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Haemorrhoids - Complete Surgery Exam Notes

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DEFINITION & ETYMOLOGY

Key point: Haemorrhoids are normal anatomical structures (anal cushions). Treatment is indicated ONLY when they become symptomatic.

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ANATOMY & PATHOPHYSIOLOGY

Normal Anal Cushions

• Three main haemorrhoidal complexes: left lateral, right anterior, right posterior
• These cushions form the submucosal component of the anal canal
• Function: aid in complete closure of the anal canal at rest and contribute to continence by protecting the sphincter

Internal vs External

Why Haemorrhoids Develop

1. Man's upright posture
2. Absence of valves in the portal venous system
3. Raised intra-abdominal pressure (constipation, straining, pregnancy)
4. Shearing forces during defecation → mucosal trauma → bleeding
5. Caudal displacement of anal cushions → prolapse → impaired venous drainage → local stasis → transudation of fluid (causing pruritus)
6. Fragmentation of supporting structures (normal ageing, accelerated in haemorrhoid patients) → loss of elasticity → cushions no longer retract after defecation

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CLASSIFICATION (DEGREES OF INTERNAL HAEMORRHOIDS)

• "Mixed haemorrhoids" = significant cutaneous component to the haemorrhoidal prolapse (external extension of internal haemorrhoids through repeated congestion and oedema)

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CLINICAL FEATURES

Symptoms

• Bleeding - the earliest symptom; characteristically:
  • Bright red, painless
  • Separate from the stool
  • Seen on the paper on wiping OR as a fresh splash in the pan
  • Rarely sufficient to cause anaemia (but must exclude other causes)
• Pruritus - due to mucus discharge (common)
• Mucus discharge
• Prolapse - lump at anal orifice (grades 2-4)
• Pain - uncommon with internal haemorrhoids; pain should alert to another diagnosis (e.g. anal fissure, thrombosis)

Important Rules

• Symptoms spontaneously come and go
• Always exclude other causes of rectal bleeding, especially colorectal malignancy
• Symptomless haemorrhoids should NOT be treated

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COMPLICATIONS

1. Strangulation and thrombosis - circumferential haemorrhoidal prolapse with impending mucosal necrosis
2. Ulceration
3. Gangrene
4. Portal pyaemia (systemic antibiotics reduce this risk)
5. Severe haemorrhage (usually in those with bleeding diathesis or on anticoagulants)

Thrombosed External Haemorrhoid (Perianal Haematoma)

• Anatomically related to the superficial/external haemorrhoidal plexus
• Presents as: sudden onset, olive-shaped, painful, blue subcutaneous swelling at the anal margin
• Usually due to straining at stool, coughing, or lifting
• Usually in a lateral region of the anal margin
• If patient presents within first 48 hours: clot can be evacuated under local anaesthesia
• If untreated: may resolve, suppurate, fibrose → cutaneous tag, OR burst with extrusion of clot
• In the majority of cases, resolution or fibrosis occurs

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DIFFERENTIAL DIAGNOSIS

• Anal fissure (painful bleeding)
• Rectal prolapse (circumferential vs radial in haemorrhoids)
• Perianal abscess / fistula
• Colorectal malignancy (must always be excluded)
• Skin tags (not true haemorrhoids - residua of thrombosed external haemorrhoid)
• Rectal polyp / prolapsing rectal mucosa

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INVESTIGATION

• Proctoscopy / anoscopy: direct visualisation, asking patient to strain
• Rigid/flexible sigmoidoscopy: exclude proximal cause of bleeding
• Colonoscopy: if malignancy suspected, older patients, anaemia
• Differentiate haemorrhoidal prolapse (radial folds) from full-thickness rectal prolapse (circumferential)

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MANAGEMENT

Step 1: Conservative (All Grades)

• Dietary fibre increase + stool softeners + bulking agents
• Adequate fluid intake
• Avoid straining at defecation
• Improve defecatory position
• Proprietary creams at night and before defecation
• Reassurance after full examination

Over 90% of haemorrhoids are managed by conservative methods; less than 10% require haemorrhoidectomy.

