Subtotal Colectomy

What is a subtotal colectomy?

A subtotal colectomy (sometimes called a total abdominal colectomy) is an operation to remove most or all of your large bowel (the colon), from where the small bowel meets it all the way to the sigmoid colon or upper rectum. Importantly, the rectum — the last section of bowel that leads to the back passage — is usually left in place. Once the colon is removed, there are two main options for how the remaining bowel is managed:

• An ileorectal anastomosis (IRA) — the end of your small bowel (ileum) is joined directly to the rectum. This restores a normal route for your bowel motions and means you do not need a stoma (bag). This is the preferred choice when the rectum is healthy and working well.
• An end ileostomy — the end of the small bowel is brought out through a small opening in your tummy and connects to a discreet bag. The remaining rectal stump is either stitched shut inside (called a Hartmann's procedure) or, occasionally, brought to the skin as a mucous fistula (a very small opening that produces a small amount of mucus). This is the safer option in emergencies, or when the rectum is too inflamed or diseased to join safely.

Which option is right for you depends on several things — how urgent the surgery is, what your rectum looks like and how well it functions, your overall health and personal preferences, and what condition is being treated. Mr Nguyen will talk through all of these with you before the operation.

Who needs this operation?

This is a significant operation, recommended when a large portion of the colon needs to be removed. Common reasons include:

• Ulcerative colitis (UC) — a form of inflammatory bowel disease that causes the inner lining of the large bowel to become inflamed and ulcerated. If UC flares severely and stops responding to even strong medications (steroids, biologics), surgery may become urgent or necessary. In planned (elective) UC surgery, the colectomy is usually the first step — the rectum can be removed and an internal pouch (called an IPAA or J-pouch) created at a later stage if you wish.
• Familial adenomatous polyposis (FAP) — an inherited condition that causes hundreds or thousands of polyps (growths) to develop in the colon. Because the cancer risk from so many polyps is very high, the colon needs to be removed — this is done to prevent cancer from developing in the first place.
• Two or more bowel cancers at separate sites (synchronous cancers) — in this situation, removing each area individually could leave too little bowel remaining, or the cancer risk in the bowel left behind would be unacceptably high
• Emergency bowel blockage — if a cancer or a narrowing (stricture) from diverticular disease has completely blocked the large bowel and it is very distended, removing the whole colon can be safer than trying to join two ends of an unprepared, swollen bowel
• Complicated diverticular disease — for example, if a pocket in the bowel wall has burst and caused widespread infection in the abdomen (peritonitis), or if the disease affects many segments of the colon
• Colonic volvulus — where the bowel twists on itself and the blood supply is cut off; if the whole colon is affected and the tissue is not viable, it needs to be removed
• Severe slow-transit constipation — in very rare cases where constipation is extreme and has not responded to any medication or conservative treatment, a subtotal colectomy with ileorectal anastomosis is a last-resort surgical option

How is it performed?

You will be completely asleep under general anaesthesia throughout — you will not feel anything. The operation typically takes 2.5–4 hours. In planned (elective) cases, Mr Nguyen performs this using a keyhole (laparoscopic) or robotic approach. In emergencies, an open or hand-assisted technique may be needed to work more quickly and safely.

Planned surgery — keyhole (laparoscopic or robotic) approach

Four to six small ports are placed in your tummy. Using a camera and fine instruments, Mr Nguyen carefully separates the entire colon from its attachments. The blood vessels feeding the colon are divided, and the colon is removed through a small protected incision — usually a short cut in the midline or along the bikini line (a Pfannenstiel incision). If an ileorectal anastomosis is being performed, the end of your small bowel is then joined to the rectum using a circular stapler.

