Cortical somatosensory-evoked potentials during spine surgery in patients with neuromuscular and idiopathic scoliosis under propofol-remifentanil anaesthesia

BACKGROUND: Intraoperative monitoring of the spinal cord via cortical somatosensory-evokedpotentials (SSEP) is a routine during spinal surgery. However,especially in neuromuscular scoliosis, the reliability of corticalSSEP has been questioned. Therefore, we compared the feasibilityof cortical SSEP in idiopathic and neuromuscular scoliosis usinganaesthetics known to have only minimal effect on SSEP recordings. METHODS: Total intravenous anaesthesia with propofol and remifentanilas continuous infusion was standardized for all the patients.Median and tibial nerve cortical SSEP were monitored in 54 patientswho underwent surgery for spinal deformity. Twenty-seven hadidiopathic scoliosis and 27 had neuromuscular scoliosis. Theportion of reproducible results and intraoperative changes werecompared between the groups. RESULTS: In both groups, cortical SSEP could be monitored with sufficientreliability. Only in two patients with idiopathic and four patientswith neuromuscular scoliosis no reproducible traces could beobtained. The amplitudes in patients with neuromuscular scoliosiswere lower than in those with idiopathic scoliosis, but notstatistically significant. There were no postoperative neurologicaldeficits. The number of false positive and true positive didnot differ between the groups. CONCLUSIONS: Assessment of cortical SSEP during spine surgery was equallyeffective and reliable in patients with neuromuscular scoliosisand in patients with idiopathic scoliosis, possibly as a resultof propofol–remifentanil anaesthesia.