WO2015050466A1

WO2015050466A1 - System of devices for interspinous stabilisation of the spine

Info

Publication number: WO2015050466A1
Application number: PCT/PL2014/000109
Authority: WO
Inventors: Piotr SZYDLIK
Original assignee: Praktyka Lekarska Espinen Piotr Szydlik
Priority date: 2013-10-01
Filing date: 2014-09-30
Publication date: 2015-04-09
Also published as: PL237800B1; PL417018A1

Abstract

The invention relates to a system of devices for interspinous stabilisation of the spine. The system's feature is simultaneous application of interspinous devices (100, 101 and 102) and rails (200, 201) for multi-level fixation of a spine (A) comprising at least three spinous processes (B) at two levels so that at least two interspinous devices (100, 101 and 102) are placed between the spinous processes (B) on at least two levels of the spine (A) and two rails (200, 201) mounted by them, one on each side of the spinous processes (B). The invention relates also to a method of spinal stabilisation.

Description

SYSTEM OF DEVICES FOR INTERSPINOUS STABILISATION OF THE SPINE

The present invention relates to a system of devices used for interspinous stabilisation of the spine and a method of spinal stabilisation.

Known systems for multi-level spinal fixation and methods of spinal stabilisation include: widely used transpedicular stabilisation introduced in the 1960s and 70s and a newer method of interspinous fixation with application of interspinous devices of, coflex type or combination of both. The latter method is used in the lumbar region of the spine {Can low-grade spondylolistesis be effectively treated by either coflex interlaminar stabilization or laminectomy and posterior spinal fusion ? J Neurosurg Spine 19:174-184, 2013).

The disadvantages of the multi-level transpedicular stabilisation are: substantial tissue retraction and damage of the paravertebral muscles to acquire a wide surgical approach to the spine exposing the laminas of the vertebrae, intervertebral facet joints and sometimes also the transverse processes, substantial blood loss during procedure, complications connected with using transpedicular screws such as a risk of damage or compression of the nerve roots, dural sac or vessels, frequent intraoperative x-ray examinations, longer recovery of patients after procedure with more pain and longer hospital stay in relation to less invasive procedures. The disadvantages of interspinous multi-level coflex stabilisation of the spine are: substantial rate of pain remissions resulting from loosening, slippage of interspinous devices, damage (fracture) of its arms, fracture of the spinous process(es), small degree of spine stabilisation, small possibility of correction of the spinal curvature(s) (solely excessive lordosis), substantial rate of reoperations as a consequence of the above-mentioned factors. Therefore, interspinous devices are not implanted in numerous spinal departments.

The present disclosure of the invention provides a concept of simultaneous application of interspinous devices and rails for multi-level stabilisation of a spine comprising at least three spinous processes at two levels so that at least two interspinous devices are placed between the spinous processes on at least two levels of the spine as well as two rails secured by them, one at each side of the spinous processes.

Preferably curvatures of rails are adjusted by bending to the curvature(s) of the spine i.e. lordosis or kyphosis and/or scoliosis.

Also preferably an end of a rail is cut at an angle adjusted to the angle of the sacral bone.

Furthermore, preferably one or both surfaces of the rail or a part thereof are smooth, ribbed, roughened or porous or have other surface modifications including introduction of bioactive agents.

Also preferably an interspinous device is composed of a body, a body mounting part as well as two movable arms and the body the arms have through holes, wherein the body is connected to the arms through the mounting part using a bolt and a nut.

Furthermore, preferably the rails are secured to the interspinous device using the arms tightened by means of the bolt and the nut.

Also preferably the surface of the interspinous device or a part thereof including the inner surface of the arms and/or the surfaces adjacent to spinous processes is smooth, ribbed, roughened or porous or have other surface modifications, among them introduction of bioactive agents.

Also preferably a rail is provided with a longitudinal opening and the interspinous device is composed of a body with wings and a hole.

Furthermore, preferably the rails are fastened to the interspinous device using a bolt and a nut.

Also preferably an interspinous device is composed of a body with wings and threaded studs attached to both sides of the body.

Also preferably the rails are mounted to the interspinous device using nuts screwed onto the threaded studs protruding from both sides of the interspinous devices.

Also preferably the surface of the interspinous device or a part thereof including the inner surface of the wings is smooth, ribbed, roughened or porous or have other surface modifications, among them introduction of bioactive agents.

Also preferably the rail or a part thereof is made of a porous material. Also preferably the interspinous device or a part thereof is made of a porous material.

Also preferably the rail is produced from titanium, a titanium alloy, stainless steel and/or polymers, ultra high molecular weight polyethylene (UHMWPE) or polyetheretherketone (PEEK) or combinations of above-mentioned materials.

