Motor-evoked potential monitoring from urinary sphincter muscle during pediatric lumbosacral spine surgery: A case series

Purpose: Postoperative urinary dysfunction following lumbosacral spine surgery is devastating. To assess urinary function, we invented a pediatric urinary catheter equipped with electrodes for the direct transurethral recording of myogenic potential from the external urethral sphincter (EUS). This paper presents two cases in which urinary function was monitored intraoperatively by recording of motor-evoked potential (MEP) from EUS during lumbosacral spine surgery in children. Methods Two children (aged 2 and 6 years) were included in this study. One patient had no preoperative neurological dysfunction, while the other had frequent urination and urinary incontinence. A pair of surface electrodes was attached to a silicone rubber urethral catheter (6 or 8 Fr; diameter, 2 or 2.6 mm). The MEP from the EUS were recorded to assess the function of the centrifugal tract from the motor cortex to the pudendal nerve. Results Baseline MEP waveforms from the EUS were successfully recorded with latency and amplitude of 39.5 ms and 66 µV in patient 1 and 39.0 ms and 113 µV in patient 2, respectively. A significant decrease in amplitude was not observed during surgery in the two cases. No new urinary dysfunction and complications associated with the urinary catheter-equipped electrodes developed postoperatively. Conclusion Using an electrode-equipped urinary catheter, monitoring of MEP from the EUS could be applicable during lumbosacral surgery in pediatric patients.