DYNAMIC STABILIZING VERTEBRAL IMPLANT
Patent Information
- Application Number
- FR2023002100
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-03-07
- Publication Date
- 2025-03-07
- Estimated Expiration
- 2043-03-07
Smart Images
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Abstract
Description
Title of the invention: DYNAMIC STABILIZATION SPINAL IMPLANT Technical field
[0001] The present disclosure relates to the field of implants used in spinal surgery and more particularly to dynamic stabilization vertebral implants. Prior art
[0002] Operations in the field of spinal surgery may involve the cervical region (neck), the dorsal region or, more frequently, the lumbar region.
[0003] When there is instability, such as a vertebra sliding relative to adjacent vertebrae, there are spine stabilization devices which comprise intervertebral implants composed of a stabilization wedge, a flexible textile braid type link, a mobile assembly and a locking member. The stabilization wedge is intended to be placed between the spinous processes of two consecutive, i.e. adjacent, vertebrae to be stabilized. The flexible link (for example a textile braid) encloses the processes. The mobile assembly is adapted to engage with the stabilization wedge so as to block the flexible link in movement relative to the stabilization wedge. This blocking is obtained by pinching the flexible link between the mobile assembly and the stabilization wedge.The locking member (e.g. a screw) is adapted to lock the engagement of the moving assembly with the stabilizing wedge, and thus the final blocking of the flexible link which results directly from it.
[0004] Examples of such implants are described in document EP 1 009 311 B1 now in the public domain. In these devices, a wedge receives a flexible link forming a loop and the flexible link is locked by a quarter-turn rotary lock which is maneuvered in the wedge. This easy-to-implement device does not, however, guarantee correct locking of the flexible link, the positioning of the rotary lock in its locking position not being guaranteed, in particular in the case where the flexible link is a flat strap on which the rotary lock can slide and turn.
[0005] Another example of an intervertebral implant is described in document FR 3 047 657 A1 in the name of the applicant. In this device, an implant is described comprising a stabilizing wedge, adapted to stabilize at least two adjacent vertebrae between them by interposition between spinous processes of said vertebrae, comprising a recess provided with a longitudinal axis and receiving radially on at least one side of the recess at least a portion of a strap forming a flexible link for fixing the stabilizing wedge to the spinous processes of the vertebrae to be stabilized, the implant comprising a rotary lock having a longitudinal axis and a profile substantially complementary to the shape of the recess, to engage with the stabilizing wedge by displacement along the direction of the longitudinal axis inside the recess and to block said at least one portion of strap by pinching the latter between the rotary lock and the internal wall of the recess. This device which comprises a locking member of the rotary lock coaxial with the latter offers great security but the rotary lock, possibly integral with its locking member, must be inserted into the recess after positioning the flexible link. Summary
[0006] The present disclosure provides an improved quarter-turn type device providing more secure positioning of the rotary lock of the flexible link and thus ensuring more secure locking of this flexible link.
[0007] The present disclosure thus proposes a dynamic stabilization intervertebral implant which comprises: a. - a parallelepiped spacer wedge provided with a tubular housing, with a longitudinal axis perpendicular to an upper face of the wedge and to a lower face of the wedge and opening at least into said upper face, and provided with two slots passing through the wedge from a first lateral face of the wedge to a second lateral face of the cage opposite the first lateral face, extending in a direction perpendicular to the longitudinal axis of said housing and passing through the housing on sides of said housing, b. - a flexible flat braid comprising two strands, each of the strands passing through one of said slots and, c. - a rotary lock received in said housing and extending along said longitudinal axis, for which the rotary lock comprises a paddle-shaped body, extending longitudinally in the tubular housing and provided with an oval or oblong section in a direction perpendicular to said longitudinal axis, said rotary lock comprising an operating head, provided with a compatible imprint of a rotating operating tool, accessible from said upper face of the wedge, said rotary lock being configured to rotate around said longitudinal axis between a position for releasing said strands and a position for blocking said strands against first opposite wall parts of said tubular housing and for which at least one spring rod fixed in the wedge comprises an end which rests against the head of the rotary lock in the position for releasing said strands and is housed in a notch or groove of the head of the rotary lock in the locking position of said strands.
[0008] According to a first aspect, said pallet may comprise two first facing faces extending, in the position of release of said strands, between said slots so that the rotary lock allows said strands to pass into said slots.
