Off-target effects of percutaneous epidural spinal cord and dorsal root ganglion stimulation with task-specific training on lower urinary tract function in individuals with chronic spinal cord injury.
OBJECTIVE This study aimed to evaluate the off-target effects of motor-optimized SCS-enabled task-specific training (SCS-TST) on lower urinary tract function through self-reported data from individuals with chronic spinal cord injury (SCI), using the Neurogenic Bladder Symptom Score (NBSS). A secondary objective was to explore whether participant characteristics or bladder treatments were associated with changes in NBSS outcomes. DESIGN Datasets from two prospective pilot trials using percutaneous spinal cord stimulation (SCS) to enable motor function were analyzed and reported. SETTING Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota. PARTICIPANTS Adults ≥ 1-year post traumatic SCI. INTERVENTIONS Participants received either 12 days of epidural stimulation (ES) or 10 days of ES and dorsal root ganglion stimulation (ESDRS), each coupled with 6-8 SCS-TST sessions. OUTCOME MEASURES NBSS was administered pre- and post-intervention. RESULTS Analysis of 23 participants (ES, n = 3; ESDRS, n = 20) showed no significant group-level changes in total NBSS (p = 0.49) or functional domains (p = 0.56-0.85). Individually, 83% demonstrated no clinically meaningful change, while 9% improved and 9% worsened. Exploratory analyses identified that symptom change was associated with neurological level of injury (p = 0.017), age (p = 0.026), and marginally associated with injury severity (p = 0.055). Oxybutynin use was associated with lower symptom variability, without statistical significance (p = 0.074). CONCLUSIONS Motor-optimized SCS-TST did not lead to significant group-level changes in patient-reported urinary symptoms. However, a subset of individuals experienced improvement or worsening, suggesting that injury characteristics and medication use may influence urinary outcomes. These preliminary findings warrant confirmation in larger, adequately powered trials.Trial Registration: ClinicalTrials.gov identifiers: NCT05095454, NCT04736849.