Entubulization Repair of Severed Cavernous Nerves in the Rat Resulting in Return of Erectile Function

Abstract

Erectile dysfunction is a significant complication of radical pelvic surgery in men. Using the rat as an experimental model, we investigated the feasibility of repairing surgically ablated cavernous nerves utilizing silastic tube nerve growth conduits filled with nerve growth enhancing media. Known fertile male Sprague-Dawley rats were randomly divided into four surgical groups consisting of nerve ablation, immediate nerve reconstruction utilizing the entubulization technique (two groups) and control. The nerve ablation group had five mm. sections of the cavernosal nerve excised bilaterally. The entubulization nerve graft group had five mm. sections of the cavernous nerve excised bilaterally, followed by immediate microsurgical reconstruction with a silastic nerve tube conduit filled with either Matrigel and heparin (MA) or Matrigel and heparin plus acidic fibroblast growth factor (MA/aFGF), interposed between the severed cavernous nerve stumps bilaterally. The control group underwent sham operations with the cavernous nerves being exposed only. Erectile function was evaluated at one, two, and four months postoperatively. Return of erectile function was defined as tumescence of the corporal bodies with application of direct electrical stimulation (four volts of five millisecond pulses at 20Hertz) to the proximal cavernous nerves.The two and four month electrical stimulation studies resulted in tumescence from 50% and 58% of the entubulization nerve reconstructed nerves with MA/aFGF versus 29% and 30% for the MA only group and only 5% and 11% for the ablated group, respectively. We conclude that in this experimental model immediate nerve graft repair utilizing entubulization techniques with the addition of nerve growth enhancing media appears to be a successful method of salvaging erectile function when the cavernous nerves have been divided.