ASG-LIFT
Autologous Skin Graft Intersphincteric Implantation versus Standard LIFT for complex cryptoglandular transsphincteric anal fistula.
An international, prospective, multicentre, randomized controlled trial designed to compare healing, recurrence, treatment failure and fistula conversion after two sphincter-preserving surgical strategies.
A direct randomized comparison of ASGIIFT and standard LIFT.
The ASG-LIFT Trial is being developed to provide multicentre comparative evidence for two sphincter-preserving approaches to complex cryptoglandular transsphincteric anal fistula. The ASGIIFT procedure retains the standard LIFT pathway and adds implantation of an autologous dermal graft in the intersphincteric space.
Design
Prospective, multicentre, parallel-group randomized controlled trial.
Allocation
Central concealed allocation to ASGIIFT or standard LIFT.
Population
Complex cryptoglandular transsphincteric anal fistula meeting MRI-defined criteria.
Follow-up
Structured clinical follow-up for 12 months from the date of the index operation. Follow-up assessment is clinical only; routine postoperative MRI or ultrasound is not required.
What ASG-LIFT is designed to answer.
Where ASG-LIFT is today.
The trial is in protocol-development phase. Recruitment should begin only after the final protocol, statistical analysis plan, EDC, ethics approvals and site onboarding are complete.
Protocol development
In progressCentre expressions of interest
In progressEthics & regulatory approvals
PlannedEDC build & pilot
PlannedTrial activation
Planned for 1 Jan 2027A standardized journey, captured prospectively.
Screening & MRI
Clinical assessment, pelvic MRI, fistula anatomy and eligibility confirmation.
Consent & randomization
Written informed consent followed by concealed central 1:1 randomization.
Index operation
ASGIIFT or standard LIFT using the harmonized operative protocol.
Early healing phase
Structured wound review, healing assessment, pain and complication capture.
Long-term follow-up
Recurrence, non-healing, conversion, continence, pain and reintervention through 12 months using clinical assessment only.
ASGIIFT
Standard LIFT steps with implantation of a prepared autologous dermal graft into the intersphincteric space.
Standard LIFT
Ligation of the intersphincteric fistula tract using the standardized LIFT pathway without dermal graft implantation.
Provisional sample-size target
100 participants total — 50 per arm. This is the current planned recruitment target for the multicentre randomized trial. The final sample-size justification should be confirmed in the statistical analysis plan before trial activation.
Eligibility mirrors the published ASGIIFT cohort.
Final criteria will be locked in the protocol before trial activation. MRI is central to preoperative eligibility assessment.
Inclusion criteria
- Age ≥18 years.
- Complex cryptoglandular transsphincteric anal fistula.
- More than 30% involvement of the external anal sphincter.
- Single fistula tract.
- Maximum tract length ≤10 cm on preoperative pelvic MRI.
- Eligible for both randomized procedures under the final operative protocol.
- Written informed consent.
- Patient treated at a participating centre performing at least 50 sphincter-preserving anal fistula procedures per year.
- Index operation performed by a surgeon with ≥50 prior LIFT procedures during their career and a documented primary healing rate ≥60%.
Exclusion criteria
- Suprasphincteric or extrasphincteric fistula.
- Low simple transsphincteric fistula.
- Crohn's disease.
- Intersphincteric or extrasphincteric collections requiring exclusion under the final MRI definition.
- Extension into the ischioanal fossa.
- Any condition that prevents safe performance of either randomized technique or protocol follow-up.
Healing, failure, recurrence and conversion.
Sustained clinical fistula healing at 12 months
Clinical healing is defined as complete epithelialisation of the skin at the site of the previous external fistula opening, with no pain, swelling, discharge or other clinical signs of recurrence. Follow-up is clinical only and continues for 12 months from the index operation; routine postoperative MRI or ultrasound is not required.
Planned minimum dataset domains.
The final trial database should contain only pseudonymised research data. Direct patient identifiers remain at the local site.
Centre & eligibility
Centre code, local trial ID, consent, eligibility checklist and screening status.
Demographics
Year of birth, sex, smoking status and relevant baseline characteristics.
Fistula history
Duration of symptoms, primary versus recurrent disease, prior procedures and seton history.
