Surgery chapters
Large intestine: large bowel cancer, diverticular disease and volvulus
Polyps and polyposis syndromes, colon cancer (spread, staging, operations by site, emergencies, follow-up), diverticular disease with the Hinchey grades, sigmoid and caecal volvulus, pseudo-obstruction, angiodysplasia and ischaemic colitis.
- Large bowel cancer arises from adenomas (APC → KRAS → p53); left-sided tumours bleed and obstruct, right-sided ones cause iron-deficiency anaemia and a mass. Staging (Dukes/TNM) and lymph node status decide prognosis and adjuvant chemotherapy.
- Diverticular disease is sigmoid, acquired (no muscle coat) and graded by Hinchey I–IV; emergency surgery for perforation is usually Hartmann's.
- Sigmoid volvulus (elderly, constipated): huge "coffee bean" loop; first-line endoscopic decompression with a flatus tube, then consider elective resection.
On this page
Overview
The large intestine runs from the ileocaecal valve to the anus, about 1.5 m long. Its main job is to absorb water and sodium. Surgically it matters for:
- Large bowel cancer, one of the commonest cancers worldwide, and usually preceded by an adenoma.
- Diverticular disease, with its complications (abscess, perforation, fistula, bleeding).
- Volvulus and other causes of large bowel obstruction.
- Bleeding from angiodysplasia and ischaemic colitis.
The rectum is covered in its own chapter; this chapter focuses on the colon.
Applied anatomy
- Superior mesenteric artery supplies the caecum to the distal transverse colon (midgut); inferior mesenteric artery supplies the rest (hindgut).
- Branches join along the colon as the marginal artery (of Drummond).
- The splenic flexure is a watershed between SMA and IMA territories → most prone to ischaemia.
- Colon is recognised by taeniae coli (three bands), haustra and appendices epiploicae (fatty tags).
- Midgut pain is felt around the umbilicus; hindgut pain is suprapubic.
- At right colon surgery protect the right ureter, gonadal vessels and duodenum; on the left, the left ureter, gonadal vessels and tail of pancreas.
Polyps
| Type | Examples | Cancer risk |
|---|---|---|
| Inflammatory | Pseudopolyps of ulcerative colitis | None |
| Hyperplastic (metaplastic) | Small, rectosigmoid | Very low |
| Hamartomatous | Peutz–Jeghers, juvenile polyp (child with painless rectal bleeding) | Low in the polyp itself |
| Neoplastic (adenoma) | Tubular, tubulovillous, villous | Rises with size, villous pattern and dysplasia |
- Risk is about 10% in a 1 cm tubular adenoma; nearly one-third of adenomas over 3 cm already contain cancer.
- Villous adenomas are flat and sessile; they may secrete large amounts of mucus causing hypokalaemia and low protein.
- Adenomas are removed at colonoscopy (snare polypectomy or endoscopic mucosal resection).
The polyp with the highest malignant potential is a large, sessile, villous adenoma with high-grade dysplasia.
Inherited syndromes
| Feature | FAP | Lynch syndrome (HNPCC) |
|---|---|---|
| Gene | APC, chromosome 5q | DNA mismatch repair (MLH1, MSH2): microsatellite instability |
| Inheritance | Autosomal dominant | Autosomal dominant |
| Bowel | Over 100 adenomas; cancer risk 100% if untreated | Few polyps; cancer often right-sided, at a young age |
| Other | Duodenal/ampullary adenomas, desmoid tumours, osteomas, epidermoid cysts (Gardner), CHRPE | Endometrial, ovarian, gastric, small bowel and urinary tract cancers |
| Management | Prophylactic colectomy (late teens): ileorectal anastomosis or restorative proctocolectomy with ileal pouch; upper GI surveillance | Regular colonoscopy |
Amsterdam II criteria for Lynch (the "3-2-1" rule): three relatives with a Lynch-type cancer (one of them being a parent, sibling or child of the other two), two successive generations, one diagnosed under 50, and FAP excluded.
3-2-1 for Amsterdam: 3 relatives, 2 generations, 1 under 50.
Large bowel cancer
Causes and pathology
- Adenoma–carcinoma sequence: APC loss (early) → KRAS activation → p53 loss (invasion).