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Step 2: Office Procedures (Minimally Invasive)

1. Injection Sclerotherapy (1st degree, bleeding with little prolapse)

• Agent: 5% phenol in arachis oil, 3-5 mL per haemorrhoid
• Site: submucosa at the level of the upper anal canal (apex/pedicle of haemorrhoid), above dentate line
• Aim: sclerosis around supplying vessels
• Correct injection: mucosa swells with submucosal vessels visible
• Too superficial → mucosa turns white
• Too deep → no swelling
• Too low → pain (other structures e.g. prostate may be damaged if too deep → give antibiotics)
• Complications: 10% pain, mucosal ulceration, haematuria, haematospermia

2. Rubber Band Ligation (2nd & 3rd degree; prolapsing haemorrhoids)

• Most effective office technique
• Band placed 1-2 cm proximal to the dentate line (mucosa is insensate here)
• Rubber band strangulates tissue → ischaemia → scarring → prevents bleeding/prolapse
• Only 1-2 quadrants banded per visit (to reduce pain)
• Mechanism: occludes the feeding vessel of the haemorrhoid
• Complications:
  • Pain (25%) - usually if band placed too low; remove band immediately if severe pain
  • Urinary retention (~1%) - if internal sphincter accidentally included
  • Bleeding at 7-10 days post-ligation (when ligated pedicle necroses and sloughs) - usually self-limited
  • Necrotising infection (rare but life-threatening) - triad: severe pain + fever + urinary retention → exam under anaesthesia + debridement + broad-spectrum antibiotics

3. Infrared Photocoagulation (1st & 2nd degree; small haemorrhoids)

• Instrument applied to apex of each haemorrhoid to coagulate the underlying plexus
• All three quadrants can be treated in the same visit
• Not effective for large haemorrhoids or significant prolapse

4. Sclerotherapy (1st, 2nd, some 3rd degree)

• Injection of sclerosant (sodium tetradecyl sulfate or phenol)
• Into submucosa of haemorrhoidal complex via 25-gauge needle

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Step 3: Surgical Treatment (3rd & 4th degree; failed conservative/office procedures)

A. Milligan-Morgan Haemorrhoidectomy (Open Technique) - UK standard

• Patient: lithotomy or prone jack-knife position
• General or regional anaesthesia; preoperative enema
• Dilute adrenaline (1:300,000) injected into anoderm to reduce bleeding
• Artery forceps applied to skin-covered external components
• V-shaped incision through the skin (lateral to haemorrhoid)
• Dissection proceeds up the anal canal, exposing the lower border of the internal sphincter (which remains separate and intact)
• Transfixion ligature (strong Vicryl) applied to pedicle at apex
• Pile excised well distal to the ligature
• Wounds left open to heal by secondary intention
• Skin bridges preserved between each haemorrhoid (prevent stenosis)
• Parks technique: secondary haemorrhoids under bridges can be excised by submucosal dissection
• Order: posterior → left lateral → right anterior

B. Ferguson Haemorrhoidectomy (Closed Technique) - USA standard

• Identical excision of haemorrhoidal tissue
• Pedicle transfixed with 3/0 polyglactin suture
• Mucosal defect closed with continuous suture
• Associated with: decreased postoperative pain, faster wound healing, reduced risk of postoperative bleeding vs. open technique

C. PPH - Stapled Haemorrhoidopexy (Longo Procedure)

• Also called: Procedure for Prolapse and Haemorrhoids
• Uses a circular stapling device (PPH-03 stapler)
• Excises a cylinder of mucosa and submucosa above the dentate line + simultaneously staples mucosal ends together
• Effect: draws prolapsed haemorrhoids back up into the anal canal ("pexy")
• Advantages: less painful, quicker recovery
• Disadvantages:
  • Higher recurrence rates than conventional haemorrhoidectomy
  • External haemorrhoids may persist
  • Risk of serious morbidity: staple line dehiscence, infection, rectovaginal fistula
  • Tenesmus (mucosal stimulation by staples) - may require reoperation + staple removal

D. HAL - Haemorrhoidal Artery Ligation (Transanal Haemorrhoidal Dearterialization - THD)

• Doppler-guided ligation of feeding vessels
• With or without suture mucopexy
• Minimally invasive; promising early results

E. LigaSure Haemorrhoidectomy

• Bipolar electrocautery ligation
• Surgical method for excisional haemorrhoidectomy

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COMPLICATIONS OF HAEMORRHOIDECTOMY

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SPECIAL SITUATIONS

Haemorrhoids in Pregnancy

• Conservative management preferred
• Increase in fibre, fluids; topical agents
• Most resolve postpartum

