RESUMO
BACKGROUND: Neurophysiological monitoring (IOM) consisting of somatosensory (SEPs), muscle (MEPs) and spinal motor evoked (D-wave; spinal MEPs) potentials is used to indicate injury related to surgical treatment of intradural and intramedullary lesions. Combining spinal and muscle MEPs reliably predicts long-term motor deficit. If spinal MEPs recording is not possible, additional markers-e.g. S100B, a serum marker for glial injury-may be a helpful adjunct. Thus, serial serum S100B measurements were related to both the intraoperative IOM recordings and the long-term neurological outcome in patients surgically treated for cervical and thoracic intradural lesions. METHODS: In 33 patients (9 men, 24 women, 54 ± 17 years) during intramedullary (8) or intradural (25) cervical or thoracic spinal surgeries significant intraoperative SEP-amplitude decrement >50 % or MEP loss and serial S100B serum concentration (perioperative days 0, 1-3, 5) were related to outcome (>1 year after discharge, grouped into improved and unchanged/altered neurological symptoms). RESULTS: Differences in S100B levels between patients with improved and unchanged/altered neurological outcome were significantly on postoperative days 2 (0.085 ± 0.08 µg/l vs 0.206 ± 0.07 µg/l, p = 0.005) and 3 (0.076 ± 0.03 µg/l vs 0.12 ± 0.05 µg/l, p = 0.007). All patients with permanent altered neurological symptoms developed S100B levels >0.08 µg/l (0.09-0.35 µg/l). Eighty-one percent of patients with improved neurological symptoms presented with S100B levels ≤0.08 µg/l (0.02-0.08 µg/l). Nine out of ten patients (90 %) without changes in EP and S100B had an improved long-term outcome, whereas 9/13 patients (69 %) with changes in EP and S100B had altered neurological symptoms in long-term outcome. CONCLUSION: Intraoperative stable EPs and S100B ≤0.08 µg/l may be used as a marker to predict long-term neurological improvement, whereas EP-changes and elevated S100B levels on the 3rd postoperative day may be useful as a marker to predict long-term neurological alteration. In summary, the combined use of S100B and EPs might be helpful in the prediction of the severity of adverse spinal cord affection following surgery and guidance of patients.