Implant for connecting adjacent vertebrae, and medical system
The spinal implant with deformable bending sections and complementary tool-receiving grooves addresses the challenge of adapting to individual spine curvature, reducing deformation force and enhancing stability during intraoperative adjustment.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- AESCULAP AG
- Filing Date
- 2025-12-12
- Publication Date
- 2026-06-25
AI Technical Summary
Existing spinal implants, such as the cervical plate system ABC2, require complex deformation processes to adapt to individual patient anatomy, leading to potential unintentional deformation and increased force requirements during intraoperative adjustment.
A spinal implant with longitudinally extending through-openings and plastically deformable bending sections, featuring tool-receiving grooves and complementary bending tools, allows for intraoperative adjustment to the spine's curvature, reducing deformation force and enhancing stability through optimized material distribution.
The implant achieves precise adaptation to the spine's contour with reduced deformation force and minimized risk of unintentional deformation, ensuring stable and efficient connection of vertebrae.
Smart Images
Figure EP2025086774_25062026_PF_FP_ABST
Abstract
Description
[0001] Implant for connecting adjacent vertebrae and medical system
[0002] The invention relates to an implant for connecting adjacent vertebrae and to a medical system comprising such an implant and a bending tool.
[0003] Spinal implants are used to connect multiple vertebrae and stabilize the spine. These implants are particularly common in the cervical spine, where they are referred to as cervical plates. The implant is attached to the vertebrae using screws. Dynamic implants are available that allow rotation and translation of the screws, which are located in corresponding radiographs of the implant. This allows the connected vertebrae to move relative to each other even with the implant in place, while simultaneously being supported by it. Before the implant is attached to the vertebrae, it is individually adapted to the patient's spine. This is achieved by plastically deforming the implant during the operation (intraoperatively) using a bending tool. Such a bending tool typically consists of a bending shape and two counter-positions.The implant is bent around the bending die. The retaining processes hold the implant firmly and are moved around the bending die. In doing so, the retaining processes engage a portion of the implant, so that the implant is bent between the retaining processes and the bending die.
[0004] An implant offered on the market by the applicant is known as the cervical plate system ABC2. The known plate system comprises a plate-shaped implant and several fixing screws, which are received in corresponding through-holes in the implant and screwed into the vertebrae to be connected. To adapt the implant to the patient's needs, the implant has a groove on the side facing away from the vertebrae, so that the implant material is weakened at this point and deformation occurs essentially in the area of the groove.
[0005] The object of the invention is to provide an implant for connecting adjacent vertebrae that has an improved design compared to the prior art and allows for easy application.
[0006] This problem is solved by providing an implant with the features of claim 1 and a medical system with the features of claim 9. The implant according to the invention has a front and a back surface, the latter being opposite the front surface in the thickness direction of the implant. The implant also has at least two through-openings, each extending longitudinally between the front and back surfaces and designed to receive a fastening screw. The implant comprises at least one bending section, which is plastically deformable under the influence of a bending tool to adapt intraoperatively to a longitudinal curvature of the implant extending along a longitudinal axis of the implant. The bending section has at least one tool-receiving groove, which is recessed in the thickness direction into the front or back surface and extends longitudinally along a transverse axis of the implant.At least one tool receptacle is designed to receive a working section of the bending tool. The implant, designed specifically as a spinal implant, is intended for connecting two, three, or more vertebrae, which may be cervical vertebrae in particular. The rear of the implant faces the vertebrae in the implanted state. The front faces the patient. At least one of the through-holes is assigned to each of the vertebrae to be connected, so that the fastening screws received in the through-holes connect the multiple vertebrae to each other via the implant.
[0007] To adapt to the aforementioned longitudinal curvature, the bending tool engages in the bending section, so that deformation of the implant occurs essentially locally within the bending section. Specifically, in use, an active section of the bending tool, such as the aforementioned bending die or one of the counter-holding extensions, is accommodated in the tool's mounting groove. Furthermore, one or more windows in the cervical plate can advantageously serve as a means of aligning the bending tool relative to the bending section by allowing a portion of the bending tool to enter the window.