MRI anatomy
Location, tract length, sphincter involvement, single-tract status, collections and extensions.
Operative data
Randomized arm, internal opening identification, operative duration, protocol adherence and complications.
Follow-up outcomes
Clinical healing, recurrence, non-healing, conversion, fistulotomy, pain (VAS at follow-up), Wexner score and reinterventions.
Investigator EDC portal
The live database should use role-based authentication, audit trail, data validation and a GCP/GDPR-compliant electronic data capture platform. This public website should never be used to submit patient clinical data.
An international collaborative network.
Colorectal and proctology centres in Croatia and internationally can express interest before formal onboarding. Participation requires local approvals, training and adherence to the shared trial protocol.
Who should join?
- Specialist colorectal or proctology units treating complex anal fistula.
- Minimum centre volume: at least 50 sphincter-preserving anal fistula procedures per year.
- Centres with established experience in LIFT and sphincter-preserving fistula surgery.
- Each participating surgeon must have performed at least 50 LIFT procedures during their career and must document a primary healing rate of at least 60% for their own previous LIFT cases.
- Academic and non-academic hospitals.
- Centres able to provide preoperative pelvic MRI and structured 12-month follow-up.
- Teams willing to complete ASGIIFT protocol training before recruitment.
Expression of interest
Preview only. No form data are transmitted from this offline demonstration.
Do not submit patient-identifiable or clinical data through the public website.
Planned trial oversight and data protection.
International steering group
Scientific leadership, protocol oversight, site onboarding and publication strategy. Participating centres must document ≥50 sphincter-preserving anal fistula procedures/year. Each submitting surgeon must have performed ≥50 LIFT procedures during their career and have a documented primary healing rate ≥60%.
Randomized trial protocol
Pre-specified eligibility, operative standards, outcome definitions and statistical analysis.
Central pseudonymised EDC
Role-based access, audit trail, validation rules and no transfer of direct patient identifiers.
Local ethics & approvals
Each participating site obtains the approvals required by its country and institution before recruitment.
Data quality monitoring
Range checks, missing-data review, query resolution and periodic site feedback.
Collaborative authorship
A transparent publication policy recognizing participating sites and investigators.
Documents in development.
Full trial protocol
Background, objectives, eligibility, interventions, endpoints and follow-up.
Statistical analysis plan
Primary estimand, sample size, randomization, missing data and sensitivity analyses.
eCRF & data dictionary
Standardized variables and definitions for participating centres.
Operative manual
Standardized LIFT and ASGIIFT operative steps and protocol-deviation rules.
Site onboarding manual
Training, credentialing, ethics, activation and data-entry workflow.
Publication & authorship policy
Transparent contribution and collaborative authorship rules.
Frequently asked questions.
Is ASG-LIFT already recruiting?
No. This preview represents a trial in development. Recruitment should start only after protocol finalization, ethics and regulatory approvals, EDC validation and formal site activation.
How are patients allocated?
The planned design uses concealed central 1:1 randomization to ASGIIFT or standard LIFT, with centre-level stratification and additional stratification to be finalized in the statistical plan. Each participant is followed for 12 months from the date of the index operation.
Which patients are eligible?
Adults with complex cryptoglandular transsphincteric anal fistula meeting the MRI-defined criteria derived from the published ASGIIFT study. Final criteria will be locked in the protocol.
What are the main outcomes?
Sustained healing, recurrence, persistent non-healing/treatment failure, conversion to an intersphincteric fistula, continence, complications and reintervention.
Is MRI or ultrasound required during follow-up?
No. Follow-up is based on structured clinical assessment only. Routine postoperative MRI and ultrasound are not part of the planned follow-up protocol.
Where will patient data be stored?
Clinical trial data should be entered only into a secure pseudonymised EDC with role-based access and audit trail. The public website is for information and centre contact only.
Which surgeons can participate?
Participating surgeons should have performed at least 50 LIFT procedures during their career and should be able to document a primary healing rate of at least 60% for their own previous LIFT cases.
Can centres outside Croatia participate?
Yes. The project is intended as an international multicentre trial, subject to local regulatory, ethics and site-activation requirements. Participating centres must meet the predefined annual procedural-volume criteria.