Pattern of anatomic disorder and surgical management of anorectal prolapse in anorectal malformation

Due to the paucity of data and controversy regarding the etiology and surgical approach for managing anorectal prolapse (ARP) after anorectoplasty, we sought to investigate the underlying anatomic disorder and the surgical outcome in managing this challenging complication.

We performed a retrospective study on 83 patients with ARP related to anorectal malformations (ARM). Logistic regression analyses were performed to detect the risk factors for the ARP severity. Surgical procedures were stratified according to identified anatomical abnormalities and surgical outcomes were analyzed.

50 patients (62.7%) had high-type ARM. The original anorectoplasty had a higher rate of ARP in laparoscopic-assisted anorectoplasty (n = 49, 59.0%) versus posterior sagittal anorectoplasty (n = 11, 13.3%). ARP was associated with rectal fat hyperplasia (67.5%), dilated muscular tunnel (79.5%), longitudinal muscle (LM) discontinuity (16.9%), rectal dilation (22.9%), mislocated anus (7.2%), and excessive mobile mesorectum (3.6%). Based on the ARP severity, the patients were divided into a severe group (Group 1, n = 38) and a moderate group (Group 2, n = 45). Binary logistic regression analysis showed that hyperplasia rectal fat (OR 4.55, 95% CI 1.16–17.84), rectal dilation (OR 4.21, 95% CI 1.05–16.94), and high-type ARM (OR 2.90, 95% CI 1.14–7.39) were independent risk factors for the development of severe ARP. Complications after stratified surgical repair included wound infection in six patients (7.2%), anal stenosis in one patient (1.2%), and ARP recurrence in two patients (2.4%). Twenty-six patients without colostomy before prolapse repair were followed up for 2 to 12 years. All the patients maintained voluntary bowel movements. Following ARP repair, there was an overall higher rate of no soiling or grade 1 soiling (88.5 vs. 65.4%), but 3 of 12 patients with grade 2 constipation were upgraded to grade 3.

Our study shows that ARM-related anorectal prolapse is associated with excessive rectum, hyperplasia of rectal fat, mobile mesorectum, loose muscular tunnel, LM discontinuity, and anal mislocation. Surgical repair with techniques stratified according to the patients’ underlying risk factors is effective to prevent recurrence and improve the soiling continence.