Intraoperative neuromonitoring in degenerative cervical myelopathy surgery: a systematic review and meta-analysis of diagnostic accuracy and postoperative neurological outcomes.

OBJECTIVES

Degenerative cervical myelopathy (DCM) often requires surgical decompression but carries a risk of intraoperative neural injury. Intraoperative neurophysiological monitoring (IONM) is widely used to detect impending spinal cord compromise during such surgery, yet its impact on postoperative neurological outcomes remains debated. This systematic review and meta-analysis evaluated (1) the diagnostic accuracy of IONM modalities - somatosensory evoked potentials (SSEP), motor evoked potentials (MEP), and multimodal monitoring - and (2) the effect of IONM versus no IONM on postoperative neurological outcomes in DCM.

METHODS

Conducted under PRISMA and PRISMA-DTA guidelines (PROSPERO: CRD420251133125), we systematically searched PubMed, Embase, Scopus, and the Cochrane Library through August 2025. Eligible studies involved adult DCM surgery with IONM. Two meta-analyses were performed: a diagnostic test accuracy meta-analysis (pooled sensitivity, specificity, diagnostic odds ratio (DOR), and area under the curve (AUC) for SSEP, MEP, and multimodal IONM), and a comparative meta-analysis (pooled risk ratios (RR) of new or worsened postoperative neurological deficits with vs. without IONM).

RESULTS

Forty-four studies (N = 154,972 patients) were included. SSEP had low pooled sensitivity (~ 33%) but high specificity (~ 99%) (DOR ~ 34, AUC 0.79); MEP showed moderate sensitivity (~ 61%) with high specificity (~ 95%) (DOR ~ 38, AUC 0.91). Multimodal IONM achieved higher sensitivity (~ 76%) with similarly high specificity (~ 94%) (DOR ~ 70, AUC 0.91). Five comparative studies found no significant reduction in postoperative neurological deficits with IONM (pooled RR ≈ 0.6, p = 0.23).

CONCLUSION

Multimodal IONM demonstrates high diagnostic accuracy for detecting intraoperative neural injury in DCM surgery. However, its routine use did not significantly reduce postoperative neurological complication rates in this analysis, a finding that may partly reflect the limited number of comparative studies and the low absolute event rates. Our findings suggest that multimodal IONM should be considered most valuable for high-risk DCM patients and in complex procedures, where early detection of signal changes may alter surgical strategy.