (28), which has an externally projecting projection (44) at its proximal end for lifting the sleeve (42) against the effect of the elastic restoring force. 9. Surgical device according to one of the preceding claims, characterized in that the shaft (28; 47) carries a handle (34; 50) at its end facing away from the pulling arms (30, 31; 48, 49). 10. Surgical device according to claim 9, characterized in that the handle is designed as a crossbar (34; 50). 11. Surgical device according to claim 9 or 10, characterized in that the handle (34; 50) is aligned parallel to the pulling arms (30, 31; 48, 49).