Medical set for vertebral distraction

Abstract

Medical set for distracting vertebral bodies, in particular for the treatment of vertebral body fractures, for use with at least one first and one second holding element (10, 11), wherein each of the holding elements (10, 11) comprises a distal section (12, 13) and a proximal section (14, 15) with a proximal end (16, 17) for receiving a bone anchor (18), in particular a bone screw, wherein the set has at least one compression device (19) which, in use, can be connected to the distal section (12, 13) of each of the first and second holding elements (10, 11) and is configured to change the distance between the distal sections (12, 13) of the first and second holding elements (10, 11), wherein the set has at least one spacer device (20) with a first receiving element (21) and a second receiving element (22),wherein the first receiving element (21) is configured for arrangement on the first holding element (10) corresponding to a projection section (23) of the proximal section (14) of the first holding element (10) and the second receiving element (22) is configured for arrangement on the second holding element (11) corresponding to a projection section (24) of the proximal section (15) of the second holding element (11) in order to form a rotation range and induce a rotation of the holding elements (10, 11) about the projection sections (23, 24) when the distance between the distal sections (12, 13) of the first and second holding elements (10, 11) is changed by the compression device (19).

Description

[0001] The invention relates to a medical set for distracting vertebral bodies, particularly in the treatment of vertebral fractures, for use with at least one first and one second holding element. A medical set according to the preamble of claim 1 is known, for example, from WO 2018 / 083000 A1 or EP 3 636 185 A1.

[0002] In modern spinal surgery, particularly in the treatment of vertebral fractures, it is often necessary to spread the vertebrae, i.e., move them away from each other (distraction), in order to create space for the fractured vertebra and / or to realign it. The new position of the spread vertebrae can then be fixed, for example, using appropriate osteosynthesis devices.

[0003] It is common practice to first insert bone screws (for example, monoaxial or multiaxial pedicle screws) into the adjacent healthy vertebral bodies using elongated retention elements or insertion sleeves, also called towers. It is known that the distance between the vertebral bodies can be altered or increased with the aid of these retention elements, which engage firmly with the bone screws.

[0004] Devices are already known in the art that connect the holding elements in an adjustable manner, thus enabling distraction of the vertebral bodies. Such devices are known, for example, from the aforementioned WO 2018 / 083000 A1 or EP 3 636 185 A1. However, these devices are complex to manufacture and operate. Furthermore, the view of the surgical field, particularly during X-ray examinations, is impaired by these devices.

[0005] The invention is therefore based on the objective of providing an improved medical set for the distraction of vertebral bodies. In particular, the set should be easy to use and ensure a substantially unrestricted view of the surgical field, especially during X-ray examinations.

[0006] According to the invention, this problem is solved by a medical set having the features of claim 1.

[0007] In one embodiment, this problem is solved by a medical set for distracting vertebral bodies, particularly in the treatment of vertebral fractures, for use with at least one first and one second holding element, wherein each of the holding elements comprises a distal section and a proximal section with a proximal end for receiving a bone anchor, in particular a bone screw. The set has at least one compression device which, in use, can be connected to the distal section of each of the first and second holding elements and is configured to change the distance between the distal sections of the first and second holding elements.The set comprises at least one spacer device with a first receiving element and a second receiving element, wherein the first receiving element is designed to correspond to a projection section of the proximal section of the first holding element for arrangement on the first holding element, and the second receiving element is designed to correspond to a projection section of the proximal section of the second holding element for arrangement on the second holding element, in order to form a rotation range and induce a rotation of the holding elements about the projection sections when the distance between the distal sections of the first and second holding elements is changed by the compression device.

[0008] The invention has several advantages.

[0009] The set according to the invention is thus suitable for use with conventional retention elements and bone anchors (e.g., pedicle screws) and is therefore versatile in its application. One aspect of the invention is that no parallel displacement of the vertebral bodies takes place. Instead, the vertebrae are rotated around a rotational area that lies very close to the body, for example, directly above the skin.

