Tubularized Urethral Reconstruction Using Everted Saphenous Vein Graft in A Beagle Model

Abstract

Background: The repair of anterior urethral stricture and hypospadias require urethral reconstruction. We conduct the study to investigate the efficacy of anterior urethral reconstruction using everted saphenous vein graft in tubular fashion. Methods: Twelve male beagles were randomly divided into three groups: experimental group( n=5), control group( n=5) and normal group( n=2). A 3 cm defect in anterior urethra was created. Autologous saphenous vein graft was harvested. In experimental group, urethral defect was replaced by everted saphenous vein graft in tubular fashion. In control group, urethral reconstruction was performed using uneverted saphenous vein graft. At 6 months postoperatively, beagles in all groups received retrograde urethrography to evaluate urethral patency and were killed for histological examination. Results: Retrograde urethrography showed the urethral caliber of beagles in experimental group were similar to those of normal. Ether urethral stricture or fistula were detected in all animals in control group. In experimental group, the everted saphenous vein graft completely integrated into the urethra. The reconstructed urethra had a wide lumen and was completely covered by urothelium. The subepithelial collagen and muscle fibers were well formed and highly organized. Everted saphenous vein graft had a high ability of neovascularization. In control group, the reconstructed segment had a fibrotic urethral lumen in which urothelium was not intact. And there were few newly formed capillaries. Conclusions: Everted saphenous vein graft can be used as tubular substitute material for anterior urethral strictures and hypospadias.

Preliminary Application of a Novel Anatomic Urethroplasty Technique Using Everted Saphenous Vein Graft for Long Penile Urethral Strictures

“…Later, Kim et al [14] used a rabbit model to show that the SVG repair of urethral stricture is feasible. Li et al [15] also published similar reports, confirming that SVG is safe and feasible. Moreover, many studies have shown that everted SVG (eSVG) is more effective than non-everted SVG.…”

“…Second, the key factor for successful reconstruction of the urethra is the rapid neovascularization of the graft to ensure sufficient blood supply. A study on Beagle dogs [15] found that the graft can be supplied with better nutrition via the surrounding tissues through the endothelium instead of the outer membrane. Therefore, the survival time of the eSVG is longer, so the newly formed epithelium will be better and smoother, and the incidence of fistula will be rather low.…”