Surgical Technique to insert and retrieve BIONs (microstimulators) safely near deep Nerves for Functional Electrical Stimulation.

The first generation BIONs  have a glass encased microstimulator with an external tantalum capacitor electrode and have been injected through a 12-gauge (OD: 2.8 mm) needle. This second generation of BION  devices are encased in a ceramic cylinder, approximately 10 times stronger than the glass case, with platinum-iridium electrodes. Over a period of 7 months, a surgical technique has been developed to insert this BION  through a 5 mm incision, using a stimulating electrode probe to find the deep nerves, followed by a tailored plastic introducer (dilator + sheath) used to insert and test the BION’s  position before depositing it adjacent to the nerve. The BION  can be retrieved up to the next 8-10 days by reopening the small wound and withdrawing a subcutaneous placed suture attached to the BION’s  proximal end. The BION  can then be reinserted. Beginning in June 2001, 10 sheep had a total of 34 BIONs implanted adjacent to the hypoglossal nerves in the lower jaw. All BION  units implanted and stimulated have continued to produce visible movement of the tongue as view through an endoscope, except one that functioned at the time of implant.