FR2816197A1 - Interspinal prosthesis is X-shaped and is made from flexible material, two arms being compressed together and held in position by clip to introduce prosthesis - Google Patents

Abstract

The interspinal prosthesis is X-shaped and is made from material which has multidirectional flexibility. It has a narrow central area (3a, 3b) which fits against the spinal apophyses. In order to introduce the prosthesis, two of its arms (6, 7) are compressed towards each other. A U-shaped clip (11) is then fitted over them to hold them in position while the prosthesis is inserted, after which it is removed, allowing the arms to fit around the vertebrae. Independent claims are included for: (a) a method for making the prosthesis and (b) a tool for use in inserting it.

Description

<Desc / Clms Page number 1>

 The present invention relates to an interspinous prosthesis and to a method and a tool for its preparation.

 It will find its application in particular in the field of the manufacture of prostheses intended to be implanted in the interspinous space of the human vertebral column.

 Interspinous prostheses are currently already used to deal with certain pathologies.

 It should be remembered that the ligament system of the lumbar spine constitutes a passive whole contributing with the muscles to the maintenance of segmental balance called vertebral static.

 The posterior control is ensured by a capsuloligamentary complex comprising successively the posterior common ligament, the articular capsules, the yellow ligament and finally the inter and supraspinous ligaments.

 The latter extend between the interspinous processes.

By their composition and their orientation, they ensure control of certain vertebral movements.

 Their tensioning plays a fundamental role in the dynamic maintenance of the profile curvature called sagittal arch. This pre-stress in lordosis provides analgesic protection of flexion by reducing the stresses transmitted through the three support columns constituting the lumbar spine.

 As part of physiological aging or in the course of so-called degenerative conditions, there is a relaxation of the support elements, capsulo-ligaments, and discs.

 Disturbances in the anatomical reports accompanied by pathological movements, are at the origin of painful lumbago and radicular affections.

 To remedy these shortcomings, palliative techniques have been devised.

 Some called ligamentoplasties are intended as a reminder

<Desc / Clms Page number 2>

 posterior of thorny. Unfortunately, these procedures produce hyper-bone supports and do not allow the re-tensioning of the posterior ligament structures.

 The interposition, by the posterior route, at the blade-thorny junction, of a rigid wedge, induces a transfer of stresses at the level of the anterior column and therefore pathologies.

 To overcome these harmful iatrogenic effects, a prosthesis acting as a biocompatible cushioning wedge with an anatomical profile has been proposed by document FR-A-2775183. This implant, by its distracting effect, restores tension to the posterior ligament structures during movements.

 According to FR-A-2775183, the prosthesis is made of a multidirectionally flexible and elastic material, and comprises an interspinous portion having a thickness slightly greater than an anatomic interspinous space when the spine is in lordosis. It has two pairs of ears protruding longitudinally on either side of its interspinous portion, these ears having significant heights relative to the total height of the prosthesis, of the order for each pair of ears, from 30 to 45% of this total height; each pair of ears delimits a deep obviously suitable for receiving the corresponding spinous process with a large contact surface of these ears and this process.

 Its function is twofold.

 On the one hand, during dorsal flexion, it allows damping and therefore absorbs stresses.

 On the other hand, during an anterior flexion, its progressive stretching recalls the posterior arches, limiting the transmission of stresses to the discs. This disc assist function operates through two independent links, joining each end of the implant to the adjacent thorny.

<Desc / Clms Page number 3>

 This prosthesis is very effective. However, its installation currently requires a surgical procedure with harmful consequences.

 Indeed, the installation of the prosthesis, in a postero-anterior direction, leads the surgeon to resect the inter and supraspinous ligament complex, thereby eliminating its function of posterior hinge of the movement. Under these conditions, the lumbar prestressing function in lordosis is not really restored until the ligament remains healed, the mechanical qualities of which are random because they are impaired.

 Furthermore, the median surgical approach leads to bilateral detachment of the muscle compartments, a source of post-operative pain and functionally disturbing anatomical changes.

 The present invention overcomes these drawbacks.

 It exploits the mechanical properties of elastic deformation of the proposed prosthesis to reduce its size before finalizing the implantation.