[0009] According to a second aspect, said pallet may comprise two second faces, of curved section complementary to a curvature of the tubular housing, the first faces being of a width such that the second faces adjoin second opposite wall parts of the tubular housing between said slots.
[0010] According to a third aspect, in the position of locking said strands, the pallet can intersect the slots and constrain the strands against said first opposite wall parts of the tubular housing so as to lock the strands in the housing.
[0011] Advantageously, the rotary lock comprises at one end opposite the operating head means for retaining the lock in the wedge, so as to implant the wedge already equipped with its lock in a patient.
[0012] The retention means may advantageously comprise an annular collar provided with a bearing face perpendicular to said longitudinal axis and bearing against a shoulder produced by means of a counterbore in a lower face of the wedge around an outlet orifice of the tubular housing and a foot of the pallet at its end opposite the head resting on a bottom of the housing provided with said outlet orifice.
[0013] Said annular collar is part of a tip crimped or glued onto an end stud of the rotary lock opposite said head.
[0014] The retention means are here shaped as embedding means.
[0015] The implant may comprise two spring rods arranged on either side of the head relative to said longitudinal axis.
[0016] The spring rod(s) are advantageously received in tubular cutouts made in the wedge parallel to said longitudinal axis and comprising a first open end, on the head side of the rotary lock, leaving one end of the rod free to bend at said head, and a second tightened end, in a central part of the wedge, said rod(s) being inserted by force into said second end of said tubular cutout.
[0017] The lock can in particular be made of stainless steel or titanium. Brief description of the drawings
[0018] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which:
[0019] [Fig.lA] shows an exploded view of an implant produced according to the invention;
[0020] [Fig.lB] shows a top view of the implant of [Fig.lA] in the ver- rusty;
[0021] [Fig.lC] shows a top view of the implant of [Fig.lA] in the waiting position;
[0022] [Fig.2] shows a side view of the implant of [Fig.1A];
[0023] [Fig.3] shows a sectional side view of the implant of [Fig.1A] in a position releasing strands from the braid;
[0024] [Fig.4] shows a sectional side view of the implant of [Fig.1A] in a braid strand locking position;
[0025] [Fig.5] shows a top sectional view of the implant of [Fig.1A] in the position of release of the strands of the braid;
[0026] [Fig.6] shows a top sectional view of the implant of [Fig.1A] in a position for locking the strands of the braid. Description of the embodiments
[0027] Reference is now made to [Fig. 1 A] In this figure is shown a vertebral implant for dynamic stabilization of vertebrae comprising a wedge 10, a rotary lock 20 and a braid 50 shown in dotted lines. According to [Fig.lB], the braid 50 comprises strands passing through a first slot 13, a second slot 14 and a third slot 19 passing through the wedge from a first lateral side of the wedge to a second lateral side of the wedge.
[0028] The rotary lock comprises an operating head 23, provided with an imprint 24. Under the head, the lock comprises a pallet 21 provided parallel to the longitudinal direction Z with four faces 21a, 21b, 21c, 21d according to the section shown in [Fig.5]. The pallet comprises two wide faces 21a, 21b and two narrow faces 21c, 21d. At the lower end opposite the head of the lock, the latter comprises a stud 26 under the pallet 21.
[0029] The lock is received in a housing 15 of the wedge and as seen in [Fig.2] which represents the wedge seen from the second lateral side 10b, only the top of the head protrudes slightly from the upper face 11 of the wedge.
[0030] The wedge can in particular be made from a biocompatible polymer such as PEEK and the lock from stainless steel or titanium.
[0031] The implant further comprises at least one spring rod 30, in particular made of stainless steel or titanium, here two spring rods 30 are present. The purpose of the spring rod(s) as will be seen later is to block the lock in a position for blocking the strands passing through the two slots 13, 14 passing through a tubular housing 15 passing through the wedge in which the lock 20 is inserted.
[0032] The spring rod(s) are received in tubular cutouts 18, made in the wedge 10 parallel to the longitudinal axis of insertion of the lock into the housing 15 and comprising a first open end 18a on the head side of the rotary lock leaving free to bend one end of the rod at said head and a second end tightened 18b in a central part of the wedge.
