Hydrogen Peroxide-Enhanced 3D Endoanal Ultrasonography: Still a Key Tool in the Diagnosis of Fistula-in-Ano. Single-Center Experience

Abstract Purpose This study aimed to evaluate the relevance of endoanal ultrasound (EAUS) in the diagnosis of cryptoglandular perianal fistulas, to identify the internal opening, and to assess the benefit of H2O2 enhanced three-dimensional endoanal ultrasound (3D-EAUS), 2D ultrasound, and 3D printed model. Methodology An eight-year analysis of 282 patients examined with endoanal ultrasonography and subsequently operated for perianal fistula. Patients were divided into two groups for comparison: group A, 164 patients, had 3D image reconstruction, and group B, 118 patients, did not. Intraoperative findings were considered standard reference for comparison with clinical examination and EAUS findings. Results The accuracy of preoperative and perioperative findings regarding fistula morphology was higher in all cases of perianal fistula in group A patients. A statistically significant difference was found when evaluating the correlation between preoperative findings and operative findings in the whole group of patients (p < 0.0001), in the diagnosis of the primary tract (p < 0.0001), secondary tract (p = 0.010), and in trans sphincteric fistulas (p = 0.0001). 3D ultrasound was also more accurate in diagnosing internal fistula orifice in the whole group (p < 0.0001), in the primary tract group (p = 0.0002), and in patients with trans sphincteric fistula (p = 0.0005). Conclusions The use of an H2O2-enhanced 3D EAUS in diagnosing anorectal fistulas has the potential to significantly increase the diagnostic efficacy of ultrasound due to its high agreement with intraoperative assessment and to facilitate surgical planning.