 Its advantage is therefore to limit the area of introduction of the implant and consequently to reduce the invasiveness of the procedure.

 Furthermore, the deformation imposed by the prosthesis before implantation is maintained by removable clamping means which easily makes it possible to recover the initial shape of the prosthesis as soon as the operation is completed.

 Another advantage of the invention is that the bringing together of two homolateral arms by the elastic deformation gives a wedge profile to the longitudinal lateral face.

 Under these conditions, the implant can be introduced into the intervertebral space by a unilateral route. The most posterior ligament structures remain intact, as do the contralateral muscle insertions.

<Desc / Clms Page number 4>

 Another object of the invention is to provide a method and a tool capable of preparing such a prosthesis. Their implementation is very practical and allows, in particular, to consider a preparation of the prosthesis by the surgeon before the operation.

 Other objects and advantages will emerge from the description which follows, which however is not given by way of limitation of the invention.

 The present invention relates to an interspinous prosthesis made of multidirectionally flexible and elastic material capable of being inserted into the anatomic interspinous space, comprising two pairs of arms each protruding longitudinally on either side of an interspinous portion. and delimiting an obviously suitable for receiving the corresponding spinous process, characterized in that: a first arm, belonging to one of the pairs, is elastically deformed in bending in an orientation opposite to the other arm of its pair; a second arm, belonging to the other pair and located on the same side of the interspinous portion as said first arm, is elastically deformed in bending in an orientation opposite to the other arm of its pair; it has removable clamping means capable of holding said first and second arms in the deformed position.

 According to a variant, the clamping means consist of a clip whose lateral parts are applied to the first and second arms, by the inner face to the recesses which they delimit.

 According to two other variants: the body of the clip has an ogival profile to facilitate

<Desc / Clms Page number 5>

 its insertion into the anatomical interspinous space. the outer face of the first arm and / or of the second arm and / or the intermediate side wall of the interspinous portion comprises a groove along the axis of flexion of said first and second arms, to facilitate the deformation of the arms.

 The invention also relates to a method for preparing an interspinous prosthesis in multidirectionally flexible and elastic material capable of being inserted into the anatomic interspinous space, comprising two pairs of arms each protruding longitudinally from right and left other of an interspinous portion and delimiting a recess, capable of preparing a prosthesis according to the invention, characterized in that: a bending force is exerted on one of the arms of each pair, said arms being located on the same side of the interspinous portion to create an elastic deformation tending to bring them together in an orientation opposite to the other two arms, the deformed arms are kept in the bent position by releasing removable clamping means to the prosthesis.

 The invention finally relates to a tool for the preparation of an interspinous prosthesis made of multidirectionally flexible and elastic material capable of being inserted into the anatomic interspinous space, comprising two pairs of arms each protruding longitudinally from right and left another of an interspinous portion and delimiting a recess suitable for the preparation of a prosthesis according to the invention. characterized by the fact that it consists of a clamp having two jaws such that: the jaws have pressure surfaces which are

<Desc / Clms Page number 6>

 face and able to be applied, to deform them, on a first and a second arm by the inner face to the recesses which they delimit, said second arm belonging to the other pair and being located on the same side of the inter- thorny as said first arm, the jaw pressure surfaces each have a groove, the grooves facing each other and being oriented in the same direction, for the introduction of the lateral parts of a staple capable of being applied to the faces interior of said first and second arms when they are deformed.

 According to one embodiment, the grooves are oriented transversely to the long direction of the jaws.

 The attached drawings are given by way of non-limiting example. They represent an embodiment according to the invention. They will allow the invention to be easily understood.

 Figure 1 is a perspective view of the prosthesis according to the invention in a preferred configuration mode.

 Figure 2 is a sectional view of the prosthesis along line A-A-of Figure 1.

 Figures 3 and 4 show examples of implantation of the prosthesis according to the invention at the interspinous space.

 Figures 5 to 9 show successive stages of preparation of said prosthesis.

 Figures 10 to 12 illustrate a preferred embodiment of the prosthesis preparation tool.

 Figures 13 and 14 illustrate an operating mode of the preparation tool according to the invention.