[0008] The longitudinal curvature of the implant is adjusted during the operation (intraoperatively), allowing the implant to be individually adapted to the contour of the vertebrae, i.e., the course of the spine in the area of the vertebrae to be fused. If multiple bending sections are planned along the longitudinal axis of the implant, the implant can be deformed independently in each bending section. This allows the implant to be given a complex curved shape along its longitudinal axis, if necessary, which can, for example, be adapted to the contour of three or more vertebrae. The tool-receiving groove runs transversely to the longitudinal axis along the bending section, so that deformation of this section changes the radius of curvature in the direction of the longitudinal axis. In the area of the tool-receiving groove, the material is weakened in the thickness direction of the implant.This results in deformation of the implant, initially and primarily in the area of the tool holder groove. By constructively adjusting the depth of the tool holder groove, and thus the remaining thickness of the material in the thickness direction within this groove, the desired bending stiffness of the implant can be achieved. The longitudinal axis, transverse axis, and thickness direction are each oriented perpendicular to one another.
[0009] Preferably, the tool holder groove is concave, and the bending tool engages in the tool holder groove with a convex working section. Particularly preferably, the tool holder groove and the working section of the bending tool are designed to be complementary to each other, so that the largest possible bearing surface and / or contact area between the implant and the bending tool is achieved. In preferred embodiments, the working section is engaged in the tool holder groove by a positive locking mechanism, particularly along the longitudinal axis.
[0010] By reducing the force required for deformation and increasing the contact area, the risk of unintentional deformation of the implant due to contact with the bending tool in the working section, for example in the form of pressure points, is reduced or avoided.
[0011] In an embodiment of the invention, the bending section comprises a front tool-receiving groove on the front side and a rear tool-receiving groove on the back side, which overlap each other at least partially with respect to the longitudinal axis. "Overlap" means that the front and rear tool-receiving grooves are at least partially at the same height with respect to the longitudinal axis. The two tool-receiving grooves reduce the cross-section of the implant on both sides, which can improve the deformation behavior and stability of the implant. Furthermore, this design allows for more uniform bending in both directions, i.e., towards the front or the back. Advantageously, one tool-receiving groove serves to receive the bending die, and the other tool-receiving groove serves to receive one or both of the counter-retaining extensions of the bending tool.Particularly preferred are the front and rear tool-holding grooves designed to be mirror images and / or symmetrical with respect to the thickness direction. In a further embodiment of the invention, the tool-holding groove comprises a groove base with at least one flat surface. This ensures consistently uniform contact of the working section of the bending tool against the implant with a comparatively large contact area. The contact of the working section against the groove base remains constant regardless of its relative positioning, which facilitates use. In advantageous embodiments, the groove base consists of a single surface or of several parallel or mutually inclined flat surfaces.
[0012] In a further embodiment of the invention, the tool-receiving groove is multi-stage, comprising a first groove section with a first groove depth and a second groove section with a second groove depth, the first groove depth being less than the second groove depth. Due to the smaller cross-section in the second groove section, deformation occurs predominantly in that area. Simultaneously, the first and second groove sections serve to receive the bending die and the counter-support projections, and to align the bending tool and the implant. In preferred embodiments, a first groove section is provided on both sides of the second groove section along the longitudinal axis. In other words, in these embodiments, the first groove section is two-part, such that a first part of the first groove section lies along the longitudinal axis in front of the second groove section and a second part lies behind the second groove section.
[0013] In a further embodiment of the invention, the second groove section is longer than the first groove section when viewed along the longitudinal axis. This provides a particularly long area along the longitudinal axis in which the deformation of the implant predominantly occurs. The bending stiffness is thus kept very low. At the same time, the overall length of the bending section can be kept short.
[0014] In a further embodiment of the invention, the first groove section and the second groove section are connected to each other by a transition section in which the groove base rises from the second groove section to the first groove section. The transition section can serve, firstly, to align the bending tool relative to the bending section and, secondly, to provide an additional contact surface against which an active section of the bending tool, or a partial section of such an active section, in particular the bending die, rests during use. The transition section creates a transition from the second to the first groove section, which can rise abruptly or continuously. In preferred embodiments, the transition section comprises a flat surface that rises uniformly between the second and the first groove sections, for example, at an angle of 10° to 80°, preferably 30° to 60°, with respect to the orientation of the groove base.In other preferred embodiments, the transition section comprises a curved surface that rises in a radius between the second and the first groove section, for example in a radius of 1mm to 3mm.