[0010] Retaining elements are elongated devices that can be attached to a bone anchor, particularly a bone screw. The retaining elements are preferably hollow or tubular, especially to facilitate the insertion of the bone anchors into the vertebral bodies. In one embodiment, polyaxial screws are used, characterized by a clevis head that is pivotable relative to a screw anchor.

[0011] As explained in the introduction, bone anchors are preferably inserted into those vertebral bodies adjacent to the fractured vertebral body. In other words, the bone anchors are preferably inserted into the vertebral bodies located cranially or caudally to the fractured vertebral body.

[0012] It is also possible to insert two bone anchors, each with a retention element, into each vertebral body. Preferably, the two bone anchors are inserted laterally, on either side of the spinous process of the vertebral body. In this case, a total of four bone anchors with four retention elements are used, resulting in an arrangement symmetrical with respect to the longitudinal axis of the spine. Two retention elements form a pair, which is used to spread the vertebral bodies. At least one pair, and preferably both pairs, are used to distract the vertebral bodies. Advantageously, each pair of retention elements is equipped with a compression device and a spacer device.

[0013] This arrangement allows the vertebral bodies adjacent to the fractured vertebral body to be easily moved away from it. This is achieved by moving the distal sections of the retaining elements towards each other using compression devices. This advantageously causes the proximal sections of the retaining elements, to which the bone anchors are attached, to move away from each other. In this way, the vertebral bodies into which the bone anchors are inserted can be spread apart, creating space for the fractured vertebral body. The spacer device is preferably positioned between the proximal sections of the retaining elements to create a rotational range. In other words, the spacer device advantageously forms a hypomochlion and thus significantly contributes to the leverage. This has the advantage of making the medical set easy and requiring minimal effort to operate.

[0014] Furthermore, the spacer device comprises at least two receiving elements, each shaped to correspond to a corresponding section of the proximal sections of the retaining elements. In other words, the shape of the receiving elements preferably corresponds substantially to the shape of the sections of the retaining elements. The receiving elements can be concave. This is particularly advantageous for retaining elements that have a corresponding convex shape. Other configurations of the receiving elements are conceivable. Advantageously, the receiving elements position the spacer device on the sections of the proximal sections of the retaining elements in such a way that lateral displacement (relative to the longitudinal axes of the retaining elements) is prevented. The spacer device thus at least partially surrounds the retaining elements, securing them in their position.Furthermore, the receiving elements are designed to induce a rotation of the holding elements around the receiving elements of the spacer device when the distance of the distal sections changes.

[0015] Advantageous embodiments of the invention are specified in the dependent claims.

[0016] In one embodiment, the compression device and the spacer device (specifically their points of application or areas of application) are arranged at a significant distance from each other on the retaining elements, particularly by a first minimum distance. According to the invention, the spacer device is designed such that it can be arranged close to the skin, in particular lying on the skin. Thus, the spacer device surrounds the retaining elements in the proximal area. The compression device is advantageously arranged at least 40%, in particular at least 50%, and in particular at least 60%, further from the proximal end of the retaining elements than the spacer device.In one embodiment, the spacer device and the compression device, in particular their points / areas of application on the retaining elements, are spaced apart by at least 15 cm, in particular at least 20 cm, and in particular at least 25 cm. The distance between the compression device and the spacer device advantageously forms a lever arm. This has the advantage that the set is particularly easy to operate with minimal effort. In other words, the vertebral bodies can be easily spread apart.

[0017] Furthermore, the spacer device can have at least one first and one second leg, at the ends of which the first and second receiving elements are arranged. In other words, the spacer device is formed from at least two elongated elements whose ends are designed as receiving elements. The receiving elements can be arranged essentially perpendicular to the longitudinal axis of the legs.

[0018] The spacer device, or its arms, advantageously have a low height compared to its longitudinal extension. The spacer device can have a maximum height of 1.5 cm, particularly 1 cm, and especially 0.5 cm. Thus, the spacer device hardly obstructs the surgeon and can be easily placed on the patient.