Also preferably the interspinous device is manufactured from titanium, an alloy of titanium, stainless steel and/or polymers, ultra high molecular weight polyethylene (UHMWPE) or polyetheretherketone (PEEK), ceramics or combinations of above-mentioned materials.

According to the second invention a method of spinal stabilisation is characterised by simultaneous usage of interspinous devices and rails on at least two levels of the spine so that the interspinous devices are placed in at least two interspinous spaces comprising at least three spinous processes and so that two rails are applied, one at each side of the spinous processes.

Preferably, the interspinous devices are adjusted to the interspinous spaces between two adjacent spinous processes.

The invention alleviates disadvantages of both spinal stabilisation methods mentioned at the beginning of this disclosure, while maintaining their relevant advantages, namely: small retraction of tissues including paravertebral muscles due to a narrow less invasive surgical approach needed and consequently, lower blood loss during the procedure (as in interspinous stabilisation), substantially good fixation of the spine (better than in the interspinous stabilisation and probably comparable to the transpedicular one), no risk of nerve root damage or compression (as in the interspinous stabilisation and contrary to the transpedicular one), smaller possibility of damage or loosening of the device system due to a more rigid, stable mechanical construction of the system (in comparison with the interspinous stabilisation), relatively easy usage for longer spinal fixation (more than 3 levels) with or without omission of (a) selected level(s) and/or including different spinal segments, greater range of correction of spinal curvature(s) (in comparison to interspinous stabilisation), relatively short period of recovery after procedure.

Embodiments of the invention are shown in the drawing where

Fig. 1 illustrates a perspective view of a rail;

Fig. 2 illustrates a perspective view of a rail comprising the Ll/Sl level of the spine;

Fig. 3 shows a perspective view of an interspinous device;

Fig. 4 shows a cross-sectional front view of an interspinous device;

Fig. 5 illustrates a perspective view of another embodiment of a rail;

Fig. 6 illustrates a perspective view of still another embodiment of a rail comprising the L5/S1 level of the spine;

Fig. 7 illustrates a perspective view of another embodiment of an interspinous device;

Fig. 8 shows a perspective view of still another embodiment of an interspinous device;

Fig. 9 illustrates a perspective view of an embodiment of a system with interspinous devices and rails; Fig. 10 illustrates a top view of the embodiment of the system with devices and rails shown in Fig. 9;

Fig. 11 illustrates a perspective view of another embodiment of a system with devices and rails; and

Fig. 12 shows a top view of the embodiment of the system with devices and rails of Fig. 11.

As illustrated in Fig. 9, Fig. 10, Fig. 1 1 and Fig. 12, a system of interspinous stabilisation of the spine A is based on the concept that interspinous devices (100, 101, 102) are inserted between the interspinous processes B on at least two levels of the spine A and two rails (200, 201) mounted by them, one at each side of the spinous processes B, wherein interspinous devices (100, 101, 102) and rails (200, 201) comprise at least three spinous processes B. Curvatures of the rails (200, 201) are adjusted correspondingly to the curvature(s) of the spine A - lordosis, kyphosis and/or scoliosis.

The system of devices for interspinous stabilisation of the spine is composed of rails (200, 201) shown in embodiments in Fig. 1, Fig. 2, Fig. 5 and Fig. 6 as well as interspinous devices (100, 101, 102) depicted in embodiments in Fig. 3, Fig. 4, Fig. 7 and Fig. 8.

The rail 200, as shown in an embodiment in Fig. 1, substantially, is a flat element made of titanium but obviously it can be produced from other materials such as for example a titanium alloy or polyetheretherketone or other materials including porous ones that are tolerated well by the human body. The rail 200, as shown in another embodiment in Fig. 2, is provided with a cut in one of the corners at an angle adjusted correspondingly to the angle of the sacral bone.

Another rail 201 illustrated in Fig. 5 is, essentially, a flat element with a through aperture in its longitudinal plane extending almost from one end to the other. It is also produced from titanium but it can be made of other materials such as a titanium alloy, polyetheretherketone or other material including porous ones as well.

The surfaces of the rails 200, 201 can be modified in order to enhance engagement and adherence to bone surfaces of spinous processes B. Thus, additionally, they can be ribbed, roughened or porous or have other surface alterations. Moreover, the surfaces of the rail 200, 201 can contain bioactive agents such as osteogenic ones facilitating bonding with surrounding bone structures or other agents for example anti-inflammatory and/or analgesic ones.

