Comparison of Different Techniques for Hemostasis in a Rabbit Model of Hypospadias Repair

Abstract

We compared the cellular and ultrastructural changes in the urethral wall following application of different hemostasis techniques in a rabbit model of hypospadias surgery. Rabbits were allocated into 5 groups. In group 1 animals underwent surgery without application of any hemostasis technique; in group 2 continuous penile tourniquet was applied for 30 minutes; in group 3, 3 intermittent periods of 10-minute penile tourniquet were applied with 3-minute intervals of reperfusion; in group 4 epinephrine was injected to maintain a 30-minute period of hemostasis; and in group 5 epinephrine vehicle (normal saline) was injected during the procedure. Early urothelium ultrastructural damage was studied 1 hour postoperatively with electron microscopy. Apoptotic damage and histopathological changes were determined 48 hours following the procedure. Late onset complications were assessed with retrograde urethrography and evaluation of tissue fibrosis at 8 weeks postoperatively. Electron microscope studies demonstrated urothelium ultrastructural damage in all hemostasis groups compared to controls. However, the changes were most prominent in group 4. The apoptosis index of urethral wall myocytes in groups 1 and 5 was significantly lower compared to other groups. Moreover, the number of apoptotic myocytes in epinephrine injected animals was significantly higher than in the continuous or intermittent tourniquet group as well as the normal saline injected group. At 8 weeks postoperatively collagen deposition in the urethral wall of rabbits in group 4 was higher than that in group 1. Although urethrocutaneous fistula was found in only 1 rabbit in group 4, the difference was not significant. Hemostasis techniques applied for maintaining a bloodless surgical field during hypospadias repair may lead to ischemia/reperfusion tissue damage in the urethral wall. Our findings suggest that epinephrine injection may result in more prominent cellular changes compared to tourniquet techniques. However, further experimental and human studies are required to draw a firm conclusion.