An interventional study of Botulinum Toxin Type A (BOTOX) Injection and Lateral Internal Sphincterotomy in Anal Fissure Chronic, sponsored by Islamabad Medical and Dental College. Completed at 1 site in Pakistan. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-08-13.
Sponsored by Islamabad Medical and Dental College · Not applicable, Interventional, and Treatment
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.
84 studies on the registry are indexed under Fissure in Ano; 16 are open to participants now.
This study's enrollment of 90 is close to the median of 99 across 65 interventional studies indexed under Fissure in Ano.
Browse Fissure in Ano studies →Islamabad Medical and Dental College is the lead sponsor of 15 studies on the registry; 5 are open to participants now.
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An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
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
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.
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.
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
Ran from Mar 2026 to primary completion in Jun 2026, 2 months.
Of 25 interventional studies with no phase under Fissure in Ano, half reached primary completion within 12 months of starting (the median), counting those still running; a quarter within 5 and three quarters within 30. This study's 2 months is below that.
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This study is completed, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Botulinum toxin type A
Islamabad Medical and Dental College