RA is defined by the presence of a normally developed anus with no communication with the proximal colon [3, 5]. Unlike other types of ARM, the sphincter is well developed, and a good functional outcome is usually expected [5]. The anal canal might be about 1–3 cm in length [5]. In the Ladd and Gross classification, it was described as type 4 ARM [6]. RA is classified into 5 subgroups [5], as illustrated in Fig. 4. Our patient had a type 3 RA according to Sharma and Gupta [5], which is the most common type [5]. Due to its rarity and the normal external appearance of the anus, the diagnosis is delayed [3, 7]. It manifests with failure to pass meconium, abdominal distention, and vomiting [1]. Although intestinal perforation in closed-loop intestinal obstruction is well known, its incidence in cases of ARM is variable, probably due to underreporting [8]. A diagnostic delay of more than 48 h is usually reported [8]; however, digestive tract perforations could happen earlier, as in our case. Sites of preoperative intestinal perforations vary, 68% in the recto-sigmoid; 18% in the cecum and proximal ascending colon, as in our case; 9% in the transverse colon; and 5% in other locations [8]. The classical approach for RA has been colostomy and delayed anastomosis [9]. Many different surgical procedures have been described [3, 7], ranging from simple perforation of the atresia, posterior sagittal anorectoplasty, and sacroabdominoperineal pull-through with widely different results [7]. These procedures involve dissection and division of pelvic floor muscles [2] and the resection of the anal canal [1, 9]. Hamrick et al. managed rectal atresia by modified posterior sagittal anorectoplasty, saving the anterior wall of the anal canal and dissecting the posterior wall only [3]. The advantage behind their approach is saving at least part of the anal canal and avoiding the complications of dissection within the anterior perineum and thus avoiding urethral, vaginal, vasal, and bladder injuries [1].
In our case, we chose to approach the RA by a transanal pull-though. The advantages of this technique are numerous. First of all, using this technique we were able to spare the totality of the anal canal [10]. Second of all, we did not need to dissect the pelvic floor muscles and a double approach was not needed since the proximal rectal pouch was low in the pelvis. Finally, it was a scar-less approach. Despite all those advantages, the downsides of this approach are known from experiences derived from Hirschsprung’s disease: sphincter dilatation and adjacent hollow organs injuries. During the surgery in our case, only minimal anal sphincter retraction was practiced. The fibrous cord was avascular, and it had a small diameter. So a large working space in order to advance the dissection and the pull-through was not needed, contrary to the situation in Hirschsprung’s disease. Regarding the injury of other adjacent hollow organs, a meticulous step-by-step dissection by experienced hands was needed and was sufficient in order to avoid complications.
This entity is very rare and we had seen only one case. Although this technique is highly reproducible in the settings of Hirschsprung’s disease, we need to practice it more in the case of RA before confirming its reproducibility.
