Colorectal

Anal Fistula Surgery — Fistulotomy

OPERATION: Examination Under Anaesthesia and Fistulotomy
ANAESTHETIC: General / spinal anaesthesia
POSITION: Lithotomy
ANTIBIOTICS: As per local policy if sepsis present

INDICATION:
Anal fistula — [intersphincteric / low trans-sphincteric]. [External opening at [position]. [Previous perianal abscess drainage]. Preoperative assessment: [endoanal USS / MRI pelvis — findings]. Continence assessed preoperatively.

PROCEDURE:
WHO Checklist performed. Perineum prepared and draped. Examination under anaesthesia performed — bidigital assessment of sphincter tone and fistula anatomy.

External opening identified at [position]. Probe inserted into external opening and guided carefully along the fistula track. Internal opening identified at [position — clock face] at the dentate line, confirmed by gentle probing and identification of induration around the internal opening.

Fistula classified as [intersphincteric / low trans-sphincteric / superficial] with minimal sphincter involvement confirmed.

Fistulotomy performed by laying the track open over the probe under direct vision with diathermy. Track curetted and granulation tissue removed. Wound edges trimmed to allow adequate drainage and facilitate healing from base. Wound marsupialised with absorbable sutures to promote drainage, reduce postoperative bleeding risk, and accelerate healing.

Sphincters inspected — [external sphincter fibres not divided / minimal subcutaneous external sphincter divided]. Internal sphincter division [quantified / confined to intersphincteric portion only].

Haemostasis confirmed. Wound dressed.

FINDINGS:
[Intersphincteric / low trans-sphincteric] fistula. Internal opening at [position]. Track length [cm]. Sphincter muscle involvement minimal — safe for lay-open. No high components identified.

EBL: Minimal. COMPLICATIONS: None.

POST-OPERATIVE INSTRUCTIONS:
Regular analgesia. High fibre diet and softeners. Sitz baths. Wound dressings. Outpatient review at 2–4 weeks to assess wound healing. Patient counselled regarding healing time (typically 4–8 weeks).