The surgical treatment of low anal defects and vestibular fistulas.

A series of 227 patients with what are traditionally known as "low" anorectal malformations (ARM) are presented. Perineal fistulas (PF; n = 108), anterior perineal anus (APA; n = 22), and vestibular fistulas (VF; n = 97) represented 73% of the 309 patients with ARM operated on primarily. Diagnosis was based on perineal inspection. In cases of PF and APA, the rectum opens at the perineal skin, anterior to the normal site. Associated malformations were found in 23% of patients with PF and in 13% of patients with APA. Anoplasty without a colostomy was performed in patients with PF. Normal continence was achieved in 93.3%, and constipation occurred in 47%. In patients with APA and intractable constipation, a partial sphincterotomy relieved painful evacuations in 96%. VF is not a low defect; the rectum opens in the vaginal introitus, and dissection of the rectovaginal common wall is necessary for reconstruction. In neonates with VF, the authors performed a sigmoid colostomy followed by a limited posterior sagittal anorectoplasty at 2 months of age. Of the 97 patients with VF, associated malformations were found in 57%. Continence was evaluated in 67 patients with repaired VF. Normal continence was found in 71% and constipation in 50%. Only one patient with VF experienced severe complications and incontinence, after surgical mismanagement. Precise clinical diagnosis and meticulous surgical technique are essential in the management of these benign malformations.