Bladder Reinnervation Using a Primarily Motor Donor Nerve (Femoral Nerve Branches) is Functionally Superior to Using a Primarily Sensory Donor Nerve (Genitofemoral Nerve)

Abstract

Purpose To determine whether transfer of a primarily motor nerve (Femoral, F) to the anterior vesicle branch of the pelvic nerve (PN) allows more effective bladder reinnervation than a primarily sensory nerve (genitofemoral, GF). Methods Forty-one female mongrel hounds underwent bladder decentralization, decentralization and then bilateral nerve transfer (GFNT and FNT) or were sham/unoperated controls. Decentralization was achieved by bilateral transection of all sacral roots that induce bladder contractions upon electrical stimulation. The retrograde neuronal labeling dye fluorogold was injected into the bladder 3 weeks prior to euthanasia. Results Increased detrusor pressure after direct stimulation of the transferred nerve, lumbar spinal cord or spinal roots was observed in 12/17 GFNT dogs (mean detrusor pressure = 7.6±1.4 cmH2O) and in 9/10 FNT-V dogs (mean detrusor pressure = 11.7±3.1 cm H2O). The mean detrusor pressures after direct electrical stimulation of transferred femoral nerves were statistically significantly greater than after stimulation of the transferred genitofemoral nerves. Retrogradely labeled neurons from the bladder observed in upper lumbar cord segments after GFNT and FNT confirmed bladder reinnervation as did labeled axons at the nerve transfer site. Conclusions While transfer of either a mixed sensory and motor nerve (GFN) or a primarily motor nerve (FN) can reinnervate the bladder, using a primarily motor nerve provides greater return of nerve-evoked detrusor contraction. This surgical approach may be useful for patients with lower motor spinal cord injury to accomplish bladder emptying.

Neuromuscular Nicotinic Receptors Mediate Bladder Contractions Following Bladder Reinnervation with Somatic to Autonomic Nerve Transfer after Decentralization by Spinal Root Transection

“…Thirty-seven female mongrel hound dogs, 6 to 8 months of age, 16 to 20 kg (Marshall BioResources, North Rose, NY) were used. These were part of bladder reinnervation studies 5 and were divided into the following experimental groups: 17 genitofemoral nerve transfer (GFNT) animals, 12 with abdominal vesicostomies (GFNTV) and 5 without vesicostomies (GFNTNV); 10 femoral nerve transfer (FNT) animals, 5 with abdominal vesicostomies (FNTV) and 5 without vesicostomies (FNTNV); and 8 control animals, 3 sham-operated and 5 un-operated normal controls (3 of the latter were used only for immunohistochemical assays).…”

“…1-5 Briefly, after bladder decentralization by S1-3 spinal root transection, 17 of the 37 animals underwent GFN identification and nerve coaptation of the GFN distal end to the proximal end of the anterior vesical branch of the pelvic nerve, bilaterally. In 12 GFNTV dogs, radiofrequency (RF) micro-stimulators (Alfred Mann Foundation, Valencia, CA) interfaced with nerve cuff electrodes were placed on the transferred GFNs bilaterally.…”

“…Detrusor pressure was obtained as described previously. 5 Briefly, a Foley catheter was passed into the vesicostomy or through the urethra in dogs without vesicostomy. Bladder capacity was determined with 3 successive filling cystometrograms using normal saline at 30 mL/minute.…”

“…While both GFN and FN contain motor and sensory components, the branches of the FN contain primarily motor fibers and more effectively restores nerve evoked bladder contraction than using the GFN. 5 …”

This Month in Investigative Urology

“…3 They performed bilateral FN and GFN transfer in dogs after bladder decentralization. Other dogs served as sham operated or unoperated controls.…”