First, we have to define the two intestines in our bodies. The large intestine, also known as the colon or large bowel spans most of the length and width of the abdomen in an upside-down U shape. We categorize the colon in five distinct parts. From right to left, it is composed of the cecum, ascending colon, transverse colon, descending colon and sigmoid colon. The colon removes and absorbs water, is the catalyst for the fermentation of remining material and expels solid matter in the form of feces into the rectum for removal from the body.
The small intestine or small bowel, on the other hand, has three parts – the duodenum, jejunum and ileum. The small intestine absorbs vitamins and nutrients from the food and drink we consume.
Which organ is longer? Contrary to how the terminology makes it seem - small and large - the small intestine is longer (22 feet) and the large intestine shorter (5 feet). Small and large actually refers to the diameter of the two organs.
So – Do You Need Your Large Intestine?
The answer to the first question, believe it or not is - YES! You can live without a large intestine - something that comes as a shock to many people. The large intestine or colon has one primary role, water and electrolyte absorption to concentrate the stool. It plays little role in metabolism and people can live full lives without their large intestine.
There are several diseases that may require removal of the entire large intestine:
- Ulcerative colitis,
- Crohn’s colitis and
- Familial polyposis
are the most common indications for a total proctocolectomy (removing the colon and rectum).
When the anus is not involved with disease and does not need to be removed, the small intestine can be reconstructed to work like the rectum (a J-pouch) which is connected to the anus to maintain continence. After J-pouch surgery, since the stool in the small intestine is more liquid, patients will have very watery bowel movements postop until the pouch adapts and learns to absorb fluid like the colon once did.
While less commonly employed than in years past, significant disease that inhibits the natural elimination of stool may require a colostomy – where a stoma is created in the abdominal wall to allow for the elimination of waste from the large intestine.
You Cannot, Live Without Your Small Intestine.
The small intestine cannot be completely removed. Some patients may undergo surgery to remove some of their small bowel. These can be done for several reasons:
- A malabsorptive bariatric surgery such as gastric bypass to address morbid obesity, by limiting the calories absorbed by the small intestine
- Diseases requiring extensive small bowel resection such as Crohn’s, traumatic injury, cancer and intestinal blockages
Patients undergoing extensive small bowel resection may be left with short bowel. Short bowel syndrome can happen if the majority of one’s small intestine is removed, taking one from, say, 22 feet of small intestine, down to 4 feet. Patients with short bowel syndrome will most often require supplemental fluid and sometimes intravenous nutrition because the small intestine plays a profound role in absorption of nutrients and electrolytes.
Karen Zaghiyan, MD, FACS, FASCRS, is a double board-certified colorectal surgeon and one of the leading experts in J-pouch surgery in Los Angeles, California. You may schedule a consultation by phone or internet to learn if you are a candidate for a colon resection or J-pouch surgery.