Effects of intravenous methylprednisolone on intraoperative neurophysiological monitoring during spinal cord tumor surgery: a case report

Abstract

In spinal cord tumor surgery, muscle motor-evoked potentials (mMEPs) and direct wave (D-wave) have been used to predict neurological outcomes. A severe deterioration of mMEPs in the presence of intact D-wave may indicate temporary postoperative weakness. A 58-year-old man complaining of lower extremities’ weakness was diagnosed as cavernous malformation at T3/T4 level. During removal surgery, the amplitudes of mMEPs were reduced more than 80% in the right tibialis anterior and abductor halluces compared to the baseline in the absence of a change in D-wave. After administration of high-dose intravenous methylprednisolone (IVMP), the D-wave considerably amplified while the mMEPs did not change. The postoperative motor score was increased. This is the first report of the large amplification of D-waves immediately after administration of IVMP. It is suggestive that perioperative administration of high-dose IVMP immediately after the detection of the significant reduction of mMEPs amplitudes may improve neural conduction during spinal cord surgery.