Intraoperative Spinal Cord Monitoring in Children Under 4 years Old

Purpose: The purpose was to study intraoperative spinal cord monitoring (IOM) particularities and performances in children under 4 years old with congenital spinal deformities. IOM is characterized by specific difficulties due to the immaturity of sensory-motor pathways in such young patients. To the best of our knowledge, this study is the largest dedicated to IOM in this challenging population.

Methods: This study was retrospective and monocentric. 78 IOM in children under 4 years old were analyzed. Somatosensory evoked potentials (SSEP), neurogenic mixed evoked potentials (NMEP) and D waves were performed. Patients were classified into one of four categories with respect to IOM data and clinical outcome: true positive, false positive, true negative and false negative. Sensitivity and specificity were then calculated accordingly.

Results: There were 6 true positive, 3 false positive, 67 true negative and 1 false negative outcomes. One patient was characterized by unreliable baseline IOM data. IOM sensitivity was 86 %. IOM specificity was 96 %. The false negative case was monitored using SSEP alone. IOM was difficult in 10/77 cases, being unilateral because of a planned fibular graft harvest. NMEP were characterized by higher signal-to-noise ratio than SSEP.

Conclusions: Immaturity of sensory-motor pathways predominates in the central rather than the peripheral nervous system in young children. MEP and D waves could thus be difficult to obtain. Although non-specific to motor pathways, it could be useful to "by-pass" the brain, using NMEP. In regard to maturational particularities, IOM in children under 4 years old should be performed by experienced neurophysiologists, avoiding in these cases surgeon-guided devices.