An implantable system for Functional Electro-Stimulation (FES) is disclosed which includes an environmentally sealed implant case and a nerve cuff for attaching to the nerve. A plurality of leads connect the nerve cuffs to the case. The implant case provides redundant seals for entrance of the leads in a double wall/double environmental seal to provide long term sealing reliability for the case. Inside the case, the wires in each lead attach to connectors, which establish contact with an enclosed master circuitry case. The connectors allow the leads to be individually removed and replaced, thereby providing a maintainable system.
At the other end of the leads is attached the nerve cuff. Each nerve cuff has a hollow, gapped cylindrical shape, and includes electrodes on its inner surface. The cuff is deformable to allow placement around the nerve, holding the electrodes in electrical contact therewith.
In other embodiments of the invention, the nerve cuff includes a micro circuit which is capable of demultiplexing stimulation signals from a single pair of wires in the lead to drive multiple electrodes. These embodiments reduce the number of wires needed in each lead to facilitate the stimulation of a large number of nerves with a single implant.