Strangulated / Acutely Thrombosed Haemorrhoids

• Conservative: bed rest, cold saline compresses, adequate analgesia, laxatives, systemic antibiotics (reduce portal pyaemia risk)
• Resolution usually in 3-4 days
• Urgent haemorrhoidectomy possible but: great care to avoid later anal stenosis; distinction must be made from rectal prolapse

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HIGH-YIELD EXAM POINTS

1. Internal haemorrhoids lie at 3, 7, 11 o'clock (lithotomy position)
2. Earliest symptom = painless bright-red bleeding (separate from stool)
3. Pain = think another diagnosis (fissure, abscess, thrombosis)
4. Rubber band above dentate line = painless; below = severe pain
5. PPH = less pain + quicker recovery but higher recurrence
6. Milligan-Morgan = open (UK); Ferguson = closed (USA)
7. Thrombosed external haemorrhoid evacuated under LA if <48 hours
8. Necrotising infection after RBL: pain + fever + urinary retention = emergency
9. Whitehead deformity = complication of Whitehead (circumferential) haemorrhoidectomy
10. Symptomless haemorrhoids are NOT treated
11. Exclude colorectal malignancy before attributing bleeding to haemorrhoids

12. 90% managed conservatively; <10% need surgery

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Fissure-in-Ano - Complete Surgery Exam Notes

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DEFINITION

• Acute fissure = superficial tear of the distal anoderm
• Chronic fissure = present for >6-8 weeks; ulceration with heaped-up edges, exposed internal sphincter fibres, sentinel tag, and hypertrophied anal papilla

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AETIOLOGY & PATHOPHYSIOLOGY

The Vicious Cycle (KEY CONCEPT)

Hard stool / diarrhoea / trauma
        ↓
   Tear in anoderm
        ↓
    Severe PAIN
        ↓
Internal anal sphincter SPASM (hypertonia)
        ↓
↑ Anal canal pressure → ↓ blood flow to posterior midline
        ↓
Relative ISCHAEMIA → impaired healing
        ↓
Repeated trauma at next defecation → CHRONIC fissure

Why the Posterior Midline?

1. Shearing forces are greatest at the posterior midline during defecation
2. Less elastic anoderm at that site
3. Increased density of longitudinal muscle extensions posteriorly
4. Relatively poor blood supply to the posterior midline (confirmed angiographic studies)

Position Statistics

Rule: <1% of fissures occur off midline - a lateral fissure = atypical → suspect an underlying cause

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ACUTE vs CHRONIC FISSURE

The Classic Triad of Chronic Fissure:

1. Sentinel skin tag / pile (external, at the lower end)
2. Chronic ulcer (exposing internal sphincter fibres)
3. Hypertrophied anal papilla (internal, at the upper end)

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CAUSES OF ATYPICAL / LATERAL FISSURES (EXAM FAVOURITE)

• Crohn's disease (most common cause of lateral fissure; associated with shiny skin tags)
• HIV / AIDS-related ulcers
• Sexually transmitted infections: Syphilis, Chlamydia, Chancroid, Lymphogranuloma venereum, HSV, CMV
• Tuberculosis
• Malignancy: SCC, Kaposi's sarcoma, B-cell lymphoma
• Previous anorectal surgery → scarring, stenosis
• Leukaemia
• Chronic diarrhoea

Any fissure not in the midline or with atypical features → Examination Under Anaesthesia (EUA) with biopsy and culture

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CLINICAL FEATURES

Symptoms

• Severe anal pain during defecation - the dominant symptom
  • Described as: "passing glass", "a knife cutting", "razor blades"
  • Pain starts during defecation, then continues as throbbing/spasm for minutes to hours afterwards
  • Severity of pain can cause patients to dread bowel movements, reduce oral intake → weight loss
  • In severe cases: fear of defecation → voluntary constipation → harder stool → worsens fissure
• Bright-red bleeding - on toilet paper (usually minimal; separate from stool)
• Mucus discharge from the ulcer or associated intersphincteric fistula
• Pruritus - secondary to irritation from sentinel tag
• Constipation - secondary to fear of defecation

Signs

• Often diagnosed on history alone
• Gentle separation of buttocks reveals the fissure / sentinel tag at the anal verge
• Patients are often too tender to tolerate DRE, anoscopy, or proctoscopy
• Focal gentle pressure at posterior/anterior anal canal with fingertip or cotton-tip applicator reproduces the pain
• If diagnosis unclear or malignancy suspected: Examination Under Anaesthesia (EUA)

