Electrode Encapsulation

Tissue Response to Open Cuff Electrode


In an effort to avoid trapping a nerve in a cuff, and permitting some error in sizing as well as accommodating post implant swelling from damaging the nerve, a U shaped electrode has been tried. Here is shown a cross section of a histological section where such an electrode was used. The carrier was fabricated from silicone rubber and the approximate position of the stimulating contact is here. Note, that over the time period of the implant the target nerve has been displaced and is outside the carrier and a considerable distance from the stimulating electrode. A high magnification view is shown here of the connective tissue occupying the electrode region, the original position of the nerve in the carrier. On close examination of the tissues in this area, revealed a laying of the connective tissues. Speculation on the cause of the layering was that repeated mechanical movement of the carrier, relative to the local tissues damaged small blood vessels, and the growth pushed the nerve out of the carrier. The take-home message here is that the electrode carrier must completely encompass the target nerve.