Colon and Rectal Resections
It is necessary to surgically remove a section or length of the colon or rectum for a variety of conditions including cancers, large benign polyps, diverticulitis, inflammatory bowel disease (Ulcerative Colitis and Crohn’s Disease), rectal prolapse, constipation, and for other large bowel problems that can develop. Most often a 7 to 10 inch segment of the colon or rectum is removed although in some situations a lengthier resection is carried out. Each segment of the colon has a mesentery that is a ½ to 1 inch thick leaf of tissue that contains the blood vessels and lymph nodes that supply the bowel in question. The rectum has a much broader mesentery that actually envelops the entire rectum in places. Every colon or rectal resection includes removal of some or all of the adjacent mesentery. In patients with cancer a more thorough resection of the mesentery is necessary in order to remove the lymph nodes which may contain tumor. In contrast, in patients with benign problems such as diverticulitis only a minimal removal of the mesentery is needed. If necessary, the entire colon and rectum can be removed. In the great majority of patients it is possible to immediately rejoin the remaining ends of the bowel (an anastomosis) so that, after surgery, the patient will have bowel movements through the anus in the usual way.
In some patients in whom an anastomosis is constructed, where it is judged there is a higher than usual risk for an anastomotic leak (which usually leads to an abscess and infection) a temporary ileostomy or colostomy may be made. In this case, a part of the bowel closer to the stomach than the anastomosis is brought outside the body through a circular opening in the abdominal wall. The externalized large bowel is opened and sewn to the skin edge to create a colostomy (colon) that redirects or “diverts” the stool to the abdominal wall and away from the anastomosis. An alternate way to divert the intestinal contents is to bring the small bowel through the abdominal wall in a similar way to create an ileostomy.
In some patients, after resection of the colon or rectal segment, a decision is made not to rejoin the remaining ends of the bowel together during that operation. Patients who undergo emergency operations for bowel obstruction, bleeding, or severe colitis often fall into this category. Also, on occasion in very obese patients, or those in whom the colorectal resection was extremely difficult an anastomosis may not be constructed. In these patients either a colostomy or ileostomy will be made. A colostomy is also needed for patients who require complete removal of the anus and anal sphincter in addition to excision of the rectum for their problem (usually cancer or inflammatory bowel disease). If the entire colon, rectum, and anus are removed, most often for Ulcerative Colitis or a congenital polyp syndrome called Familial Polyposis, then an ileostomy is required.
There are 2 basic methods by which trans-abdomen operations are carried; “open” and minimally invasive methods. A description of each method follows.
Open Surgical Methods
Up until the 1990’s the only way to carry out a colon or rectal resection was through a 5 to 9 inch long single incision in the abdominal wall that exposed the intestine. This is called the “open” approach. The most common incisions are vertical midline (up and down) and transverse (side to side). The ultimate size of the incision depends on how much colon is being resected and also on which part is being removed. Parts of the colon are mobile or “free floating” whereas others are fixed in their position. The first task for the surgeon is to mobilize the attached portions of the colon by carefully cutting the thin fibrous attachments that hold it in place. The second task is to divide and detach the blood vessels and mesentery that supply the colon segment being removed. Next, the bowel itself is divided and the specimen removed. Finally, the remaining 2 ends of the intestine are either sewn or stapled together to re-establish the continuity of the bowel. The final step is to irrigate and then close the abdominal wall incision.
Laparoscopic Colorectal Resection
The goal of minimally invasive colorectal surgery, which was introduced in 1991, is to minimize the trauma and injury to the abdominal wall during bowel resection. Traditionally, intestinal resections have been carried out through a lengthy incision made in the abdominal wall which provides the surgeon access to the abdominal cavity. It has been well shown that by avoiding the longer incision the patient experiences less pain and requires less pain medications. Other short term benefits include a more rapid resumption of diet, return of bowel function, and discharge home as well as the ability to walk sooner and farther than patients receiving a traditional or “open” operation. It has also been shown that laparoscopic operations cause less marked physiologic and immunologic changes than the equivalent big incision operation (see Research Section). Also, most often patients are able to return to work and full activity more rapidly. Cancer patients who require chemotherapy can also start those treatments sooner because of the faster recovery. A brief description of a laparoscopic operation follows.
After anesthesia is administered, a laparoscopic operation is begun by making a small incision (< 1 cm) near the belly button through which a hollow needle is inserted into the abdominal cavity. Carbon dioxide gas (CO2) is then pumped through the needle into the abdomen which lifts the abdominal wall off of the internal organs and creates a space in which the surgeon can work; this is called a pneumoperitoneum. A hollow tube (port) is then inserted into the abdomen through the small incision. A rigid telescope with a powerful light is then inserted into the abdomen through the port and attached to a camera which projects the image on several television monitors in the operating room. The camera provides the surgeon and his assistants with a magnified internal view of the abdominal organs. The images obtained with the high definition image systems that are used today are excellent. An additional 3 to 4 port, with diameters ranging from a little more than a ¼ inch to ¾ inch are then placed. The ports have airtight valves on their exterior end which prevent gas leakage while allowing insertion of specially designed long surgical instruments into the abdomen. Using these instruments while watching the monitors the surgeons can work in all areas of the abdomen and can carry out the operation.
