Closed Versus Open Lateral Internal Sphincterotomy for Chronic Anal Fissure (LIS-CLOSED Tri)

Outcomes of Closed Versus Open Lateral Internal Sphincterotomy for Chronic Anal Fissure: A Randomized Controlled Trial

This randomized controlled trial will compare closed versus open lateral internal sphincterotomy (LIS) under spinal anesthesia in patients with chronic anal fissure. The study will evaluate wound healing rates, postoperative pain, return to work, anal incontinence, and recurrence. A total of 160 patients will be randomized equally to either closed LIS or open LIS. The primary outcome will be complete wound healing at 6 weeks. Secondary outcomes include pain at 24 hours measured by Visual Analog Scale (VAS), return to work (days), anal incontinence at 6 weeks and 1 year, and recurrence at 1 year. Multivariate analysis will identify independent predictors of non-healing.

Study Overview

• Status: Completed
• Conditions: Chronic Anal Fissure
• Intervention / Treatment: Procedure: Closed Lateral Internal Sphincterotomy; Procedure: Open Lateral Internal Sphincterotomy

• Study Type: Interventional
• Enrollment (Actual): 160
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Pakistan
  • Punjab Province
    • Lahore, Punjab Province, Pakistan, 54000
      • Services Institute of Medical Sciences

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Diagnosis of chronic anal fissure (symptoms > 6 weeks)
• Failure of conservative medical management (dietary fiber, stool softeners, topical lignocaine, and at least 4 weeks of topical glyceryl trinitrate 0.2%)
• Willing to provide informed consent

Exclusion Criteria:

• Multiple fissures
• Concomitant anorectal pathology (anal fistula, abscess, significant hemorrhoids, rectal cancer)
• Inflammatory bowel disease
• Previous anorectal surgery
• History of anoreceptive intercourse
• Psychiatric disease or inability to consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Group A-CLIS; Closed Lateral Internal Sphincterotomy (CLIS) under spinal anesthesia	Procedure: Closed Lateral Internal Sphincterotomy; A bivalve anal retractor will be inserted to visualize the intersphincteric groove. A number 11 scalpel blade will be introduced into the intersphincteric groove in the left lateral position, advanced to the level of the dentate line, and then rotated medially to divide the internal anal sphincter. A dry gauze wick soaked with xylocaine gel will be placed in the anal canal for hemostasis and removed on the evening of the operation day.
Active Comparator: Group B-OLIS; Open Lateral Internal Sphincterotomy (OLIS) under spinal anesthesia	Procedure: Open Lateral Internal Sphincterotomy; A 1-2 cm curvilinear incision will be made in the intersphincteric groove in the left lateral position. The intersphincteric plane will be dissected to expose the internal anal sphincter, which will then be divided under direct vision up to the level of the dentate line. The wound will be left open to heal by secondary intention.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Patients with complete wound healing	Defined as evidence of scarring at the fissure site	6 weeks
Anal incontinence	Wexner Continence Grading Scale	6 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain score	Pain score through visual analog score	24 hours
Return to work in days		2 weeks
Recurrence	Reappearance of ulcer or tear in previously healed scar	1 year

Collaborators and Investigators

• Sponsor: Services Hospital, Lahore
• Collaborators: Services Institute of Medical Sciences, Pakistan
• Investigators: Study Director: Awais Amjad Malik, MBBS, FCPS, Services Institute of Medical Sciences

Study record dates

Study Major Dates

• Study Start (Actual): February 1, 2019
• Primary Completion (Actual): December 31, 2025
• Study Completion (Actual): January 15, 2026

Study Registration Dates

• First Submitted: March 22, 2026
• First Submitted That Met QC Criteria: March 22, 2026
• First Posted (Actual): March 27, 2026

Study Record Updates

• Last Update Posted (Actual): March 27, 2026
• Last Update Submitted That Met QC Criteria: March 22, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Chronic Anal Fissure, Lateral Internal Sphincterotomy, Closed Technique, Open Technique, Wound Healing
• Other Study ID Numbers: RCT30SIMS

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

IPD Plan Description

Informed consent did not explicitly include permission for sharing de-identified data with external researchers

Institutional ethical approval was obtained only for the primary analysis and publication, not for data sharing

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No