Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
  • A61B5/316—Modalities, i.e. specific diagnostic methods
  • A61B5/388—Nerve conduction study, e.g. detecting action potential of peripheral nerves
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/02—Details
  • A61N1/04—Electrodes
  • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
  • A61N1/0551—Spinal or peripheral nerve electrodes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2210/00—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
  • A61F2210/0014—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof using shape memory or superelastic materials, e.g. nitinol
  • A61F2210/0019—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof using shape memory or superelastic materials, e.g. nitinol operated at only one temperature whilst inside or touching the human body, e.g. constrained in a non-operative shape during surgery, another temperature only occurring before the operation
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/02—Details
  • A61N1/04—Electrodes
  • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
  • A61N1/0551—Spinal or peripheral nerve electrodes
  • A61N1/0556—Cuff electrodes

Definitions

• the present invention relates to an annular neural electrode intended to ensure, in a given operating temperature range, electrical contact at the periphery of a nerve so as to induce electrical excitation there.
• the invention finds an advantageous application in the general field of electrical stimulation of the nerves allowing the control of muscles or other organs, and in particular when, following a rupture of the spine no nerve impulse is susceptible to reach the muscles of the lower limbs in order to set them in motion.
• the electrode, object of the invention, associated with complex gait simulation programs must allow paraplegics to recover certain locomotion by replacing the nerve impulse lacking an electric excitation propagated in the nerve. himself.
• neural electrode is meant an electrode intended to stimulate a muscle by means of the excitation of a nerve, in contrast to the epimysial electrodes which, directly applied to the envelope of the muscle, have a less selective action.
• the electrode described above cannot react to a possible increase in the section of the nerve, which is then excessively constrained by the electrode and therefore definitively destroyed.
• the technical problem to be solved by the object of the present invention is to produce an annular neural electrode conforming to the preamble which would make it possible to avoid, whatever the circumstances. excessive stress on the nerve in the electrode, which would also provide good mechanical strength.
• the solution to the technical problem posed consists, according to the present invention, in that said electrode is made of a shape memory material capable of exhibiting, in said operating temperature range, a superelastic effect accompanying the transformation under stress of the phase austenitic in martensitic phase.
• the annular neural electrode according to the invention can easily deform over a wide range of deformations, for example under the effect of an increase in the diameter of the nerve, without developing on the nerve strong stresses which would permanently damage it. Consequently, it is possible to provide, during the positioning of the electrode object of the invention around the nerve, a slightly tight contact but nevertheless much more adjusted than in the case of the electrodes known from the state of the art, knowing that in any event the stress will remain below the tolerable limit stress.
• the annular neural electrode conforms to the invention has the additional advantage of a particularly easy installation by implementing the characteristic properties of shape memory materials.
• the shape memory material is shaped so as to ensure electrical contact with said nerve in a shape memory state in the austenitic phase.
• the electrode is brought to a low temperature in the martensitic phase, placed in the open position and engaged on the nerve. Then, by simple heating beyond the transition temperature to the austenitic phase, the electrode returns to the closed position in which it had been previously shaped.
• said shape memory material is shaped so as to ensure electrical contact with said nerve in a first shape memory state, and to ensure the release and / or engagement of said electrode in a second state of shape memory.
• Figure 1a is a side view of an annular neural electrode according to the invention.
• Figure lb is a sectional view along line II-II of Figure l a.
• Figure 2 is a stress-strain diagram of a shape memory material in the superelastic state.
• Figure 3a is a side view of a first alternative embodiment of the electrode according to the invention.
• Figure 3b is a sectional view along line II-II of Figure 3a.
• Figure a is a side view of a second alternative embodiment of the electrode according to the invention.
• Figure b is a side view along line II— II of Figure ⁇ + a.
• Figure 5 is a front view showing a first mode of association of two electrodes according to Figure 1b.
• Figure 6 is a front view showing a second mode of association of two electrodes according to Figure 1b.
• Figure 7 is a front view of a double electrode according to the invention.
• Figures la and lb show in a side view and in section an annular neural electrode intended to ensure, in a given operating temperature range, electrical contact at the periphery of a nerve 10 so as to induce an electrical excitation therein .
