Imaging in anorectal malformations: What does the surgeon need to know?

Abstract

Imaging is essential in the diagnosis, management, surgical planning and eventual outcome in patients with anorectal malformation (ARM). This article outlines the imaging that may be required and the information needed by the surgeon to attain the best possible surgical outcome. ARM encompasses a wide spectrum of congenital malformations relating to the distal rectum and anus as well as the urinary and or gynaecological systems. The malformations range from a relatively simple perineal fistula with the potential for an excellent functional outcome, to complex cloacal malformation that requires specialist care and intervention. Approximately half of these children will have associated abnormalies. In the first 24–48 hours of life, imaging is used to determine if any associated anomalies are severe enough to preclude an operation, and what operation will be required so that the child can grow as normally as possible. If a colostomy is done, pre-definitive repair imaging in the form of a high-pressure distal colostogram determines the surgical approach required to repair the malformation. In more complicated cases of cloacal malformation, advanced imaging in the form of MRI or 3D fluoroscopy is valuable. In the South African setting, 2D fluoroscopy with the surgeon present is adequate to help in planning for the surgical management. Communication between the radiologist and paediatric surgeon is essential to ensure that such patients have the best possible outcome.

Overview of Anorectal Malformations in Africa

“…Imaging support is crucial in the care of patients with ARM ( 83 ). This includes abdominal and pelvic ultrasound scans to evaluate associated urinary and reproductive tract malformations shortly after birth, cross table lateral radiograph to classify the malformation and a high pressure distal colostogram ( Figure 4 ) to define the specific type of rectourethral fistula in boys ( 1 , 25 , 83 , 84 ).…”

“…This includes abdominal and pelvic ultrasound scans to evaluate associated urinary and reproductive tract malformations shortly after birth, cross table lateral radiograph to classify the malformation and a high pressure distal colostogram ( Figure 4 ) to define the specific type of rectourethral fistula in boys ( 1 , 25 , 83 , 84 ). Others include radiographs to prognosticate the condition and magnetic resonance imaging (and ultrasound scan) to define the anatomy, screen for tethered cord and evaluate for other associated malformations ( 25 , 83 – 86 ). While basic imaging is available in many centers, many patients will not benefit from some important evaluations because of absence of facilities, lack of radiologist, lack of fluoroscopy guidance or economic considerations ( 87 ).…”

Accuracy of pre-operative fistula diagnostics in anorectal malformations

“…A standard method to estimate fistula presence is pre-operative registration of symptoms: stool-colored urine, urinary tract infection (UTI), and urine in diverted ostomy. Pre-operative radiologic examinations for fistula level determination traditionally include high-pressure colostogram [ 13 ], possibly combined with voiding cystourethrogram (VCUG) including additional urinary tract anomaly diagnostics [ 14 , 15 ]. Other methods to establish uro-genital and fistula anatomy include peri-operative cystoscopy and ostomy endoscopy of the atretic rectum [ 16 ].…”

Frequency of congenital cardiac anomalies in patients with anorectal malformations.

“…Other systems affected with associated anomalies are cardiovascular, gastrointestinal tract (GIT), vertebra, and nervous system. 4,5 Unlike normal newborns, the frequency of CHDs is greater in patients with malformations of GIT. In general population the incidence of CHD is <1%, but the significant association between major GI malformations and CHDs has been historically emphasized.…”