 Prosthesis 1 according to the invention may be produced on the basis of a prosthesis which is the subject of patent application FR-A-2 775 183 already cited.

 An embodiment of this prosthesis is presented to

<Desc / Clms Page number 7>

 Figures 1 and 2 where we see that it includes an interspinous portion (5) able to be introduced between two successive processes (2) and two recesses (3 a, 3 b) delimited by pairs of arms (4 a , 4 b) capable of being applied to the spinous processes (2).

 Figures 3 and 4 show phases of implantation of such a prosthesis (1).

 According to this example, but not limited to, the prosthesis (1) is covered with a sheath (17) which may be made of a fabric more easily tolerated by the body. Furthermore, links (18) are present to reinforce the fixing of the prosthesis (1) between the two processes (2). In this regard, passages (19) visible in particular in Figure 2 are made at the heart of the interspinous portion (5) of the prosthesis (1) to ensure the introduction of the links (18). These links (18) can then surround the processes (2) as shown in Figures 3 and 4.

 Advantageously, and as already known from the aforementioned document FR-A-2 775 183, the prosthesis (1) could be made of silicone.

Its flexible and elastic nature will allow work in compression in the vertebral interspinous portion.

 As indicated above and as it is deduced from Figures 3 and 4, the implantation of the figured prosthesis requires making a passage of relatively substantial size.

 On the contrary, the improved prosthesis 1 according to the invention greatly reduces the area of introduction necessary for implantation between the two processes (2).

 To achieve this, a first arm (6) and a second arm (7) are deformed, each belonging to a different pair (4 a, 4 b) by subjecting them to a bending force. This bending stress is represented by two arrows in FIG. 5. The result obtained is visible in FIG. 6 where the arms (6,7) are oriented towards the outside at the recess (3 a,

<Desc / Clms Page number 8>

 3b) that they delimit. During this step, the arms (6, 7) tend to approach in a bent position and, on the other hand, to move away from the other arm making up their respective pair (4 a, 4 b).

 To facilitate the deformation of the arms (6,7), a groove oriented in the direction of the axis of flexion of the arms (ie the height of the prosthesis) can be formed either on an arm (6,7) , either on the two, or on the intermediate part of the interspinous portion.

 This or these grooves are located on the faces opposite to the inner faces 8, 9.

 Of course, the elasticity properties of the material used are used here to constitute the prosthesis (1). It is thus possible to strongly deform in bending the arms (6, 7) without however achieving rupture or plastic deformation. Furthermore, the initial shape of the prosthesis as it appears in Figure 5 can be recovered later.

 Meanwhile, to keep the arms (6,7) in a deformed position, use is made of clamping means which will advantageously be removable.

 An embodiment of the clamping means is particularly illustrated in FIGS. 6 to 8 in which they consist of a clip (10) comprising a body (11) connected in two lateral parts (12 a, 12 b).

 The clip (10) could be made of rigid metallic material or plastic or even composite material. It should of course include mechanical strength characteristics capable of keeping the arms in the deformed position (6,7). A common type of plastic deformed steel to form the U of the clip (10) may be suitable.

 The prosthesis (1) according to the invention thus clamped is visible in Figure 7. According to the example of clamping means

<Desc / Clms Page number 9>

 constituted by a staple (10), the lateral parts (12 a, 12 b) are applied to the internal faces (8, 9) of the arms (6,7). By inner faces (8, 9) is meant the lateral walls of the arms (6,7) which are located inside the recess (3 a, 3 b) that the arms (6,7) participate in delimiting.

 As is clear from FIG. 7, the size of the prosthesis (1) is particularly limited as regards the span of the two homolateral arms (6,7). The insertion of the prosthesis into the interspinous space is then greatly facilitated and the invasiveness of this surgical step is reduced.

 To further facilitate the insertion of the prosthesis (1), the clip (10) may have a particular profile, substantially in the form of a point at the level of the body (11) and in continuity with the lateral parts (12 a, 12 b ). This generally ogival shape of the clip, avoids any angular aspect of the clip (10).

