Ultrasound Guided Wire Localization of Anal Tract in Imperforate Anus

Objectives: The present study aimed to investigate the efficacy of the ultrasound-guided wire localization of the anal tract and sphincter muscle complex in the patients with imperforate anus. Methods: This study was conducted on 20 patients (4 females and 16 males) with imperforate anus referring to the Doctor Sheikh and Akbar Pediatric Hospitals, Mashhad, Iran, between2016 and 2017. The trans-perineal ultrasonography was performed under general anesthesia to identify the location and direction of the anal tract, which was checked by a muscle stimulator. Then, the localization needle was inserted in the center of the anal pit and anal sphincter muscle complex until it reached the rectal pouch. Eventually, by using the wire as a guide, the rectum was brought to the middle of the sphincter complex through the minimally invasive pull-through procedure. Results: The anal sphincter muscle complex (concentric hypoechoic muscle) could be seen in all patients with the thickness of 1.8 - 3.6 mm and mean of 2.6 mm. The anal pit (the multi-layer view) was visualized in all patients, except in two cases with clinically lowtype imperforate anus. Muscle stimulator findings showed that the wire was located in the middle of the sphincter muscle complex in all patients. Mean localization time was 38 min. Conclusions: The ultra sound-guided wire localization of the anal tract facilitated the implementation of a less invasive and anatomically corrected rectal pull-through operation in patients with imperforate anus.