Based on animal experiments, spinal root anastomoses were performed in two paraplegic patients who had traumatic lesions of the conus medullaris. The aim was to reinnervate the paralyzed urinary bladder. At operation, the functioning T12 nerve roots above the lesion were transected and anastomosed bilaterally to the S2 and S3 ventral and dorsal roots emerging from the injured cord area. About 1 year postoperatively, both patients demonstrated restoration of the micturition reflex as recorded in the cystometrogram. Both patients could feel the urge to void, could initiate micturition voluntarily, and could empty their bladders satisfactorily. The patients' relatively good bladder functions were the result of either regeneration of the newly constructed nervous pathways or spontaneously developed reflex bladders in partial upper neuron lesions.