- Risks: age, red and processed meat, low fibre, smoking, alcohol, obesity, ulcerative colitis or Crohn colitis, FAP, Lynch, previous adenoma or cancer, family history.
- Nearly all are adenocarcinomas.
- Site: most are left-sided: rectum most common, then sigmoid; caecum is the commonest right-sided site.
- Shapes: annular (obstructs), ulcerating, cauliflower (polypoid), tubular.
- Synchronous second cancers occur in about 3–5%.
Spread
- Direct: along and through the wall into nearby organs.
- Lymphatic: along nodes that follow the arteries; hence the high tie of the feeding artery in cancer surgery.
- Blood: mainly to the liver via the portal vein, then lung.
- Transcoelomic: peritoneum, ovaries (Krukenberg-type deposits), omentum.
Clinical features
| Right colon (caecum, ascending) | Left colon (descending, sigmoid) |
|---|---|
| Iron-deficiency anaemia, tiredness | Change in bowel habit |
| Mass in right iliac fossa | Rectal bleeding, mucus |
| Weight loss; presents late | Obstruction (narrow lumen, solid stool, annular tumours) |
About one in five present as an emergency (obstruction, perforation or bleeding), with a worse outcome.
An older adult with unexplained iron-deficiency anaemia needs the colon examined (especially the caecum), even with no bowel symptoms.
Investigations
- Colonoscopy with biopsy: test of choice; also finds synchronous lesions.
- CT colonography if colonoscopy is unsuitable; barium enema (old) shows an "apple-core" stricture.
- Staging: CT chest, abdomen and pelvis. MRI pelvis for rectal cancer.
- CEA: baseline before surgery; mainly used in follow-up to detect recurrence, not for screening or diagnosis.
- Screening: faecal occult blood (or faecal immunochemical) test followed by colonoscopy; flexible sigmoidoscopy is an alternative.
Staging
| Dukes | Meaning | TNM equivalent |
|---|---|---|
| A | Within the wall, not through the muscularis propria | T1–T2, N0 |
| B | Through the muscularis propria, nodes clear | T3–T4, N0 |
| C | Lymph nodes involved | Any T, N1–N2 |
| (D) | Distant metastases (not in Dukes' original system) | M1 |
TNM: T1 submucosa; T2 muscularis propria; T3 into pericolic fat; T4 through serosa or into another organ. N1 = 1–3 nodes; N2 = 4 or more.
Operations by tumour site
| Tumour site | Operation | Main artery tied |
|---|---|---|
| Caecum, ascending colon | Right hemicolectomy | Ileocolic (and right colic) |
| Hepatic flexure | Extended right hemicolectomy | Plus right branch of middle colic |
| Transverse colon, splenic flexure | Extended right hemicolectomy (or left hemicolectomy for splenic flexure) | Middle colic |
| Descending colon, sigmoid | Left hemicolectomy / sigmoid colectomy | Inferior mesenteric (high tie) |
- Laparoscopic surgery gives the same cancer results as open surgery, with less pain and faster recovery; tattoo small tumours at colonoscopy.
- Anastomotic leak (about 4–8% for colonic anastomoses) usually shows in the first postoperative week with fever, tachycardia, pain, or just "not progressing"; CT confirms it.
Emergency presentation
- Right-sided obstruction: emergency right hemicolectomy with primary anastomosis if the patient is stable.
- Left-sided obstruction: options are Hartmann's procedure (resection, end colostomy, closed rectal stump), resection with on-table lavage and anastomosis, or a self-expanding metal stent (palliation, or bridge to surgery in high-risk patients).
- With a competent ileocaecal valve, a distal cancer creates a closed loop: the caecum, being widest, has the highest wall tension (law of Laplace) and perforates first. Tenderness in the right iliac fossa is a warning sign.
In large bowel obstruction always exclude pseudo-obstruction with CT or a water-soluble contrast enema before operating.
Adjuvant treatment and prognosis
- Adjuvant chemotherapy is given for node-positive (Dukes C) disease and high-risk node-negative disease.
- Resectable liver metastases can be removed with useful long-term survival; do not biopsy resectable liver deposits (risk of seeding).
