Bladder, Urethra and Anal Sphincter Reinnervation

Temple Univ Of The Commonwealth, Philadelphia PA

Investigators

Linked publications, trials & patents

Abstract

Aim 1 - To determine whether reinnervation of the bladder by obturator nerve transfer and reinnervation of the urethral and anal sphincters by transfer of femoral nerve branches provides return of both continence and emptying function. We found that transfer of a primarily motor donor nerve (femoral nerve branches) provides superior bladder reinnervation than a mixed sensory and motor nerve (GFN).25 We also found that the pudendal nerve could be reinnervated by transfer of motor branches of the femoral nerve.15, 47 We have not yet reinnervated the bladder, urethra and anal sphincters in the same animal that would be important to human patients to restore voiding function, fecal and urinary continence. The obturator nerve, like the femoral nerve, is a primarily motor nerve, and its natural path runs very close to the pelvic plexus. Animals will be decentralized by bilateral transections of L7 and all roots caudal to L7 in the spinal column. The obturator nerve will be transferred bilaterally to the anterior vesical branch of the pelvic nerve (OBNT-to-PN) and branches of the femoral nerve will be transferred bilaterally to the pudendal nerve (FNT-to-PudN) as it emerges from the pudendal (Alcock's) canal. Un-anesthetized urodynamics will be performed monthly for 6 months; half receiving implanted radiofrequency (RF) micro-stimulators for FES of transferred obturator and femoral nerve branches to monitor return of nerve stimulation evoked detrusor, urethra and anal sphincter pressures, before the terminal assays at 6 months. Aim 2 - To determine whether the bladder, urethra and anal sphincters remain capable of being reinnervated after prolonged decentralization for up to one year. We found in a group of 5 dogs that 4.5±0.9 months after decentralization, stimulation of sacral roots or spinal cord segments does not increase detrusor pressure, proving decentralization. However, stimulating anterior vesical branches of the pelvic nerve (between the pelvic plexus and bladder dome) increases detrusor pressure in 5 of 5 decentralized animals.25 We also proved that the bladder can be reinnervated by genitofemoral nerve transfer (GFNT) at 1 and 3 months after decentralization.46 The longer after decentralization that the bladder remains capable of being reinnervated, the more feasible this approach would be for human patients with long standing flaccid bladder paralysis. Bladders will be decentralized, as described for aim 1. Cuff electrodes interfaced with RF micro-stimulators will be placed on anterior vesical branches of the pelvic nerve and on pudendal nerve branches as they emerge from the pudendal canal in a subset of these animals. The effects of nerve stimulation on detrusor, urethral and anal sphincter pressure will be determined at monthly intervals starting 3-4 weeks after decentralization and continuing to 6 or 12 months. OBNT-to-PN and FNT-to-PudN will be performed in separate groups of animals at 6 and 12 months after decentralization. These groups will be compared to sham-decentralized animals with identically implanted RF micro-stimulators.