Utility of Ultrasound in the Evaluation of Chronic Anal Fissure

Introduction: Anal fissure is a linear tear in the anal mucosa seen distal to the dentate line. The diagnosis of chronic anal fissure depends on clinical history, physical exam, anoscopy and other imaging modalities are uncommonly recommended unless an associated condition was suspected. Management is either by chemical sphincterotomy or surgery through lateral internal sphincterotomy when chronic anal fissure was resistant to treatment. Purpose of the Study: The current study aimed to evaluate the sonographic findings that can be observed in cases with chronic anal fissure and their significance. Methodology: 15 asymptomatic patients and 30 patients with chronic anal fissure were examined with 3 dimensional transperineal ultrasound and if females an additional transvaginal ultrasound was performed. Results: 26 patients (86.5%) showed diffusely thickened internal anal sphincter of mean thickness >3.5mm, ranging from 3.7 mm to 6.4mm and the mean value was 5mm. 3 patients (10%) with posterior fissure showed a lucent narrow defect in the internal anal sphincter at the midline of the distal aspect of the anal canal wall. One of them showed associated localized intersphincteric plane sepsis. Conclusion: Use of ultrasound in cases with chronic anal fissure may show gapping of the internal anal sphincter and an associated intersphincteric plane sepsis corresponding to the high morphological grade of anal fissure which predict poor healing response to chemical sphincterotomy and further studies that correlate between the thickness and texture of IAS and the healing response to chemical sphincterotomy recommended.