WO2007135322A1

WO2007135322A1 - Support device for a surgical implant with shape memory

Info

Publication number: WO2007135322A1
Application number: PCT/FR2007/051284
Authority: WO
Inventors: Bernard Prandi
Original assignee: Memometal Technologies
Priority date: 2006-05-19
Filing date: 2007-05-16
Publication date: 2007-11-29
Also published as: FR2901119B1; FR2901119A1

Abstract

The implant (4) has anchoring tabs for its impaction into a bone part. The device comprises arrangements (5) or means (2) able to cooperate with only some of the anchoring tabs in order, on the one hand, to keep them in a splayed position corresponding to their introduction into the bone part in question and, on the other hand, to permit said introduction in said splayed position.

Description

DEVICE FOR SUPPORTING A SURGICAL IMPLANT WITH SHAPE MEMORY

The invention relates to the technical sector of surgical implants with shape memory, and more particularly to the material for their storage and handling.

It is well known to a person skilled in the art to use orthopedic implants with shape memory to reduce fractures or others requiring osteosynthesis. This is particularly the case for interphalangeal arthrodesis of the hand and foot. Among these different types of implants, mention may be made of osteosynthesis staples of the bipod or quadripod type, for example, and intramedullary implants. In addition, depending on the type of alloy used, there are the hot shape memory implants and the cold shape memory implants. Generally, the implants are stored constrained in a holder in order to retain a shape allowing their introduction into the bone part (s) considered (s).

For example, a bipode clip of the type known as MEMOCLIP is subjected to an operation to hold the tabs in parallel. The two tabs of the clip are positioned in two holes formed parallel in the thickness of a polyethylene support for example. These provisions make it possible to maintain parallel the two tabs of the clip during storage and transport. This parallel position of the two legs corresponds to the form of introduction of the clip. The entire support with the staple is stored cold, the staple being removed with a suitable clip for implantation. In a known manner, at body temperature, the tabs of the clip are closed to compress the focal osteosynthesis considered.

This solution is not completely satisfactory since the supports used are relatively massive and above all impose a surface contact with moving parts of the implant. For example, in the case of a staple, as indicated above, the entire length of the tabs is in contact in the holes of the support.

The same disadvantages are found in the case of a shape memory implant of the intramedullary type, for example of the type whose legs form substantially an X, and where the entire length of said tabs is in contact in the hole of the support.

Referring to Figure 1 which shows an osteosynthesis staple positioned in a support according to the prior art and in Figure 2 which shows an intramedullary implant positioned in a support also considered according to the prior art. This results in several disadvantages.

The friction of the implant, in its support, being important, we can not exclude the risk of tearing of the material. Likewise, the importance of the contact surface in the support makes it necessary to have as smooth a contact surface as possible, so that it is difficult to envisage using shape memory implants whose legs have, for example, for example, anchoring asperities.

It is also observed that when removing the implant from its support, it is not possible to keep the moving parts (the legs, by example) by an instrument or directly by the bone. This can result in unwanted movements, especially when the implant is not cold enough, prohibiting its installation or, at least, making it particularly delicate.

The object of the invention is to remedy these disadvantages in a simple, safe, effective and rational manner.

The problem to be solved by the invention is to maintain, in their insertion position, the moving parts of the orthopedic implant with shape memory, from storage until the moment of its impaction on the patient. , with the possibility to have greater freedom in the profile of the implant.

To solve this problem, it has been designed and developed a support device for a surgical implant with shape memory having anchoring tabs for its impaction in a bone part. This device comprises arrangements or means able to cooperate with only part of the anchoring tabs to keep them constrained in a spaced position corresponding to their introduction into the part of bone considered.

Given these characteristics, it follows that the support device allows the maintenance of the implant with a zone of contact as low as possible and at a specific location to allow to create, for example, grounding asperities level legs and leave free areas for, for example, the establishment of a gripper and handling. Depending on the type of implant used, the invention relates to one or more support devices that can optionally be combined with a clamp for manipulating said implant.

Thus, different technical solutions are envisaged.

In the case of an implant in the form of a bipod or quadripode clip, the device comprises a gripping body having arrangements for holding the tabs of the clip in parallel position, said arrangements being shaped to cooperate substantially at the level of the clip. a connecting portion of said tabs, so as not to interfere with the anchoring asperities that can present the tabs.

