Prognostic value of intraoperative MEP signal improvement during surgical treatment of cervical compressive myelopathy.

Abstract

The purpose of the current study was to evaluate the prognostic value of intraoperative improved transcranial motor evoked potential (MEP) after cervical cord decompressive surgery for cervical compressive myelopathy (CCM). A consecutive series of 59 CCM patients who underwent cervical cord decompressive surgery were studied between December 2013 and April 2015 in this study. And all patients were divided into three subgroups: the patients with intraoperative improved MEP, without obvious MEP change and MEP degeneration. MEP and modified Japanese Orthopedic Association (mJOA) score were mainly utilized to assess intra-, pre- and post-operative neurologic function; all patients had reliable and stable MEP baseline. The early neurologic outcomes and the long-term mJOA improvement rate were evaluated after surgery. There were 21 patients with intraoperative monitoring improvement (MEP improved rate, 140±76%), 32 patients without obvious MEP change and six patients with MEP degeneration. The early motor or sensory outcome showed varying degrees of recovery in the MEP improvement group. The long-term mJOA improvement rate among the three groups was 59.5±4.2, 48.9±3.9 and 40.6±7.4%, respectively, after 6-month follow-up, and the improvement group was better than the other two groups with statistical significance (59.5±4.2 vs. 48.9±3.9%, p<0.05; 59.5±4.2 vs. 40.6±7.4, p<0.05). Patients with intraoperative MEP improvement after cervical cord decompression have better prognosis in early and long-term neurologic recovery in CCM surgery.