Motor Nerve Transfer for Voluntary Physiological Voiding: Scientific Foundations, Historical Review, and Case Report.

Abstract

We present the surgical transfer of a somatic motor nerve to an autonomic target nerve to recover detrusor activation for functional voiding. The scientific basis of this hybrid nerve transfer, details of the surgical procedure, and results of its initial clinical application as they progressed over 2 years are reported. A 30-year-old man presented with deteriorating bladder function and underwent resection of a sacral chondrosarcoma with sacrifice of all sacral nerve roots below S1 bilaterally. This eliminated bladder function and the potential for spontaneous recovery. The patient underwent functional and neurophysiological assessments and was determined to be a candidate for the procedure. Nerve transfers were performed bilaterally using a portion of the obturator nerve to reinnervate the bladder through the distal vesical branches of the inferior hypogastric plexus. He was re-evaluated at regular intervals for 2 years. Sensation of bladder fullness first returned at 6 months, and volitionally activated bladder contraction was demonstrated 12 months after transfer and confirmed at both 18 and 20 months by urodynamic studies. As expected, these new bladder contractions were driven by activation of the donor obturator nerve through thigh adduction and squatting and provided corresponding urinary flow. We present the results of a novel nerve transfer in which somatic axons are directed to innervate a parasympathetic target to drive volitional activation of the bladder. We delineate the baseline function and progression of recovery, including serial urodynamic assessments. These findings represent the successful clinical translation of a well-established animal model of bladder reinnervation. Although this procedure would serve a limited population and addresses only 1 key component of voiding, it provides an important clinical proof of concept that will aid in the further development of nerve transfer-based restorative options after loss of sacral innervation to the bladder.