[0015] In a further embodiment of the invention, the tool-receiving groove extends only over a portion of the implant's width. Thus, the tool-receiving groove does not extend across the entire width of the implant along its transverse axis. This allows the implant to be configured as desired along the transverse axis in the area adjacent to the tool-receiving groove without the tool-receiving groove or the rest of the implant's structure interfering with, for example, one of the through-openings or a locking mechanism located on the front face. Preferably, the implant comprises a tool-receiving groove on each side opposite the transverse axis, and these grooves are mirror images of each other. In other words, the tool-receiving groove continues along the transverse axis on the opposite side of the implant after being interrupted in a central region.In this embodiment, a bending tool can act on both sides of the implant during use, without having to do so across the entire width of the implant.
[0016] In a further embodiment of the invention, at least one locking mechanism is provided for locking the fastening screws in the through-holes. In a locked state, the locking mechanism prevents unintentional movement of the fastening screws out of the through-holes. Advantageously, the locking mechanism is arranged in a central region with respect to the transverse axis.
[0017] For the medical system, the problem underlying the invention is solved by the system comprising an implant according to the invention and a bending tool that is configured for intraoperative adjustment of the implant's longitudinal curvature and has at least one working section. The working section is configured for insertion into the at least one tool receptacle of the implant. Advantageously, the working sections of the bending tool are shaped to match the tool receptacle(s) of the implant, so that the working sections are optimally inserted into the tool receptacles and the contact surface between the implant and the bending tool is as large as possible. In an embodiment of the invention, the at least one working section of the bending tool is inserted into the at least one tool receptacle of the implant during intraoperative adjustment of the implant's longitudinal curvature.Further advantages and features of the invention will become apparent from the claims and from the following description of a preferred embodiment of the invention, which is illustrated with reference to the drawings.
[0018] Fig. 1 shows a schematic perspective view of a front face of an embodiment of an implant according to the invention for connecting adjacent vertebrae,
[0019] Fig. 2 shows a schematic perspective view of the back of the implant according to Fig. 1.
[0020] Fig. 3 shows a schematic side view of the implant according to Figs. 1 and 2, and
[0021] Fig. 4 shows a schematic perspective view of an embodiment of a medical system according to the invention with a bending tool and the implant according to Figs. 1 to 3.
[0022] Figure 4 shows a medical system 10 with an implant 100 and a bending tool 200, the bending tool 200 serving to deform the implant 100. The implant 100 is shown in detail in Figures 1 to 3. The implant 100 is designed to connect three adjacent cervical vertebrae and has a back surface 102 (Figure 2) and a front surface 104 (Figure 1) opposite the back surface 102 in the thickness direction D. In the implanted state, the back surface 102 faces the vertebrae and the front surface 104 faces away from the vertebrae. Typically, the implant 100 is connected ventrally to the vertebrae of the cervical spine. The front surface 104 then faces the patient's line of sight.