It is possible to mobilize the colon, to seal and divide blood vessels, and to divide the bowel using laparoscopic tools and without a large incision. In this way, a portion or all of the colon and rectum can be resected. Next, in order to remove the specimen it is necessary to either enlarge one of the port incisions or make a separate small incision (length is usually between 2 and 3 inches). In contrast, the standard “open” abdominal incisions usually range in size from 4 to 9 inches in length. Once the specimen has been removed, in the great majority of patients, the remaining bowel ends are rejoined and an anastomosis constructed. In some cases the rejoining of the bowel ends is done inside the abdomen laparoscopically whereas in other situations the reconnection is done externally, through the extraction incision. After completion of the anastomosis the ports and instruments are removed and the wounds carefully closed.
There are number of different minimally invasive methods that can be used. In addition to the standard laparoscopic approach, described above, there are several other methods including; hand-assisted laparoscopic, hybrid laparoscopic/open, and the robotic laparoscopic approach. Surgeons at Mount Sinai St. Luke’s Roosevelt Hospital routinely use the standard laparoscopic approach as well as the hand-assisted laparoscopic method. The latter calls for an incision large enough to accommodate the insertion of one hand into the abdomen (between 3 and 3 ½“). A special device is placed in the wound that allows the hand to be inserted yet doesn’t permit the CO2 gas in the abdomen from escaping. In this way a laparoscopic operation is carried out with one hand in the abdomen. It is then possible to palpate the bowel and to grasp and retract it which facilitates the carrying out and completion of the operation. This method is used by the colorectal surgeons at Mount Sinai St. Luke’s Roosevelt Hospital when the segment of colon or rectum to be removed is large and bulkier than usual. It is also commonly used in obese patients in whom the standard laparoscopic operation may be more difficult. Although the final incision is usually a 2-4 cm larger than after a standard laparoscopic operation it is still at least 50% smaller than the incisions needed to do an open or big incision bowel resection.
Although at first controversial, it is now well accepted that laparoscopic colon resection is the gold standard. Laparoscopic methods have been used for almost 20 years and there are many studies and published reports attesting to the safety and presently, all parts of the colon and rectum can be removed laparoscopically; if necessary, the entire colon and rectum can be removed using minimally invasive methods. Surgeons of the Section of Colon and Rectal Surgery have done over 1,800 laparoscopic colorectal resections and have also been involved with one of the large multi-center randomized cancer trials mentioned above. In addition, section surgeons at Mount Sinai St. Luke’s and Mount Sinai Roosevelt Hospital have published over 85 peer reviewed publications concerning laparoscopy and the physiologic and immunologic changes associated with both laparoscopic and open bowel resection.
MIS Methods for Colon Cancer
As mentioned, during the 1990’s and up to about 2003 there was great concern and fear that laparoscopic methods might be associated with lower survival rates, higher tumor recurrence rates, and a higher rate of abdominal wall tumors. These fears led to at least 3 large randomized multicenter clinical trials which compared the traditional open (big incision) method to laparoscopic colon resection methods. Preliminary reports from these studies made it clear that there was no difference in the size of the surgical specimens removed, in the distance from the tumor to the ends of the colon specimen (called the margins), or in the number of lymph nodes removed per specimen when the open and laparoscopic pathology results were compared. Thus, it is possible to do a “radical” cancer resection laparoscopically given a skilled and experienced surgeon. Thankfully, the 3 and 5 year cancer follow up results have become available from several of these studies. The 5 year survival and local recurrence rates for the laparoscopic and open or traditional surgical methods are very similar. Also, there was no difference in the rate of abdominal wall tumors in the open and laparoscopic groups. Since the short term recovery results of the laparoscopic approach are significantly better than those of the big incision method and the long term cancer results are similar, the laparoscopic method is the surgical approach of choice.
Colostomy and Ileostomy
Some patients undergoing either a laparoscopic or an open (big incision) colon or rectal resection require a colostomy or ileostomy. In these patients, a small circular patch of skin from the left or right lower abdominal wall is excised and a path or tunnel made through the abdominal wall into the abdominal. Then either the small bowel (ileostomy) or the colon (colostomy) is brought out through this opening and the stoma (another name for an ileostomy or colostomy) is constructed. With a stoma the stool exits the body through the abdominal wall instead of the anus. The output from an ileostomy is usually liquid or semi-formed whereas, for most patients, the output from a colostomy is formed stool. The stoma is covered by an “appliance” which includes an airtight and odor free bag that collects the output. The appliance or colostomy bag can be easily emptied via several ways. In some cases the colostomy or ileostomy is temporary while for some patients it is permanent. A permanent colostomy or ileostomy is required when the entire rectum and anal sphincter are surgically removed, usually because of a rectal cancer but sometimes for inflammatory bowel disease or other less common problems. Temporary stomas are most commonly made to “protect” a colorectal anastomosis made following a large bowel resection. By redirecting the stool to the abdominal wall and away from the newly joined bowel, it is possible to greatly lower the chances that an anastomotic leak or intra-abdominal abscess will develop. If all goes well the temporary stoma is closed at a second much smaller operation 2 to 3 months later after a test(s) is done to verify that the rejoined bowel is well healed and there is no leak present.