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DIAGNOSIS

• Clinical diagnosis based on history and inspection
• Anoscopy/proctoscopy: deferred if too painful; confirms diagnosis, shows internal papilla
• EUA + biopsy + culture: if atypical fissure, off midline, or diagnosis in doubt
• Colonoscopy: if Crohn's or malignancy suspected

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TREATMENT

Step 1: Conservative Management (All Fissures - First Line)

• Dietary fibre increase (bulk agents) + stool softeners + adequate water intake
• Warm sitz baths - significant pain relief in >90% of patients with acute fissures
• Topical local anaesthetic (2% lidocaine jelly) for symptomatic relief
• Normalisation of bowel habits
• Anorectal biofeedback if excessive straining

Heals almost all acute fissures; but only ~50% of chronic fissures

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Step 2: Chemical Sphincterotomy (Topical Agents - For Chronic Fissures)

A. Glyceryl Trinitrate (GTN) 0.2%

• Mechanism: Nitric oxide donor → smooth muscle (internal sphincter) relaxation → ↓ sphincter tone → ↑ blood flow → healing
• Application: 2-3 times per day to the anal margin
• Healing rate: ~50% of chronic fissures
• Main side effect: Headaches (limits acceptability in up to 20% of patients)

B. Topical Calcium Channel Blockers

• Agents: Diltiazem 2% (twice daily) or Nifedipine topically
• Mechanism: Calcium channel antagonism → smooth muscle relaxation → ↓ sphincter tone
• Efficacy: Similar to GTN (~50% healing rate)
• Fewer side effects than GTN (fewer headaches)
• Often preferred over GTN in practice

C. Botulinum Toxin (Botox) Injection

• Mechanism: Blocks release of acetylcholine at neuromuscular junctions → temporary paralysis of internal anal sphincter
• Dose: 10-100 IU (typically 20-100 IU) injected into internal sphincter
• Duration of effect: ~3 months
• Route: Directly into the internal sphincter (office or outpatient sedation)
• Efficacy: ~50% healing; similar to topical therapies as first-line; modest improvement as second-line after failed topical therapy
• Side effects:
  • Temporary flatus incontinence (most common - up to 10%)
  • Increased urinary residual volume
  • Heart block, skin irritation, allergic reactions (rare)

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Step 3: Surgical Treatment (Chronic Fissures Failing Medical Therapy)

A. Lateral Internal Sphincterotomy (LIS) - PROCEDURE OF CHOICE

• Patient: lithotomy or prone jack-knife position; LA, regional, or GA
• Bivalved speculum at intersphincteric groove to palpate distal internal sphincter
• Closed: small longitudinal incision over intersphincteric groove → develop submucosal and intersphincteric planes → divide internal sphincter with knife/scissors to level of fissure apex → close with absorbable sutures
• The fissure itself needs no direct attention
• Problematic papillae and external tags may be excised at the same time

• Healing rate: 85-95% (Schwartz's: >95%)
• Immediate pain relief in most patients
• Recurrence: <10%
• Superior to topical nitrates, CCBs, or Botox

• Baseline incontinence
• Females with prior obstetric sphincter injuries
• Normal or low resting anal pressures
• Previous anorectal operations
• Documented anal sphincter injury

B. Anal Sphincter Dilatation (Lord's Procedure) - LARGELY ABANDONED

• Reduces sphincter tone by stretching
• Problem: disrupts anal sphincters at multiple sites → high risk of incontinence
• Rarely indicated today

C. Fissurectomy

• Excision of fibrotic edge + curettage of the base + excision of sentinel tag and/or anal papilla
• Used as an alternative to LIS when LIS is contraindicated
• Frequently combined with anal advancement flap anoplasty

D. Anal Advancement Flap Anoplasty (VY Flap / House Flap)

• Indications:
  • Increased risk of incontinence after LIS
  • Postpartum women
  • Normal or low resting anal pressures
  • Previous sphincter injury
• Technique: After fissurectomy, an inverted house-shaped flap of perianal skin is carefully mobilised on its blood supply, advanced without tension to cover the fissure, and sutured with interrupted absorbable sutures
• Postoperative: stool softeners + bulking agents
• Minor breakdown of one anastomotic edge does not herald failure

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DIFFERENTIAL DIAGNOSIS

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SUMMARY BOX - HIGH-YIELD EXAM POINTS