In the case of an implant of the intramedullary type whose legs form substantially an X, the device is constituted, for each of the transverse sides of the X, by a gripper assembly having arrangements adapted to grip a portion of the two tabs considered on the same side transverse so as to keep them in close position. The arrangements are constituted by a semi-open loop adapted to grip a portion of the tabs having no anchoring asperities and able to leave a free intermediate area for the positioning of a clamp at the moment of impaction.

The invention is described below in more detail with reference to the figures of the accompanying drawings, in which: - Figure 1 is a sectional view, schematic, showing a support according to the state of the art in the case of a shape memory osteosynthesis clip;

FIG. 2 is a schematic sectional view showing an intramedullary shape memory implant positioned in a support according to the prior art;

FIG. 3 is a perspective view of a known example of a shape memory implant constituting a quadripode clip;

- Figures 4 and 5 are perspective views showing an embodiment of the support device according to the invention, in the case of a shape memory implant of the type shown in Figure 3;

FIG. 6 is a perspective view of a shape memory implant of the intramedullary type and whose tabs substantially form an X;

FIG. 7 is a perspective view showing an embodiment of the support device, in the case of an implant of the type illustrated in FIG. 6, in order to keep it positioned according to a shape corresponding to its introduction; FIGS. 8 to 15 show the use of the support device illustrated in FIG. 7, for the introduction into the bone of the intramedullary shape memory implant illustrated in FIG. 6.

As indicated, the support device according to the invention finds an application for any type of orthopedic implant with shape memory, in particular in the case of osteosynthesis staples (FIG. 3) and intramedullary implant (FIG. 5). By shape memory, we mean any material deformable by elasticity effect given the nature of the material itself or by temperature change (raising or lowering).

Whatever its embodiment, the orthopedic implant with shape memory, generally designated by (I), comprises anchoring tabs (P) for its impaction in the bone part or parts considered.

According to a characteristic underlying the invention, the support device comprises means able to cooperate with only part of the anchoring tabs (P), in order to keep them constrained, according to a spacing position corresponding to their introduction into the party or parties considered.

Figure 3 shows a shape memory osteosynthesis clip of the quadripode type. In a perfectly known manner, this type of clip (1) comprises four tabs (la), (Ib), (Ic), (Id) joined by a median portion (Ic) of any shape. The different tabs (la), (Ib), (Ic), (Id) can be approximated two by two, under the effect of the elasticity of the shape memory alloy used and under the effect of the temperature rise, according to an arrow (F) or (Fl). In this case, the support device according to the invention is constituted by a gripping body (2) having, at one of its ends, arrangements for holding in parallel position the different tabs (la), (Ib), ( Ic), (Id). For example, as shown in Figures 4 and 5, the base of the gripping body (2) has two parallel wings (2a) and (2b) which define an inverted U-shaped opening (2c). After positioning the body (2), the two wings (2a) and (2b) are arranged between the internal faces opposite the tabs (la) and (Ic), on the one hand, and (Ib) and (Id), on the other hand, thus avoiding said legs to move closer according to the arrow (Fl). In other words, wings (2a) and (2b) maintain in parallel position the legs (la) and (Ic), and (Ib) and (Id) corresponding to the insertion position.

Importantly, the wings (2a) and (2b) cooperate on a reduced surface area (If) of the legs thus forming anchoring asperities (Ig).

In the case where the tabs (la) and (Ib), on the one hand, and (Ic) and (Id), on the other hand, are shaped to approach naturally under the effect of the shape memory according to the arrows (F), an additional tab

(3) can be inserted between the inner faces facing the legs (la), (Ib) and

(Ic), (Id) (Figures 4 and 5).

In this exemplary embodiment, the support device, in the form of a gripping body (2), obviously makes it possible to grip the clip with a view to its impaction.

