Magnetic resonance T2 increased signal intensity as a risk factor for baseline motor evoked potential failure under desflurane anesthesia

Abstract

Generating motor evoked potential (MEP) is sometimes difficult in cervical spondylotic myelopathy (CSM) surgery. We investigated the relationship between baseline MEP and T2 increased signal intensity (ISI). Sixty-one CSM patients with preserved lower extremity function (MMT≥4 and Nurick scale≤4) were included. They underwent CSM surgery under desflurane anesthesia. Patients were divided into ISI (−) and ISI (+) groups. Two groups were matched with propensity score. The cases that neither bilateral target muscles could generate MEP in were defined as failure. The two groups after matching were compared for baseline MEP failure. ISI (−) and ISI (+) patients were 32 and 29 respectively. Propensity score matching was performed using age, Nurick scale and JOA score as covariants. Twenty-two pairs were selected. ISI (−) group had no failure case. ISI (+) group had 5 failure cases (23%). Baseline MEP failure was more frequently observed in ISI (+) than in ISI (−) significantly. There may be a need to prepare counter-measures for baseline MEP failure in ISI (+) patients.