Practical limitations of bioresorbable membranes in the prevention of intra-abdominal adhesions

Abstract

Introduction: Intra-abdominal adhesions are a significant source of postoperative morbidity. Bioresorbable barriers composed of hyaluronic acid and carboxymethylcellulose (HA/CMC) reduce adhesion formation by physically separating injured or healing peritoneal surfaces. To assess whether the efficacy of a physical barrier can extend beyond the site of application, we evaluated the effectiveness of an HA/CMC barrier in preventing adhesions distal to the site of placement.

Methods: Adhesions were induced in rats by creating peritoneal ischemic buttons on either side of a midline incision. An HA/CMC barrier (Seprafilm Genzyme) was intraoperatively placed either under the midline incision, unilaterally over half the ischemic buttons, or bilaterally over all ischemic buttons. Control buttons received no HA/CMC. On day 7 adhesions were scored. In similar experiments, peritoneal fluid was collected at 24 h to assess the effects of HA/CMC on tissue plasminogen activator activity.

Results: Placement of HA/CMC under the midline incision did not reduce adhesion formation to distal ischemic buttons (72 +/- 7%) compared to controls (80 +/- 8%). Unilateral placement of HA/CMC significantly (p < 0.05) reduced adhesion formation to those ischemic buttons over which the barrier was applied (35 +/- 7%) compared to both contralateral (83 +/- 9%) and control (80 +/- 8%) ischemic buttons. The bilateral application of HA/CMC also significantly (p < 0.05) reduced adhesion formation to all ischemic buttons compared to controls (22 +/- 7% vs. 66 +/- 7%, respectively). HA/CMC did not affect peritoneal tPA activity.

Conclusions: Effective adhesion reduction by the physical barrier HA/CMC appears to be limited to the site of application in this rat model. Despite the presence of a bioresorbable membrane at predicted sites of adhesion formation in the peritoneal cavity, adhesions readily form to distal unprotected sites.