Coloanal anastomosis following low anterior resection.

Low anterior resection with coloanal reconstruction is indicated for rectal cancer when APR is not necessary and conventional LAR is not possible. LAR/CAA, in properly selected patients, yields results equivalent to those achieved with APR, since it encompasses equally the primary routes for regional spread. Most patients with midrectal tumors are candidates for LAR/CAA if an intrapelvic anastomosis is technically impossible. Complete dissection of the rectum and its mesentery to the anal hiatus of the pelvic diaphragm is essential for optimal cancer treatment and appropriate selection of cases for sphincter preservation. Careful attention to five technical points are essential for a successful outcome with respect to survival and function: (1) complete mobilization of the left colon; (2) sharp dissection; (3) restoration of the anorectal right angle and complete sacralization of the transposed colonic segment; (4) meticulous pelvic hemostasis and drainage to avoid septic complications; (5) routine use of diverting colostomy until completion of healing. In the long run, the LAR/CAA offers patients good function with few side effects and is universally preferable to a permanent colostomy. By avoiding permanent colostomy, cancer treatment is improved without compromising survival.