[0033] The lock 20 comprises an operating head 23, provided with an imprint 24 compatible with a rotating operating tool, accessible from an upper face of the wedge. The imprint is compatible with a rotating operating tool such as a hexalobular, hexagonal or other screwdriver. The rotary lock is configured to rotate about a longitudinal axis of the housing 15 between a position for releasing said strands and a position for blocking said strands.
[0034] The spring rod(s) 30 are fixed in the wedge and comprise an end 31 which rests against the head of the rotary lock when the latter is in the position for releasing said strands, for example against a flat 28, and which is housed in a notch 25 or groove in the head of the rotary lock in the position for blocking said strands as shown in [Fig.lB].
[0035] Still according to this [Fig. 1B], a first strand 51 of the braid comes from the second slot 14 on a first lateral side 10a of the wedge, forms a first loop and enters the third slot 19 of the wedge. A second strand 52 of the braid comes out of the third slot 19 on a second lateral side 10b of the wedge and forms a second loop to enter the first slot 13 still on the second side 10b of the wedge. The second strand comes out of the first slot in the form of a free strand 53 which will be used to tighten the loops formed by the first and second strands 51, 52 on the spinous processes of two consecutive vertebrae.
[0036] The start of the braid consists of a folded end 54 which locks at the entrance to the second slot 14.
[0037] [Fig.2] shows the opening starting with the slots 13, 14, 19 on one side face 10b, the slots ending in a similar manner with openings on the other side face 10a as well as the head of the lock and the end 31 of a spring rod which here protrude slightly from the upper face 11 of the wedge.
[0038] [Fig. 3] represents the implant in section along plane AA of [Fig. 1B] with the lock in the strand release position. In this position the pallet is oriented around the longitudinal axis Z to be parallel to the slots 13, 14, which pass through the housing 15 between the lateral faces 10a, 10b, without encroaching on these slots so that the strands are free to pass into the slots through the housing 15. To do this, the width of the narrow faces 21c, 21d is less than the distance between the walls of the slots 13, 14 closest to the Z axis. [Fig. 5] still represents the lock in the strand release position but this time according to a section in plane BB of [Fig. 2] perpendicular to the lateral faces of the wedge. In this position, the lock leaves the passage of the strands free along the wall parts 16a, 16b of the housing 15. In this [Fig.5] are shown the tightened ends 18b of the receiving holes of the foot of the rods 30 in a central part of the wedge into which the rods are force-inserted, one of the rods 30 being shown inserted.
[0039] [Fig. 4] represents the implant in section along plane AA of [Fig. 1B] with the lock in the position for locking the strands. In this position, the pallet 21 of the lock is oriented around the longitudinal axis Z to be perpendicular to the slots 13, 14 which pass through the housing 15 and to close the passage between the latter with the exception of curved slots 15e, 15f along the wall portions 16a, 16b of the housing 15, said slots being of such thickness that the strands are wedged between the lock and said wall portions. An approximate thickness of said slots is 0.8 to 0.9 times the thickness of the braid. To do this, the maximum length of the faces 21a, 21b in a direction perpendicular to the Z axis is equal to the width of the housing in a direction parallel to the side faces minus 1.6 to 1.8 braid thickness. [Fig. 6] represents, in section in the plane BB of [Fig.2], the implant with lock in the strand locking position which shows the 15e, 15f lumens in top view.
[0040] According to this example, the faces 21c, 21d of the pallet 21 have a curved section of revolution around the Z axis. However, these faces may have another profile, for example triangular or undulating depending on the retention force that one wishes to obtain.
[0041] Returning to [Fig.1A], the lock comprises a stud 26 extending the pallet opposite its head 23 on which a tip 40 is positioned. According to Figures 3 and 5, the tip 40 is provided with a collar 41 which bears against a shoulder produced by a lower face 17b of a bottom 17 of the housing 15 provided with an orifice through which the stud 26 passes. The tip 40 forms, with a foot 27 of the pallet 21 and the annular part 17 of the bottom around the stud, means for retaining the lock 20 in the wedge 10, so as to implant the wedge already provided with its lock in a patient.
[0042] According to the example, the shoulder 17b is produced by means of a counterbore in a lower face of the wedge around the outlet orifice of the tubular housing so that the end piece 40 practically does not protrude from the lower face of the wedge. The embedding of the annular part 17 of the bottom around the stud 26 between the foot 27 of the pallet 21 and the collar 41 of the end piece 40 securely holds the rotary lock while the end piece crimped or glued onto the end stud 26 of the rotary lock opposite said head makes it possible to implant the implant with its lock already mounted.