[0023] In the illustrated embodiment, the implant 100 comprises six through-openings 106, two of which are assigned to each of the vertebrae. Three through-openings 106 are arranged along a longitudinal axis L of the implant 100, and two through-openings 106 are arranged along a transverse axis B. Fastening screws are accommodated in the through-openings 106 for securing the implant 100 to the vertebrae. These screws are inserted into the vertebrae in pairs, connecting the implant 100 to the vertebrae and thus connecting the vertebrae to each other. The implant 100 is designed as a dynamic implant, meaning that the fastening screws in the through-openings 106 are rotatably mounted about the longitudinal axis L and the transverse axis B, and longitudinally movable along the length of the through-openings 106, thereby allowing small movements of the vertebrae relative to each other.Before the implant 100 is screwed to the vertebrae, it is plastically deformed using the bending tool 200 to adapt to the patient's anatomy. Specifically, a radius of curvature along the longitudinal axis L is locally modified so that the implant 100 follows a ventral outer contour of the vertebrae. The implant 100 comprises two bending sections 108, in which the deformation essentially takes place. The bending sections 108 are arranged one behind the other along the longitudinal axis L and allow for a change in the longitudinal curvature at two points. Each bending section 108 has two tool-holding grooves 110, a rear tool-holding groove 110-R on the back side 102 and a front tool-holding groove 110-V on the front side 104. In the area of the tool-holding grooves 110, the cross-section of the implant 100 is reduced by removing material in the thickness direction B, thereby reducing the bending stiffness of the implant 100 in this area.This ensures, firstly, that the deformation of the implant occurs primarily in the bending sections 108. Secondly, it reduces the required deformation force that must be applied by the bending tool 200. The front and rear tool mounting grooves 110-V, 110-R are positioned at the same height with respect to the longitudinal axis L. In this way, both tool mounting grooves 110 contribute to the reduction in cross-section.
[0024] The bending tool 200, shown in Fig. 4, comprises several working sections 202 with which it comes into contact with the implant 100 and acts upon it by introducing the deformation force. The bending tool 200 comprises, as working sections 202, a bending form 204 and two counter-supporting extensions 206, which are arranged opposite the bending form 204 and symmetrically with respect to a bending or curvature axis K of the implant. During use, i.e., during deformation, the implant 100 is positioned between the bending form 204 on the one hand and the counter-supporting extensions 206 on the other, such that the bending form 204 is received in the front tool mounting groove 110-V or in the rear tool mounting groove 110-R, and the counter-supporting extensions 206 are received in the opposite rear tool mounting groove 110-R or in the front tool mounting groove 110-V.By moving the bending form 204 on the one hand and the counter-supporting processes 206 on the other hand towards each other, the implant 100 is curved around the bending form 204 by deformation in the bending section 108. The further the counter-supporting processes 206 are moved towards the bending form 204, the greater the resulting curvature of the implant 100. The bending tool 200 centers itself in an opening in the implant 100, designated as a window 120, along the thickness direction D, by means of a guide projection 208 of the bending tool 200, which is shaped complementarily to the window 120, entering the window 120 as the implant 100 is deformed. The tool receiving groove 110 includes a groove base 112 with a flat surface, which is designed to abut against one of the working sections 202. The functional section 202 rests against the groove base 112 along the transverse axis B, thus providing a comparatively large bearing surface. As shown particularly in the figures.As can be seen in Figures 1 to 3, the tool-holding groove 110 is designed in multiple stages. The tool-holding groove 110 comprises two first groove sections 114 and a second groove section 116 arranged between them along the longitudinal axis L. The first groove section 114 has a first groove depth T1, which is measured from an outer contour of the implant 100 along the front 104 or the back 102. The second groove section 116 has a second groove depth T2, which is greater than the first groove depth T1, so that, with respect to an outer surface of the implant 100, the groove base 112 in the second groove section 116 is deeper than in the first groove section 114. In conjunction with the bending tool 200, the second groove section 116 is designed to receive the bending die 204, so that the bending die 204 abuts against the groove base 112 of the second groove section 116. The counter-support extensions 206 are designed to lie against the groove base 112 of the two first groove sections 114.This results in a comparatively small distance between the counter-support extensions 206 on the one hand and the bending form 204 on the other.
[0025] The second groove section 116 is longer in the direction of the longitudinal axis L than the first two groove sections 114, thus providing a relatively large area in which the deformation of the implant 100 can occur. At the same time, the total extent of the bending section 108 along the longitudinal axis L, i.e., the combined longitudinal extent of both first groove sections and the second groove section, is kept as small as possible.
[0026] The first groove sections 114 and the second groove section 116 are connected by a transition section 118, in which the groove base 112 rises linearly from the second groove section 116 to the first groove section 114. Overall, the bending section 108, viewed along the longitudinal axis L, is thus designed as several adjacent and overlapping, planar surfaces. Due to the transition section 118, the tool holder groove 110 is concave in the area between the first groove sections 114, and the convex bending form 204 engages in this area during use.
