Feasibility and Predictability of Intraoperative Monitoring in Patients with Intradural Extramedullary and Epidural Metastatic Spinal Tumors

Abstract

Objectives: To evaluate the feasibility, sensitivity and specificity of IOM for IDEM and ED metastatic spinal tumours, and to assess usefulness of SSEP for patients in whom MEP was not measurable. Methods and materials:One hundred and one consecutive patients with IDEM and ED metastatic spinal tumours at the cord level (C1 to L1) received surgery under SSEP and/or MEP was included. Feasibility of IOM was defined to be negative in case of no measurable MEP or SSEP under general anaesthesia after confirmation of reversal of neuromuscular block. More than 50% change of MEP or SSEP amplitude and more than 10% delay of SSEP latency were evaluated as positive signs of IOM change.Results: MEP was measurable in 74 out of 101 trials, thus feasibility is 73%. Patient with normal motor power showed higher feasibility than those with motor power 3 or less. (93% vs. 39%) Among 74 patients with measurable MEP, 19 patients showed positive MEP change and 14 patients got worse of their motor power postoperatively.

Reliability of Intraoperative Monitoring in Patients with a Preexisting Motor Deficit: Case Report and Literature Review

“…In a study of MEPs and preoperative motor deficit in intradural extramedullary and epidural metastatic spinal tumors, only 7 of 18 patients with MRC grade 3 power (i.e., the nonambulatory cohort) showed a measurable MEP. 9 Less data are available regarding the reliability of IOM in supratentorial tumors causing preoperative motor deficits. Krieg and colleagues reported on their series of supratentorial metastases with 56 patients in eloquent motor areas with measurement of MEPs.…”