Anorectal Stricture

DEFINITION
Narrowing in anal canal; from pelvic floor to anal verge distally.

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EPIDEMIOLOGY

Vast majority are iatrogenic

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AETIOLOGY

Pathogenesis

Iatrogenic

Eg. during haemorrhoidectomy; if too much anoderm excised, leads to stricture.
Also with fistulae, fissure, anal warts, congenital defects, ileal pouch-anal anastomoses

Tumours

Bowen; Paget
Giant conduloma acuminatum
SCC anus
Verrucous Ca
Rectal AdenoCa


Inflammatory
Post Radiation
TB
STDs
IBD

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BIOLOGICAL BEHAVIOUR

Pathophysiology

Varies by causes above

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MANIFESTATIONS

Symptoms


'Constipation'
Decrease in stool caliber
Difficult or incomplete evacuation
Some may have incontinence

Signs

Observation and exam confirms stricture
Mild = tight but still allows DRE
Moderate = requires forceful DRE only achievable under anaesthetic
Severe = does not even allow DRE under anaesthetic.

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INVESTIGATIONS

Biopsy to rule out malignancy if reqd

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MANAGEMENT

Pts will have tried laxatives, enemas and suppositories
Offer therapy to all.

1. EUA
Under anaesthetic to rule out stricture

2. Principles
Treat stricture but preserve continence
- warn all that they may become incontinent.
Treat asymptomatic only if serious underlying cause eg neoplasia.

3. Mild
Stool bulking agents
--> naturally dilating action of stool passage
And possibly dilatation.
- though repeated use can cause additional scarring and stricture
--> thus generally limit to patients who fail conservative Rx, are not good operative candidates and have IBD or pelvic radiation.
Often will resolve after some months.

4. Stricturotomy and Stricturoplasty
Effective in mild to moderate disease
E.g. past low coloanal anastomoses, ileal-anal pouch or stapled haemorrhoidectomy.
1. Small anoscope to visualize stricture
2. Divide stricture longitudinally in 3-4 quadrants
- leave open
Highly successful for short mild strictures.
- if fails, move to advancement flaps.

5. Advancement Flaps
Scar excision followed by advancing normal local tissue onto the defect.
Principles are adequate blood supply and adequate mobilization (no tension)
Lone Star retractor.
Bowel prep, antibiotics, prone jack-knife for best exposure.
YV and VY flaps
House Flap
- best option; ~90% improvement rate, 80% satisfaction
image
S Flap
 
Major flap for severe / complex cases; plastics

IBD or Post Rads
Surgical options limited by potential for non-healing wound
Bulking, anal dilatation and stricturotomy are mainstays
Specialists can do advancement flaps in complex cases, but if non-healing will require a permanent colostomy.


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REFERENCES
Cameron 10th