[0019] In one embodiment, the spacer device is essentially U-shaped and / or its legs are arranged in an essentially U-shape. Advantageously, the spacer device is positioned in use such that it extends away from the surgical field. In other words, the legs of the spacer device extend away from the surgical field, forming a U-shape. This is advantageous because it ensures a substantially unobstructed view of the surgical field, particularly during X-ray examinations. This is advantageously achieved by ensuring that the medical set, and especially the spacer device, leaves the area to be imaged clear or does not block the imaging area during an anterior-posterior (AP) radiograph.This is preferably understood to mean that the spacer device is not positioned directly above the spine during use. Furthermore, the retention elements are advantageously arranged such that, in the implanted state, they extend obliquely away from the spine. In other words, the imaging area or surgical field is advantageously essentially free of devices and / or components of the set. Consequently, both during the operation itself and during X-ray imaging, a substantially unobstructed view of the surgical field can be ensured.

[0020] In a further embodiment, the spacer device has at least one adjusting element, allowing it to be adapted to the distance between the proximal section of the first retaining element and the proximal section of the second retaining element. The distance between the proximal sections of the two retaining elements can vary depending on a patient's anatomy. The adjusting element advantageously allows the spacer device to be adapted to this individual distance. In this way, an optimal fit of the spacer device between the proximal sections of the two retaining elements can be ensured. The spacer device can be individually adapted to specific conditions, such as the vertebral body spacing and the resulting distance between the retaining elements.

[0021] The legs of the spacer device can be connected to each other via a rotary joint. The adjusting element can be positioned between the legs of the spacer device and connect them. The rotary joint forms an axis of rotation around which the legs can be rotated when the distance between them is changed. In other words, a change in the distance between the legs via the adjusting element causes the legs to rotate around the axis of rotation. This arrangement of the adjusting element and the rotary joint allows the distance between the legs to be easily adjusted to match the distance between the proximal end of the first retaining element and the proximal end of the second retaining element.

[0022] Preferably, the adjusting element comprises at least one threaded rod and an adjusting wheel for adjusting the distance. The adjusting wheel can be engaged with the threaded rod. By turning the adjusting wheel, the spacer device can therefore be easily adjusted to the distance between the proximal section of the first retaining element and the proximal section of the second retaining element. It is advantageous that the spacer device or the adjusting element is easy to operate.

[0023] Furthermore, the first and second receiving elements can each comprise a receiving surface, particularly a concave one, and / or the spacer device can each have a contact part, preferably extending transversely to the receiving surface, and in particular a convex one, which is designed to provide a surface of rotation for the rotation of the retaining elements. The particularly concave shape of the receiving elements advantageously serves to securely receive the retaining elements. In particular, the receiving elements are intended to prevent or at least reduce undesired movements of the retaining elements, such as transverse displacements about the longitudinal axes of the retaining elements. Furthermore, the contact parts are designed such that the retaining elements roll on the contact parts when the distance between the distal sections changes. The contact parts advantageously form the rotational area of ​​the retaining elements around the mounting sections.

[0024] In a further embodiment, the compression device comprises at least one spacer adjustment element to change the distance between the distal sections of the first and second retaining elements during use. In other words, the distance between the distal sections of the first and second retaining elements can be varied, and in particular reduced, by the spacer adjustment element. The compression device connects the retaining elements to each other in an adjustable manner during use. Advantageously, the spacer adjustment element can induce a tilting movement of the retaining elements, thereby spreading the vertebral bodies. In other words, the distal sections of the retaining elements can be moved towards each other by the spacer adjustment element, causing the proximal sections of the retaining elements, and consequently the vertebral bodies, to move away from each other.

[0025] Furthermore, the spacing element preferably comprises a spindle thread with at least one spindle rod extending along a longitudinal axis L and engaging with at least one spindle wheel. By rotating the spindle wheel, the distance between the distal sections of the first and second retaining elements can be easily changed. The spacing element of the compression device is advantageously easy to operate and requires little space, so that the view of the surgical field is not obstructed.