- Overall 5-year survival is roughly 50%: Dukes A over 90%, B about 60–70%, C about 30%, metastatic disease under 10%.
- Lymph node status is the strongest single predictor of survival.
- Follow-up: CEA, CT of liver and surveillance colonoscopy (metachronous cancers occur in about 3%).
Diverticular disease
- Diverticulosis: pouches present, no symptoms. Diverticular disease: symptoms. Diverticulitis: inflamed.
- Acquired, false diverticula: mucosa pushes through the circular muscle where blood vessels enter, between the taeniae. No muscle coat (unlike Meckel).
- Cause: low-fibre diet, high pressure in the narrow sigmoid, ageing collagen. Sigmoid is the usual site in the West; right-sided disease is commoner in South-East Asia.
- The rectum is spared (complete muscle coat, wide lumen).
Complications
- Diverticulitis: left iliac fossa pain, fever, tenderness; "left-sided appendicitis".
- Abscess (pericolic or pelvic).
- Perforation → purulent or faecal peritonitis.
- Obstruction (fibrotic stricture, or small bowel stuck to the inflamed loop).
- Haemorrhage: sudden, painless, often heavy bright red bleeding in the elderly.
- Fistula: colovesical commonest → recurrent UTI, pneumaturia, faecaluria; colovaginal after hysterectomy.
Hinchey classification
| Grade | Finding | Usual treatment |
|---|---|---|
| I | Pericolic or mesenteric abscess | Antibiotics; drain if large |
| II | Pelvic (distant) abscess | Percutaneous CT-guided drainage |
| III | Purulent peritonitis | Laparotomy (or laparoscopic washout in selected cases) |
| IV | Faecal peritonitis | Laparotomy, Hartmann's procedure |
Hinchey goes near, far, pus, poo.
Management
- CT abdomen confirms diverticulitis and shows abscess or perforation.
- Uncomplicated: analgesia, fluids, antibiotics covering Gram-negatives and anaerobes.
- Abscesses over about 5 cm usually need drainage.
- Avoid colonoscopy and contrast enema for about 6 weeks after an acute attack (risk of perforation); then examine the colon to exclude cancer.
- Emergency surgery for generalised peritonitis or failure to improve: Hartmann's procedure is the safe standard; primary anastomosis in selected fit patients.
- Fistulas need resection of the diseased sigmoid. Elective resection for recurrent attacks is decided case by case.
A stricture in the sigmoid after diverticulitis may hide a carcinoma; it must be examined once the attack settles.
Volvulus and pseudo-obstruction
Volvulus = a twist of bowel on its mesentery. Over 180° blocks the lumen; tighter twists cut the blood supply.
| Feature | Sigmoid volvulus | Caecal volvulus |
|---|---|---|
| Who | Elderly, chronic constipation, psychiatric or neurological illness, institutionalised; also high-fibre diets (Africa, South Asia) | Younger adults, often women; mobile caecum |
| Predisposition | Long sigmoid mesocolon with a narrow base, loaded colon | Failure of caecal fixation |
| Direction | Usually anticlockwise | Usually clockwise |
| X-ray | Massive "coffee bean" (bent inner tube) loop rising from the left iliac fossa toward the right upper quadrant | Dilated caecum displaced to the left upper quadrant or midline |
| Contrast | Bird's beak at the twist | Bird's beak |
| First treatment | Sigmoidoscopic (rigid or flexible) decompression and flatus tube left in about 24 hours | Surgery (right hemicolectomy if ischaemic; caecopexy if viable) |
| After | Elective sigmoid colectomy in fit patients (recurrence is common) | - |
- Gangrene, peritonitis or failed decompression → laparotomy: resection with Hartmann's or Paul–Mikulicz procedure.
- Ileosigmoid knotting (compound volvulus): the ileum wraps around the sigmoid; both may become gangrenous; needs resection.
Sigmoid volvulus is a major cause of large bowel obstruction in Africa and parts of South Asia; in the West carcinoma dominates.
Acute colonic pseudo-obstruction (Ogilvie syndrome)
- Massive colonic dilatation without a mechanical block.
- Causes: recent surgery (e.g. hip fracture, caesarean), trauma, sepsis, cardiac or neurological illness, hypokalaemia, uraemia, hypothyroidism, opioids, tricyclics, phenothiazines.