An interspinous device 100, shown in Fig. 3 and Fig. 4, is composed of a body 2, a mounting part 3 and two movable arms 4. The body 2 and the mounting part 3 are configured as one element in this embodiment; however, in other embodiments they can be formed as separate elements. The body 2 with the mounting part 3 and the arms 4 are provided with coaxial through holes, through which a bolt 5 with a nut is inserted. The bolt 5 and the nut 6 join all the elements of the interspinous device 100 together.

In Fig. 7 another interspinous device 101 is shown. It encompasses a body 2 with wings 7 protruding from its flat sides. The body 2 of the interspinous device 101 has a hole in its central part through which a bolt 5 is passed with a nut 6 for tightening.

Still another embodiment of an interspinous device is illustrated in Fig. 8. The device differs from the one depicted in Fig. 7 in that the body 2 of the interspinous device 102, composed of a body 2 with wings 7 protruding along its flat sides, has threaded studs attached to the central parts of its sides. Nuts 6 are screwed on these threaded studs.

The interspinous device 100, 101, 102 is made of titanium but can be produced of other materials such as a titanium alloy, polyetheretherketone or other material including porous ones as well.

The surfaces of the interspinous devices 100, 101, 102, in particular, of the wings 7 and/or inner surfaces of the arms of the interspinous device 100 can be modified in order to enhance engagement and adherence to the adjacent bone surfaces and/or to the rails 200, 201. Thus, they can be smooth, ribbed, roughened or porous or have other surface alterations. Moreover, these surfaces can contain bioactive agents such as osteogenic ones facilitating bonding with surrounding bone structures or other agents, for example anti-inflammatory and/or analgesic ones.

In the first embodiment of the method of spinal stabilisation illustrated in Fig. 9 and Fig. 10, after a surgical midline approach is performed e.g. in the lumbosacral segment of the spine A, at least two interspinous spaces between the spinous processes B are suitably adapted. The lateral surfaces of the spinous processes B are prepared for rails as needed. The relevant sizes of the interspinous devices 100 and the length of the rails 200 are chosen correspondingly to the width of the interspinous spaces and the number of spinal levels to be stabilised, respectively. Further, the rails 200 shown in Fig. 1 are placed at the sides of the spinous processes B. If the fixation is to comprise the L5/S1 level the second type of the rail 200 shown in Fig. 2 should be used. The curvature(s) of the rails 200 is (are) changed in two planes by bending correspondingly to the curvatures of the spine A, which can be corrected to some extent as needed. Then, holding the rails 200 in position at the sides of the spinous processes B the interspinous devices 100 shown in Fig. 3 and Fig. 4 are inserted in the spaces between the adjacent spinous processes B. The devices 100 have loose, unscrewed arms 4 so that the rails 200 can go between them and the bodies 2 of the devices 100. Depending on a situation, preference of a surgeon or in case of difficulties with placing interspinous devices in this way, alternatively, first the bodies 2 of the interspinous devices can be positioned in the spaces between the spinous processes B and the rails 200 and then the arms 4 are attached to the bodies 2. It should be noted that the size of a body 2 is adjusted to the width of the interspinous space, therefore interspinous devices 100 in this embodiment may have different sizes. The rails 200 may be cut to the relevant length or selected from a set of ready-to-use rails of different lengths. After all the interspinous devices 100 have been inserted, the arms 4 of the devices 100 are pushed to the rails 100 by tightening the nuts 6 on the bolts 5 which is depicted in Fig. 9 and Fig. 10.

In the second embodiment of the method of spinal stabilisation, after having performed a surgical midline approach e.g. in the lumbosacral segment of the spine A, in the first phase of effecting stabilisation of the spine A, at least two interspinous spaces between the spinous processes B are suitably prepared. The relevant sizes of the interspinous devices 101, 102 are chosen. Next, in the case of the interspinous devices 101, the rails 201 shown in Fig. 5 are placed at the sides of the spinous processes B. The length of the rails 201 is adjusted correspondingly to the length of spinal stabilisation, and if the fixation is to comprise the L5/S 1 level the second type of the rail 201 shown in Fig. 6 should be used. The curvature(s) of the rails 201 is (are) altered in two planes by bending to be in accordance with the curvatures of the spine A, which can be corrected to some extent as desired. When holding the rails 201 in position at the sides of the spinous processes B the interspinous devices 101 shown in Fig. 7 are inserted in the spaces between the spinous processes B. Then the bolt 5 is passed through the longitudinal aperture in the rail 201 and the hole in the interspinous device 101 and all the elements are tightened using the nut 6 put behind the second rail on the other side of the spine A. If necessary, the interspinous devices 101 can be placed first and the rails 201 next. The interspinous devices 102, shown in Fig. 8, should be implanted in the interspinous spaces first, since due to the construction of the interspinous device 102 there is no way of inserting the rails first. The rails 201 are placed on threaded studs 9 so that the threaded studs pass through the longitudinal openings 12 in the rails 201 and all the elements are tightened using the nuts 6 put before the first rail and behind the second rail on both sides of the spine A. It should be emphasized that the size of the body 2 is adjusted to the width of the interspinous space, therefore the interspinous devices 101 and 102 in these embodiment have different sizes. The rails 201 should be selected from a set of ready-to-use rails of different lengths. After all the interspinous devices 101 or 102 have been inserted, the rails 201 are pushed to the spinous processes B and moved closer to the devices 101 and 102 by tightening the nuts 6 on the bolts 5 or the studs 9 which is depicted in Fig. 11 and Fig. 12.

