Chapter IV.4: Neurophysiologic Monitoring During Spinal Cord Stimulation
Author
Marina Abramova, MD - LSU Health Sciences Center, New Orleans, LA
About this chapter
EMG, or electromyography, and SSEP, or somatosensory evoked potentials, are two methods of neurophysiologic monitoring. This chapter describes how they can assist in ensuring correct placement of electrodes in spinal cord stimulation. Particular attention is paid to the mention of epidural paddle electrode systems.
Index of Sections
Section 4.1: General Uses of Neurological Monitoring in Spine Surgery
Section 4.2: Laminectomy Electrode Implantation, General Methods
Section 4.3: Technique of Midline Positioning of the Spinal Cord Stimulator – Tripolar paddle
Section 4.4: New frontiers of intraoperative EMG application
Section 4.5: References
Section IV.4.1: General Uses of Neurological Monitoring in Spine Surgery
Intraoperative neurophysiological monitoring has become a routine procedure in complex spine surgery. Somatosensory-evoked potential (SSEP) recording has been advocated to monitor the functional integrity of the nervous system during surgical manipulation [22-24, 35]. When stimulated, sensory afferents give rise to signals, carried via the dorsal columns (DC), within the spinal cord to the medial lemniscus and spinocerebellar tracts, ending in the primary somatosensory cortex [4]. SSEP monitoring does not involve the motor pathways, which in some clinical situations can lead to false-negative results and postoperative neurological deficits undetected intraoperatively [1-3, 5, 6, 7, 12]. Dermatomal SSEP testing allows for assessment of individual nerve roots during surgery and has been shown to be more sensitive [7, 8]. However, the sensitivity and specificity of this method varies and is less well-liked than electromyographic (EMG) monitoring [8, 9]. EMG has become the standard of practice in complex spine surgery, providing surgeons with accurate feedback about individual nerve root activity during surgical manipulation of neural structures [10-14].
Section IV.4.2: Laminectomy Electrode Implantation, General Methods