The Role of Intraoperative Neurophysiologic Monitoring on Surgical Decision Making and Neurologic Outcomes in Pediatric Patients With Intramedullary Spinal Cord Tumors.

Purpose: Maximal safe resection is recommended for intramedullary spinal cord tumors (IMSCT). Tools to minimize surgical morbidity are, therefore, critical. We review intraoperative neurophysiologic monitoring (IONM) in a large series of pediatric IMSCTs, focusing on its relationship with functional outcomes and surgical decision making.

Methods: A single-institution, retrospective review of all IMSCT resections with IONM from 2000 to 2022 was conducted. Univariate analysis evaluated IONM changes with clinical and functional outcomes across an extended follow-up period.

Results: Among the 59 IMSCT cases with IONM that met inclusion, somatosensory evoked potentials were used in 89.8%, motor evoked potentials in 86.4%, and Direct wave monitoring in 18.6%. Almost a third of patients experienced intraoperative changes in motor evoked potentials, somatosensory evoked potentials, and Direct waves, respectively, depending on the modality of IONM used. Monitoring alerts were more common in older patients (≥15 years) and those with larger tumors, and often led to longer hospital/intensive care unit stays and a higher rate of discharge to inpatient rehabilitation. Motor evoked potential and Direct wave alerts significantly affected the surgeon's decision to stop further resection (p = 0.001 and p = 0.067). Marked somatosensory evoked potential changes were associated with worse immediate postoperative sensory deficits (<6-weeks, p < 0.05). At 1-year follow-up, most patients experienced improved functional outcomes, with favorable motor and sensory recovery.

Conclusions: Multiple IONM modalities are technically feasible in pediatric IMSCTs and help guide surgical decision making. Intraoperative neurophysiologic monitoring alerts were more common in patients with larger tumors and older ages, significantly affecting the surgeon's decision to stop further resection. Although associated with longer hospital/intensive care unit stays and increased discharge rates to rehabilitation, IONM changes did not significantly affect long-term functional outcomes.