FIG. 6 shows a shape-memory implant of the intramedullary type (4) whose tabs (4a), (4b), (4c) and (4d) form a substantially X. For this type of implant, the support device according to FIG. the invention comprises two quasi-identical assemblies (E1) and (E2) each cooperating with the transverse sides of the X, that is to say with the tabs (4a) and (4b), on the one hand, and the legs (4c) and (4d), on the other hand. Each of the gripper assemblies (El) and (E2) has arrangements capable of gripping a portion of the two tabs (4a) and (4b), on the one hand, and the two tabs (4c) and (4d), on the other hand on the other hand, so as to keep them in close position corresponding to their introduction form (FIG. 7). More particularly, the approximation arrangements are constituted by a semi-open loop (5) adapted to grip, on a reduced area, a portion (4e) of the tabs having no anchoring asperities (4f). Each loop (5) is extended, on both sides, by branches (5a) and (5b) shaped at their free end to form an open ring (5c), (5d) able to act by elasticity on said loop . Of course, these loop-shaped arrangements should not be considered as limiting.

As shown in FIG. 7, after placement of the gripper assemblies (E1) and (E2), on either side of the implant (4), the loops (5) keep the tabs (4a) and ( 4b), on the one hand, and (4c) and (4d), on the other hand, and leave a free intermediate zone for the positioning of a clamp (6) at the moment of the impaction of said implant (4). . Referring to Figures 8 to 15 which show the main steps for the introduction of the implant (4) in two bones (01) and (02), for example.

In Figure 8, the clamp (6) is disposed on the side of the branches (4c) and (4d) kept closed by the corresponding loop (5).

The gripper assembly (El) is then removed, the tabs (4c) and (4d) being kept closed by the clamp (6) (Figure 9). It is then possible to introduce, halfway, the implant (4) in the bone (01) (Figure 10). It is observed that the tabs (4c) and (4d) remain in the closed position by the bone (01), while the tabs (4a) and (4b) remain closed by the loop (5) of the gripper assembly (E2 ). The clamp (6) is then moved to the free zone that appears on the side of the tabs (4a) and (4b) (Figure 11). It is then possible to remove the gripper assembly (E2), since the tabs (4a) and (4b) remain closed by the clamp (6) (Figure 12).

The operator can then engage the bone (02) halfway on the legs (4a) and (4b) which remain closed by the clamp (6), observing that the bone (02) has taken the relay (Figure 13).

It is then sufficient to remove the clamp (6) and finish engaging the bone (02) on the implant (4) (Figure 14), the branches (4a), (4b) and (4c) being then fit to deviate under the effect of shape memory (temperature rise) or by superelasticity effect.

It therefore appears that the support device according to the invention makes it possible to ensure, in a reliable and simple manner, the real maintenance of the shape memory implants since the device is removed only when the bone or a pincer took over to ensure such a hold.

It is also recalled that the support device cooperates with only a reduced scope area of the implant thus allowing toothed tabs to improve the anchoring in the bone.

The advantages are apparent from the description.

Claims

R E V E N D I C A T IO N S

-1- Support and gripping device of a surgical implant with shape memory having anchoring tabs for its impaction in a bone part, characterized in that it comprises arrangements (5) or means (2) adapted to cooperate with only part of the anchoring tabs to, firstly, keep them constrained in a spaced position corresponding to their introduction into the part of bone considered and, secondly, allow said introduction into said spacing position.

-2- Device according to claim 1, characterized in that, in the case of an implant (4) of the intramedullary type whose legs form substantially an X, said device is constituted for each of the transverse sides of the X, by a set gripper (El) and (E2) having the arrangements (5) adapted to grip a portion of the two legs considered the same transverse side so as to keep them in close position.

-3- Device according to claim 2, characterized in that the arrangements (5) are constituted by a semi-open loop adapted to grip a portion of the tabs having no anchoring asperities and able to leave a free intermediate area for positioning a clamp (6) at the moment of impaction.

-4- Device according to claim 3, characterized in that the loop (5) is extended, on either side, by branches (5a) and (5b) shaped at their free end to form an open ring (5c ) able to act on said loop by elasticity. -5- Device according to claim 1, characterized in that, in the case of an implant in the form of a bipod or quadripode clip (1), the means is constituted by a gripping body (2) having arrangements ( 2a) and (2b) holding in parallel position the tabs of the clip (1).

-6- Device according to claim 5, characterized in that the arrangements (2a) and (2b) for maintaining in parallel position of the tabs are shaped to cooperate substantially at a connecting portion of said tabs, so as not to interfere with anchor asperities (Ig) that can present the legs.