Ultrasound Guided Wire Localization Of Anal Tract In Imperforate Anus Patients

Abstract

<strong>Objectives:</strong> The exact anus reconstruction is critical in patients with imperforated anus. It is related to the correct diagnosis of sphincter complex. The aim of this study was accurate investigation of the perineal region for ultrasound detection of the location and pathway of sphincter muscle complex and the efficacy of the ultrasound-guided wire localization of the anal tract and sphincter muscle complex in the patients with imperforate anus. <strong>Methods:</strong> This study was conducted on 34 patients with imperforate anus referring to the Doctor Sheikh and Akbar Pediatric Hospitals, Mashhad, Iran, between2016 and 2018. 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 two multi-layer structure in surface and depth of perineal area 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.

<strong>Results:</strong> The deep concentric hypoechoic structure (probably levator ani muscle) could be seen in all patients with the thickness of 1.8 – 5.8 mm and occasionally asymmetric. The superficial multi-layerview structure (the anal pit probably contains of subcutaneous and superficial external muscle complex and parasagittal fibers) is visualized in all patients. These two had a curved and occasionally parasagittal pathway. The shortest distance between the rectal pouch and skin was 8 to 20 mm, but the distance between the rectal pouch and skin via the muscle sphincter path was longer (11 to 23 mm). 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.

<strong>Conclusions:</strong> in imperforate anus patients, two anatomic- sonographic structure as multi-layer view in surface and depth of perineal area were seen that adapted with anal pit (subcutaneous and superficial external muscle sphincter) and the levator ani muscle. These two important sonographic findings can act as an indicator for the location of this procedure. 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.