- Confirm no block with CT or water-soluble enema.
- Treat the cause (correct K+, stop drugs), then IV neostigmine with ECG monitoring and atropine available, then colonoscopic decompression.
- Perforation risk rises as the caecum widens: worry at about 12 cm, and the risk is high at 14 cm or more.
Bleeding and ischaemia
| Condition | Key facts |
|---|---|
| Angiodysplasia | Elderly; dilated submucosal veins, usually right colon; anaemia or brisk bleeds; linked to aortic stenosis (Heyde syndrome); found at colonoscopy or mesenteric angiography (needs bleeding over about 1 mL/min) or tagged red cell scan; treat with argon/endoscopic ablation; resection if it fails |
| Diverticular bleeding | Painless, heavy, often stops; angiography or colonoscopy to localise |
| Ischaemic colitis | Elderly vascular patient; pain then bloody diarrhoea; splenic flexure most often; "thumb-printing" on X-ray; most settle; gangrene needs resection; may heal with a stricture; also after aortic surgery when the IMA is tied |
Ulcerative colitis: surgical points
- Indications: acute severe colitis failing IV steroids (decide by about 3–5 days), toxic megacolon or perforation, chronic symptoms or steroid dependence, intolerable drug effects, dysplasia or cancer, severe bleeding.
- Emergency operation: subtotal colectomy with end ileostomy, leaving the rectal stump.
- Elective: restorative proctocolectomy with ileal pouch–anal anastomosis, or panproctocolectomy with permanent ileostomy.
Expect: adenoma–carcinoma sequence starting with APC; polyp with highest cancer risk (large villous adenoma) and its hypokalaemia; FAP versus Lynch genes and extracolonic features; right versus left colon cancer presentation; Dukes staging and node status as the key prognostic factor; CEA for follow-up; operations by tumour site and arteries tied; why the caecum perforates in closed-loop obstruction; Hinchey grades and Hartmann's procedure; colovesical fistula with pneumaturia; sigmoid volvulus coffee-bean sign and endoscopic decompression; Ogilvie syndrome and neostigmine; angiodysplasia with aortic stenosis; splenic flexure ischaemia.
Quick revision
- APC → KRAS → p53; FAP = APC, over 100 polyps; Lynch = mismatch repair, right colon, endometrium.
- Right colon cancer: anaemia, mass. Left: altered habit, bleeding, obstruction.
- Colonoscopy and biopsy; CT staging; CEA for follow-up.
- Dukes C = nodes = adjuvant chemotherapy.
- Caecal tumour: right hemicolectomy; sigmoid tumour: left hemicolectomy/sigmoid colectomy with IMA high tie.
- Hinchey IV (faecal peritonitis) → Hartmann's.
- Sigmoid volvulus: coffee bean from the left iliac fossa; flatus tube first.
- Ogilvie: no block; neostigmine; a caecum of 12–14 cm or more is dangerous.
- Angiodysplasia + aortic stenosis = Heyde. Ischaemic colitis = splenic flexure, thumb-printing.
Written by The House Job from standard references (Bailey & Love).
FAQ
Which large bowel polyp is most likely to become malignant?
A large, flat (sessile) villous adenoma, especially with high-grade dysplasia. Risk rises with size, villous pattern and degree of dysplasia.
What decides whether adjuvant chemotherapy is given after colon cancer surgery?
Mainly whether the lymph nodes contain cancer. Node-positive (Dukes C) disease is the main indication.
What is a Hartmann's procedure?
Resection of the sigmoid (or diseased segment) with an end colostomy and a closed rectal stump, without an anastomosis. It is the safe emergency choice for faecal peritonitis or obstruction in an unstable patient.
How is a sigmoid volvulus first treated?
If there are no signs of gangrene, the twist is decompressed through a sigmoidoscope and a flatus tube is left in place. A fit patient is then offered elective sigmoid colectomy because recurrence is common.
What is Ogilvie syndrome?
Acute dilatation of the colon with no mechanical obstruction, usually in very ill or postoperative patients. After correcting the cause, IV neostigmine or colonoscopic decompression is used.