THE ROLE OF RADIOLOGY IN CHILDREN WITH ANORECTAL ANOMALIES - WITH PARTICULAR EMPHASIS ON MRI

Anorectal anomalies have a reported incidence of between 1 per 1000 an d 1 per 9630 live births [1]. The international classification subdivi des anorectal malformations into high, intermediate, low and miscellan eous deformities with emphasis on the sex of the child [2]. The classi fication is based on where the rectum terminates in relation to the le vator ani muscles - above the levator is termed a high (supralevator) lesion, at the level of the levator intermediate, and below is a low o r translevator anomaly. A modified classification has recently been pr oposed by Pena based on his anatomic observations during posterior sag ittal anorectoplasty - the terms high, intermediate and low lesions co ntinue to be used but with slightly different connotations [3]. Approx imately 50% of all patients with anorectal anomalies have associated o ther congenital lesions. These lesions necessitate a variety of radiol ogical investigations which will be outlined briefly. The pertinent mu scular anatomy of the pelvic floor and recent advances in surgical tec hniques will be discussed. The particular role of MRI in the evaluatio n of the pre-operative newborn or infant prior to definitive pull-thro ugh repair surgery and the post-operative, older, paediatric patient w ith continuing problems will be reviewed. Reference to the other radio logical options, and their usefulness, in the evaluation of anorectal malformations will be made throughout the text. (C) 1998 Elsevier Scie nce Ireland Ltd.