Structured magnetic resonance imaging and endoanal ultrasound anal fistulas reporting template (SMART): An interdisciplinary Delphi consensus

Background: There is still considerable heterogeneity regarding which features of cryptoglandular anal fistula on magnetic resonance imaging (MRI) and endoanal ultrasound (EAUS) are relevant to surgical decision-making. As a consequence, the quality and completeness of the report are highly dependent on the training and experience of the examiners.

Aim: To develop a structured MRI and EAUS template (SMART) reporting the minimum dataset of information for the treatment of anal fistulas.

Methods: This modified Delphi survey based on the RAND-UCLA appropriateness for consensus-building was conducted between May and August 2023. One hundred and fifty-one articles selected from a systematic review of the literature formed the database to generate the evidence-based statements for the Delphi study. Fourteen questions were anonymously voted by an interdisciplinary multidisciplinary group for a maximum of three iterative rounds. The degree of agreement was scored on a numeric 0-10 scale. Group consensus was defined as a score ≥ 8 for ≥ 80% of the panelists.

Results: Eleven scientific societies (3 radiological and 8 surgical) endorsed the study. After three rounds of voting, the experts (69 colorectal surgeons, 23 radiologists, 2 anatomists, and 1 gastroenterologist) achieved consensus for 12 of 14 statements (85.7%). Based on the results of the Delphi process, the six following features of anal fistulas were included in the SMART: Primary tract, secondary extension, internal opening, presence of collection, coexisting lesions, and sphincters morphology.

Conclusion: A structured template, SMART, was developed to standardize imaging reporting of fistula-in-ano in a simple, systematic, time-efficient way, providing the minimum dataset of information and visual diagram useful to referring physicians.