| OBJECTIVE1,To investigate long-term electrophysiological manifestation after implantation of intrafascicular electrode by different implantation modes in sciatic nerve of rabbits, the influence upon surviving of intrafascicular electrode and electric signals of nerve with modified form and implantation mode. 2,To investigate histological changes of sciatic nerve after implantation of intrafascicular electrode and the relationship with electrophysiology. 3,To study the information of 3 major nerves and the feasibility of nerve-signal controlled prosthesis after implantation of intrafascicular electrodes in the ulnar, radial, median nerve of upper arm in amputee volunteer. METHODS18 rabbits were divided into 2 groups. 14 of them were divided as experimental group by different experimental periods. Both hind limbs of each rabbit were divided into 2 groups by isobody control researches: one side was implanted with straight intrafascicular electrode (straight group, Z group); another side was implanted with modified intrafascicular electrode (modified group, T group). The rest 4 rabbits belonged to control group for pathologic study. Intrafascicular electrode fabricated from external insulated wire 60μm in diameter (95%Pt-5%Ir alloy), and spring-structure made in the head end as modified intrafascicular electrode. Intrafascicular electrode was implanted as recording electrode directly by microsurgery technique into the fascicle of the sciatic nerve inrabbit and fixed to epineurium with microsuture. Straight intrafascicular electrode was implanted at one side and modified intrafascicular electrode at the other side in the same rabbit respectively. Another straight electrode was placed outside the fascicle as reference electrode. Both distal ends were coupled to electromyogram. Stimulating with concentric pin electrode inserted at a proximal point (Along-nerve-trunk conduction, Group A) or a distal point (Contra-nerve-trunk conduction, Group B) from the point which the recording electrode threaded the fascicle, the signal of the fascicle was recorded. Stimulating with 2 superficial ringed electrodes at depilated 1st toe of rabbit, sensory nerve action potential (SNAP) (Group C) was recorded. Then threaded concentric pin electrode into gastrocnemius with intrafascicular electrode as stimulating electrode, the signal was recorded. As electric signals of the sciatic nerve be harvested at different intervals, the latent period, amplitude and nerve conduction velocity were recorded. Isobody control researches were performed within modified group and straight group at different intervals: the differences of electric signals of group A, B, C, the surviving individual number and the surviving period of intrafascicular electrodes. The electric signals of group A, B, C were compared respectively during different period after implantation of electrodes.As detection of electric signals completed, microstructural changes in sciatic nerve at the level of implant, the levels proximal and distal to the implant zone were studied with Hematoxylin and Eosin (HE) staining, Ammonia Silver staining, and the ultrastructural changes were studied with transmission electron microscope. The diameters of myelinated axons were quantitatively determined by Image Analysis System. The relationship with electrophysiology was investigated. As animal experiments confirmed that long-term implanted self-made intrafascicular electrode has good compatibility, stably conducting and recording characters, signals of nerves were harvested by intrafascicular electrodes which were inserted directly as recording electrodes into the fascicles of the three major nerves of upper arm in the amputation stump of amputee volunteer. An electrode was placed outside the fascicle as reference electrode. All distal ends were coupled to electromyogram. When the volunteer in wakefulness imaged various kinds of actions of the lost hand with consciousness, the nerve information sent out by central nerve system to control motions was recorded. Th...
|
PDF Full Text Request