 The prosthesis as presented in a preferred mode in FIG. 7 can be placed in a non-dilapidated lateral way. Once this implementation has been carried out, the removable clamping means can be removed from the prosthesis (1), which naturally generates the initial shape resumption of the first (6) and second arms (7). This step is shown diagrammatically in FIG. 8 where a horizontal arrow illustrates the withdrawal of the clip (10) while two vertical arrows in opposite directions schematize the resumption of shape of the arms (6,7).

 In the case of a staple (10), its extraction can be carried out by a small counter-incision.

 FIG. 9 finally shows the result obtained, namely the return to the initial shape of the prosthesis (1).

 It will be noted that the positioning approach is lateral, which has the advantage of preserving the interspinous ligament (not shown in FIGS. 3 and 4). By this preservation, we can

<Desc / Clms Page number 10>

 avoid using links 18, the holding of the prosthesis (1) being ensured.

 In this configuration, the arms of each pair (4 a, 4 b) are applied to the upper and lower processes (2).

 The dimensions of the prosthesis (1) presented here are not limited and will be adapted to the anatomy of the individual in which it is to be implanted. Reference may be made to examples of dimensions as known from the prior art and in particular from the previously cited prior document FR-A-2 775 183.

 More specifically described below is a tool allowing the preparation of a prosthesis (1) according to the invention as well as the implementation of the preparation process as described above.

 This tool and its use are more particularly illustrated in Figures 10,1, 14.

 The tool will allow the production of a prosthesis (1) according to the invention from a prosthesis as known in particular from document FR-A-2 775 183.

 The tool according to the invention essentially consists of a clamp (13) provided with two jaws (14 a, 14 b) located on two branches of the clamp (13) connected by a tang (20).

This configuration is visible in Figure 10.

 Furthermore, each jaw (14 a, 14 b) has pressure surfaces (15 a, 15 b) substantially at its distal end. The pressure surfaces (15 a, 15 b) can be applied to the first (6) and the second arm (7) of the prosthesis (1). This application is carried out by the internal face (8, 9) as previously presented. Figure 13 shows the approach of the two jaws (14 a, 14 b) of the clamp (13) at the arms (6,7) to be deformed.

 FIG. 14 shows how the deformation is achieved by applying the bearing surfaces (15 a, 15 b) to the faces

<Desc / Clms Page number 11>

 interior (8, 9). The two other homolateral arms constituting the pairs (4 a, 4 b) of arms are held outside the pressure surface (15 a, 15 b) of the clamp (13).

 By adjusting the approximation force of the jaws (14 a, 14 b) of the clamp (13), the desired deformation for the arms (6, 7) is adjusted.

 When this is obtained, it is a question of keeping these arms in position.

 To this end, the pressure surfaces (15a, 15b) each have a groove (16a, 16b), an exemplary embodiment of which is shown in FIGS. 11 and 12.

 Preferably, these grooves (16 a, 16 b) consist of recesses made in the pressure surfaces (15 a, 15 b) and are oriented transversely in the long direction of the jaws (14 a, 14 b). say substantially along the axis of the pivot of the entablature (20).

 The grooves (16 a, 16 b) are used, in the embodiment of the prosthesis (1) in which the removable clamping means are constituted by a clip (10), to effect the introduction of the two lateral parts (12 a , 12 b) of the clip (10) for their application on the inner faces (8,9) of the arms (6,7).

 Of course, the width of the grooves (16 a, 16 b) is adapted to the dimensions of the lateral parts (12 a, 12 b).

 Once the introduction has been made, the user can relax the pressure he applies to the forceps (13) and the prosthesis is thus prepared in the state visible in FIG. 7.

 Of course, the clamp (13) here presented in a manual mode of use could be used industrially for chain production in which case the actuation of the jaws (14 a, 14 b) can be motorized by any known means .

 Given the low cost of its realization and

<Desc / Clms Page number 12>

 the interest in terms of the surgical technique, the indications for placing the prosthesis according to the invention are considerably enlarged compared with the state of the art. In particular, it can henceforth be applied to the field of pathology of herniated discs to date only treated in a palliative manner by ablation of the disc matrix. It is now also possible to add a prosthesis during a micro-technique discectomy.