Emergency surgery

When surgery is urgent — for example, during a severe flare of colitis or because of an acute bowel blockage — Mr Nguyen's priority is to remove the diseased colon as safely and efficiently as possible. In these circumstances, joining the bowel immediately would carry too high a risk of the join leaking, especially in a patient who is unwell or malnourished. So an end ileostomy is almost always the safer choice. The rectal stump is either stitched closed inside (a Hartmann's procedure) or, occasionally, brought to the surface as a small mucous fistula. Both options can be dealt with in a further planned operation once you have recovered.

What happens after an emergency colectomy — future surgery options

If you have had an emergency subtotal colectomy and ileostomy — particularly for ulcerative colitis — there are usually further surgical options once you have recovered, your medications (especially steroids) have been reduced, and your nutrition is back on track. These options include:

• Ileal pouch–anal anastomosis (IPAA) — also called a J-pouch. The terminal ileum is shaped into a small internal reservoir (the "pouch"), the rectal lining is removed, and the pouch is joined to the anal canal. This means you can pass stools in the normal way without a permanent bag. It is the most popular option for people with ulcerative colitis who want to avoid a permanent stoma.
• Completion proctectomy with end ileostomy — the rectum is removed and the ileostomy becomes permanent. This is the right choice for those who do not want or are not medically suitable for a pouch.
• Ileorectal anastomosis — if the rectum is healthy and has little or no disease, the small bowel can be joined to it directly, and the ileostomy closed. This avoids a permanent bag and is simpler than a pouch, though the rectum remains and needs regular monitoring.

Before the operation

For planned (elective) surgery:

• A CT scan and, if not already done, a colonoscopy with biopsies to confirm your diagnosis and plan the operation
• A nutrition assessment — if you have been unwell for a while, making sure your nutrition is as good as possible before surgery helps your body heal. Any anaemia (low iron) will also be addressed.
• If you take immunosuppressant tablets or biologic injections (such as infliximab or adalimumab), Mr Nguyen will work with your gastroenterologist on timing around surgery; steroid doses are reduced as much as safely possible beforehand
• If an ileostomy is planned, a stomal therapy nurse will visit before your operation to mark the best position for the stoma opening on your tummy — the site is chosen carefully to suit your body shape and lifestyle
• A discussion about ERAS (the enhanced recovery program) and steps to prevent blood clots after surgery

For emergency surgery:

• IV fluids to rehydrate you and correct any salt imbalances in your blood
• IV antibiotics and, if you have been taking long-term steroids, a steroid "stress dose" to protect your body during the operation
• Urgent assessment by Mr Nguyen and the team to prepare for theatre as quickly as safely possible

What to expect on the day

• You will be put fully to sleep under general anaesthesia — you will not feel or be aware of anything. The operation takes 2.5–4 hours; emergency cases or those with significant scar tissue from previous operations may take longer.
• You will wake up with a urinary catheter (a thin tube draining your bladder — you won't feel it), a drip, and pain relief already running. Pain control may include an epidural (pain-numbing medication fed into your back) or a PCA (a patient-controlled pump that lets you give yourself small doses of pain relief by pressing a button).
• If an ileostomy has been formed, a stomal therapy nurse will visit you on day 1 or 2 to introduce you to the stoma, show you how to manage it, and answer any questions you have.
• Small amounts of fluid and then food are usually introduced from day 1–2 if you are following the ERAS pathway for planned surgery. In emergency cases, this timeline may be longer depending on how you are feeling.

Recovery

Planned (elective) surgery — in hospital (4–7 days): Your diet builds up gradually over 2–3 days, from clear fluids to normal food. Your bowel (or your ileostomy) usually starts working within 2–4 days. The urinary catheter is typically removed on day 2–3. Most patients go home when they are eating, managing their pain with tablets, and comfortable looking after themselves (or their ileostomy).

Emergency surgery: Your hospital stay will be longer — how long depends on how unwell you were before and how quickly your body recovers. A short stay in intensive care or a high-dependency unit (HDU) may be needed at first, and that is completely normal after major emergency surgery.

