We all have about six feet of colon, which is also known as the large intestine. Its main function is to absorb water and some electrolytes from fecal matter so that it can be passed as solid waste from the rectum. The colon begins in the right lower abdomen and is connected there to the end of the small intestine, or ileum. The ileocecal valve is located between the beginning of the colon or cecum and the end of the small intestine. This a landmark that is seen inside the colon during a colonoscopy and marks the most proximal end (closest to the center of the body) of the colon. It serves as a one-way valve that prevents fecal matter from moving back into the small intestine.
Located at the base of the cecum, in the right lower quadrant, is the appendix. This is covered in depth on the Appendectomy page. The colon then ascends (ascending colon, or right colon) to the right upper quadrant where the first turn occurs. This turn is called the hepatic flexure because it is located just inferior to the right lobe of the liver. The colon then traverses the mid-abdomen (transverse colon) to the next turn in the left upper abdomen called the splenic flexure. This turn is just inferior to the spleen. The colon then descends (descending colon, or left colon) to the left lower quadrant where it then makes a turn to the right and forms a loop (sigmoid colon). This loop then continues into the pelvis and joins the rectum.
We will address polyps and cancers first. Polyps can be pedunculated (mushroom-like) or flat. They can occur anywhere in the lining of the colon, including the appendix. Some polyps are precancerous, and if they are left to grow, they become cancerous masses. Colon cancers can then spread in various ways: through the muscular wall of the colon into adjacent structures; by lymphatics into the lymph nodes that drain the colon and accompany the blood vessels to and from the colon wall; or by the blood stream to other organs, such as the liver or lungs.
Another common surgical condition of the colon is diverticulitis. Diverticulosis is the development of small pockets on the inside lining of the colon that protrude through small openings in the muscle wall of the colon where the blood vessels enter and leave the colon. These pockets are not covered by the full thickness of the colon wall and, if they become infected, can leak stool and infected material into the abdominal cavity, causing peritonitis. This can be a life-threatening infection. When these pockets, or diverticula, become infected, the condition is called diverticulitis. Thankfully, most cases of diverticulitis just cause pain and fever, and are localized infections that can be treated with antibiotics. The diverticulosis can occur throughout the colon but it’s usually most concentrated and symptomatic in the sigmoid and left colon segments. Complications of diverticulitis include perforation; stricture or narrowing of the colon due to scarring from infection; fistula formation or abnormal connections to other organs, such as the bladder or vagina; and recurring episodes of infection. All of these complications are most commonly treated with colon surgery. Diverticulosis can also cause bleeding but this is a less common indication for colon surgery. Colitis, infection or inflammation of the colon, can also lead to surgery in certain situations.
Causes, Risk Factors & Prevention
We do not know what causes colon polyps and cancers. Some cases are hereditary; these conditions can be diagnosed by genetic tests.
Diet definitely plays a role in the formation of polyps, cancers and even diverticulosis. In certain cultures where the diet is mainly fruits, vegetables and grains, there is very little colon disease. Constipation is felt to increase the risk of diverticulosis, but some patients with constipation never develop diverticula and some patients with diverticulosis have very little constipation. Eating a high-fiber diet, limiting processed foods and maintaining a healthy weight can all reduce the risk of developing these diseases. Taking a low-dose aspirin (81 mg) is associated with a lower risk of colon polyps. Polyps can be detected and removed during a colonoscopy screening, starting at age 45. This prevents colon cancer.
Stool tests, such as Cologuard, that can detect polyps and cancers in the colon can be helpful. However, they are not as effective as a colonoscopy and do not detect all polyps and cancers. At most annual physicals at your primary care doctor’s office, you will probably be given a rectal exam beginning at age 40. The stool specimen from this exam is tested for occult (not visibly apparent) blood in the stool, which can also help to detect polyps and cancers.
Some hereditary polyp and cancer conditions can be so severe that a prophylactic colectomy, or removal of the entire colon, is needed to prevent cancer. This procedure is also sometimes necessary for inflammatory bowel diseases such as ulcerative colitis.
Tests, Detection & Imaging
The most common technique for detecting colon disease—including polyps, cancers and diverticulosis—is a colonoscopy. This procedure uses a flexible, fiberoptic maneuverable scope that is introduced into the rectum and advanced to the cecum under conscious sedation. The most difficult part of the procedure is the prep that must be taken prior to the procedure to flush the fecal matter from the colon, which allows the endoscopist to see clearly during the colonoscopy. Propofol is the most common anesthetic used intravenously and allows for rapid recovery from the procedure. Polyps found during the colonoscopy can be removed or, if too large, they can be sampled with a biopsy. The polyp or the biopsy can then be submitted to a pathologist to determine the type of polyp. The same is done for cancerous masses found in the colon. Biopsies can also be done to diagnose colitis and other inflammatory conditions of the colon.
