Comparison of Botulinum Toxin Injection and Lateral Internal Sphincterotomy in Chronic Anal Fissure Management (BOT-LIS-CAF)

April 28, 2026 updated by: Islamabad Medical and Dental College

A Prospective Comparative Study of Clinical Outcomes Between Botulinum Toxin Injection and Lateral Internal Sphincterotomy in the Management of Chronic Anal Fissure

This study aims to compare two commonly used treatments for chronic anal fissure: botulinum toxin injection and lateral internal sphincterotomy. Chronic anal fissure is a painful condition that causes severe discomfort during bowel movements and can significantly affect a patient's quality of life.

Botulinum toxin injection is a minimally invasive procedure that temporarily relaxes the anal sphincter muscle to promote healing. In contrast, lateral internal sphincterotomy is a minor surgical procedure that permanently reduces sphincter pressure and is considered the standard treatment with high healing rates.

A total of 90 adult patients with chronic anal fissure will be enrolled and divided into two groups. One group will receive botulinum toxin injection, while the other group will undergo lateral internal sphincterotomy. Patients will be followed up regularly to assess healing, pain relief, recurrence of the fissure, and any complications such as incontinence.

The purpose of this study is to determine which treatment provides better outcomes in terms of effectiveness and safety, helping doctors choose the most appropriate treatment for patients.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

90

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:Age 18-65 years Diagnosed chronic anal fissure (>6 weeks duration) Failure of conservative management Both male and female patients Willingness to provide informed consent -

Exclusion Criteria:Acute anal fissure Previous anal surgery Inflammatory bowel disease Pregnancy Neurological disorders affecting continence Known hypersensitivity to botulinum toxin

-

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Botulinum Toxin Injection
Participants in this arm will receive an intrasphincteric injection of 20 units of botulinum toxin type A. The toxin will be diluted in 1 ml of normal saline and administered as two injections of 10 units each at the 3 o'clock and 9 o'clock positions in the intersphincteric plane under aseptic conditions using a 26-30 gauge needle.
Drug: Botulinum Toxin Type A (BOTOX) Injection
A total dose of 20 units of botulinum toxin type A will be administered via intrasphincteric injection. The toxin will be diluted in 1 ml of normal saline and injected into the internal anal sphincter in two equal doses of 10 units each at the 3 o'clock and 9 o'clock positions in the intersphincteric plane using a 26-30 gauge needle under aseptic conditions.
Active Comparator: Lateral Internal Sphincterotomy
Participants in this arm will undergo open lateral internal sphincterotomy under spinal anesthesia. A small incision will be made at the lateral position (3 o'clock), and the lower one-third of the internal anal sphincter will be divided under direct vision. Hemostasis will be secured, and the wound will be left open for secondary healing
Procedure: Lateral Internal Sphincterotomy
An open lateral internal sphincterotomy will be performed under spinal anesthesia. A small lateral incision will be made at the 3 o'clock position, and the lower one-third of the internal anal sphincter will be divided under direct vision. Hemostasis will be achieved, and the wound will be left open to heal by secondary intention.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Proportion of patients with complete fissure healing at 3 months after treatment (Botulinum toxin vs. Lateral Internal Sphincterotomy). This is the main endpoint on which your sample size calculation and comparative effectiveness analysis are based.
Time Frame: 3 months for healing after intervention
3 months for healing after intervention

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Islamabad Medical and Dental College

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 2, 2026

Primary Completion (Estimated)

June 1, 2026

Study Completion (Estimated)

August 31, 2026

Study Registration Dates

First Submitted

April 28, 2026

First Submitted That Met QC Criteria

April 28, 2026

First Posted (Actual)

May 5, 2026

Study Record Updates

Last Update Posted (Actual)

May 5, 2026

Last Update Submitted That Met QC Criteria

April 28, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • ANTH-GS-CAF-2026

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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