Claims

The system of devices for interspinous stabilisation of the spine characterised by simultaneous application of interspinous devices (100, 101 and 102) and rails (200, 201) for multi-level fixation of a spine A comprising at least three spinous processes B at two levels so that at least two interspinous devices (100, 101 and 102) are placed between the spinous processes B on at least two levels of the spine A and two rails (200, 201) mounted by them, one on each side of the spinous processes B.

The system of claim 1 wherein the curvatures of the rails (200, 201) are adjusted by bending to the curvatures of the spine - lordosis or kyphosis and/or scoliosis.

The system of claim 1 wherein a terminal segment of the rail (200, 201) is cut at an angle adjusted to the angle of the sacral bone.

The system of claim 1 wherein one or both sides of the rail (200, 201) or a part thereof are smooth, ribbed, roughened or porous or have other surface alterations including introduction of bioactive agents.

The system of claim 1 wherein an interspinous device (100) is composed of a body (2) and a mounting part (3) of the body (2) and two moving arms (4) wherein the body (2) the arms (4) are provided with a through hole (8) so that the body

(2) through the mounting part

(3) is connected to the arms

(4) using a bolt

(5) and a nut (6).

6. The system of claim 5 wherein the rails (200) are secured to the interspinous device (100) using the arms (4) which are tightened by means of the bolt (5) and the nut (6).

7. The system of claim 5 wherein the surface of the interspinous device (100) or a part thereof including the inner surface of the arms (4) and/or the surfaces adjacent to the spinous processes are smooth, ribbed, roughened or porous or have other surface alterations including introduction of bioactive agents.

8. The system of claim 1 wherein a rail (201) has a longitudinal aperture (12) and an interspinous device (101) is composed of a body (2) with wings (7) and a hole (8).

9. The system of claim 8 wherein the rails (201) are fastened with the interspinous device (101) using a bolt (5) with a nut (6).

10. The system of claim 1 wherein an interspinous device (102) is composed of a body (2) with wings (7) and threaded studs (9) which are attached to both sides of the body (2).

11. The system of claim 10 wherein the rails (201) are mounted to the interspinous device (102) using the nuts (6) which are screwed on the threaded studs (9) sticking out from the sides of the interspinous devices (102).

12. The system of claim 8 or 10 wherein the surface of the interspinous devices (101, 102) or a part thereof including the inner surface of the wings (7) is smooth, ribbed, roughened or porous or have other surface alterations including introduction of bioactive agents.

13. The system of claim 1 wherein the rail (200, 201) or a part thereof is made of a porous material.

14. The system of claim 1 wherein the interspinous device (100, 101, 102) or a part thereof is produced of a porous material.

15. The system of claim 1 wherein the rail (200, 201) is made of titanium, its alloy, stainless steel and/or polymers, ultra high molecular weight polyethylene (UHMWPE) or polyetheretherketone (PEEK) or combinations of the above-mentioned materials.

16. The system of claim 1 wherein the interspinous device (100, 101, 102) is produced from titanium, its alloy, stainless steel and/or polymers, ultra high molecular weight polyethylene (UHMWPE) or polyetheretherketone (PEEK), ceramics or combinations of the above-mentioned materials.

17. The method of spinal stabilisation characterised by simultaneous application of interspinous devices (100, 101, 102) and rails (200, 201) on at least two levels of a spine A wherein interspinous devices (100, 101,102) are located in at least two interspinous spaces comprising at least three spinous processes B as well as by usage of two rails (200, 201), one at each side of the spinous processes B.

18. The method of spinal stabilisation of claim 17 wherein the interspinous devices (100, 101, 102) are adapted to the interspinous spaces between the adjacent spinous processes.