Effects of hyaluronic acid/carboxymethylcellulose gel on bowel anastomoses in the New Zealand white rabbit

Abstract

Intra-abdominal adhesions form in more than 90% of patients undergoing major abdominal surgery and can lead to significant complications. Application of a bioresorbable gel consisting of chemically modified hyaluronic acid (HA) and carboxymethylcellulose (CMC) has shown promise as a means of preventing intra-abdominal adhesions, but there have been concerns that the presence of the gel might interfere with the integrity and healing of bowel anastomoses. We tested the effects of HA/CMC gel on adhesion formation and anastomotic healing in 60 New Zealand white rabbits after transection and complete (100%) or incomplete (90%) anastomosis of the ileum. Half of the animals underwent application of HA/CMC gel and half served as control subjects. Animals were killed at 4, 7, or 14 days after surgery. Anastomotic adhesions were scored in a blinded fashion. Integrity of the anastomosis was tested by measuring bursting pressure at the anastomotic site and in an adjacent section of intact bowel. With complete anastomosis HA/CMC gel significantly reduced adhesion formation at 7 and 14 days after surgery ( P <0.05), but gel application did not inhibit adhesion formation when the anastomosis was incomplete. Anastomosed segments of bowel burst at a lower pressure than intact bowel 4 days after surgery, but bursting pressures were normal at 7 and 14 days. Burst pressures of anastomoses receiving an application of HA/CMC gel were nearly identical to control anastomoses at all three time points. HA/CMC gel did not interfere with the normal healing process of bowel anastomoses. Furthermore, HA/CMC gel decreased adhesion formation after complete anastomoses, yet it did not affect adhesion formation in the presence of anastomotic disruption.