X-rays for the colon include CT scanning with oral and/or rectal contrast, and enemas with contrast. Diverticulitis of the colon is most commonly diagnosed with a CT scan, which shows the inflammation around the infected diverticulum and can also show if any complication has occurred.
Enemas with contrast can help to determine where narrowing of the colon may be located; diagnose abnormal connections of the colon to other organs such as the bladder or vagina; and determine if there is a perforation or leak from the colon.
Blood in the stool can be the first indication of a polyp or cancer. If this occurs, you should seek attention from your primary care physician. Iron deficiency anemia can sometimes may be the only symptom. Anemia develops when there is occult blood loss from a polyp or cancer, usually on the right side of the colon, that is not copious enough to be seen as blood in the stool. However, that amount of blood is enough to indicate anemia in a complete blood count (CBC). This is also an indication for a colonoscopy to look for a problem in the colon.
All segments of the colon can be removed surgically (colectomy). The approach can be open or minimally invasive, performed with either the laparoscope or a robotically-assisted laparoscope.
When colon surgery is done for a polyp that is too large or too flat to be removed with a colonoscope or when colon cancer is present, removal of the involved segment of colon is required. In most cases, this can be done using a minimally-invasive approach. You must prepare for the procedure beginning two days prior to the surgery. You will be given detailed instructions by our office staff to perform a bowel prep. You will be asked to be on a clear liquid diet for two days, with a laxative taken by mouth on the first day to help evacuate the fecal matter from the colon. On the second day, we give patients two antibiotics by mouth in three doses, separated by two hours between each dose. These antibiotics, which have been used for years by surgeons for colon preparation, are erythromycin base and neomycin. Erythromycin base causes the stomach to contract, which then moves both of the antibiotics through the small intestine into the colon, where they will kill bacteria. Neither of the two antibiotics are absorbed well into the body and stay inside the colon where they kill the bacteria normally living there. This decreases the risk of all types of infection associated with colon surgery. Lomotil is given the night before the surgery to settle down the intestines and diminish the diarrhea and cramping that can be associated with the antibiotic prep. Nothing can be had by mouth after midnight, but we now use an enhanced surgical recovery protocol that will allow carbohydrate drinks even the morning of the surgery for the purpose of preventing dehydration and maintaining a healthy gut lining.
Most colon surgery patients will be offered an epidural catheter for post-operative pain management. This catheter is placed in the holding area (just prior to going back to the operating room) by an anesthesiologist while the patient is under local anesthesia. This catheter is used to drip medicine that bathes the pain nerves as they exit the spinal column to prevent pain at the surgery sites. This allows early ambulation and movement and lessens the use of narcotics pre-operatively. This is also part of the enhanced recovery protocol. Most colon surgeries are done under general anesthesia and require placement of a Foley catheter into the bladder to measure urine output during the operation. This catheter is usually removed on postoperative Day 1 or 2. If your colon surgery is completed laparoscopically, the epidural catheter for pain management is usually removed on postoperative Day 2. If the surgery is done with an open approach, then the epidural can be left in place for up to a week, if needed. Even with the laparoscopic or robotic approach, an incision large enough to remove the colon must be made and, in most cases, it is at least five to six inches in length. For most minimally invasive colon surgeries, the hospital stay is three to five days and, with the open approach, five to seven days. The biggest factor determining length of stay is how fast normal colon function returns so that a diet can be resumed prior to the time of discharge. At the time of discharge, you will be eating your usual diet and able to get around to perform most daily tasks. The time to full recovery is usually three to six weeks, depending on the technique used and the condition for which the surgery was performed. With diverticulitis, the segment of the involved colon is removed and the normal ends are reconnected.
Our surgeons have many years of experience performing colon surgeries. We are skilled at both minimally invasive approaches—laparoscopic and robotic—as well as the open techniques. We are trained in the use of the SPY Elite which is a fluorescence imaging technique used to ensure that the blood supply to the colon is adequate for healing when a segment is removed and the two remaining ends are reconnected. This ensures a smaller leakage risk where the colon is reconnected and prevents stricture formation at this site.
Our laparoscopic equipment and surgical robots at the hospital are the most up-to-date available. During your consultation, your surgeon will discuss the indications for colon surgery depending on your problem. The technique best suited for you will be discussed in detail as well and tailored to your specific needs. Risks, possible complications and issues will also be discussed in detail so that you are prepared completely for the procedure. We also use the best bowel prep technique, an enhanced surgical recovery protocol and pain-control methods that lead to the best overall outcomes and fastest recovery.