A colostomy is a surgical procedure that creates an opening, known as a stoma, on the abdomen to divert the path of the large intestine. This opening is formed by bringing a segment of the colon through the abdominal wall and stitching it to the skin, creating a pink, moist surface through which waste collects into an external pouching system. The need for a colostomy is determined by a range of conditions that damage the colon or rectum, making the natural function impossible or unsafe. The procedure can be temporary, allowing a diseased or injured section of the bowel to heal, or it can be permanent if a portion of the lower bowel or the anal sphincter muscle is removed or non-functional.
The Medical Necessity for Bowel Diversion
Bowel obstruction is a frequent reason for colostomy, occurring when a tumor, severe inflammation, or scar tissue creates a physical blockage that prevents the passage of stool and gas. This obstruction can cause pressure to build up, leading to severe pain and the risk of rupture in the intestinal wall.
Another significant indication is perforation, which is a full-thickness tear or hole in the wall of the colon. When a perforation occurs, intestinal contents, including bacteria, leak out into the sterile abdominal cavity, quickly leading to a life-threatening infection called peritonitis and subsequent sepsis. Diverting the fecal stream away from the perforated area is necessary to immediately stop the contamination and allow for emergency surgical cleaning of the abdomen.
A third major reason for creating a temporary colostomy is to allow a damaged or newly repaired section of the bowel to rest and heal. By diverting the flow of stool, the colostomy protects the lower section of the intestine or a surgical connection, known as an anastomosis, from infection. This protective measure is often used following low-lying rectal surgeries, with the expectation that the colostomy will be reversed once healing is complete.
Chronic Conditions Leading to Colostomy
Many patients require a colostomy due to chronic, progressive diseases that necessitate planned surgical intervention. Colorectal cancer is a common cause, particularly when the tumor is located very low in the rectum. Surgical removal of these low-lying rectal cancers often requires the removal of the anal sphincter muscles, making it impossible to maintain voluntary bowel control and thereby requiring a permanent colostomy.
Inflammatory Bowel Disease (IBD), specifically Crohn’s disease and ulcerative colitis, can also lead to the need for long-term diversion. In ulcerative colitis, chronic, widespread inflammation of the colon can increase the risk of developing colorectal cancer over time, making a total colectomy and permanent diversion a necessary preventative measure. For both Crohn’s disease and ulcerative colitis, severe, non-responsive inflammation can lead to complications such as deep ulcers, fistulas, or toxic megacolon.
When medical management fails to control these severe complications, surgical removal of the diseased segment is often necessary. This frequently involves the creation of a colostomy to save the patient’s life.
Additionally, some individuals are born with congenital abnormalities of the colon or rectum that require early surgical intervention and diversion. Conditions such as Hirschsprung’s disease (missing nerve cells in the large intestine) or an imperforate anus (absent or blocked anal opening) necessitate a colostomy to allow for waste elimination and subsequent reconstructive surgery.
Acute Events and Severe Injuries
A colostomy may be created as an emergency measure following sudden, acute events or severe trauma. Severe diverticulitis, involving the inflammation and infection of small pouches in the colon wall, is a frequent cause of emergency colostomy. If an infected diverticulum perforates the bowel wall, it can cause a widespread leak of fecal matter into the abdomen, leading to a severe infection and often requiring an emergency procedure, such as a Hartmann’s procedure.
Abdominal trauma, such as that sustained in a car accident or a penetrating injury, can cause extensive damage to the colon that cannot be safely repaired immediately. In these situations, a colostomy is performed as a form of damage control, diverting the fecal stream to prevent contamination while the patient stabilizes and the injured tissues begin to heal. The bowel segment is often brought to the surface to prevent leakage and further peritonitis.
Another severe, acute cause is ischemic colitis, which results from a lack of adequate blood flow to a segment of the colon. While milder cases may resolve spontaneously, a severe reduction in blood supply can lead to tissue death and subsequent perforation. When full-thickness necrosis occurs, the dead tissue must be urgently removed, and a colostomy is required to divert the waste stream away from the surgical site to prevent leakage and infection.