Colorectal Surgery

Each disease with the image that defines it: what it looks like, what the scan shows, and which operation answers it.

Colorectal cancer

The specialty's central disease, operated on embryological planes.

The disease

Adenoma to carcinoma over years, which is why screening works: find the polyp before it is a cancer, or the cancer before it has left the wall.

Presentation

Right-sided tumours bleed silently into a capacious colon and present as anaemia; left-sided and rectal tumours obstruct and bleed visibly; and a fifth arrive as emergencies, obstructed or perforated.

Staging

Colonoscopy for tissue, CT chest-abdomen-pelvis for spread, MRI for the rectum's margins, CEA as a baseline: the MDT reads all four before anyone books a theatre.

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The operations

Right hemicolectomy for the right colon, anterior resection with total mesorectal excision for the rectum: each removes the cancer inside its intact mesenteric envelope with its draining nodes, because the envelope is the oncology.

Rectal cancer's extra layer

The mesorectal margin on MRI decides whether radiotherapy shrinks the tumour first, and height above the sphincters decides whether the join is possible or the operation ends in a permanent stoma.

After

The anastomotic days (five to seven) are the watch; the pathology staging decides adjuvant chemotherapy; and surveillance hunts the metachronous polyp and the liver.

Right hemicolectomyLow anterior resection with TMECase: Six weeks of constipation, then nothing at all Case: Bright red bleeding, and a low tumour

Endoscopy

• Diverticular disease

  Pockets of pressure, and what happens when one bursts.

  Pathophysiology

  High intraluminal pressure herniates mucosa through the sigmoid's muscular gaps where vessels pierce the wall: diverticula are hernias of the bowel wall, common with age and low-fibre diets.

  The spectrum

  Most diverticula stay silent. Diverticulitis inflames them; the complicated forms are abscess, fistula (to bladder, classically), stricture and free perforation.

  Graded treatment

  Uncomplicated: antibiotics, sometimes not even those. Abscess: percutaneous drain. Purulent or faeculent peritonitis: theatre, usually Hartmann's. The CT grade maps almost directly to the plan.

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  The elective question

  Recurrent attacks no longer buy an automatic colectomy: elective resection is now a judgement about frequency, complications, immunosuppression and the patient's life, made in clinic rather than by rule.

  Hartmann's procedureCase: Sudden pain, silent abdomen

• Inflammatory bowel disease

  Two diseases, one shared emergency, and surgery as part of the plan rather than its failure.

  Two patterns

  Ulcerative colitis inflames the colonic mucosa continuously from the rectum up; Crohn's disease inflames any gut segment, full thickness, with skips, strictures and fistulas. The distinction drives every surgical decision.

  Where surgery enters

  For colitis: the acute severe attack failing medical rescue, dysplasia, or disease that steroids cannot leave. For Crohn's: strictures, fistulas and abscesses, operated sparingly because the disease recurs and bowel is a finite resource.

  The acute severe attack

  Intravenous steroids with a decision at day three: rescue therapy or subtotal colectomy. The operative timing is a joint custody arrangement with gastroenterology, and delay is the classic error.

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  Operating principles

  In colitis, subtotal colectomy first and reconstruction (pouch) later; in Crohn's, resect short, spare bowel, and treat the disease medically around the operations. Nutrition and steroid exposure shape every anastomotic decision.

  Small bowel resection & anastomosisCase: Ten bloody stools a day

• Perianal sepsis & fistula

  An anatomy lesson taught in pus.

  Origin

  The anal glands at the dentate line get obstructed and infected; pus tracks along the path of least resistance into the perianal, ischiorectal or higher spaces. The cryptoglandular theory explains both abscess and fistula.

  The acute presentation

  Throbbing pain, a hot swelling, fever: examination sometimes shows little in the deeper abscesses, which is why severe perianal pain with fever earns an examination under anaesthesia.

  Treatment

  Incision and drainage, promptly: antibiotics alone are for cellulitis without collection or as cover, not as a substitute. The immunosuppressed and diabetic move to the front of the list.

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  The fistula that follows

  A third to a half develop a fistula-in-ano. Its treatment is a truce between healing and continence: low tracts can be laid open, high tracts get setons and staged surgery, because the sphincter is spent only once.

  EUA and drainage of perianal sepsisCase: Three days of perianal pain