Lateral internal sphincterotomy for fissure-in-ano
- Usual anaesthesia
- Saddle block (low spinal) or short general anaesthesia; local infiltration with adrenaline in selected day-care cases
- Position
- Lithotomy (prone jackknife or left lateral are alternatives)
- Setting
- elective
Operative note template for lateral internal sphincterotomy for chronic anal fissure, with a filled example for a closed LIS with sentinel tag excision done as a day-care case.
Blank template
Follow this order in the case sheet. Tick the options that apply and fill the blanks.
Patient and case
- Name / Age / Sex
- UHID / IP no. / Ward-Bed
- Date of surgery / OT no.
- CaseElectiveEmergency (non-elective)if emergency, state urgency and reason
- Timesin OT ___ anaesthesia start ___ incision ___ closure ___ out of OT ___
Team
- Operating surgeonname, designation
- Assistant(s)
- Supervising consultantpresent in OT / available / not applicable
- Steps done by the residentwhole procedure / named steps, under whose supervision
- Anaesthetist
- Scrub nurse / circulating nurse
Diagnosis and procedure
- Pre-operative diagnosis
- Post-operative diagnosis
- Procedure planned
- Procedure performedif different from plan, state why
- Extra procedure done and reason'none' if none. Only to save life or health if not consented
Consent and safety checks
- Informed consentGeneralProcedure-specificHigh-riskAnaesthesiain a language the patient understands: language ___ witness ___
- Site / side markedYesNot applicable
- WHO Surgical Safety ChecklistSign inTime outSign out
- Antibiotic prophylaxisdrug, dose, route, time given before incision
- VTE prophylaxisMechanicalPharmacologicalNot indicated
Risks to explain in the consent for this operation
- bleeding or haematoma at the sphincterotomy site
- incontinence to flatus, usually temporary
- faecal soiling or incontinence, rarely permanent
- perianal abscess or fistula at the stab site
- tear of the anal lining (anoderm)
- fissure not healing or coming back
- need for further surgery
Pre-operative details for this operation
- Fissure details on examinationsite (posterior / anterior midline / other), duration of symptoms, sentinel tag, hypertrophied papilla
- Conservative treatment trieddrug (e.g. diltiazem 2% or GTN ointment), duration, fibre, sitz bath, and result
- Continence status before surgeryFully continentSome impairment (describe)record it now, so any later change can be compared
- Risk factors against sphincterotomyprevious vaginal delivery with tear or forceps, previous anorectal surgery, known sphincter injury, IBD, HIV, TB
- Atypical fissure featuresNoneLateral / multiple / painless / indurated: biopsy planned
- Anticoagulants or antiplateletsdrug and date stopped, or not on any
Anaesthesia and position
- AnaesthesiaSaddle block (low spinal)Short GAGA with pudendal blockLocal infiltration with adrenaline 1:200,000
- PositionLithotomyProne jackknifeLeft lateralclock positions in the note refer to this position
Operative findings
- Fissure position and lengthclock position, length in cm from the anal verge towards the dentate line
- Signs of chronicitysentinel tag, hypertrophied papilla, rolled or fibrosed edges, internal sphincter fibres visible in the base
- Anal tone under anaesthesiaIncreased (hypertonic)NormalReduced
- Associated diseaseNoneHaemorrhoidsFissure abscessSuperficial fistulaOther
- Intersphincteric grooveEasily palpableDifficult to feel
Procedure (steps)
- Examination under anaesthesiaanal canal lubricated with lignocaine jelly, gentle digital examination and anoscopy
- Retractor placedParks speculumBivalve anal retractoropened gently to put the internal sphincter on stretch
- Side of sphincterotomyRight lateralLeft lateralwrite the clock position; always away from the fissure
- TechniqueClosed (stab)Open
- Closed method: blade and planeNo. 15 bladeNo. 11 bladeBeaver / cataract bladeblade passed in the intersphincteric groove parallel to the anoderm, then turned towards the internal sphincter with a finger in the canal as guard
- Open method: incision and division1 to 2 cm circumferential or radial incision at the anal verge, white internal sphincter lifted on a clamp, divided with scissors or cautery
- Extent of divisionUp to the proximal end of the fissure (tailored)Up to the dentate linenever above the dentate line; write the length in cm
- Release confirmedgroove felt on palpation, residual fibres broken with the finger, blade not re-inserted
- HaemostasisPressure for 3 minBipolar cauterySuture
- Sentinel tag / hypertrophied papillaExcisedNot present
- Fissure edgesFreshenedLeft alone
- Associated abscess or superficial fistulaNoneLaid open
Closure, drains and dressing
- Sphincterotomy woundLeft openClosed with absorbable sutureif closed, material and size, e.g. polyglactin 910 (Vicryl) 4-0
- Anoderm integrity checkedIntactBreached and repaired (suture)
- Local anaesthetic infiltration for post-op paindrug, strength, volume
- Dressinggauze pad, anal pack (yes / no)
Specimens and implants
- Sentinel tag / papilla sent for HPEYesNot excised
- Fissure biopsy or swabNot neededBiopsy sent (atypical fissure)Swab sent for culture
End of procedure
- Estimated blood lossml
- IV fluids and blood / products givenfluids (ml); blood: type, units, bag nos.
