The role of the neurophysiological intraoperative monitoring to prevention of postoperative neurological complication in the surgical treatment of scoliosis

Bearing in mind that the technique of surgical treatment of scoliosis and skills are high enough, iatrogenic spinal cord injury is still one of the most feared complication of scoliosis surgery. It is well known that the function of the spinal cord may be estimated by combining somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP). We have retrospectively evaluated the results of intraoperative neurophysiological monitoring (IOM) in a large population of patients underwent surgical treatment of spinal deformity. Intraoperative neuromonitoring SSEP and transcranial electrostimulation (TES) – MEP in conjunction with the assessment of the correct position of the screws was performed in 142 consecutive cases, i. e. all patients who had undergone surgical treatment of idiopathic (127 pts), congenital (10 pts) or neurogenic (5 pts) scoliosis. A neurophysiological “alarm” was defined as a decrease in amplitude (uni- or bilateral) of at least 50 % for SEPs and of 70 % for TES-MEP compared with baseline. Total intravenous anesthesia (TIVA) in 138 cases was achieved by infusion of propofol (8–16 mg / kg / h) and in 4 cases by halogenate anesthesia – sevoflurane (0.4–1.8 MAC). Seven patients (4.9 %) were reported intraoperative neurophysiological parameters significant changes that require action by the surgeons and anesthetists, with deterioration of ostoperative neurologic status in one case. Of these three cases, the amplitude drop SSEPs and TESMEPs-was due, to the pharmacological aspects of anesthetic management, in the other four cases – with surgical procedures (response halo-traction – 1 case, mechanical damage of sheath of the spinal cord by pliers Kerrison – 1case, overcorrection – 2 cases). In five cases (3.5 %) required reposting of pedicle screws (1–2 levels). Only one patient (0.7 %) had a persistent postoperative neurological disorder (neuropathic pain), respectively from a level of re-reposition of pedicle screws.