Comparison of Botulinum Toxin Injection and Lateral Internal Sphincterotomy in Chronic Anal Fissure Management

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.

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Key information

Conditions

Anal Fissure Chronic

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Islamabad Medical and Dental College

Islamabad, Federal, 44000, Pakistan

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Botulinum Toxin Type A (BOTOX) Injection

Drug

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.

lateral internal sphincterotomy

Procedure

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.

Primary outcomes

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

Sponsors and collaborators

Lead sponsor

Islamabad Medical and Dental College

Other

Registry information

Official study title

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

Acronym: BOT-LIS-CAF

Important dates

Study start: 2026
Primary completion: 2026
Study completion: 2026
First posted: May 5, 2026
Registry last updated: Aug 13, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

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