- Swab, needle and instrument countCorrectIncorrect: action taken
- Intra-operative complications / difficultieswhat happened and what was done; 'none' if none
- Implant stickersNo implantAffixed in case sheet, OT register and for discharge summary
- Condition at end of surgery / shifted toPACUWardICU/HDU
Post-operative orders
- Check dressing for bleedingbefore discharge; look for a swelling at the stab site (haematoma)
- Voidingnote time of first void before discharge
- Analgesiadrug, dose, frequency
- Dietoral fluids when awake, then normal diet with plenty of fibre and 6 to 8 glasses of fluid a day
- Stool softener or bulk laxativedrug and timing, to avoid hard stools
- Warm sitz bathplain warm water, after each motion and 2 to 3 times a day
- Dischargesame day or next morning once pain is controlled and patient has voided
- Follow-upOPD date to check healing and ask about control of flatus and stool; HPE report
Signature
- Name and designation of person writing note
- Medical Council registration no.
- Signature / date / time of writingwrite before the patient leaves recovery
Worked example
Fictional case: Mr. A.K., 34 years, 4-month history of pain after defecation with streaks of blood, chronic posterior fissure with sentinel tag, not healed after 8 weeks of diltiazem 2% ointment.
Case details
Date: 04/02/2026. Elective, day-care list. OT 3.
In OT 10:05. Saddle block 10:10. Incision 10:22. Procedure ended 10:40.
Surgeon: Dr A. (2nd-year resident, General Surgery). Assistant: Dr B. (1st-year resident). Consultant: Dr C., present in OT.
Anaesthetist: Dr D. Scrub nurse: Sr E.
Indication and pre-op
Indication: chronic anal fissure at 6 o'clock with sentinel tag, failed 8 weeks of topical diltiazem 2%, fibre and sitz baths.
Fully continent to flatus and stool before surgery. No previous anorectal surgery. Not on antiplatelets or anticoagulants.
Consent: general, procedure-specific and anaesthesia consent taken in Marathi. Risk of flatus incontinence, bleeding and recurrence explained.
WHO checklist sign in and time out done. Antibiotic prophylaxis: not given, as per unit protocol for LIS.
Anaesthesia and position
Under saddle block, patient in lithotomy. Parts painted with povidone-iodine and draped.
Findings
Chronic fissure at 6 o'clock, about 1 cm long, with rolled edges and white internal sphincter fibres in the base.
Sentinel tag at the outer end. Hypertrophied anal papilla at the inner end.
Anal tone increased. Intersphincteric groove easily felt. No abscess, no fistula. No haemorrhoids.
Procedure
Anal canal lubricated with lignocaine jelly 2%. Gentle digital examination and anoscopy done.
Parks speculum placed and opened laterally to stretch the internal sphincter.
Closed left lateral internal sphincterotomy at 3 o'clock. No. 15 blade passed through the skin into the intersphincteric groove, flat and parallel to the anoderm, up to the level of the top of the fissure. Blade turned towards the internal sphincter with the left index finger in the canal as guard, and the lower internal sphincter divided for about 1 cm. Blade withdrawn.
