Special Surgery 22. Anorectal Benign Diseases: Hemorrhoids, Perianal Fistula, Anal Fissure, Anorectal Abscesses

I. Hemorrhoids

Definition

• Hemorrhoids = symptomatic enlargement/displacement of normal anal vascular cushions
• Not simply varicose veins; cushions contribute to fine continence
• Symptoms: bleeding, prolapse, itching, discomfort, thrombosis

Classification

Internal Hemorrhoids

• Above dentate line
• Visceral innervation → usually painless
• More likely to cause painless bright red bleeding and prolapse

• Grade I: bleeding, no prolapse
• Grade II: prolapse with straining, reduces spontaneously
• Grade III: prolapse with straining, needs manual reduction
• Grade IV: permanently prolapsed/irreducible

External Hemorrhoids

• Below dentate line
• Somatic innervation → painful when thrombosed or inflamed
• Can cause perianal lump and skin tag after thrombosis resolves

Etiology and Risk Factors

• Chronic constipation
• Excessive straining during defecation
• Low-fiber diet
• Obesity
• Pregnancy and increased intra-abdominal pressure
• Heavy lifting
• Aging and connective tissue weakening
• Prolonged sitting/toilet time

Clinical Features

• Fresh bright red blood on toilet paper, dripping into toilet or coating stool
• Palpable/prolapsing lump
• Pruritus ani / itching
• Mucus discharge and soiling in prolapse
• Discomfort/pressure
• Pain mainly with thrombosed external hemorrhoid, strangulated prolapse, fissure or abscess

Diagnosis

• History and physical examination
• Inspection of perianal area:

• External hemorrhoids
• Thrombosis
• Prolapsed internal hemorrhoids
• Fissure, abscess, skin disease, tumor differential

• DRE:

• Assess mass, pain, tone, blood
• Internal hemorrhoids may not be palpable unless thrombosed/prolapsed

• Anoscopy:

• Best office test for internal hemorrhoids and distal rectum

• Colonoscopy/flexible sigmoidoscopy if alarm signs or CRC screening indicated:

• Age/risk appropriate screening
• Iron-deficiency anemia
• Change in bowel habit
• Weight loss
• Family history
• Bleeding pattern not typical

Treatment

Conservative Therapy

• Fiber supplementation and high-fiber diet
• Adequate fluids
• Stool softeners if needed
• Avoid straining and prolonged toilet sitting
• Weight loss and exercise
• Sitz baths / warm bathing for symptom relief
• Topical anesthetic/steroid creams only short term for temporary symptom relief

Office Procedures

• Mainly grade I-II and selected grade III internal hemorrhoids
• Rubber band ligation:

• Most common/effective office procedure
• Band placed above dentate line
• Causes ischemic necrosis and fixation/scarring

• Sclerotherapy:

• Injection of irritant/sclerosant chemical into hemorrhoidal tissue
• Useful when bleeding risk makes banding less suitable in selected patients

• Infrared coagulation:

• Coagulates mucosa/submucosa, more useful for smaller bleeding hemorrhoids

Surgical Therapy

• Indications:

• Grade III-IV symptomatic hemorrhoids
• Large external component
• Combined internal/external disease
• Failure of office treatment
• Complicated strangulated/prolapsed disease
• Selected painful thrombosed external hemorrhoid within early presentation window

• Excisional hemorrhoidectomy:

• Milligan-Morgan: open hemorrhoidectomy
• Ferguson: closed hemorrhoidectomy
• Most definitive, but more postoperative pain

• Stapled hemorrhoidopexy:

• For internal circumferential prolapse
• Less early pain but higher recurrence/prolapse risk in some patients
• Not for large external hemorrhoids

• Doppler-guided hemorrhoidal artery ligation / transanal hemorrhoidal dearterialization:

• Reduces arterial inflow
• Can be combined with mucopexy for prolapse

II. Anal Fissure

Definition

• Longitudinal tear in anoderm of distal anal canal
• Typical location: posterior midline
• Anterior midline fissure more common in women than men
• Lateral/multiple/atypical fissures suggest Crohn disease, TB, HIV, syphilis, malignancy or trauma

Etiology

• Hard stool / constipation
• Prolonged diarrhea
• Childbirth
• Anal intercourse/trauma
• Internal sphincter hypertonia → local ischemia → chronic fissure

Types

• Acute fissure:

• <6 weeks
• Superficial fresh tear

• Chronic fissure:

• >6 weeks
• Sentinel skin tag
• Hypertrophied anal papilla
• Exposed internal sphincter fibers

Clinical Features

• Severe sharp/stabbing pain during defecation
• Pain can persist minutes-hours after stool
• Fresh bright red bleeding on paper/stool surface
• Internal sphincter spasm
• Fear of defecation → constipation → worsens fissure

Diagnosis

• History often typical
• Gentle inspection by separating buttocks
• DRE/anoscopy can be very painful and may be deferred until pain improves
• Examination under anesthesia if diagnosis unclear, severe pain prevents exam, abscess suspected or atypical lesion

Treatment

Conservative Therapy

• High-fiber diet and fiber supplements
• Fluids
• Stool softeners
• Warm sitz baths
• Topical anesthetic short term for pain

Chemical Sphincterotomy

• Topical nitroglycerin/glyceryl trinitrate:

• Relaxes internal sphincter
• Side effect: headache

• Topical calcium channel blocker:

• Diltiazem or nifedipine
• Often better tolerated than nitrates

• Botulinum toxin injection into internal sphincter:

• Temporary sphincter relaxation
• Useful if topical therapy fails or surgery is high-risk

Surgical Therapy

• Lateral internal sphincterotomy:

• Gold standard for chronic fissure refractory to medical therapy
• Divides part of internal anal sphincter to reduce resting pressure
• Very effective
• Risk: flatus/fecal incontinence, especially in patients with baseline sphincter weakness, obstetric injury or diarrhea

• Advancement flap can be considered in selected patients at high incontinence risk

III. Anorectal Abscesses

Definition and Etiology

• Anorectal abscess = collection of pus in perianal/perirectal space
• Most common cause: cryptoglandular infection of anal glands
• Typical bacteria: mixed aerobic/anaerobic flora

• E. coli and other Gram-negative rods
• Gram-positive organisms
• Bacteroides and other anaerobes

• Other causes/risk factors:

• Crohn disease
• Trauma
• Anal fissure
• Immunosuppression, diabetes, HIV
• Malignancy or radiation injury in atypical/recurrent cases

Classification by Location

• Perianal abscess: most common, superficial near anal verge
• Ischiorectal / ischioanal abscess: deeper lateral space, buttock swelling
• Intersphincteric abscess: between internal and external sphincters
• Supralevator abscess: above levator ani, deep pelvic pain/systemic illness
• Submucosal abscess: under rectal/anal mucosa
• Horseshoe abscess: crosses midline through deep postanal space

Clinical Features

• Sudden severe perianal/rectal pain
• Perianal swelling, redness, cellulitis
• Tender fluctuant mass if superficial
• Fever, malaise
• Tachycardia/systemic toxicity if severe
• Purulent discharge if spontaneously draining
• Deep abscess may cause rectal pain, urinary retention, fever with minimal external signs

Diagnosis

• Clinical examination is enough for most superficial perianal abscesses
• Inspection and gentle DRE if tolerable
• Anoscopy/proctoscopy only if pain allows and useful
• Examination under anesthesia if severe pain, deep abscess, unclear anatomy or drainage needed
• MRI pelvis, CT or endoanal ultrasound if:

• Deep/supralevator abscess suspected
• Recurrent abscess
• Complex fistula suspected
• Crohn disease
• Immunosuppression or atypical presentation

Treatment

• Prompt surgical incision and drainage = gold standard
• Do not treat routine abscess with antibiotics alone
• Drainage principles:

• Incision close to anal verge to shorten future fistula tract
• Adequate drainage and break loculations
• Avoid sphincter injury
• Drain deep spaces according to origin/anatomy

• Antibiotics only as adjunct if:

• Cellulitis
• Systemic signs/sepsis
• Immunosuppression
• Diabetes or significant comorbidity
• Valvular heart disease/prosthetic risk according to local policy

• Follow-up is important because fistula develops after abscess in a substantial proportion of patients
• Primary fistulotomy at abscess drainage only in selected simple low fistula with clear anatomy and low continence risk

IV. Perianal Fistula

Definition

• Abnormal epithelialized tract between anal canal/rectum and perianal skin
• Usually follows anorectal abscess
• Common cryptoglandular origin
• Main treatment balance: cure fistula while preserving continence

Etiology

• Complication of anorectal abscess
• Crohn disease
• Tuberculosis
• Radiation proctitis
• Malignancy
• Trauma / previous surgery

Parks Classification

• Intersphincteric:

• Between internal and external sphincter
• Most common

• Transsphincteric:

• Passes through internal and external sphincters into ischioanal fossa

• Suprasphincteric:

• Loops above puborectalis then descends through levator ani

• Extrasphincteric:

• Bypasses sphincter complex from rectum to perianal skin
• Often due to Crohn disease, trauma, malignancy or pelvic sepsis

Goodsall Rule

• External opening posterior to transverse anal line → curved tract to posterior midline internal opening
• External opening anterior to transverse anal line → usually straight radial tract to nearest anal crypt
• Exception: anterior opening >3 cm from anal verge may still curve posteriorly
• Rule is approximate; MRI/EUA defines complex anatomy

Clinical Features

• Persistent or recurrent purulent discharge from perianal opening
• Intermittent pain and swelling
• Recurrent abscess
• Skin irritation, itching
• External opening with granulation tissue
• Gas or stool discharge from tract in complex cases

Diagnosis

• Inspection and DRE
• Identify external opening, induration, internal opening if possible
• Anoscopy/proctoscopy to look for internal opening and proctitis
• Examination under anesthesia often needed for mapping and treatment
• MRI pelvis:

• Best imaging for complex/high/recurrent fistulas
• Defines sphincter involvement, secondary tracts, abscess

• Endoanal ultrasound is alternative in experienced hands
• Consider colonoscopy/IBD workup if multiple fistulas, recurrent disease, diarrhea or Crohn suspicion

Treatment

Simple / Low Fistula

• Fistulotomy:

• Lay open tract
• High healing rate
• Appropriate when little sphincter muscle is divided and continence risk is low

• Fistulectomy removes tract but can create larger wound; less commonly preferred than fistulotomy for simple disease

Complex / High Fistula

• Drain sepsis first
• Loose draining seton:

• Maintains drainage
• Prevents abscess recurrence
• Preserves sphincter
• Useful as bridge to definitive operation or long-term control in Crohn disease

• Sphincter-sparing options:

• LIFT: ligation of intersphincteric fistula tract
• Endorectal advancement flap
• Video-assisted or laser techniques in selected centers; long-term data variable

• Cutting seton:

• May be used selectively
• Higher continence risk than loose seton

• Anal fistula plug/fibrin glue have relatively low/recurrent success and are not main standard options

Crohn-Associated Fistula

• Combined surgical + medical treatment
• Drain abscess and place loose seton if needed
• Control rectal inflammation with biologic therapy, commonly anti-TNF
• Avoid aggressive sphincter division when proctitis/complex fistula present
• Stem-cell therapy can be considered for selected refractory complex Crohn fistulas where available