<Desc / Clms Page number 13>

REFERENCES 1-Prosthesis 2-Spiny process 3 a, 3 b-Recesses 4a, 4b-Pairs of arms 5-Interspinous portion 6-First arm 7-Second arm 8-Inner face of the first arm 9-Inner face of the second arm 10-Clip 11-Body of clip 12 a, 12 b-Lateral parts 13-Clamp 14 a, 14 b-Jaw 15 a, 15 b Pressure surface 16 a, 16 b-Grooves 17-Sheath 18-Links 19 -Passages 20-Fitting

Claims (7)

 1. Prosthesis (1) interspinous in multidirectionally flexible and elastic material able to be inserted into the anatomic interspinous space, comprising two pairs of arms (4a, 4b) each protruding longitudinally on either side of an interspinous portion (5) and delimiting an obviously (3a, 3b) capable of receiving the corresponding spinous process (2), characterized in that: a first arm (6), belonging to the one (4 a) of the pairs, is elastically deformed in bending in an orientation opposite to the other arm of its pair; a second arm (7), belonging to the other pair (4 b) and located on the same side of the interspinous portion as the said first arm (6), is elastically deformed in bending in an orientation opposite to the other arm of his pair; it has removable clamping means capable of holding said first (6) and second arm (7) in the deformed position.  2. prosthesis (1) interspinous according to claim 1, characterized in that: the clamping means consist of a clip (10) whose side portions (12 a, 12 b) are applied to the first (6) and second arm (7), by the inner face (8,9) to the recesses (3a, 3b) which they delimit.  3. Prosthesis (1) interspinous according to claim 2, characterized in that, the body (11) of the clip (10) has an ogival profile to facilitate its insertion into the interspinous anatomical space.  4. Interspinous prosthesis (1) according to any one of <Desc / Clms Page number 15>  Claims 1 to 3, characterized in that the outer face of the first arm (6) and / or the second arm (7) and / or the intermediate side wall of the interspinous portion (5) comprises a groove along the bending axis of said first (6) and second (7) arms, to facilitate the deformation of the arms (6,7).  5. Method for preparing an interspinous prosthesis in multidirectionally flexible and elastic material capable of being inserted into the anatomic interspinous space, comprising two pairs of arms (4a, 4b) each protruding longitudinally from one side and on the other side of an interspinous portion (5) and delimiting a recess (3a, 3b), capable of receiving the corresponding spinous process 2, capable of preparing a prosthesis (1) according to any one of claims 1 to 4 characterized in that: a bending force is exerted on one (6,7) of the arms of each pair (4 a, 4 b), said arms (6,7) being located on the same side of the interspinous portion (5) to create an elastic deformation tending to bring them together in an orientation opposite to the two arms other arms, the deformed arms (6,7) are kept in the bent position by bringing the prosthesis (1) removable bridles.  6. Tool for the preparation of an interspinous prosthesis in multidirectionally flexible and elastic material able to be inserted into the anatomic interspinous space, comprising two pairs of arms (4a, 4b) each protruding longitudinally from one side and other of an interspinous portion (5) and delimiting a recess (3 a, 3 b), suitable for the preparation of a prosthesis (1) according to claim 2 or 3 <Desc / Clms Page number 16> 14 b) each have a groove (16 a, 16 b), the grooves (16 a, 16 b) facing each other and being oriented in the same direction, for the introduction of the lateral parts (12 a, 12 b) a clip (10) capable of being applied to the interior faces (8,9) of said first (6) and second (7) arms when they are deformed.  characterized by the fact that it consists of a clamp (13) provided with two jaws (14 a, 14 b) such that: the jaws (14 a, 14 b) have pressure surfaces (15 a, 15 b ) facing each other and capable of being applied, to deform them, on a first (6) and a second arm (7) by the internal face (8,9) to the recesses (3a, 3b) which they delimit , said second arm (7) belonging to the other pair and being located on the same side of the interspinous portion as said first arm (6), the pressure surfaces (15 a, 15 b) of the jaws (14 a,  7-Tool according to claim 6, characterized in that: the grooves (16 a, 16 b) are oriented transversely to the long direction of the jaws (14 a, 14 b)