• the electrode of Figures la and lb is made of a shape memory material capable of having, in the operating temperature range, a superelastic effect accompanying the transformation under stress of the austenitic phase in mantensitic phase.
• a stress ⁇ / deformation ⁇ diagram representing this effect is given in FIG. 2. It can be seen on the diagram in FIG.
• the operating temperature range of the electrode is chosen between the temperature A-- at the end of the austenitic transition and the temperature A-.
• the temperature A p of the shape memory material must be taken at least equal to 42 ° C while the temperature A p at the end of the austenitic transition is chosen at most equal to 35 ° C.
• the shape memory properties under the effect of temperature can be advantageously implemented in the operations aimed at placing the electrode according to the invention on the nerve and, possibly, at removing it .
• the memory material forming the electrode is shaped so as to ensure electrical contact with the nerve 10 in a state of memory in austenitic shape. The positioning is then carried out as follows: the electrode is brought into the martensitic phase around 0 ° C. for example, which supposes that the temperature - at the end of the martensitic transition is close to 0 ° C., and conformed in the open position.
• the electrode resumes under the effect of temperature warming the holding configuration which had been given to it initially in the austenitic phase, provided however that the temperature A-. at the start of the austenitic transition is greater than 0 ° C.
• the shape memory material must be shaped so as to ensure electrical contact with the nerve in a first state of shape memory, and to ensure the release and / or engagement of the electrode in a second shape memory state.
• the first and second shape memory states are defined respectively in the austenitic phase and in the martensitic phase. The passage from one to the other of the shape memory states can be effected in a reversible manner by the mere fact of crossing the transition temperature of the shape memory material.
• the electrode according to the invention is subjected to an education process, examples of which are given in European patent application No. 0 161 952.
• the electrode has on its outer part a sheath 21, for example made of bio-compatible silicone, making it possible to avoid contact between the tissues and the Ni-Ti alloy, for example, forming the 'electrode.
• the polarization of said electrode is provided by a conductor 30.
• the electrical connection with the nerve 10 is obtained by direct contact on the nerve of the shape memory material constituting the electrode. In order to further limit the harmful reactions which could occur between the material of the electrode and the biological medium, it is provided, as illustrated in FIGS.
• FIGS. 4a and 4b illustrate an alternative embodiment of the electrode of FIGS. 3a and 3b in which the electrical contact zone 23 is composed of a plurality of conductive pads arranged annularly on the interior wall of the electrode.
• FIGS. 4a and 4b illustrate an alternative embodiment of the electrode of FIGS. 3a and 3b in which the electrical contact zone 23 is composed of a plurality of conductive pads arranged annularly on the interior wall of the electrode.
• FIG. 5 shows neural excitation devices composed essentially of two annular electrodes 20, 20 'intended to be brought to different electrical potentials so as to produce a longitudinal electrical excitation inside the nerve 10.
• the embodiments of Figures 5 and 6 consist of two electrodes identical to that shown in Figures la and l b.
• the conductors 30 and 30 ′ are united in the same insulating envelope 40 exiting at the end of the device, while in the example of FIG. 6, the envelope 50 exits between the two electrodes 20 and 20 '.
• the insulating envelopes 40 and 50 are produced by epoxy resin as a coating.
• FIG. 7 shows another neural excitation device which can be described by a double electrode formed in a single piece of two electrodes similar to those of FIGS. 4a and 4b which would be joined together so as not to form only one piece.
• the conductors 30 and 30 ' are also combined in an insulating envelope 60 made of epoxy resin.

Landscapes

• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• Veterinary Medicine (AREA)
• Public Health (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• General Health & Medical Sciences (AREA)
• Surgery (AREA)
• Neurosurgery (AREA)
• Molecular Biology (AREA)
• Medical Informatics (AREA)
• Pathology (AREA)
• Biophysics (AREA)
• Neurology (AREA)
• Physics & Mathematics (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Cardiology (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Radiology & Medical Imaging (AREA)
• Electrotherapy Devices (AREA)
• Prostheses (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9396797

Family Applications (1)

Country Status (4)

Cited By (10)

Families Citing this family (7)

Citations (5)

• 1990
  • 1990-05-21 FR FR9006314A patent/FR2662084A1/fr active Granted
• 1991
  • 1991-05-21 AU AU79631/91A patent/AU7963191A/en not_active Abandoned
  • 1991-05-21 WO PCT/FR1991/000404 patent/WO1991017791A1/fr unknown
  • 1991-05-21 CN CN91103931A patent/CN1025285C/zh not_active Expired - Fee Related

Patent Citations (5)

Also Published As

Similar Documents

Legal Events