[0043] The embodiment shown is not limiting for the field of protection of the invention which is defined by the claims, the second faces 21c, 21d and the tubular housing being able to have a conical profile of section reducing from the head 23 towards the foot 27 of the lock along the axis Z.
Claims
Claims
1. Dynamic stabilization intervertebral implant which comprises: - a wedge (10) of parallelepipedal size provided with a tubular housing (15), with a longitudinal axis (Z) perpendicular to an upper face (11) of the wedge and to a lower face (12) of the wedge and opening at least into said upper face, and provided with two slots (13, 14) passing through the wedge from a first lateral face of the wedge to a second lateral face of the cage opposite the first lateral face, extending in a direction perpendicular to the longitudinal axis (Z) of said housing and passing through the housing on sides of said housing, - a flexible flat braid (50) comprising two strands (51, 52), each of the strands passing through one of said slots and, - a rotary lock (20) received in said housing and extending along said longitudinal axis, characterized in that the rotary lock (20) comprises a paddle-shaped body (21),extending longitudinally in the tubular housing (15) and provided with an oval or oblong section (22) in a direction perpendicular to said longitudinal axis, said rotary lock comprising an operating head (23), provided with an imprint (24) compatible with a rotating operating tool, accessible from said upper face (11) of the wedge, said rotary lock being configured to rotate around said longitudinal axis between a position for releasing said strands and a position for locking said strands against first opposite wall parts (16a, 16b) of said tubular housing (15) and for which at least one spring rod (30) fixed in the wedge comprises an end (31) which rests against the head of the rotary lock in the position for releasing said strands and is housed in a notch (25) or groove in the head of the rotary lock in the position for locking said strands.,
2. Dynamic stabilization intervertebral implant according to claim 1, wherein said pallet (21) comprises two first facing faces (21a, 21b) extending, in the position of release of said strands, between said slots (13, 14) so that the rotary lock allows said strands to pass into said slots.
3. Dynamic stabilization intervertebral implant according to claim 2, for which said pallet comprises two second faces (21c, 21d), of curved section complementary to a curvature of the tubular housing. (15), the first faces being of a width such that the second faces adjoin opposite second wall portions (15a, 15b) of the tubular housing (15) between said slots.
4. Dynamic stabilization intervertebral implant according to claim 2 or 3, wherein in the locking position of said strands, the pallet intersects the slots and forces the strands against said first opposite wall portions (16a, 16b) of the tubular housing (15) so as to lock said strands in the housing.
5. Dynamic stabilization intervertebral implant according to any one of the preceding claims, for which the rotary lock comprises, at an end opposite the operating head, means (17a, 27, 40, 17b) for retaining the lock (20) in the wedge (10), so as to implant the wedge already equipped with its lock in a patient.
6. Dynamic stabilization intervertebral implant according to claim 5, for which the retention means comprise an annular collar (41) provided with a bearing face perpendicular to said longitudinal axis and bearing against a shoulder (17b) produced by means of a counterbore in a lower face of the wedge around an outlet orifice of the tubular housing (15) and a foot (27) of the pallet 21 at its end opposite the head (23) resting on a bottom (17a) of the housing provided with said outlet orifice.
7. Dynamic stabilization intervertebral implant according to claim 5, wherein said annular collar (41) is part of an end piece (40) crimped or glued onto an end stud (26) of the rotary lock opposite said head.
8. Dynamic stabilization intervertebral implant according to any one of the preceding claims comprising two spring rods (30) arranged on either side of the head (23) relative to said longitudinal axis (Z).
9. Dynamic stabilization intervertebral implant according to any one of the preceding claims, for which the spring rod(s) are received in tubular cutouts (18), made in the wedge (10) parallel to said longitudinal axis, comprising a first open end (18a) on the head side of the rotary lock allowing one end of the rod to flex freely at said head and a second tightened end (18b) in a central part of the wedge, said rod(s) being inserted by force into said second tightened end (18b) of the tubular cutouts.
10. Dynamic stabilizing intervertebral implant according to any one of the preceding claims, wherein the lock (20) is made of stainless steel or titanium.