Division felt as a groove. Remaining fibres gave way to gentle finger pressure. Blade not re-inserted.
Pressure applied over the site for 3 minutes. No haematoma. Anoderm intact.
Sentinel tag and hypertrophied papilla excised. Fissure edges freshened.
Closure
Stab wound left open. Tag excision wound left open.
Gauze pad applied. No anal pack.
Specimens
Sentinel tag and papilla in one container, formalin, sent for HPE. Labelled with name, age, IP number and site.
End of procedure
Estimated blood loss 5 ml. No transfusion.
Swab, needle and instrument count correct, confirmed by scrub nurse.
No intra-operative complications.
Shifted to day-care ward in stable condition. Pulse 76/min, BP 124/80 mmHg.
Post-op orders
Check pad for bleeding and stab-site swelling before discharge.
Oral fluids after 2 hours, then normal diet with fibre.
Tab paracetamol 1 g orally 6-hourly for 3 days.
Ispaghula (psyllium) husk at bedtime with a glass of water.
Warm plain-water sitz bath after each motion and twice a day.
Discharge in the evening after voiding. Review in surgery OPD after 1 week with HPE report.
Signature
Dr A., JR-2, General Surgery. Reg. no. ________. 04/02/2026, 10:55.
Must document for this operation
- Continence status before surgery. Flatus or faecal incontinence is the main complaint after LIS, and without a baseline you cannot show it was new.
- Side, clock position and patient position. A clock position means nothing unless the reader knows whether the patient was in lithotomy or prone.
- Length of internal sphincter divided and its upper limit. Division tailored to the fissure length carries less incontinence than division up to the dentate line, and the next surgeon needs to know what is left.
- Open or closed technique and the blade used. Explains a later submucous fistula or anoderm tear and guides any repeat operation.
- Conservative treatment given before surgery. LIS is offered after medical treatment fails; the note must show this for audit and in case of a complaint.
- What was sent for histopathology (HPE). An atypical fissure can be Crohn disease, TB or carcinoma, and the pathologist needs the site.
Common mistakes in these notes
- Writing 'LIS done' without the side, clock position and length divided.
- Not recording pre-operative continence.
- Not mentioning the sentinel tag or papilla and whether it went for HPE.
- Using clock positions without stating the patient position.
- Leaving out that conservative treatment was tried first, and for how long.
Indian practice and paperwork
- Bio-Medical Waste Management Rules 2016 put excised human tissue in Yellow category (a) human anatomical waste, and discarded formalin is chemical waste. Write where the specimen went: sent for HPE in formalin, given to relatives with a note, or discarded as Yellow (a) waste. (DGHS/CPCB Guidelines for Management of Healthcare Waste as per BMW Rules 2016)
Sources
- Moran B, Mittal R, Lord A, eds. Farquharson's Textbook of Operative General Surgery. 11th ed. CRC Press; 2026, Ch 15, Surgery of the anus and perineum: Anal fissures, pp. 312-314.
- Bhat SM. SRB's Surgical Operations: Text and Atlas. Jaypee; 2014, Ch 25, Anorectal surgeries: Treatment of anal fissure, pp. 1027-1030.
- Scott-Conner CEH, ed. Scott-Conner and Dawson Essential Operative Techniques and Anatomy. 4th ed. Wolters Kluwer; 2014, Ch 123, Management of perirectal abscesses, anal fistulas, and chronic anal fissure, pp. 671-672.
- Singla SK, Mital K. Operative Manual of Minimally Invasive and LASER Ano-proctology. Springer; 2025, Ch 9, Fissure in ano: lateral partial internal sphincterotomy (LIS), pp. 75-80.
- NHS. How and when to take paracetamol for adults (1 g per dose, at least 4 hours apart, not more than 4 g in 24 hours). www.nhs.uk/medicines/paracetamol-for-adults/how-and-when-to-take-paracetamol-for-adults/
Educational template for residents. Adapt it to your institution's case-sheet format and your consultant's instructions. Patient details in the example are fictional.
Videos of this operation
Teaching videos and pages for this operation, listed under the curriculum item that asks for it.