A PC-based system for H-reflex and single sweep SEP coupled monitoring of spinal cord function in vertebral column surgery

A system to monitor the spinal cord functionality during vertebral column surgery has been developed with the aim of applying a new technique based on the simultaneous monitoring of the single sweep somatosensory evoked potential (SswSEP) and of the soleus muscle H-reflex, both elicited by the same electrical stimulus. The extraction of the SswSEP is obtained by means of digital signal processing (DSP), based on autoregressive model with an exogenous input (ARX). In order to comply with the necessary hardware and software specifications, a flexible PC-based system has been developed. The software is based on the LabVIEW and MatLab platforms. The hardware is an integration of commercial components and a programmable battery powered stimulator expressly developed to satisfy the particular requirements of the proposed technique. Moreover the system satisfies the International Electrotechnical Commission (IEC) standards for electro-medical equipments. In this paper, the basics of the neuromonitoring system along with its specifications and some preliminary results are described.