1. Fissure = longitudinal ulcer, anal verge → dentate line (not beyond)
2. Site: Posterior midline (most common); anterior more common in women
3. Lateral fissure = atypical → think Crohn's, HIV, TB, STI, malignancy → EUA + biopsy
4. Dominant symptom = severe pain on defecation ("passing glass") lasting hours
5. Chronic triad: sentinel tag + chronic ulcer (visible internal sphincter fibres) + hypertrophied anal papilla
6. Vicious cycle: pain → IAS spasm → ischaemia → non-healing
7. GTN and diltiazem 2%: ~50% healing; GTN causes headaches (diltiazem better tolerated)
8. Botox: temporary IAS paralysis, lasts ~3 months, ~50% healing, main SE = flatus incontinence
9. LIS = treatment of choice for chronic fissure failing medical therapy
10. LIS divided laterally to avoid keyhole deformity at posterior midline
11. LIS healing: >95%; recurrence <10%; risk of flatus incontinence 5-15%
12. Advancement flap: preferred when low resting tone or risk of incontinence
13. Lord's dilatation: largely abandoned due to risk of incontinence
14. Patients often too tender for DRE/anoscopy - diagnosis made on inspection alone

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Fistula-in-Ano - Complete Surgery Exam Notes

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DEFINITION

• Internal opening: usually at the dentate line (at an anal crypt)
• External opening: on the perianal skin
• Lined by granulation tissue (not epithelium - this is why spontaneous healing is poor)

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AETIOLOGY & PATHOGENESIS

Primary / Cryptoglandular (Most Common - ~90%)

Anal gland infection (at dentate line crypt)
         ↓
Obstruction of draining duct by faecal debris
         ↓
   Stasis → bacterial overgrowth
         ↓
  Abscess in intersphincteric space
         ↓
Spreads along planes (perianal → ischiorectal → supralevator)
         ↓
Spontaneous / surgical drainage → fistula tract persists
         ↓
        FISTULA-IN-ANO

Secondary Causes

• Crohn's disease (most important - associated with lateral/complex fistulae, "watering can perineum")
• Tuberculosis
• Lymphogranuloma venereum
• Actinomycosis
• Malignancy (rarely arises within a long-standing fistula)
• Foreign body
• Rectal duplication
• Previous anal surgery
• HIV-related / STI ulcers

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ANATOMY ESSENTIAL TO UNDERSTAND CLASSIFICATION

The Sphincter Complex

• Internal anal sphincter (IAS): involuntary smooth muscle (continuation of circular muscle of rectum)
• External anal sphincter (EAS): voluntary striated muscle
• Puborectalis: highest part of the sphincter; forms the anorectal ring
• Intersphincteric space: the potential space between IAS and EAS - origin of most fistulae
• Ischiorectal fossa: lateral to EAS, bounded by EAS medially, ischium laterally, levator ani superiorly

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PARKS CLASSIFICATION (THE STANDARD - EXAM ESSENTIAL)

Type 1 - Intersphincteric (45% - Most Common)

• Track passes through internal sphincter only and runs in the intersphincteric plane to the skin
• Does NOT cross the external sphincter
• Variants: may track upward blindly, or reach the upper anal canal via a second internal opening
• LOW fistula - safe to lay open

Type 2 - Transsphincteric (40%)

• Track crosses both internal AND external sphincters (at variable level) → passes through ischiorectal fossa → skin of buttock
• May have secondary tracks to roof of ischiorectal fossa or through levators into pelvis
• Circumferential (horseshoe) spread possible in intersphincteric and ischiorectal planes
• LOW if crosses lower third of EAS; HIGH if crosses upper two-thirds

Type 3 - Suprasphincteric (10%)

• Runs upward in the intersphincteric plane, above the puborectalis, then curls downward through the levator ani and ischioanal fossa to the skin
• Often caused by excessive probing of an abscess cavity during EUA
• HIGH fistula - complex to treat

Type 4 - Extrasphincteric (5% - Rarest)

• Runs without specific relation to the sphincters
• Usually results from pelvic disease, trauma, or iatrogenic injury
• Bypasses the sphincter mechanism entirely
• Most complex; often secondary to pelvic pathology (Crohn's, carcinoma, foreign body)

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HIGH vs LOW FISTULA - CRITICAL CLASSIFICATION

GOLDEN RULE: The anorectal ring (puborectalis) must NEVER be divided - if divided, permanent incontinence results. A fistula above the anorectal ring is a HIGH fistula.

