448 Motor Control of Bladder Function by Nerve Transfer

Abstract

INTRODUCTION: A normal detrusor muscle is activated by parasympathetic efferents that release acetylcholine to muscarinic receptors to contract and expel urine. Through canine work by our group, the scientific underpinning of a somatic nerve transfer to a visceral target (hybrid synapse) was established. We present the scientific basis of this hybrid nerve transfer and report the first-in-human functional outcome. METHODS: Our patient presented with deteriorating bladder function over 1 year and underwent en bloc resection of a sacral chondrosarcoma in December 2020. The sacral roots from S1 caudally were divided – resulting in loss of bowel and bladder function. Urodynamics demonstrated an acontractile bladder (0 cm H20). In May 2021 bilateral obturator nerve transfers to the vesical branches (to bladder) of the inferior hypogastric plexus (6 months after surgery). Patient bladder function and pelvic visceral sensation were followed with serial urodynamic studies. RESULTS: The patient was asked to adduct the thighs and relax the abdomen to initiate a detrusor (bladder) contraction. This provided definitive activation of the nerve transfer in November 2022 (1.5 years after transfer), which was confirmed in January 2023 (∼20 cm H20). Concomitantly, the filling volume at which “full bladder” was perceived appeared at 6 months and progressed until detected within normal range of bladder volumes. CONCLUSIONS: This is a first-in-human nerve transfer that has clear evidence of visceral sensation recovery (need to void) at normal volumes, and functional detrusor contraction. While bladder pressures produced were not within normal range, we expect transfers earlier after loss of function (e.g. within 6 months instead of 18) will result in greater functional gains.