People get stomas when part of their digestive or urinary system can no longer function safely on its own. A stoma is a surgically created opening in the abdomen that reroutes waste (stool or urine) out of the body and into an external pouch. Between 800,000 and 1 million people in the United States currently live with one. The reasons range from cancer and inflammatory bowel disease to traumatic injuries and conditions present at birth.
Colorectal and Rectal Cancer
Cancer is one of the most common reasons for stoma surgery. When a tumor grows in the colon or rectum, surgeons often need to remove the affected section of bowel. If the cancer sits low in the rectum, close to the anus, there may not be enough healthy tissue left to reconnect the bowel and preserve normal function. In some cases, a surgeon can attach the colon directly to the anus to avoid a permanent stoma, but this depends entirely on how close the tumor is to the sphincter muscles.
Even when the bowel can eventually be reconnected, a temporary stoma is often created to give the surgical site time to heal without stool passing through it. The stoma protects the fresh connection and lowers the risk of leaking, which can cause dangerous abdominal infections. For bladder cancer, the situation is different: if the bladder needs to be partially or fully removed, a urostomy reroutes urine through a small piece of intestine to an opening in the abdomen. Bladder cancer is the single most common reason people need a urostomy.
Inflammatory Bowel Disease
Ulcerative colitis and Crohn’s disease cause chronic inflammation that can progressively damage the lining of the colon. Most people with these conditions manage symptoms with medication for years, but surgery becomes necessary when drugs stop working or when the disease triggers a crisis the body can’t control.
Sudden, severe ulcerative colitis is the leading cause of emergency surgery in these patients. When intravenous steroids and other treatments fail to bring a flare under control, the colon can become dangerously distended, a condition called toxic megacolon that causes fever, rapid heart rate, severe pain, and dehydration. Left untreated, chronic inflammation can also weaken the colon wall until it perforates, spilling intestinal contents into the abdomen and causing a life-threatening infection called peritonitis.
There’s also a cancer link. Long-standing inflammation raises the risk of precancerous cell changes in the colon. If biopsies reveal these changes, surgeons typically recommend removing the colon and rectum entirely, even before cancer develops, to eliminate that risk. The result is usually an ileostomy, where the end of the small intestine is brought to the surface of the abdomen.
Diverticulitis Complications
Diverticulitis occurs when small pouches in the colon wall become inflamed or infected. Most cases resolve with antibiotics, but advanced stages can lead to perforation, where a hole forms in the colon and leaks bacteria into the abdominal cavity. This is a surgical emergency.
The most common procedure in this situation is called a Hartmann’s procedure. The surgeon removes the damaged section of colon and creates a temporary colostomy because the remaining ends of the bowel can’t be safely reattached while infection and inflammation are still present. The colon needs time to heal before reconnection is even possible. The colostomy lets the surgeon solve the immediate, dangerous problem while preserving the option to reverse the stoma later.
Trauma and Abdominal Injury
Gunshot wounds, stabbings, car accidents, and other forms of abdominal trauma can tear or puncture the bowel. When the risk of complications from repairing the injury in one operation is high, surgeons create a stoma as part of a damage-control strategy. The priority is stopping bleeding and preventing contamination of the abdominal cavity. Reconnecting the bowel happens in a later, planned surgery once the patient has stabilized and the tissue has healed.
Bladder Damage and Urinary Conditions
A urostomy isn’t only for cancer. People with spinal cord injuries, radiation damage to the bladder, or congenital conditions like spina bifida may need one if their bladder can no longer store or release urine effectively. Severe urinary incontinence that doesn’t respond to other treatments, a damaged urethra, or structural abnormalities that make urination difficult can also lead to this type of stoma. In cancer cases, the surgery may involve removing not just the bladder but also nearby organs, including the prostate in men or the uterus in women, along with lymph nodes.
Conditions Present at Birth
Some babies are born with digestive tract abnormalities that require a stoma within the first days or weeks of life. Anorectal malformations, where the anus and rectum don’t form correctly, are the most common congenital digestive defect in newborns, occurring in roughly 1 in 1,500 to 1 in 5,000 births. Children with moderate to severe forms often need a diverting stoma while reconstructive surgery is planned and completed in stages.
Hirschsprung’s disease is another cause. In this condition, nerve cells are missing from a section of the bowel, preventing it from moving stool forward normally. Though rarer, it sometimes requires a temporary stoma to bypass the affected segment until definitive surgery can be performed.
Temporary Versus Permanent Stomas
Not all stomas are permanent. Surgeons create temporary stomas to let the bowel heal after cancer surgery, diverticulitis, inflammatory bowel disease flares, or trauma. Most reversals are planned six weeks to six months after the initial surgery, though the exact timing depends on how well the body is recovering.
A stoma becomes permanent when reversal isn’t safe or feasible. This happens when the bowel hasn’t healed well enough, when too much intestine has been removed to allow a reconnection, when the anal sphincter muscles are too weak (which would mean severe incontinence after reversal), when a patient’s overall health is too fragile for another major abdominal operation, or when the original disease has come back. Of the roughly 800,000 to 1 million Americans living with a stoma, an estimated 160,000 to 360,000 have a permanent colostomy. Those numbers are projected to grow over the next decade as the population ages and colorectal cancer rates shift.
Other Reasons for Stoma Surgery
Beyond the major categories, several less common situations can lead to a stoma. Bowel obstructions caused by scar tissue from previous surgeries, advanced cancers pressing on the intestine, or adhesions can block the passage of stool entirely. A stoma bypasses the blockage. Nerve damage to the rectum or anus from surgery, injury, or neurological disease can also leave a person unable to control bowel movements, making a colostomy a more manageable option than chronic, severe incontinence.