[0026] Preferably, the compression device comprises at least one first fastening element and one second fastening element, wherein the first fastening element is connectable to the distal section of the first retaining element and the second fastening element is connectable to the distal section of the second retaining element. The fastening elements can be designed to be slid or clipped onto the retaining elements. In other words, the fastening elements can be detachably connected to the distal sections. Alternatively, the fastening elements can be permanently connected to the distal sections of the retaining elements. The advantage here is that the fastening elements ensure a secure fit of the compression device on the retaining elements. The fastening elements can, for example, be designed as a cap or an eyelet.This design has the advantage that the compression device can be attached to the mounting elements easily and securely, but also removed easily and with little force. Other designs are conceivable.

[0027] Furthermore, at least one of the two fastening elements can be movably arranged on the spindle rod of the compression device. Preferably, this means that one of the two fastening elements is slidable on the spindle rod, while the other fastening element is fixedly arranged on the spindle rod or rigidly connected to it. In other words, at least one of the two fastening elements is movable along the longitudinal axis L of the spindle rod. This easily ensures that the distance between the distal sections of the fastening elements can be adjusted.

[0028] In another embodiment, the fastening elements are connected to the spindle rod via a swivel joint to allow the fastening elements to rotate radially along the longitudinal axis L during use. This is preferably understood to mean that the orientation of the fastening elements, and thus of the retaining elements, can be changed radially along the longitudinal axis L. This allows the tilting movement of the retaining elements to occur when the compression device is actuated, which advantageously leads to the spreading of the vertebral bodies.

[0029] Furthermore, the medical set can include the first and second retaining elements. In other words, in one embodiment, at least two retaining elements are part of the set according to the invention. It is possible that four retaining elements are part of the set.

[0030] According to dependent claim 15, the invention relates to a system with a first and a second set, wherein the sets can be arranged on the left and right sides of the spine. In this case, the bone anchors can be inserted on both sides next to the spinous process of the vertebral body.

[0031] The invention is explained in more detail with reference to an exemplary embodiment in conjunction with the schematic drawings. These show Fig. 1 a schematic view of the spacer device as part of the medical set according to the invention, which is arranged on two holding elements; Fig. 2 a top view of the spacer device according to Fig. 1; Fig. 3 a perspective view of the spacer device according to Fig. 1 with adjustment element; Fig. 4 a perspective view of the spacer device according to Fig. 1 with contact parts; Fig. 5 a schematic view of the compression device as part of the medical set according to the invention; Fig. 6 a side view of the fastening elements of the compression device according to Fig. 5; and Fig. 7 an example of a polyaxial screw suitable for use with the medical set according to the invention.

[0032] Fig. Figure 1 shows a medical set for the distraction of vertebral bodies. Specifically, the medical set can be used in the treatment of vertebral fractures. The set includes a compression device 19 ( Fig. 5) and a spacer device 20 and is suitable for use with at least one first and one second retaining element 10, 11. Specifically, four retaining elements 10, 11 are used in a spinal operation, with each pair of retaining elements 10, 11 forming a pair, on which a compression device 19 and a spacer device 20 are arranged. Consequently, in an operation, two compression devices 19 and two spacer devices 20, each with two (a total of four) retaining elements 10, 11, can be used for distracting the vertebral bodies. Alternatively, it is conceivable that only two retaining elements 10, 11 are used together with the medical set for distracting vertebral bodies, although some asymmetry may occur during the spreading.

[0033] In Fig. The retaining elements 10, 11 are tubular and laterally slotted along their longitudinal extent. Several lateral slots extend along the longitudinal extent of the retaining elements 10.

[0034] The retaining elements 10, 11 have a distal section 12, 13 and a proximal section 14, 15, the distal section 12, 13 being used to connect the retaining elements 10, 11 to the compression device 19.

[0035] The proximal sections 14, 15 extend to a proximal end 16, 17, which serves to receive a bone anchor 18 or a bone screw. The bone anchors 18 are designed as polyaxial screws, with a clevis head 39 pivotable relative to a screw anchor 40. An example of a polyaxial screw is shown in Fig. Figure 7 shows the retaining elements 10, 11 being hollow or tubular for inserting and tightening the bone screws 18. For this purpose, a suitable instrument is inserted from a distal, open end through the interior to the proximal end 16, 17 of the retaining elements 10, 11.

