Nerve cuff electrode with shape memory alloy armature: design and fabrication

In this paper, a new nerve cuff electrode with shape memory alloy armature is presented. The proposed electrode is dedicated either to peripheral nerve stimulation or recording and its manufacturing does not require any expensive or complex technique. Shape Memory Alloy (SMA) armature ensures the complete and firm closing of the electrode, so that the complexity of the installation procedure is considerably reduced. A preliminary analysis of the electrode mechanical behavior prior, during and after installation has been done through numerical simulations and in vitro testing. It was proved theoretically and experimentally that the SMA electrode closes completely with an appropriate few second delay after its installation. No external fixation such as sutures is needed to secure permanent electrode-nerve contact. Furthermore, theoretical analysis has shown that the design of SMA electrode can be adapted for safe close-fitting installation, thanks to the device partial opening in case of nerve swelling.