A partial colectomy is surgery to remove a diseased or damaged section of the colon while leaving the healthy portions intact. The remaining ends of the colon are then reconnected so your digestive system can continue functioning. It’s one of the most common abdominal surgeries, performed for conditions ranging from colon cancer to severe diverticulitis, and most people return to normal bowel function afterward.
Types of Partial Colectomy
Your colon is roughly five feet long and shaped like an inverted U. It has four main segments: the ascending colon (right side), the transverse colon (top), the descending colon (left side), and the sigmoid colon (the S-shaped curve that connects to the rectum). Which segment is removed determines the name of the procedure.
A right hemicolectomy removes the ascending colon on the right side. It sometimes includes the very end of the small intestine and the beginning of the transverse colon. The remaining colon is reconnected directly to the small intestine.
A left hemicolectomy removes the descending colon on the left side, typically from the middle of the transverse colon down through the descending colon. The remaining right side of the colon is reconnected to the sigmoid colon or upper rectum.
A sigmoidectomy removes the sigmoid colon, that curved portion just above the rectum. This is the most common type for diverticulitis, since the sigmoid is where diverticula most often form.
A segmental resection removes only a short, isolated segment of diseased colon rather than an entire anatomical section. This is used when the problem is confined to a small area.
Why It’s Performed
Colon cancer is the most frequent reason for a partial colectomy. Removing the cancerous segment along with a margin of healthy tissue and nearby lymph nodes gives the best chance of eliminating the disease. Diverticulitis, particularly when it causes repeated flare-ups, abscesses, or perforations, is the second most common reason. Inflammatory bowel disease (Crohn’s disease or ulcerative colitis) can also require removal of badly inflamed or strictured segments. Less commonly, the surgery is performed for large precancerous polyps that can’t be removed during a colonoscopy, bowel obstructions, or traumatic injuries to the colon.
Open, Laparoscopic, and Robotic Approaches
The surgery itself can be performed three ways. In an open colectomy, the surgeon makes a single larger incision in the abdomen. In a laparoscopic colectomy, several small incisions allow the surgeon to work with a camera and specialized instruments. Robotic surgery is similar to laparoscopic but uses a robotic system that the surgeon controls from a console.
Laparoscopic and robotic approaches generally mean less post-surgical pain and a slightly faster return to normal activity, though hospital stays are similar. A large analysis of over 4,300 patients found no meaningful difference between robotic and laparoscopic surgery in hospital stay, time to eating solid food, or time for bowel function to resume. However, robotic procedures were about 1.8 times more likely to be converted to an open surgery mid-operation, typically because of limited visibility or technical difficulty. Your surgeon will recommend the approach based on the location and complexity of your specific case.
What Happens Before Surgery
Preparation varies by surgeon and institution. Traditionally, patients were asked to drink a bowel prep solution (similar to colonoscopy prep) the day before surgery to clean out the colon. However, current evidence does not show a clear benefit to mechanical bowel preparation before elective colorectal surgery, and an increasing number of surgical organizations now recommend against routine use. Some surgeons still prescribe it, while others skip it entirely. You will receive intravenous antibiotics before the operation to reduce infection risk. You’ll also be asked to stop eating and drinking at a specific time the night before.
Hospital Stay and Early Recovery
The average hospital stay after a partial colectomy is 3 to 4 days, assuming no complications. During that time, your medical team will monitor for signs that your bowel is “waking up,” the clearest signal being the ability to pass gas. Until that happens, you won’t be eating solid food.
Diet comes back in stages. You’ll start with clear fluids like water, broth, and weak tea. Once tolerated, you’ll move to thicker liquids like juice and milky drinks. The next step is a light diet of small portions of soft, low-fiber foods: things like white bread, eggs, well-cooked vegetables, and tender chicken. This temporary light diet lets your bowel adjust to digesting food again. Over the following weeks, you’ll gradually return to a normal diet.
Full recovery at home typically takes 4 to 6 weeks for laparoscopic surgery and somewhat longer for open surgery. During this time you’ll be advised to avoid heavy lifting and strenuous activity while the internal reconnection site heals.
Risks and Complications
The reconnection point where the two ends of the colon are joined is called an anastomosis, and the most serious specific risk of this surgery is a leak at that site. Leak rates depend heavily on where in the colon the connection is made. Right-sided connections (where the small intestine meets the remaining colon) have the lowest risk, in the range of 1 to 3%. Left-sided colorectal connections carry higher risk, reported anywhere from 0.5 to 18% depending on how low in the pelvis the connection sits. One large study found that right-sided colectomies for cancer had a leak rate of about 1.4%, compared to 5.2% for left-sided procedures.
A leak can cause fever, increasing abdominal pain, and rapid heart rate in the days after surgery, and it sometimes requires a return to the operating room. Other possible complications include surgical site infection, blood clots, bleeding, and temporary bowel obstruction from post-surgical swelling.
When a Stoma Is Needed
In most planned partial colectomies, the surgeon reconnects the bowel immediately and no stoma (an opening in the abdomen for waste to pass into a bag) is needed. But in certain situations, particularly emergency surgery for an obstructed or perforated colon, a temporary stoma may be created to allow the reconnection site to heal without stool passing through it.
The plan is usually to reverse a temporary stoma in a second surgery several months later. However, reversal doesn’t always happen. Studies of patients who had left-sided obstructive colon cancer resections found that 10 to 30% of temporary stomas become permanent, often because of the patient’s overall health, cancer progression, or complications that make reversal surgery too risky. If a stoma is a possibility in your case, your surgeon will discuss this before the operation.
Long-Term Bowel Function
Most people worry about permanent changes to their digestion, but the research is reassuring. A study tracking patients at a median of 16 months after colectomy for colon cancer found that overall bowel function scores did not significantly change compared to before surgery. In fact, stool-related symptoms like pain during bowel movements, bleeding, and anal skin irritation actually improved over time.
In the first few months, it’s common to have more frequent or looser stools than you’re used to, particularly after a right hemicolectomy, since the right colon is responsible for absorbing water. This usually improves as the remaining colon adapts. Some people settle into a pattern of one or two extra bowel movements per day compared to their pre-surgery baseline, while others notice no lasting change at all. Eating smaller, more frequent meals and avoiding very high-fiber or greasy foods in the early months can help your system adjust more comfortably.