Neural electrode arrangement

Details Neural electrode arrangement Neural electrode arrangement

1999-10-08

2001-09-18

Jastrzab, Jeffrey R. (Department: 3737)

Surgery: light, thermal, and electrical application

Light, thermal, and electrical application

Electrical energy applicator

Reexamination Certificate

active

06292703

ABSTRACT:

FIELD OF THE INVENTION
The invention concerns a neural electrode arrangement.
BACKGROUND OF THE INVENTION
Neural electrodes are used to detect neural activity and excitation signals on a nerve and/or to provide for electrical stimulation of the nerve and must enjoy sound reliable electrical contact with the nerve for the duration of the detection or stimulation period which can extend over months or years without exerting an excessively high pressure on the nerve or even damaging it.
In previous arrangements therefore the actual electrode surfaces are fitted in the form of metal foils to the inside surface of an elastically expandable. spiral or helical main body of plastic material, which after implantation elastically embraces the nerve and in that way provides for a uniform contact pressure with the nerve even in the event of vigorous movements on the part of the patient and even in the event of the nerve swelling. A further development in an arrangement of that kind is to be found for example in WO-A-90/03824.
Besides helical carriers which involve a relatively complicated procedure for fitting them to the nerve and which generally require a special tool for that purpose. carriers of different shapes have also been put forward. Thus US-A-5 487 756 describes a cylindrical elongate sleeve which is divided in the direction of its longitudinal axis and which therefore can be easily opened up and closed again, with a locking bar which is inserted into the sleeve after it has been fitted to the nerve in order securely to close the sleeve around the nerve. In this case the electrodes are formed directly on the carrier by a thin-film process or by galvanisation.
EP-B-O 610 301 describes an arrangement with a carrier of a specific configuration such as to embrace the nerve with two Y-shaped arms of a connecting portion which extends along the nerve The connecting portion and the arms consist of flat silicone material and in this case the electrodes are preferably formed from an iridium foil or band and the carrier body is molded thereon.
In terms of clinical application of arrangements of the above-indicated kinds. it was found that the assembly suffers from unsatisfactory long-term stability.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a neural electrode arrangement which enjoys improved long-term stability.
Another object of the invention is to provide a neural electrode arrangement which is of a simplified structural configuration while ensuring satisfactory and reliable fitting of the neural electrode arrangement to a nerve.
In accordance with the principles of the present invention the foregoing and other objects are attained by a neural electrode arrangement including an elastically deformable carrier body defining a cylindrical internal space therein. and at least one electrode which is fixedly connected to the carrier body and which is peripheral to the cylindrical internal space. The electrode is formed from an elongate wire coil.
As will be apparent from the description hereinafter of a preferred embodiment of the present invention. the invention provides that the electrode or electrodes is or are formed by a structure which is elastically deformable in a plurality of directions. and is or are spatially integrated into the carrier. That serves to at least alleviate or prevent the formation of cracks or ruptures or detachment of the electrode from the carrier, even after use over a relatively prolonged period of time, in conjunction with an elastic carrier. A particularly suitable configuration in that respect is a helical shape which enjoys tensile elasticity in the direction of the longitudinal axis of the coil configuration and which enjoys flexural elasticity and compressive elasticity perpendicularly to the direction of the longitudinal axis.
In accordance with a preferred feature of the invention the at least one electrode is formed from a multiple coil and is flexibly glued into grooves or slots which are specifically pre-formed for same in the carrier body, in such a way that the at least one electrode is disposed at least substantially flush with the inside surface of the carrier body. That substantially eliminates nerve irritation as a consequence of the non-planar electrode surface.
In particular the at least one electrode is glued or cast into the carrier body by means of an elastic materl. more especially a siliconebased casting material or adhesive. By virtue of its own specific elasticity. the electrode is capable of following deformation phenomena or movements of the elastic carrier body without cracks being formed or material detachment phenomena occurring.
In a further preferred feature of the invention the carrier body has a wall which is formed by portions of a hollow cylinder and the thickness of which is at least equal to the diameter of the wire coil. The wall in a technologically advantageous manner has a slot which extends therethrough from the outside surface to the inside surface and into which the coil is inserted. The above-mentioned elastic material for glueing or casting the electrode in place is then introduced into the through slot from the outside surface of the carrier body so that the side of the electrode that faces towards the nerve remains substantially adhesive-free and the electrical properties of the assembly are not adversely affected.
In a further preferred feature of the invention the wire coil is preferably in the form of a double coil comprising two individual metal wires, in order thereby to afford additional safety reserves. The resulting combination of very good electrical properties and a high level of biocompatibility is advantageously achieved by the wire coil being made from platinum and in particular receiving a coating with a fractal surface structure for increasing the effective surface area by at least two orders of magnitude, in a manner which is known per se in relation to pacemaker electrodes.
In accordance with another preferred feature of the invention, with the generally conventional inside diameters of between 2 and 3 mm in respect of the overall arrangement. The wire coil may be of an outside diameter in a range of between 0.2 and 0.6 mm. more especially about 0.45 mm.
In accordance with still another preferred feature of the invention. the at least one electrode is connected to a supply line which is in the form of a stranded wire or a coil and the outside diameter of which is in particular at most equal to the inside diameter of the wire coil constituting the electrode, by means of crimping using a crimping sleeve.
In a preferred configuration of the carrier body it has a central portion and five lateral portions which extend from same substantially perpendicularly and alternately towards both sides and which together with the central portion define the basic shape of a hollow cylinder. A respective electrode is inserted at least into two lateral portions extending towards different sides; preferably, two portions which extend successively towards one side each carry a respective electrode of one polarity. and the portion which is disposed therebetween and which extends towards the other side carries an electrode of the other polarity.
Further objects, features and advantages of the invention will be apparent from the description hereinafter of a preferred embodiment of the invention.


REFERENCES:
patent: 5215089 (1993-06-01), Baker, Jr.
patent: 5265608 (1993-11-01), Lee et al.
patent: 5351394 (1994-10-01), Weinberg
patent: 5487756 (1996-01-01), Kallesoe et al.
patent: 5531778 (1996-07-01), Maschino et al.
patent: 5689877 (1997-11-01), Grill, Jr. et al.
patent: 196 45 162 (1998-05-01), None
patent: 0 610 301 (1994-08-01), None
patent: 0 865 800 (1998-09-01), None
patent: WO 90/03824 (1990-04-01), None
patent: WO 91/08016 (1991-06-01), None
patent: WO 96/08290 (1996-03-01), None
G. Naples et al; A Spiral Nerve Cuff Electrode for Peripheral Nerve Stimulation; IEEE Transactions on Biomedical Engineering, vol. 35, No. 11, Nov. 1988, pp. 905-916.

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