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.