Effects of some pharmacological agents on the survival of unipedicled venous flaps: an experimental study.
Clinical and experimental studies have been conducted to improve the survival of venous flaps. As a result of these studies, although various survival mechanisms were raised, none obtained satisfactory information. Venous stasis, and the resultant venous thrombosis, is a factor that decreases the survival of venous flaps. In this study, we evaluated the effects of two antiinflammatory agents, etodolac and etofenamate, on the survival of unipedicled venous flaps. In this study, 35 male New Zealand white rabbits (3,500-4,000 g) (70 ears) were used. Perichondrocutaneous flaps, 3 x 4.5 cm in size, were designed and raised, keeping the central veins intact in the middle of venous flap. Central arteries and nerves were ligated and transected both proximally and distally, to prepare unipedicled venous flaps. A silicone sheet was placed between the cartilage tissue and flap, to prevent blood flow and revascularization beneath. The subjects were divided into seven groups, consisting of five rabbits (10 ears). In the negative control group (group I), the single vascular pedicle of venous flaps, central veins were ligated and flaps sutured into their own place as the composite graft. In the positive control group (group II), after venous flaps were prepared, normal saline, 0.2 mL, was given subcutaneously. In the first of five experimental groups (group III), unfractionated heparin (100 U/day) was given subcutaneously. In the second experimental group (group IV), etodolac (5 mg/kg/day) was given subcutaneously. In the third experimental group (group V), etophenamate (5 mg/kg/day) was given orally through a feeding tube. In the fourth experimental group (group VI), parnaparin (5 anti-Xa U/kg/day) was given subcutaneously. In the fifth experimental group (group VII), nadroparin (5 anti-Xa U/kg/day) was given subcutaneously, about 7 days postoperatively. At the eighth postoperative day, surviving areas of venous flaps were measured, and the results were evaluated by Kruskal-Wallis ANOVA and Mann-Whitney U-test (P < 0.05). Biopsies were also taken from the flaps for histological evaluation of border of necrotic tissue. Surviving areas of unipedicled venous flaps were larger in experimental groups than those in negative and positive control group (P < 0.05). However, comparison of the experimental groups demonstrated no statistically significant difference (P > 0.05). We concluded that all pharmacological agents used in the experimental groups succeeded in increasing the survival of unipedicled venous flaps. Survival of the unipedicled venous flap was higher in venous flaps than that of composite graft, clearly showing the importance of the venous pedicle.