Morphology and healing resistance of abdominal wall after longitudinal and transversal laparotomy in rabbits

The abdominal wall continues to be a topic of investigation for the evaluation of its healing in terms of morphology and resistance. In the present investigation, transverse and longitudinal laparotomies were studied comparatively.

Thirty rabbits were divided into two groups: Group 1 (n=10) longitudinal laparotomy, Subgroup 1A (n=5) suture of the anterior and posterior sheaths of the abdominal rectus muscle and of the peritoneum, Subgroup 1B (n=5) suture of the anterior sheath of the abdominal rectus muscle; Group 2 (n=20) transverse laparotomy, Subgroup 2A (n=5) suture of the anterior and posterior sheaths of the abdominal rectus muscle and of the peritoneum, Subgroup 2B (n=5) suture of only the anterior sheath of the abdominal rectus muscle, Subgroup 2C (n=5) suture of the abdominal rectus muscle and of its anterior sheath on a single plane, Subgroup 2D (n=5) repair of the posterior sheath of the abdominal rectus muscle together with the peritoneum, followed by suture of the abdominal rectus muscle complemented with suture of the anterior sheath of the same muscle. After 17 days, two peritoneal aponeurotic muscular segments of the scar were removed for the evaluation of resistance and of histological aspects.

The resistance values detected for each group showed 1A>1B, 1A>2A and 1B>2B, and 2B>2C>2D>2A (P=0.014). Dehiscence, infections and adhesions were more frequent in Group 2. Histology revealed muscular degeneration and necrosis, with mature fibrous connective scar tissue replacing muscle tissue.

Transverse muscle section causes greater muscle weakening and leaving the peritoneum open does not alter the resistance of the scar.