Sequential intraoperative protocol to improve bulbocavernosus reflex monitorability during pediatric spinal surgery.

purposeBulbocavernosus reflex (BCR) monitoring assesses sacral S2 to S4 pathway integrity during pediatric spinal surgery; however, its intraoperative utility is limited when responses are absent or unilateral. We prospectively evaluated a sequential intraoperative protocol designed to improve the interpretation of these patterns and reduce uncertainty during sacral monitoring.

methodsWe prospectively studied 242 consecutive pediatric patients aged 0.4-12 years who underwent spinal surgery between 2023 and 2025. Bilateral external anal sphincter (EAS) recordings were obtained using subdermal-needle electrodes. Intramuscular placement was verified using tetanic stimulation. BCR responses were elicited using single-train stimulation (STS), followed by double-train stimulation (DTS). A persistent absence with failed EAS verification was classified as a pattern consistent with efferent nonacquisition, whereas a persistent absence despite preserved verification was classified as a pattern consistent with afferent nonacquisition.

resultsFinal BCR acquisition was achieved in 225 of 242 patients (93.0%; 95% CI, 89.3-95.7). STS produced bilateral responses in 61.2% of patients, whereas DTS increased bilateral acquisition to 87.2%, rescued 57.5% of initially absent responses, and converted 81.5% of unilateral responses to bilateral responses. Persistent absence was observed in 17 patients (7.0%), including nine patterns consistent with efferent nonacquisition and eight with afferent nonacquisition. Younger age was independently associated with persistent absence.

conclusionA sequential protocol that combines EAS verification with DTS improves the intraoperative interpretation of BCR findings during pediatric spinal surgery. It provides a practical framework for interpreting absent or unilateral responses and reducing uncertainty when nonacquisition persists.