Medical implant of the type of a wrap-around cuff electrode assembly

Abstract

The invention is a medical implant which is a wrap-around cuff comprising a flexible, biocompatible, film carrier substrate, that has a carrier substrate region which is wrapped around a wrap axis to form a tube. The invention has a protective structure directly or indirectly attached to the carrier substrate, which can be transformed from a first, open state into a second closed state that encloses the carrier substrate region that is wrapped to form a tube at least axially around a wrapping axis extending in the peripheral direction of the tube.

Claims

1. A wrap-around cuff electrode configured as a medical implant into a patient comprising: a flexible biocompatible film substrate including a substrate region comprising more than one wrap-around layer of the flexible biocompatible film substrate with ends which are loose to flex in response to movement of a person when the cuff electrode is implanted and forms a tube for containment of a nerve bundle of the patient; and a protective tube with the ends applied to the flexible biocompatible film substrate including an axial excess portion on each end facing the cuff electrode which is configurable from a first open state to a second closed state axially enclosing at least part of the substrate region and completely enclosing the tube in a peripheral direction of the tube, and the axial excess portion on each end of the cuff electrode including means for preventing growth of tissue axially into the tube.

2. The medical implant according to claim 1 wherein the protective structure when closed in the second closed state completely covers the substrate.

3. The medical implant in accordance with claim 2 wherein the protective structure in the second closed state has a surface facing radially away from a wrapping axis to which at least one contact electrode is connected with an electrical conducting structure integrated within the protective structure and extending along the substrate.

4. The medical implant in accordance with claim 3 wherein: the substrate region is one piece wrapped into the tube which includes a second substrate region on which an electromechanical connection, an electrical supply and a discharge is attached and the protective structure is attached to the electrical supply and discharge.

5. The medical implant in accordance with claim 4 wherein the second substrate region is surrounded at least in part by a sheath of elastic material.

6. The medical implant in accordance with claim 5 wherein the protective structure is connected in one piece to the sheath.

7. The medical implant according to claim 1 comprising a joining mechanism on the protective structure which is detachable and secures the protective structure when in the second closed state.

8. The medical implant according to claim 1 comprising: the protective structure is connected by at least one web to the substrate.

9. The medical implant in accordance with claim 1 wherein the protective structure comprises two half shells which are mutually complimentary to each other when the protective structure is in the second closed state to enclose a cylindrical hollow space.

10. The medical implant in accordance with claim 1 wherein the protective structure is a wrap around film cuff comprising a flat wrap which is wrapped to enclose a cylindrical hollow space.

11. The medical implant in accordance with claim 1 wherein a predetermined material is located in the first substrate region which, without any external force, is shaped into a wrapping configuration in which an end of the substrate region is radially covered by at least one wrapped layer of the substrate.

12. The medical implant in accordance with claim 1 wherein the substrate and the protective structure are each a layer of film and have a thickness from 5 micrometers to 50 micrometers.

13. The medical implant in accordance with claim 1 wherein the substrate is a flexible biocompatible substrate shaped into a tube by wrapping around an axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) As an example, the invention will be described below, without restricting the scope of the invention, by way of examples of embodiment with reference to the drawings. Here:

(2) FIGS. 1a, b show cuff electrodes with a protective structure in the open state a) and in the closed state b);

(3) FIG. 2 shows cuff electrodes in accordance with the prior art;

(4) FIGS. 3a-e show different stress states of the cuff electrode on a nerve bundle;

(5) FIGS. 4a, b show an alternative design of the cuff electrode and application of the protective structure;

(6) FIGS. 5a, b show an alternative design of a protective structure in the open state a) and in the closed state b); and

(7) FIG. 6 shows an alternative design and application of the protective structure.

DETAILED DESCRIPTION OF THE INVENTION

(8) FIG. 1a shows a medical implant 1 as a wrap-around cuff electrode or cuff electrode as already presented in FIG. 2, with the carrier substrate section 3 of the carrier substrate 2 formed by wrapping at least one and a half, and preferable two or multiple times about the wrapping axis, and through a material which inherently or a pre-determined material which is pre-tensioned to assume the shape of a tube in which the cuff electrode can be fixed in a self-supporting manner immovably on the peripheral edge of a nerve. Already discussed are the components of the medical implant 1 with reference numbers which will not be described again in order to avoid repetition.

(9) In order to mechanically protect the carrier substrate region 3 of the cuff electrode wrapped around the wrapping axis 5 to form a tube, a protective structure 8 is provided, which via a weblike connecting section 8′, is connected to the carrier substrate 2 at the second carrier substrate region 6 and more particularly on the weblike surface section 61. The protective structure 8 as well as the web connecting section 8′ are made of the same film material as the carrier substrate 2 of the cuff electrode which is preferably a thin film or a thin layer of polyamide film, which preferably has a film thickness in the range between 5 μm and 20 μm. The connecting section 8′ and the carrier substrate 2 are preferably monolithically connected.

