Development Of SEP Stimulator And Study On Methods Of Intraoperative Spinal Cord Monitoring

Because evoked potential can reflect integral function of spinal cord and centre nerve system, it is widely applied to estimate spinal cord function, especially in intraoperative spinal cord monitoring during spinal surgery. Nevertheless, there are some problems needed to be resolved. For example, existing monitoring equipment is so " large and complex" that could not adapt well to intraoperative environment. Moreover, intraoperative spinal cord function monitoring began lately in our country. There is little special report about technology of monitoring evoked potential, particularly lacking of study on characteristic information of evoked potential changes and methods of estimating damage after damaging spinal cord.This paper reviews current experience on intraoperative monitoring spinal cord, and develops a set of intelligent somatosensory stimulator, which produces pulse current to stimulate trunk and limb of patients. As a part of evoked potential instruments, it is entirely controlled by computer with high precision of current frequence, duration and intension, being continuously adjusted in large range. It is as big as a palm and keeps insulation from both human body and PC. Its power dissipation is only 1000 mW. The other research purpose is to discover characteristic information and reliable methods of reflecting spinal cord damage. Due to typical damage indicators, amplitude and latent period, have bugs such as limited information and weak stabilities, this project recommends applying time-frequency analysis to monitoring spinal cord function. Through analysing and comparing typical signal with STFT and CWT, it is proved indicators under time-frequency distribution can be better in reflecting signal changes, espcially the wavelet transformation. In the end, a new reliale indicator, energy peak, is found to used to estimate damage. Its three parameter: peak time, peak frequence and peak power are also evaluated.This study improves monitoring equipment in intelligence, low power dissipation and security. Besides, it applies time-frequence analysis as a new signal processing tool to find right time-frequency algorithms and charateristic parameters used to enhance monitoring reliability. Both in theory and in practice, this project is useful to develop medical instruments and study on automatic intraoperative monitoring.