At home (after planned surgery):

• If your bowel was rejoined (ileorectal anastomosis): Expect 3–6 bowel motions per day at first, possibly with some urgency or clustering (needing to go several times in a short period). This is your small bowel adapting to its new role — it will settle. A low-residue diet (easy-to-digest foods) helps in the first few weeks; fibre and variety are gradually reintroduced. Staying well hydrated is very important.
• If you have an ileostomy: In the first 4–8 weeks, the ileostomy tends to be "high output" — producing up to 1.5–2 litres of liquid per day, which can feel alarming at first. This is normal. Drinking enough fluid and replacing salts (electrolytes) is essential during this period. Output reduces significantly as the weeks pass and the small bowel adapts. The stomal therapy team will support you closely throughout.
• Returning to normal activities: For planned surgery, most people feel well enough to manage most daily activities at 6–8 weeks. Recovery after emergency surgery generally takes longer — listen to your body and don't rush it.
• A post-operative review with Mr Nguyen is routinely arranged 2–6 weeks following your procedure, with timing depending on the type of operation — this review is provided at no charge

If your surgery was for cancer, Mr Nguyen will arrange regular follow-up appointments — usually at least every six months — including clinic visits, blood tests, imaging, and camera tests (colonoscopy or flexible sigmoidoscopy) at set intervals. This ongoing monitoring is important and gives you the best chance of catching anything early.

Risks and complications

This is a major operation and it's important you understand the risks — but please also know that serious complications are much less common than people fear, and the team takes many active steps to prevent them.

Common

• Frequent bowel motions — your small bowel needs time to adapt to its new role. Higher frequency and some urgency are expected in the early months and improve significantly over time.
• Dehydration and low salt levels — particularly in the first weeks if you have a high-output ileostomy. Drinking enough fluid and using oral rehydration sachets (available from chemists) is essential. The stomal therapy nurse will guide you on this.
• Wound infection — managed with antibiotics or local wound care; rarely anything serious
• Temporary bowel slowdown (ileus) — the bowel "goes quiet" for a few days after surgery before starting to work again; very common and usually settles with fluids and gentle movement

Less common

• Anastomotic leak — the join between your small bowel and rectum does not seal properly; this occurs in approximately 3–5 in 100 cases. The risk is higher in patients who are on high-dose steroids or immunosuppressants, or who are malnourished at the time of surgery — which is why preparation matters. If a leak occurs, you may need further treatment and a temporary ileostomy.
• Vitamin B12 deficiency — B12 is absorbed specifically in the last part of the small bowel (the terminal ileum). A subtotal colectomy preserves the small bowel, so B12 absorption is unaffected in most cases. However, if you have Crohn's disease that has also affected the terminal ileum, or if that section was involved in the surgery, B12 absorption may be reduced. A blood test will monitor this after surgery, and some people need a B12 injection every 3 months on an ongoing basis — a simple and effective solution.
• Bowel blockage from scar tissue (adhesions) — all abdominal surgery carries a small lifetime risk of internal scar tissue causing a blockage later; keyhole surgery is associated with lower adhesion rates than open surgery
• Blood clots (DVT or PE) — you will be given compression stockings and blood-thinning injections, and encouraged to move early, all of which significantly reduce this risk
• Bladder or sexual function changes — less common than after rectal surgery, but possible if the surgery involves any work close to the pelvis

Longer-term considerations (if your rectum is kept)

• Cancer or pre-cancerous changes in the rectum — if you have FAP or ulcerative colitis and keep your rectum, the risk of cancer developing there remains. This is why regular flexible sigmoidoscopy (a camera check of the rectum) — usually every year — is an essential part of your long-term care. The team will arrange this for you.
• Pouch-related problems — if you have a J-pouch constructed later, a small number of pouches develop complications or fail over time, potentially requiring a permanent ileostomy. Mr Nguyen will discuss this risk fully before any pouch surgery.

Frequently asked questions

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