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GOODSALL'S RULE (EXAM FAVOURITE)

         ANTERIOR
            |
External opening ANTERIOR to line
→ Tracks in a STRAIGHT RADIAL line → internal opening directly ahead (corresponding crypt)

External opening POSTERIOR to line  
→ Tracks in a CURVED line → internal opening at POSTERIOR MIDLINE (6 o'clock)

EXCEPTION: Anterior opening >3 cm from anal verge
→ May be an anterior extension of a HORSESHOE fistula originating POSTERIORLY
            |
         POSTERIOR

• Anterior external opening → straight radial tract → anterior internal opening
• Posterior external opening → curved track → always opens at 6 o'clock posteriorly

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CLINICAL FEATURES

Symptoms

• Intermittent purulent discharge (may be bloody) - the hallmark
• Perianal discomfort / pain that builds until the pus discharges, then temporary relief (cyclical pattern)
• History of prior anorectal abscess
• Passage of flatus or faeces through the external opening → suggests a rectal (rather than anal) internal opening
• Multiple external openings ("watering-can perineum") → think perianal Crohn's disease

Signs on Examination

• External opening: a skin dimple or small opening discharging pus, often with granulation tissue
• Gentle palpation reveals a cord-like subcutaneous structure tracking toward the anus
• Careful inspection for multiple openings, skin tags (Crohn's), scars
• Bilateral external openings → suspect horseshoe fistula via the deep postanal space
• Anoscopy: erythematous crypt or visible internal opening at the dentate line
• Gentle pressure on external opening → discharge from internal opening
• DRE: palpable fibrotic cord / induration

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INVESTIGATION

Clinical Examination / EUA (Examination Under Anaesthesia)

• First and most important step
• Fistula probe (Lockhart-Mummery) passed gently through external opening to identify internal opening
• Caution: Never force the probe - risk of creating a false passage / iatrogenic fistula
• Injection of hydrogen peroxide, methylene blue, or milk into external opening to identify internal opening

Imaging

• MRI pelvis (anal fistula protocol) - Gold standard for complex/high fistulae
  • T2-weighted images: fistula appears as high signal
  • Identifies: primary track, secondary tracks, horseshoe extensions, relationship to sphincters, undrained collections
• Endoanal ultrasound (EUS): good for defining sphincter anatomy, identifies tracks
• CT scan: useful if supralevator extension / pelvic sepsis suspected
• Fistulogram: injection of contrast through external opening (less commonly used now; superseded by MRI)

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TREATMENT

Principles of Treatment

1. Treat any undrained infection
2. Define fistula anatomy precisely
3. Remove or ablate the epithelialised/granulating tract
4. Avoid or minimise risk of faecal incontinence
5. Prevent recurrence

Key rule: The most important determinant of continence after fistulotomy is the amount of muscle LEFT BEHIND, not the amount divided. A minimum of 2 cm of external sphincter must be retained.

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LOW FISTULA TREATMENT

1. Fistulotomy (Lay-Open) - TREATMENT OF CHOICE for low fistulae

• Among the oldest surgical procedures - described by John of Arderne in De Arte Phisicali et de Cirurgia
• Indications: Intersphincteric fistulae + transsphincteric fistulae involving <30% of the external sphincter (not anterior fistulae in women)
• Steps:
  1. EUA: lithotomy or prone jack-knife position
  2. Identify the internal opening
  3. Pass a grooved fistula probe from external → internal opening
  4. Note the amount of sphincter above and below the probe
  5. Lay the track open over the probe (divide all tissue overlying the probe)
  6. Curette granulation tissue → send for histology
  7. Trim wound edges (marsupialisation - reduces wound size, speeds healing)
  8. Secondary tracks: laid open or drained separately
• Results:
  • Recurrence rate: 2-8%
  • Faecal incontinence: <5% in low fistulae with normal sphincter function

2. Fistulectomy

• Coring out of the fistula track (usually by diathermy cautery)
• Advantage: better definition of fistula anatomy (especially level of sphincter crossing and secondary extensions) than fistulotomy
• If the sphincteric component is deemed low enough: convert to fistulotomy
• Longer healing time than fistulotomy

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HIGH FISTULA TREATMENT

1. Seton (Latin: seta = bristle)

• Long-term palliation (especially Crohn's)
• Bridge to definitive surgery after track preparation
• Converts complex to simpler anatomy for LIFT/plug

