Feasibility of multimodal intraoperative neurophysiological monitoring for extramedullary spinal cord tumor surgery in elderly patients

Abstract

Background/purpose Extramedullary spinal cord tumors (EMSCTs) are mostly benign tumors which are increasingly diagnosed and operatively treated in the elderly. While there are hints that multimodal intraoperative neurophysiological monitoring (IONM) could be influenced by age and age-related comorbidities, no study has ever systematically evaluated its feasibility and value for EMSCT surgery in elderly patients. Methods We retrospectively evaluated all patients with microsurgical EMSCT resection under continuous multimodal IONM with SSEPs, MEPs and electromyography between 2016 and 2020. Epidemiological, clinical, imaging and operative/IONM records as well as detailed individual outcomes were analyzed and compared for the cohort < / ≥ 65 years. Results Mean age was 45 years in cohort < 65 years (n = 109) and 76 years in cohort ≥ 65 years (n = 64), while baseline/operative characteristics did not significantly differ. Mean baseline SSEPs’ latencies (left–right average) were significantly higher in the cohort ≥ 65 years for both median (20.9 ms vs. 22.1 ms; p < 0.01) and tibial nerve (42.9 ms vs. 46.1 ms; p < 0.01) without significant differences for SSEPs’ amplitudes. Stimulation intensity to elicit intraoperative MEPs was significantly higher in the cohort ≥ 65 years (surrogate-marker: left–right-averaged quotient ID1-muscle/abductor-hallucis-muscle; 1.6 vs. 2.1; p < 0.001). Intraoperatively, SSEP and MEP monitoring were feasible in 99%/100% and 99%/98% for the cohort < / ≥ 65 years without significant differences in rates for significant IONM changes during surgery or postoperatively new sensorimotor deficits. Sensitivity of IONM was 29%/43%, specificity 99%/98%, positive and negative predictive values 67%/75% and 95%/93% for the cohort < / ≥ 65 years. Overall, age was no risk factor for IONM feasibility or rate of significant IONM changes. Discussion Multimodal IONM is feasible/reliable for EMSCT surgery in elderly patients. An age-related prolongation of SSEPs’ latencies and demand for higher stimulation intensities for MEPs’ elicitation has to be considered.

Diagnostic Accuracy of Somatosensory Evoked Potential and Transcranial Motor Evoked Potential in Detection of Neurological Injury in Intradural Extramedullary Spinal Cord Tumor Surgeries: A Short-Term Follow-Up Prospective Interventional Study Experience from Tertiary Care Center of India

“…Siller et al in their study had mean operative time of 200 minutes while performing resection of IDEMSCTs using IONM. 11 SSEP with typical waveform was recordable in 40.63% patients. In patients with higher deficit, amplitude was very small, where tracking of further decrease by more than 50% was difficult.…”

“…Siller et al in their study had mean operative time of 200 minutes while performing resection of IDEMSCTs using IONM. 11…”

“…15 Siller et al in their retrospective study on elderly patients (≥ 65-year age) with IDEMSCT who underwent IONM (SSEP and transcranial MEP) guided resection found 42.9% sensitivity, 98,2% specificity, 75.0% PPV, and 93.3% NPV of IONM as a composite modality. 11 van der Wal et al have cited 73% sensitivity and 78% specificity of multimodal IONM (SSEP, MEP) when used in IDEMSCT surgery. 8…”