What You Need to Know About Lower Anterior Resection

A lower anterior resection is the surgical removal of the upper two-thirds of the rectum, leaving the anal sphincter intact. You may see the procedure referred to by older terminology, anterior resection of the rectum or simply as anterior resection. This procedure is used to treat rectal cancer and in some cases of diverticulosis. The procedure is sometimes used to treat severe roundworm infestations, extremely numerous polyps, gangrene of the bowel, complications of radiation therapy for colon cancer, Crohn's disease, ulcerative colitis, inflammatory bowel disease, Hirschprung disease, extreme constipation (obstipation), or traumatic injuries to the rectum.

It is an alternative to a more drastic procedure called abdominoperineal resection, which removes the anal sphincter and rectum and part of the sigmoid colon, with permanent placement of a colostomy bag. Lower anterior resection is reversed by a procedure called anastomosis, reattaching the distal (lower) rectum to the rest of the bowel so the temporary colostomy bag can be removed.

That's where the procedure often goes wrong. Common complications of the procedure to reverse the resection include:

Leaks,
Bleeding,
Infection,
Stricture, and
Ileus, an inability to push stool outward, especially when the procedure is performed on children.

Leaks are the most common problem in reattaching the lower rectum. The healing process after anastomosis occurs in three phases. For the first five to seven days there is inflammation. The immune system removes dead and injured tissue. After inflammation, usually in the second week, inflammation gives way to fibroplasia, the rapid growth of connective tissue around in new membrane in the rectum. As healing progresses, fibroplasia gives way to remodeling, in which the immune system removes some cells and other cells are proliferate to give the rectum its new function and shape.

During the inflammation phase, the rectum has to be held together by sutures. If the surgeon did not install the sutures properly, they will leak. During the fibroplasia phase, metabolic conditions like diabetes and nutritional problems like diabetes come into play. If the body cannot generate the proteins the rectum needs to rebuild itself, the result is a still-inflamed rectum. Diabetics are especially vulnerable to leaking at this stage.

Leaking at any stage of recovery is a medical emergency. Spillage of the bowel contents can cause a potentially deadly condition called peritonitis, necessitating laporoscopy of the bowel to repair inadequate sutures.

Bleeding differs from leaking in that blood can pass into the rectum rather than back out into the body. Bleeding isn't unusual in people who have coagulation disorders, and it can be a sign of a potentially deadly condition called sepsis. The first sign may be blood appearing in an intra-abdominal drainage tube or a nasogastric feeding tube. This is a complication requiring intense medical care, both to monitor for signs of sepsis (usually by testing the blood for the presence of a compound known as lactate) and to make sure blood losses are replaced with transfusions, if necessary.

Wound infection at the site the surgeon cut the skin usually is not a medical emergency, and does not require IV antibiotics. It often can be treated with a topical antibiotic and loosening stitches to allow for draining pus.

Ileus, however, is a serious complication. If narrowing or stricture of the rectum stops bowel movement, reopening the incision to redo the surgery may be a must. Ileus is most commonly a problem in children and the elderly.

What can you do to avoid these complications after surgery to reverse lower anterior resection?

If you are well enough to discuss the procedure with your doctor before it is performed, inquire whether the doctor will hand-sew the stitches or use staples. Hand-sewn stitches are sometimes used when the doctor is more concerned about ileus. Staples are sometimes used when the doctor is more concerned about leakage. Your doctor's concerns may be a clue as to when everyone needs to be on the lookout for complications.
Make sure you are not dismissed from the hospital too soon. Close medical attention, at least during the inflammation phase, is a must.
Expect changes in your bowel movements after the surgery. You may find that bowel movements tend to "cluster." You may feel that you "still need to go" after a bowel movement, but you probably will.
Certain foods may cause you to need to go to the toilet immediately after eating after you have had your surgery. They may also cause abdominal pain until you are able to defecate. Pay attention to what you eat and avoid these foods.
Be sure to drink 6 to 8 glasses (1.5 to 2.0 liters) of water every day. Caffeinated beverages are OK unless your doctor says otherwise, but they do not count as "water" for this purpose.
Eat high-fiber foods every day. They feed the probiotic bacteria that give bulk to the stool and make bowel movement easier.

Important notification about information and brand names

Barone JE. Abnormal vital signs not a good indicator of anastomotic leaks. Medscape Medical News. March Guenaga KK, Matos D, Wille-Jørgensen P. Mechanical bowel preparation for elective colorectal surgery. Cochrane Database Syst Rev. 2009. (1):CD001544.,24, 2014.
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