Reduction in postoperative adhesion formation and re-formation after an abdominal operation with the use of N, O - carboxymethyl chitosan.

BACKGROUND

Postoperative adhesions have proven to be intractable complications after abdominal operations. This study assessed the efficacy of N, O - carboxymethyl chitosan (NOCC) to limit adhesion formation and re-formation in a rabbit abdominal surgery model.

METHODS

In study 1 (adhesion formation), injuries to the large bowel, cecum, and abdominal sidewall were generated in rabbits. The rabbits (10/group) were randomly assigned to 1 of 5 treatment groups: Group A received no NOCC treatment; in group B, NOCC gel was applied directly to the injured site and NOCC solution was applied throughout the abdominal cavity; in group C, NOCC gel was applied near the injured site and NOCC solution was applied as above; in group D, NOCC gel was applied distant to the injury and NOCC solution was applied as above; in group E, a mixture of NOCC gel and solution was applied at the injured site. Adhesions were evaluated 14 days later. In study 2 (adhesion re-formation), adhesions were generated as above but were then lysed by careful dissection. After adhesiolysis, the rabbits (9/group) were treated with NOCC gel and solution at the site of adhesiolysis or left untreated. Adhesion re-formation was assessed 14 days later. In study 3 (mechanism of action), sterile tissue culture plates were coated with NOCC and adhesion of cultured, radiolabeled murine fibroblasts to the plates was assessed.

RESULTS

In study 1, animals treated with NOCC gel and solution showed reduced adhesion formation (P<.01). NOCC gel was equally efficacious if applied on the site of injury or near the site of injury but less efficacious if applied at a site distant to the injury. In study 2, animals treated with NOCC gel and solution showed less adhesion re-formation compared with the untreated control animals (P<.01). In study 3, murine fibroblasts did not adhere to NOCC-coated tissue culture plates.

CONCLUSIONS

NOCC gel and solution can reduce adhesion formation and re-formation in this rabbit model. The inability of fibroblasts to adhere to NOCC solution-coated surfaces suggests that NOCC may act as a biophysical barrier.