A Novel MRI and Clinical-Based Scoring System to Assess Post-Surgery Healing and to Predict Long-Term Healing in Cryptoglandular Anal Fistulas

Pankaj Garg,1,2 Vipul D Yagnik,3 Sushil Dawka,4 Baljit Kaur,5 Geetha R Menon6 1Department of Colorectal Surgery, Indus Super Specialty Hospital, Mohali, Punjab, India; 2Department of Colorectal Surgery, Garg Fistula Research Institute Surgery, Panchkula, Haryana, India; 3Department of Surgical Gastroenterology, Nishtha Surgical Hospital and Research Centre, Patan, Gujarat, India; 4Department of Surgery, SSR Medical College, Belle Rive, Mauritius; 5Department of Radiology, SSRD MRI Imaging Centre, Chandigarh, Haryana, India; 6National Institute of Medical Statistics, Indian Council of Medical Research, New Delhi, IndiaCorrespondence: Pankaj Garg, Department of Colorectal Surgery, Indus Super Specialty Hospital, Mohali, Punjab, 140507, India, Fax +91 9501011000, Email drgargpankaj@yahoo.comBackground: Anal fistulas cause great uncertainty and anxiety in patients and surgeons alike. This is largely because of the inability to accurately confirm postoperative fistula healing, especially long-term healing. There is no scoring system available that can objectively assess cryptoglandular anal fistulas for postoperative healing and can also accurately predict long-term healing.Methods: Several parameters that could indicate anal fistula healing were assessed. Out of these, six parameters (four MRI-based and two clinical) were finalized, and a weighted score was given to each parameter. A novel scoring system (NSS) was developed. A minimum possible score (zero) indicated complete healing whereas the maximum weighted score (n = 20) indicated confirmed non-healing. Scoring was done with postoperative MRI (at least 3 months post-surgery), then compared with the actual healing status, and subsequently correlated with the final long-term clinical outcome.Results: The NSS was validated in 183 operated cryptoglandular fistula-in-ano patients over a 3-year period in whom 283 MRIs (preoperative plus postoperative) were performed. The postoperative follow-up was 12– 48 months (median-30 months). The NSS was found to have a very high positive predictive value (98.2%) and moderately high negative predictive value (83.7%) for long-term fistula healing. Additionally, its sensitivity and specificity in predicting healing were 93.9% and 94.7%, respectively.Conclusion: Thus, this new scoring system is highly accurate and would be a useful tool for surgeons and radiologists managing anal fistulas. By objectivizing the assessment of postoperative healing, it can both ease and streamline management. Moreover, reliable prediction of recurrence-free long-term healing will greatly allay the apprehensions associated with this dreaded disease.Keywords: anal fistula, MRI, postoperative, scoring system, internal opening, healing