Chronic Anal FissureSPHINXNCT07520552
Comparison of Lateral Internal Sphincterotomy Techniques for Chronic Anal Fissure
A study testing Lateral Internal Sphincterotomy up to Fissure Apex and Lateral Internal Sphincterotomy up to Dentate Line in people with Chronic Anal Fissure, run by Çanakkale Onsekiz Mart University at 1 site in Turkey (Türkiye).
Trial summary
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… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Chronic Anal Fissure
- What is being tested?
- Lateral Internal Sphincterotomy up to Fissure Apex and Lateral Internal Sphincterotomy up to Dentate Line
- Type of treatment
- Injection or infusion, Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 150 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 6 May 2026to 6 May 2028
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age 18 years or older
- Diagnosis of chronic anal fissure (duration ≥8 weeks)
- Failure to heal after at least 6 weeks of appropriate medical treatment (topical agents, fiber supplementation, sitz baths)
- Complete preoperative fecal continence (Wexner Incontinence Score = 0)
- Primary anal fissure (posterior or anterior midline location)
- Written informed consent
Who cannot join
- Any degree of preoperative fecal incontinence
- Secondary anal fissure (associated with Crohn's disease, tuberculosis, HIV, syphilis, or other systemic conditions)
- Previous anal sphincter surgery
- History of obstetric sphincter injury
- Active anorectal infection (abscess or fistula)
- Pregnancy or breastfeeding
- Uncorrectable coagulopathy or current anticoagulant use
- Inability to cooperate with study procedures or attend follow-up visits
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Canakkale Onsekiz Mart University
Çanakkale, Çanakkale, 00017
Emre Gülçek, MD, Assistant Professor, +905544810964, emre.gulcek@comu.edu.tr
About this study
Official title: A Prospective Randomized Controlled Trial Comparing Spasm-Controlled, Fissure Apex-Limited, and Dentate Line-Limited Lateral Internal Sphincterotomy Techniques in Chronic Anal Fissure
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.
Read the detailed description
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.
- Conditions
- Chronic Anal Fissure
- Being tested
- Spasm-Controlled Lateral Internal Sphincterotomy, Lateral Internal Sphincterotomy up to Fissure Apex, Lateral Internal Sphincterotomy up to Dentate Line
- Keywords
- Chronic anal fissure, Lateral internal sphincterotomy, Spasm-controlled sphincterotomy, Fecal incontinence, Dentate line, Fissure apex
- Medical subject headings
- Fecal Incontinence
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Spasm-Controlled Lateral Internal SphincterotomyProcedure or surgery
Also called Calibrated LIS
Serial small open sphincterotomies under local anesthesia plus IV sedation using an anal calibrator until anal caliber of 30 mm is achieved.
Lateral Internal Sphincterotomy up to Fissure ApexProcedure or surgery
Also called Tailored LIS
Open LIS extended to the proximal end of the fissure under spinal or general anesthesia.
Lateral Internal Sphincterotomy up to Dentate LineProcedure or surgery
Also called Traditional LIS / Classical LIS
Open LIS extended to the level of the dentate line under spinal or general anesthesia.
| Study group | Role | What they receive |
|---|---|---|
| Spasm-Controlled LIS | Active comparator | 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. Receives: Procedure: Spasm-Controlled Lateral Internal Sphincterotomy |
| LIS up to Fissure Apex | Active comparator | 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. Receives: Procedure: Lateral Internal Sphincterotomy up to Fissure Apex |
| LIS up to Dentate Line | Active comparator | Open lateral internal sphincterotomy extended to the level of the dentate line under spinal or general anesthesia. This is the traditional (classical) LIS technique. Receives: Procedure: Lateral Internal Sphincterotomy up to Dentate Line |
What is being measured
The primary outcome is the main question the study is designed to answer.
Fissure Healing Rate
Complete epithelialization of the anal fissure with no symptoms at 12 months postoperatively, assessed by clinical examination.
Measured: 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.
Measured: 12 months
Secondary outcomes (4)
Postoperative Pain Score
Pain assessed using the Visual Analog Scale (VAS, 0-10) at each follow-up visit.
Measured: 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.
Measured: Month 6 and Month 12
Patient Satisfaction
Patient satisfaction assessed on a numeric scale (0-10) at follow-up visits.
Measured: Month 2, Month 6, Month 12
Postoperative Complications
Rate of surgical complications including bleeding, hematoma, infection, abscess, and fistula.
Measured: 12 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Apr 2026
- Study start6 May 2026
- Primary completion6 May 2027 (estimated)
- Study completion6 May 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Chronic Anal FissureStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Three-arm parallel group randomized controlled trial comparing three lateral internal sphincterotomy techniques (spasm-controlled, up to fissure apex, and up to dentate line) in a 1:1:1 allocation ratio.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 150 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Çanakkale Onsekiz Mart University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Emre Gülçek, Çanakkale Onsekiz Mart University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07520552
- Sponsor's protocol ID
- CAF-LIS-RCT-2026-01
- Acronym
- SPHINX
- Status last verified
- May 2026
- First submitted
- 3 Apr 2026
- Last updated
- 14 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Elsebae MM. A study of fecal incontinence in patients with chronic anal fissure: prospective, randomized, controlled trial of the extent of internal anal sphincter division during lateral sphincterotomy. World J Surg. 2007 Oct;31(10):2052-7. doi: 10.1007/s00268-007-9177-1.
PubMed 17665247Mentes BB, Guner MK, Leventoglu S, Akyurek N. Fine-tuning of the extent of lateral internal sphincterotomy: spasm-controlled vs. up to the fissure apex. Dis Colon Rectum. 2008 Jan;51(1):128-33. doi: 10.1007/s10350-007-9121-3. Epub 2007 Dec 18.
PubMed 18085337Mentes BB, Ege B, Leventoglu S, Oguz M, Karadag A. Extent of lateral internal sphincterotomy: up to the dentate line or up to the fissure apex? Dis Colon Rectum. 2005 Feb;48(2):365-70. doi: 10.1007/s10350-004-0812-8.
PubMed 15711861