Can Inflammatory Index Parameters Be an Indicator of Complexity in Perianal Fistula?

Perianal fistulas, although benign, may cause significant morbidity and impaired quality of life, particularly when associated with complex anatomical features. Accurate preoperative assessment is crucial to optimize surgical outcomes. This study aimed to investigate whether routine inflammatory indices could predict fistula complexity.

This retrospective study included 134 patients who underwent surgery for perianal fistula at a single tertiary care center between 2013 and 2021. Demographic, clinical, and laboratory data were collected, and preoperative magnetic resonance imaging findings were re-evaluated by a single blinded radiologist. Inflammatory indices, including lymphocyte-to-C-reactive protein (CRP) ratio (LCR), neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, CRP-to-albumin ratio (CAR), lymphocyte-to-monocyte ratio, and neutrophil-to-CRP ratio (NCR), were analyzed in relation to magnetic resonance imaging-determined complexity criteria. Statistical analyses included receiver operating characteristic curve analysis and multivariate logistic regression.

Abscess formation was present in 30.9% of patients, and perifistular inflammation in 52.5%. LCR, CAR, and NCR demonstrated significant associations with tract length, tract thickness, abscess presence, and perifistular inflammation. Receiver operating characteristic analysis revealed high diagnostic accuracy of these indices for predicting complex features. Multivariate analysis identified LCR <0.28, CAR >1.52, NCR <0.43, tract thickness >3.2 mm, and tract length >47 mm as independent predictors of fistula complexity.

Preoperative inflammatory indices, particularly LCR, CAR, and NCR, may serve as accessible and valuable markers for predicting perianal fistula complexity. Integrating these parameters into preoperative evaluation may assist in identifying patients who require further imaging and more meticulous surgical planning, potentially improving clinical outcomes.