2. LIFT Procedure - Ligation of the Intersphincteric Fistula Tract (Rojanasakul)

• Access the fistula tract through the intersphincteric groove
• Ligate and divide the fistula tract in the intersphincteric space
• No sphincter is divided
• Requires: single, straight transsphincteric tract (tract preparation with loose seton first)
• If LIFT fails → often results in an intersphincteric fistula → amenable to subsequent fistulotomy (a favourable outcome)
• Good sphincter-preservation

3. Endorectal (Mucosal) Advancement Flap

• Indicated for: high transsphincteric fistulae (especially in women)
• Steps:
  1. Curette/excise the fistula tract
  2. Close the internal opening (the source of infection) with a vascularised flap of rectal mucosa + submucosa (raised from proximal rectum)
  3. External opening is left open to drain
• Healing rates: 66-87%
• Risk: mild-moderate incontinence if internal sphincter muscle included in flap (~35%)

4. Fibrin Glue / Fistula Plug

• Fill the fistula tract with fibrin glue or a bioresorbable porcine collagen plug
• Provides scaffold for native tissue collagen deposition
• No sphincter division
• Low long-term success rates - have not been demonstrated to achieve durable cure

5. Track Preparation (Pre-operative Concept)

• Concept: healing is prevented by epithelialisation of the track or undrained secondary collections
• A period of loose seton drainage + thorough debridement of the fistula track before definitive surgery
• Required before: LIFT, fistula plug, FiLaC

6. Novel Minimally Invasive Techniques

• VAAFT (Video-Assisted Anal Fistula Treatment): rigid fistuloscope inserted through external opening; lavage, curettage, cautery under direct vision; internal opening stapled/sutured; no sphincter division; healing rates 71-85%
• FiLaC (Fistula Tract Laser Closure): radial-emitting laser obliterates the fistula lumen throughout its length
• OTSC (Over-the-Scope Clip): nitinol clip closes the internal opening; clip migration and pain are complications

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HORSESHOE FISTULA

• A horseshoe abscess/fistula arises when sepsis from the deep postanal space spreads bilaterally around the anal canal in the ischiorectal plane
• External openings are bilateral (on both sides of the anus)
• The primary (internal) opening is almost always in the posterior midline
• Treatment: drainage of the deep postanal space + setons to the bilateral extensions
• Often associated with Crohn's disease

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SPECIAL SITUATIONS

Fistula in Crohn's Disease

• Often complex, lateral, multiple ("watering-can perineum")
• Associated with shiny skin tags typical of anal Crohn's
• Treatment is challenging - fistulotomy carries high incontinence risk
• Management:
  • Loose seton for long-term drainage/palliation
  • Antibiotics (metronidazole, ciprofloxacin) - treat sepsis + immune-modulating effect
  • Biological agents: anti-TNF (infliximab/vedolizumab), ciclosporin - for perianal Crohn's
  • Side effects of prolonged antibiotics: peripheral neuropathy (metronidazole), tendinopathy (ciprofloxacin)

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COMPLICATIONS OF FISTULA SURGERY

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SUMMARY BOX - HIGH-YIELD EXAM POINTS

1. ~90% cryptoglandular - from anal glands at the dentate line
2. ~50% of perianal abscesses develop into fistulae
3. Parks classification: Intersphincteric (45%) > Transsphincteric (40%) > Suprasphincteric (10%) > Extrasphincteric (5%)
4. HIGH fistula = above or involving >1/3 of EAS; LOW fistula = below / <1/3 EAS
5. Anorectal ring (puborectalis) must NEVER be divided - permanent incontinence
6. Goodsall's Rule: anterior opening → straight radial tract; posterior opening → curved → 6 o'clock internal opening
7. Low fistula = fistulotomy (lay-open); High fistula = sphincter-preserving procedure
8. Fistulotomy recurrence: 2-8%; incontinence: <5% in low fistulae
9. Loose seton = drain + fibrosis; Cutting seton = slow division (controversial)
10. LIFT: no sphincter division; accesses track in intersphincteric groove
11. Advancement flap: healing 66-87%; risk of incontinence if IAS included
12. Lateral / complex / multiple fistulae → think Crohn's disease
13. MRI fistula protocol = gold standard for complex fistulae
14. "Watering-can perineum" = multiple external openings → Crohn's
15. Bilateral external openings → horseshoe fistula via deep postanal space
16. Always send curetted granulation tissue for histology (exclude malignancy/Crohn's/TB)

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