An interventional study of Spasm-Controlled Lateral Internal Sphincterotomy and Lateral Internal Sphincterotomy up to Fissure Apex in Chronic Anal Fissure, sponsored by Çanakkale Onsekiz Mart University. Recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-05-14.
Sponsored by Çanakkale Onsekiz Mart University · Not applicable, Interventional, and Treatment
This prospective randomized controlled trial compares three lateral internal sphincterotomy (LIS) techniques in patients with chronic anal fissure refractory to medical treatment: (1) Spasm-Controlled LIS (serial small sphincterotomies using an anal calibrator until 30 mm anal caliber is achieved, under local anesthesia plus sedation), (2) LIS up to the Fissure Apex (spinal or general anesthesia), and (3) LIS up to the Dentate Line (spinal or general anesthesia). The primary outcomes are fissure healing rate and fecal incontinence incidence at 12 months, assessed using the Wexner Incontinence Score. Secondary outcomes include postoperative pain (VAS), recurrence rate, patient satisfaction, and complications. A total of 150 patients (50 per group) will be enrolled and followed for 12 months.
Chronic anal fissure (CAF) is a longitudinal tear in the anoderm persisting for more than 8 weeks. Lateral internal sphincterotomy (LIS) is the gold-standard surgical treatment for CAF refractory to medical management, achieving healing rates of 90-98%. However, postoperative fecal incontinence remains its most significant complication, with rates ranging from 1-15% for permanent incontinence.
To reduce incontinence risk, various techniques limiting the extent of sphincterotomy have been proposed. Mentes et al. (2005) demonstrated that LIS up to the dentate line provided faster healing but caused significant continence disturbance, while LIS limited to the fissure apex was associated with lower incontinence but a higher treatment failure rate. Mentes et al. (2008) subsequently showed that spasm-controlled LIS using anal calibrators achieved faster pain relief with lower early incontinence rates compared to fissure apex sphincterotomy. However, no randomized trial has compared all three techniques simultaneously.
This single-center, prospective, three-arm RCT will enroll 150 adult patients with CAF refractory to at least 6 weeks of medical treatment. Patients will be randomized (1:1:1) to one of three groups: Group 1 (Spasm-Controlled LIS): serial small sphincterotomies under local anesthesia plus sedation until anal caliber reaches 30 mm using an anal calibrator. Group 2 (LIS up to Fissure Apex): open sphincterotomy extended to the proximal end of the fissure under spinal or general anesthesia. Group 3 (LIS up to Dentate Line): open sphincterotomy extended to the dentate line under spinal or general anesthesia.
All procedures will use the open technique with patients in lithotomy position. Randomization will be performed using computer-generated block randomization (block size 6), stratified by sex and fissure location. Outcome assessors will be blinded to group allocation.
Patients will be evaluated preoperatively and at postoperative day 1, week 1, week 2, month 1, month 2, month 6, and month 12. The Wexner (Cleveland Clinic) Incontinence Score will be used to assess continence at each visit. Fissure healing will be defined as complete epithelialization with no symptoms. Statistical analysis will follow the intention-to-treat principle, with Bonferroni correction applied for multiple comparisons.
283 studies on the registry are indexed under Fecal Incontinence; 52 are open to participants now.
This study's planned enrollment of 150 is above the median of 50 across 203 interventional studies indexed under Fecal Incontinence.
Browse Fecal Incontinence studies →Çanakkale Onsekiz Mart University is the lead sponsor of 51 studies on the registry; 15 are open to participants now.
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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.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Serial small open sphincterotomies performed under local anesthesia plus IV sedation. Anal caliber is measured with an anal calibrator before and after each increment until a caliber of 30 mm is achieved.
Procedure: Spasm-Controlled Lateral Internal Sphincterotomy
Open lateral internal sphincterotomy extended to the proximal end of the fissure (fissure apex) under spinal or general anesthesia. The length of sphincterotomy equals the length of the fissure.
Procedure: Lateral Internal Sphincterotomy up to Fissure Apex
Open lateral internal sphincterotomy extended to the level of the dentate line under spinal or general anesthesia. This is the traditional (classical) LIS technique.
Procedure: Lateral Internal Sphincterotomy up to Dentate Line
Serial small open sphincterotomies under local anesthesia plus IV sedation using an anal calibrator until anal caliber of 30 mm is achieved.
Also known as: Calibrated LIS
Open LIS extended to the proximal end of the fissure under spinal or general anesthesia.
Also known as: Tailored LIS
Open LIS extended to the level of the dentate line under spinal or general anesthesia.
Also known as: Traditional LIS / Classical LIS
Fissure Healing Rate
Complete epithelialization of the anal fissure with no symptoms at 12 months postoperatively, assessed by clinical examination.
Time frame: 12 months
Fecal Incontinence Incidence
Incidence of de novo fecal incontinence assessed using the Wexner (Cleveland Clinic) Incontinence Score. A score increase of ≥1 point from preoperative baseline is defined as de novo incontinence.
Time frame: 12 months
Postoperative Pain Score
Pain assessed using the Visual Analog Scale (VAS, 0-10) at each follow-up visit.
Time frame: Day 1, Week 1, Week 2, Month 1, Month 2, Month 6, Month 12
Recurrence Rate
Proportion of patients with recurrence of anal fissure after an initial healing period.
Time frame: Month 6 and Month 12
Patient Satisfaction
Patient satisfaction assessed on a numeric scale (0-10) at follow-up visits.
Time frame: Month 2, Month 6, Month 12
Postoperative Complications
Rate of surgical complications including bleeding, hematoma, infection, abscess, and fistula.
Time frame: 12 months
Plan to share: Undecided
Started May 2026 (actual). Primary completion is estimated for May 2027, 12 months after the start.
Of 70 non-industry interventional studies with no phase under Fecal Incontinence, half reached primary completion within 36 months of starting (the median), counting those still running; a quarter within 16 and three quarters within 57. This study's planned 12 months is below that.
Counting every sponsor, half of 86 studies reached it within 36 months; a quarter within 20 and three quarters within 57.
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Çanakkale Onsekiz Mart University