BIPOLAR IMPLANTABLE STIMULATOR FOR LONG-TERM DENERVATED-MUSCLE EXPERIMENTS

A micropower bipolar implantable stimulator has been developed and tes ted for long-term (four weeks-six months) use in experiments involving the stimulation of denervated skeletal muscle. Implantable stimulator s are typically operated from a single lithium battery at 3 V. After t he first week of denervation, stimulation of denervated muscles of rat s requires voltages in the range of 6-12 V. The stimulator described c an deliver voltages up to 15 V, with variable pulsewidth, frequency an d duty cycle. All stimulation parameters are set prior to implantation by selection of appropriate resistors and capacitors. Each primary fa ilure mode for implantable stimulators is addressed. Longterm reliabil ity rates in excess of 95% are achievable if the construction details are followed closely. Methods for battery power management, circuit co mponent selection, electrode construction and encapsulation are descri bed in detail. This device is not intended for use in humans.