[0036] The compression device 19 (see Fig. 5) is connected in use to the distal sections 12, 13 of the first and second retaining elements 10, 11 respectively (not shown). Furthermore, the compression device 19 is designed to change the distance between the distal sections 12, 13 of the first and second retaining elements 10, 11. In use, the compression device 19 moves the distal sections 12, 13 of the retaining elements 10, 11 towards each other in order to spread the vertebral bodies.

[0037] As in Fig. As can be seen in Figure 1, the set has a spacer device 20 which is arranged between the first and second holding element 10, 11.

[0038] The Fig. Figures 2 to 4 illustrate that the spacer device 20 has a first receiving element 21 and a second receiving element 22. Fig. Figure 1 further shows that the first receiving element 21 is designed for arrangement on the first retaining element 10 and the second receiving element 22 for arrangement on the second retaining element 12. The receiving elements 21 and 22 are each shaped to correspond to a corresponding attachment section 23 and 24 of the proximal sections 14 and 15 of the retaining elements 10 and 11. Specifically, both receiving elements 21 and 22 are concave so that they can engage the tubular retaining elements 10 and 11.

[0039] When the distance between the distal sections 12, 13 of the first and second retaining elements 10, 11 is changed by the compression device 19, these sections undergo a rotational movement around the receiving elements 21, 22. A rotational range is formed. The retaining elements 10, 11 act section by section as lever arms, so that the spreading can be achieved with little force.

[0040] Specifically, the distal sections 12, 13 of the retention elements 10, 11 are moved towards each other by the compression devices 19 during use. This causes the proximal sections 14, 15 of the retention elements, to which the bone screws 18 are attached, to move away from each other. In other words, a tilting movement of the retention elements 10, 11 is performed. The spacer device 20, or the receiving elements 21, 22 of the spacer device 20, forms the rotational range around which the tilting movement of the retention elements 10, 11 is carried out. In this way, the vertebral bodies into which the bone screws 18 are inserted are spread apart, creating space for the fractured vertebral body.

[0041] The compression device 19 and the spacer device 20 are arranged at a considerable distance from each other on the holding elements 10, 11 during use (not shown). Specifically, the compression device 19 and the spacer device 20 are arranged at a minimum distance from each other. In this particular embodiment, this minimum distance is 15 cm. During surgery, the spacer device 20 is positioned close to the skin, while the compression device 29 is located further away from the skin and / or further away from the spine.

[0042] The Fig. Figures 2 to 4 further show that the spacer device 20 has a first and a second leg 30, 31. The legs 30, 31 are designed as elongated elements with a height of approximately 1 cm. The first and second receiving elements 21, 22 are arranged at the ends of the legs 30, 31, pointing outwards.

[0043] The spacer device 20 with legs 30, 31 essentially forms a U-profile. Due to the U-shape of the spacer device 20, the legs are arranged during an operation such that they extend away from the surgical field. The legs 30, 31 are connected to each other via a rotation joint 41. The rotation joint 41 forms an axis of rotation R about which the legs 30, 31 can be pivoted.

[0044] The spacer device 20 is adjusted to the distance between the proximal section 14 of the first retaining element 10 and the proximal section 24 of the second retaining element 11 by means of an adjusting element 25. A change in the distance between the legs 30, 31 by the adjusting element 25 leads to a rotation of the legs 30, 31 about the axis of rotation R.

[0045] The adjusting element 25 has a threaded rod 26 and an adjusting wheel 27, the adjusting wheel 27 being engaged with the threaded rod 26. By turning the adjusting wheel 27, the spacer device 20 is adjusted to the distance between the mounting sections 23, 24 of the retaining elements 10, 11. The adjusting element 25 is arranged centrally with respect to the spacer device 20.

