A multi-lead, multi-electrode system for neural interface-enabled advanced prostheses

We have developed a system to directly interface electrodes with multiple peripheral nerves in upper extremity amputees to allow sensory feedback and to record motor intent. For this, a multi-lead, multi-electrode system with one ground and 3 sets of bundled leads has been fabricated. Each bundle consists of six 25μm diameter insulated Pt/Ir wires coiled over part of their length. One end of each wire is soldered to a recording connector or implantable stimulator; the other has a tungsten needle. A deinsulated portion proximal to the needle constitutes the active site. Each wire and lead is encased in protective polyimide/silicone sheathing. System deployment was tested in a cadaver upper arm in a manner that routed the leads across the arm. After removing the protective sheaths, multiple electrodes were implanted at three sites in the median and ulnar nerves by longitudinally threading them through the nerve fascicles using the attached needles. The wires were anchored to the epineurium and the needles removed by cutting the wires just distal to the exit points from the nerves. This system provided distributed deployment of multiple electrodes, allowed easy routing and prevented entanglement of the individual leads and electrode wires during implantation.