IMBRICATION VERSUS EXCISION FOR FASCIAL HEALING

BACKGROUND: The purpose of this study was to determine whether imbrica tion of native fascia versus excision and closure of new raw fascia fo rms a stronger union. METHODS: We utilized the anterior rectus sheath fascia of Sprague-Dawley rats as the model. Sixty rats underwent fasci al tightening procedures. Each rat had the anterior rectus sheath shor tened by 1 cm, 30 by imbrication and 30 by excision and closure. Ten o f each group were harvested at 7 days' healing, 10 at 14 days, and 10 of each group at 28 days' healing. The anterior rectus sheath was remo ved, a ''dumbbell'' shape constructed, and the cross sectional area at the point of interest determined. The fascia was placed on an Instron tensiometer to determine the breaking strength. Tensile strength was calculated and the data analyzed by ANOVA and the Kruskall-Wallis test . Tissue samples of the closures were histologically analyzed for fibr oblast counts, degree of inflammation, and presence of dense fibrous c onnective tissue. Tissue samples were also analyzed for enzymatic coll agen crosslinking. RESULTS: There was a statistically significant diff erence in tensile strength between the two groups at 7, 14, and 28 day s. Results show that at 7 days the mean tensile strength of excision w as 0.133 kg/mm(2) +/- 0.056 and the mean tensile strength of imbricati on was 0.083 kg/mm(2) +/- .048 (P < 0.05); at 14 days the mean tensile strength of excision was 0.105 kg/mm(2) +/- 0.033 and the mean tensil e strength of imbrication was 0.057 kg/mm(2) +/- 0.014 (P < 0.002), an d at 28 days the mean tensile strength of excision was 0.279 kg/mm(2) +/- 0.143 and the mean tensile strength of imbrication was 0.145 kg/mm (2) +/- 0.061 (P < 0.03). Histologic findings showed no statistical si gnificance between the two closure methods when comparing degree of in flammation or the number of fibroblasts present. However, at 7 and 14 days there is a significantly greater presence of dense fibrous connec tive tissue in the excision group (P < 0.03 at 7 days and P < 0.044 at 14 days by ANOVA). Collagen crosslink analysis showed that by day 28 there is a significantly greater amount (P < 0.05 by ANOVA) of the dif unctional crosslink dihydroxylysinonorleucine (DHLNL) and a greater ra tio between DHLNL and the difunctional crosslink hydroxylysinonorleuci ne (HLNL) in the excision and closure group. CONCLUSION: We conclude t hat at 7, 14, and 28 days healing, excision provides a significantly s tronger closure than imbrication. According to the crosslinking analys is, it is likely that this strength advantage may continue to increase over time. These findings suggest that excision and closure may be th e preferred method for fascial tightening procedures. (C) 1996 Excerpt a Medica, Inc.