New nerve cuff electrode based on a shape memory alloy armature

The authors present a new nerve cuff electrode based on a shape memory alloy (SMA) armature. This device is dedicated to functional electrical stimulation of the bladder in spinal cord injured patients. The SMA armature performs the closing of the electrode, making its instillation around the nerve much easier, quicker and safer. Both remarkable mechanical properties of SMA materials namely shape memory effect and superelasticity, can be used to obtain the desired actuation of the electrode closing. The manufacturing procedure of this new electrode is described. It does not require any expensive or complex techniques. Bipolar and tripolar electrodes have been manufactured with an inner diameter of 1.6 mm and a cuff wall thickness of 0.8 mm. Acute studies in dogs are being carried out to validate the device and the implantation procedure. In order to test the electrical functionality of the electrode, a fully programmable biphasic stimuli generator has been designed and implemented using FPDs (Field Programmable Devices)