Submucosal Exploration of EMG and Physiological Parameters in the Bladder Wall

An implantable sensor system has been developed to explore the physiological behaviour of the bladder wall. It consists of a 3-axis digital accelerometer and a pressure sensor on the upper side of a flexible polyimide printed circuit board. On the bottom side, two metallic hooks prevent migration of the device in the bladder wall while simultaneously acting as electrodes to record the electrical activity of the detrusor muscle. The full system is inserted at the interface between the detrusor and the mucosa, preventing exposure of the transducer to the urine. This ensures protection both for inflammation of the inner bladder, and from salts deposition on the device. Three packaging layers have been applied to ensure biocompatibility of the device: Parylene-C, medical epoxy and PDMS. The device was first tested in-vitro for water diffusion. Then, the feasibility of submucosal implant was demonstrated in a cadaver pig bladder, and in-vivo recordings were successfully acquired in a rat.