[0046] From the Fig. Figures 2 to 4 further show that the first and second receiving elements 21, 22 each comprise a concave receiving surface, and the spacer device each has a convex contact part 28 extending transversely to the receiving surface, which is designed to provide a surface of rotation for the rotation of the retaining elements 10, 11. The concave shape of the receiving elements 21, 22 serves to securely receive the retaining elements 10, 11. In use, the concave receiving surface prevents or reduces unwanted movement of the retaining elements. It can also be seen that the contact parts 28 are designed such that the extension sections 23, 24 of the retaining elements 10, 11 roll on the contact parts 28 when the distance of the distal sections 12, 13 changes. The contact parts 28 thus form the rotational area of ​​the retaining elements 10, 11 around the extension sections 23, 24.

[0047] The compression device 19 has a distance-changing element 32 (see Fig. 5), which in use serves to change the distance between the distal sections 12, 13 of the first and second retaining element 10, 11.

[0048] In the exemplary embodiment, the distance-changing element 20 comprises a spindle thread 33 with a spindle rod 34. The spindle rod 34 extends along a longitudinal axis L and engages with two spindle wheels 35. By rotating the spindle wheels 35, the distance between the distal sections 12, 13 of the first and second retaining elements is changed.

[0049] The compression device 19 has a first fastening element 36 and a second fastening element 37, wherein the first fastening element 36 can be connected to the distal section 12 of the first retaining element 10 and the second fastening element 37 can be connected to the distal section 13 of the second retaining element 11. In this example, the fastening elements 36, 37 are tubular and are pushed or attached to the retaining elements 10, 11. The fastening elements 36, 37 fully encompass the retaining elements 10, 11. Furthermore, it can be seen that the fastening elements 36, 37 are firmly connected to the distal sections 12, 13 of the retaining elements 10, 11. In this specific embodiment, the fastening elements 36, 37 are designed as a cap and an eye, respectively.

[0050] Fig. Figure 5 shows that one of the two fastening elements 36, 37 is movably arranged on the spindle rod 34 of the compression device 19. In other words, the one movably arranged fastening element 36 is displaceable along the longitudinal axis L of the spindle rod 35. For this purpose, a spindle wheel 35 is arranged on both sides of the movably arranged fastening element 36. This allows the fastening element 36 to be displaced along the longitudinal axis L in both directions. Furthermore, in Fig. 5 shows that the other fastening element 37 is firmly connected to the spindle rod 34.

[0051] Fig. Figure 6 shows that the fastening elements 36, 37 are connected to the spindle rod 35 via a pivot joint 38. In other words, during the operation, the fastening elements 36, 37 and consequently the holding elements 10, 11 arranged thereon can be rotated radially along the longitudinal axis L.

[0052] It should be noted that all the parts described above, individually—even without additional features described in the respective context, even if these have not been explicitly identified as optional features in the respective context, e.g., by using: in particular, preferably, for example, e.g., parentheses, etc.—and in combination or any sub-combination, are to be considered independent embodiments or further developments of the invention as defined in particular in the introduction and the claims. Deviations from this are possible. Specifically, it should be noted that the word "in particular" or parentheses do not denote features that are mandatory in the respective context. Reference sign lists 10 first retaining elements 11 second retaining element 12 Distal section of the first retaining element 13 Distal section of the second retaining element 14 Proximal section of the first retaining element 15 Proximal section of the second retaining element 16 proximal end of the first retaining element 17 proximal end of the second retaining element 18 bone anchors 19 Compression device 20 spacer device 21 first recording element 22 second recording element 23. Starting section of the first retaining element 24. Starting section of the second retaining element 25 Adjustment element 26 threaded rod 27 Adjusting wheel 28 Contact part 29 Exclusion 30 first vent of the spacer device 31 second chamber of the spacer device 32 Distance change element 33 Spindle threads 34 Spindle rod 35 Spindle wheel 36 first fastening element 37 second fastening element 38 Swivel joint 39 Fork head 40 screw anchors 41 Rotation joint L Longitudinal axis of the spindle rod

