Ultrasound-Guided Percutaneous Transperineal Anorectoplasty of Low Imperforate Anus Without Fistula

Abstract

Background: Primary anoplasty of low imperforate anus depends on precise identification of the midpoint of the sphincter complex. Despite the use of the Peña muscle stimulator, the location of the deep sphincter anatomy can be challenging. We hypothesized that the addition of ultrasound guidance and endoscopy (when a colostomy is present) would enhance the localization of the sphincter complex and thus allow for a less invasive, percutaneous transperineal anorectoplasty. Methods and Results: Four neonates (three boys and one girl) presented following term and uncomplicated pregnancies with a low imperforate anus without associated genitourinary fistula or other congenital anomalies. All patients had a well-developed perineal musculature on physical examination and on ultrasound appeared to have a rectal pouch within 10 mm of the skin, for which they underwent an ultrasound-guided percutaneous transperineal anorectoplasty as follows (video run time 4 minutes, 24 seconds). In the operating room, under general anesthesia and in a lithotomy position, aided by muscle stimulation, an ultrasound examination identified the superficial and deep sphincter complex as well as the levator muscles. With a Seldinger technique, a needle followed by a guidewire was advanced under ultrasound guidance to the sphincter midpoint. The tract was dilated using sequential over-the-wire dilators of a gastrostomy kit, and the resulting mucosal edges were sutured across the dilated defect to the perianal skin with interrupted absorbable sutures. One of the four patients in our cohort, presented to us at 11 weeks of age with a history of neonatal colonic perforation from the imperforate anus that resulted in a diverting colostomy. We sought to enhance our technique with the addition of endoscopy. In the operating room, a flexible endoscope was advanced through the distal stoma, demonstrating rectal concentric rings that transitioned to anoderm at the dentate line, with converging folds of mucosa pointing to a central focal point. Aided by transillumination, muscle stimulation, and ultrasound guidance, a similar percutaneous transperineal anorectoplasty was effectively performed. All patients underwent planned serial anal dilations and have demonstrated satisfactory outcomes with good bowel function and continence at follow-up intervals that ranged from 1 to 6 years. Specifically, none of the patients has required cecostomy/appendicostomy, enemas, or other corrective procedures. Conclusions: Ultrasound-guided percutaneous transperineal anorectoplasty can be advantageous in a select group of healthy term newborns, with low imperforate anus, who lack associated fistula or other major congenital anomalies. Ultrasound guidance enhances the Peña muscle stimulation, and when a colostomy is present, endoscopy through the distal limb with transillumination can further localize the midpoint of the distal rectum. The blind end of the atretic rectum contains the anoderm that can be preserved by this percutaneous minimally invasive approach. No competing financial interests exist. Runtime of video: 4 mins 24 secs