[0027] The tool-holding grooves 110 extend only partially over the implant 100 along the transverse axis B, so that no tool-holding groove 110 is present in a central region located between the transverse ends. In this central region with respect to the bending sections 108, one of the windows 120 is provided along the thickness direction D. Thus, the bending stiffness of the implant 100 in the bending section 108 is further reduced. In the illustrated embodiment, the bending tool 200 is provided with the guide projection 208 in the region of the bending die 200, which, during use, engages in the window 120 and supports or provides guidance or alignment of the working sections 202 relative to the implant 100.
[0028] On the front face 104, three locking mechanisms 122 in the form of rotary slides are arranged, which are designed to secure the fastening screws received in the through-openings 106. For this purpose, the locking mechanisms 122 are rotated about an axis of rotation parallel to the thickness direction D, so that one of two locking arms 124 of each locking mechanism 122 is pivoted over a screw head of the fastening screws.
[0029] To adjust the longitudinal curvature, the implant 100 is held and clamped between the working sections 202 of the bending tool 200, see Fig. 4. By actuating the bending tool 200, the bending die 204 and the counter-holding processes 206 are moved towards each other. The counter-holding processes 206 abut the groove base 112 of the first groove sections 114, and the bending die 204 abuts the groove base 112 of the second groove section 116. The counter-holding processes 206 force the implant 100 to deform around the bending die 204, whereby the implant 100 is plastically deformed, essentially in the region of the bending section 108, until a desired longitudinal curvature of the implant 100 is achieved.
Claims
Patent claims 1. An implant (100) for connecting adjacent vertebrae, comprising a front (104), a back (102) which is opposite the front (104) in the thickness direction (D) of the implant (100), at least two through-openings (106) which each extend longitudinally between the front (104) and the back (102) and are provided for receiving a fastening screw, at least one bending section (108) which is plastically deformable under the action of a bending tool (200) on the implant (100) in order to intraoperatively adapt a longitudinal curvature of the implant (100) extending along a longitudinal axis (L) of the implant (100), wherein the bending section (108) has at least one tool receiving groove (110) which is recessed in the thickness direction (D) into the front (104) or the back (102) and extends longitudinally along a transverse axis (Q) of the implant (100),and wherein at least one tool receiving groove (110) is provided for receiving an working section (202) of the bending tool (200).
2. Implant (100) according to claim 1, wherein the bending section (108) comprises a front tool receiving groove (110-V) on the front (104) and a rear tool receiving groove (110-R) on the back (102) which overlap each other at least partially with respect to the longitudinal axis (L).
3. Implant (100) according to claim 1 or 2, wherein the tool receiving groove (110) comprises a groove base (112) with at least one flat surface.
4. Implant (100) according to one of the preceding claims, wherein the tool receiving groove (110) is multi-stage, such that the tool receiving groove (110) comprises a first groove section (114) with a first groove depth (T1) and a second groove section (116) with a second groove depth (T2), wherein the first groove depth (T1) is less than the second groove depth (T2).
5. Implant (100) according to claim 4, wherein the second groove section (116) is longer in the direction of the longitudinal axis (L) than the first groove section (114).
6. Implant (100) according to one of claims 4 or 5, wherein the first groove section (114) and the second groove section (116) are connected to each other by a transition section (118) in which the groove base (112) rises from the second groove section (116) to the first groove section (114).
7. Implant (100) according to one of the preceding claims, wherein the tool receiving groove (110) extends only over a part of the width of the implant (110).
8. Implant (100) according to one of the preceding claims, wherein at least one locking mechanism (122) is provided for locking the fastening screws in the through-holes (106).
9. Medical system (10) comprising an implant (100) according to one of the preceding claims and a bending tool (200) which is configured for intraoperative adjustment of a longitudinal curvature of the implant (100) and has at least one working section (202), wherein the working section (202) is configured for receiving in the at least one tool receiving groove (110) of the implant (100).
10. Medical system (10) according to claim 9, wherein the at least one working section (202) of the bending tool (200) is received in the at least one tool receiving groove (110) of the implant (100) during intraoperative adjustment of the longitudinal curvature of the implant (100).