Claims

[1] Medical set for distracting vertebral bodies, in particular in the treatment of vertebral fractures, for use with at least one first and one second holding element (10, 11), wherein each of the holding elements (10, 11) comprises a distal section (12, 13) and a proximal section (14, 15) with a proximal end (16, 17) for receiving a bone anchor (18), in particular a bone screw, wherein the set has at least one compression device (19) which, in use, can be connected to the distal section (12, 13) of the first and second retaining element (10, 11) and is designed to change the distance between the distal sections (12, 13) of the first and second retaining element (10, 11), characterized by , that the set comprises at least one spacer device (20) with a first receiving element (21) and a second receiving element (22), wherein the first receiving element (21) is designed to be arranged on the first holding element (10) corresponding to a projection section (23) of the proximal section (14) of the first holding element (10) and the second receiving element (22) is designed to be arranged on the second holding element (11) corresponding to a projection section (24) of the proximal section (15) of the second holding element (11) in order to form a rotation range and induce a rotation of the holding elements (10, 11) about the projection sections (23, 24) when the distance between the distal sections (12, 13) of the first and second holding elements (10, 11) is changed by the compression device (19). [2] Medical set according to claim 1, characterized by, that the compression device (19) and the spacer device (20) are arranged in use on the holding elements (10, 11) clearly spaced apart from each other, in particular by a first minimum distance. [3] Medical set according to claim 1 or 2, characterized by , that the spacer device (20) has at least one first and one second leg (30, 31) at the ends of which the first and second receiving element (21, 22) is arranged. [4] Medical set according to any of the preceding claims, in particular according to claim 3, characterized by , that the spacer device (20) is essentially U-shaped and / or the legs (30, 31) of the spacer device (20) are arranged essentially in a U-shape. [5] Medical set according to any of the preceding claims, characterized by, that the spacer device (20) has at least one adjusting element (25) so that the spacer device (20) can be adjusted to the distance between the attachment section (23) of the proximal section (14) of the first retaining element (10) and the attachment section (24) of the proximal section (15) of the second retaining element (11). [6] Medical set according to any of the preceding claims, in particular according to claim 5, characterized by , that the legs (30, 31) of the spacer device (20) are connected to each other via a rotation joint and / or their distance is adjustable via the adjusting element (25). [7] Medical set according to any of the preceding claims, in particular according to claim 5 or 6, characterized by that the adjusting element (25) has at least one threaded rod (26) and an adjusting wheel (27) for adjusting the distance. [8] Medical set according to any of the preceding claims, characterized by, that the first and the second receiving element (21, 22) each comprise a receiving surface, in particular a concave one, and / or the spacer device (20) each have a contact part (28) extending preferably transversely to the receiving surface, in particular a convex one, which is each designed to provide a surface of rotation for the rotation of the retaining elements (10, 11). [9] Medical set according to any of the preceding claims, characterized by , that the compression device (19) has at least one spacing change element (32) to change the distance between the distal sections (12, 13) of the first and second retaining element (10, 11) during use. [10] Medical set according to any of the preceding claims, in particular according to claim 9, characterized by, that the distance change element (32) comprises a spindle thread (33) with at least one spindle rod (34) extending along a longitudinal axis L and engaging with at least one spindle wheel (35). [11] Medical set according to any of the preceding claims, characterized by , that the compression device (19) has at least a first fastening element (36) and a second fastening element (37), wherein the first fastening element (36) can be connected to the distal section (12) of the first retaining element (10) and the second fastening element (37) can be connected to the distal section (13) of the second retaining element (11). [12] Medical set according to claim 11, characterized by , that at least one of the two fastening elements (36, 37) is movably arranged on the spindle rod (33) of the compression device (19). [13] Medical set according to any of the preceding claims, in particular according to claim 11 or 12, characterized by , that the fastening elements (36, 37) are connected to the spindle rod (34) via a swivel joint (38) in order to form a rotation of the fastening elements (36, 37) in the radial direction of the longitudinal axis L during use. [14] Medical set according to any of the preceding claims, characterized by , that the set includes the first and the second retaining element (10,11). [15] System comprising a first and a second set according to one of the preceding claims, wherein the sets can be arranged on the left and right sides of the spine.

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