The use of a biodegradable mesh to prevent radiation-associated small-bowel injury. Radiation-associated small bowel injury occurs in up to 50% of patients receiving postoperative radiotherapy following pelvic cancer surgery. We describe our experience using a biodegradable mesh that allows the small bowel to be supported above the pelvic inlet and is totally absorbed following radiation therapy. Between 1985 and 1989, 45 procedures were performed in patients with carcinoma of the rectum (anterior resection in 15 patients, abdominoperineal resection in 23 patients, pelvic exenteration in six patients, and proctocolectomy in one patient). In 30 patients a polyglycolic acid (Dexon) mesh was used, and in 15 patients a polyglactin 910 (Vicryl) mesh was used. Forty-four patients received postoperative radiotherapy. The mean (+/- SEM) dose was 56.8 +/- 18.4 Gy. There were no immediate complications related to the mesh. Follow-up ranged from 12 to 53 months (median follow-up, 34 months). With the exception of two patients who had a polyglactin 910 mesh and who developed bowel obstruction due to adhesions under the anterior abdominal wall, there has been no documented incidence of clinical radiation-associated small bowel injury. The use of the absorbable mesh may permit us to use higher doses of postoperative radiotherapy without the associated hazard of radiation-associated small bowel injury. 