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

NCT07568314 — Not applicable, Completed, 90 participants, Islamabad Medical and Dental College

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

Registry	NCT07568314, acronym BOT-LIS-CAF
Status	Completed
Phase	Not applicable
Study type	Interventional; non randomized, parallel, masking: single, treatment
Enrollment	90 (Actual)
Sponsor	Islamabad Medical and Dental College (Other)
Conditions	Anal Fissure Chronic
Interventions	Botulinum Toxin Type A (BOTOX) Injection, Lateral Internal Sphincterotomy (Drug, procedure)
Dates	start 2026-03-02, primary completion 2026-06-01, completion 2026-06-01, first posted 2026-05-05, last updated 2026-08-13
Locations	1 site in Pakistan

-Summary

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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+Arms and interventions

Arm	Type	Interventions	Description
Botulinum Toxin Injection	Experimental	Drug: Botulinum Toxin Type A (BOTOX) 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.
Lateral Internal Sphincterotomy	Active comparator	Procedure: 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

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.

+Outcome measures

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. [3 months for healing after intervention]

+Eligibility

Sex: All, ages: 18 Years to 65 Years

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

+Locations (1)

Facility	City	Country	Status
Islamabad Medical and Dental College	Islamabad, Federal	Pakistan