Recurrent episodes of sigmoid colonic diverticulitis prompt operative therapy. Which of the following describe the appropriate margins for resection?

b. Proximal margin, descending colon; distal margin, rectosigmoid junction

At the time of exploratory laparotomy, if the disease is localized, a segmental colectomy should be performed. The distal extent of the resection should always extend to the proximal rectum to decrease the chance of recurrence. The proximal extent of resection should include the segment involved with the acute disease plus any additional colon with signs of chronic disease or large numbers of diverticula. With this approach, the recurrence rate after surgical resection is less than 10%. The only absolute contraindications to primary anastomosis are free perforation with generalized peritonitis; obstruction with unprepared bowel; and intraoperative conditions that do not warrant primary anastomosis, such as septic shock, ureteral injury, or other medical conditions that make a prolonged operation inadvisable. If resection is thought to be unsafe in the presence of a massive phlegmon or if the patient is too unstable to undergo a resection, a diverting end colostomy with mucous fistula may be appropriate, with planned colonic resection at a later date after inflammation subsides.