(10) The protective structure 8 comprises two cylindrical half shells 9, 10 which are monolithically connected to each other, preferably by way of a solid body joint 11. The solid body joint 11 is preferably a crease.

(11) After applying the medical implant 1 along a nerve fiber bundle, for the purpose of mechanically protection, the protective structure 8 shown in the open state according to FIG. 1a is transferred into the closed state according to FIG. 1b, through which both half shells 9, 10 are joined, forming a straight hollow cylinder around the first carrier substrate region 3 wrapped in a tube. The closed state of the protective structure 8 shown in FIG. 1b, in which for better illustration both half-shells 9, 10 are each shown transparently, indicates that the hollow cylindrically-shaped in a closed protective structure 8 that completely encloses the wrap-around cuff contained therein both in the peripheral direction and also axially to the wrap axis 5. In the closed state, the protective structure 8 preferably has an axial excess portion on each side facing the wrap-around cuff, so that that the internally arranged wrap-around cuff is prevented from being functionally impaired by tissue growth.

(12) Both half shells 9, 10 of the protective structure 8 are joined together as a complete straight hollow cylinder, which can advantageously be held permanently in the closed state by a joining mechanism 12 which is only shown schematically.

(13) As an alternative to applying the web connection section 8′ directly to the surface section 61, it is also possible, to connect the web-like connecting structure 8″ indicated with the dashed line in FIG. 1b, so that the connecting structure 8″ leads away from the implant 1, preferably in the immediate vicinity of the interface S.

(14) FIGS. 4a and b show an alternative embodiment of the medical implant as the cuff electrode 1 which largely comprises a carrier substrate region 3 wrapped to form a tube, from which a surface section of the carrier substrate leads off directly, along which the electrical leads 7, (not shown in detail,) lead off. The protective structure 8, which like the embodiment in FIGS. 1a, b comprises two half shells 9, 10, which directly adjoins the carrier substrate region 3 without any connecting structure. In FIG. 4b, the closed state of the protective structure 8 is illustrated. To facilitate better understanding, the protective structure 8 is shown transparently. In this form of embodiment, the end edges of the half shells 9, 10 overlap along an overlap Ü.

(15) In FIG. 5a, an alternative design of the protective structure 8 is shown. In this case, the protective structure 8 is a film-like surface section into which are material inherently or mechanically pre-tensioned is introduced so that the protective structure 8 can only be held in the open state as shown in FIG. 5a when an external force F is applied. Like the protective structure 8 illustrated in FIG. 1a, the flatly configured protective structure 8 is monolithically connected to the second carrier substrate region 6, particularly at the surface section 61 by way of a weblike connecting section 8′.

(16) After application of the cuff electrode to the nerve bundle, the protective structure 8 is transferred into the closed state according to FIG. 5b, wherein the surface section of the protective structure 8 reshapes itself as a result of the inherent mechanical pre-tensioning to form a straight hollow cylinder. The holding force, through which the protective structure 8 is kept in the closed state, can preferably be increased in that the thickness of the surface section of the protective structure 8 is selected to be correspondingly greater, for example larger than the film thickness in the area of the carrier substrate 2.

(17) As has already been mentioned, measures regarding the an additional joining mechanism as well as an alternative application of the protective structure 8 with the connecting structure 8′ without the connecting structure, that is by direct application of the protective structure 8 to the carrier substrate region 3, is comparable with the embodiment of the cuff electrode in accordance with FIGS. 4a, b, which can be used in the case of the example of embodiment shown in FIG. 5 and b.

(18) FIG. 6 shows a protective structure 8 in the closed state, which 8 encloses the cuff electrode situated within it. Protective structure 8 can be two half shells, as shown in FIGS. 1a, b, or as a wrap-around cuff as shown in FIGS. 5a, b. In contrast to the illustrated forms of embodiment, in this case the protective structure 8 is connected via a connecting structure 8″ with a sheathing 13 made of elastomer material, preferably of silicone or a silicone-based plastic, which surrounds at least one section of the surface section 61. The preferably tubular sheathing 8 is joined in a positive manner to the film-like surface section 61 by way of an anchoring structure 14 applied in one piece to the surface section 61. The surface section 61 is part of the carrier substrate 2 and directly or indirectly adjoins the carrier substrate region 3 of the cuff electrode wound to form a tube. The shape and size of the sheathing 13 are selected for the purpose of intracorporeal application to a nerve fiber bundle, is made easier for a doctor to handle. Not necessarily, but advantageously, the protective structure 8 is made of the same material from which the sheathing 13 is made.

LIST OF REFERENCE NUMBERS

(19) 1 Medical implant 2 Carrier substrate 3 First carrier substrate region 4 Free section end 5 Wrapping axis 6 Second carrier substrate region 61 Weblike surface section 7 Connecting structure 8 Protective structure 8′, 8″, 8′″ Connecting section 9, 10 Half shells 11 Solid body joint 12 Joining mechanism 13 Sheathing 14 Anchoring structure Ü Overlap