Assessing the utility of bulbocavernosus reflex for predicting urological outcome in children with spinal dysraphism...

Surgical untethering for spinal dysraphism carries the risk of neural damage affecting sphincter control. Whilst anal sphincter motor-evoked potentials (MEP) are commonly used, they assess efferent pathways and do not directly reflect bladder innervation. The bulbocavernosus reflex (BCR) evaluates both afferent and efferent components of the sacral reflex arc, potentially serving as a better intraoperative predictor of urinary function. This study aimed to (1) assess the correlation between baseline BCR and preoperative urinary continence and (2) determine whether intraoperative BCR loss predicts postoperative urinary outcomes at one year.

A retrospective observational study was conducted on children (aged 4-18 years) undergoing spinal cord untethering with intraoperative BCR monitoring. Preoperative and 1-year postoperative urological assessments included continence status, clean intermittent catheterisation (CIC) dependency, recurrent urinary tract infections (UTI), post-void residual volume (PVR), and vesicoureteral reflux (VUR). Sensitivity, specificity, and predictive values were calculated for both baseline and intraoperative BCR changes relative to urological outcomes.

Fifty patients met the inclusion criteria. Preoperative absence of BCR correlated with preoperative incontinence with 34.5% sensitivity and 90.5% specificity. Intraoperative BCR loss predicted postoperative incontinence with 14.8% sensitivity and 82.6% specificity. CIC dependency and recurrent UTIs were unchanged postoperatively, whilst increased PVR decreased from 20 to 12%.

Baseline BCR has high specificity but limited sensitivity for preoperative continence. Intraoperative BCR loss is a specific but insensitive predictor of postoperative urinary dysfunction. Whilst BCR monitoring aids intraoperative decision-making, further studies are needed to optimise its role in predicting long-term bladder outcomes.