GASTROGRAFFIN EVALUATION OF ANORECTAL ANOMALIES: A CASE REPORT Author: Dr. Swarnava Tarafdar Senior Resident, Department of Radiodiagnosis, A.I.I.M.S. Jodhpur

Background Anorectal malformations are congenital anomalies that occur in approximately 1 in 5000 live births. 20 to 70 % patients has associated congenital anomalies They have male predominance. Spine, genitourinary, gastrointestinal and cardiac system frequently affected. Associated genitourinary anomalies found in upto 26 % patients of anorectal malformation Skeletal anomalies such as sacral bony abnormalities found in upto 21% patients.

Background High anomaly: Gas bubble above the pubococcygeal line Intermediate anomaly: Gas between pubococcygeal line and Ischial line Low anomaly: Gas below ischial line PC - Pubococcygeal line I - Ischial line

International classification Anorectal agenesis High anomaly: MALES FEMALES Anorectal agenesis Rectal atresia Anorectal agenesis Rectal atresia Without fistula With fistula Without fistula With fistula Rectovesical Rectoprostatic urethral-most common type (including H or N type) Rectovesical Clocal anomalies Rectovaginal (High)

High Anorectal anomalies in males Rectoprostatic urethral fistula Rectovesica fistula H or N Type rectoprostatic urethral fistula Rectal atresia

High ARA in Females Rectovaginal fistula

Intermediate anomaly MALES FEMALES Anal agenesis Anorectal Stenosis Without fistula With fistula Without fistula With fistula Rectobulbar Rectovaginal (low) Rectovestibular

Intermediate anomaly Males: Anal agenesis with Rectobulbar urethral fistula Females: Rectovestibular fistula

Low anomalies MALES FEMALES At normal anal site At perineal site At vulvar site Anterior perineal anus Covered anus, complete Anterior perineal anus Covered anus, complete Anovulvar anus Anal stenosis Anocutaneous fistula Anovestibular fistula Anal stenosis Anocutaneous fistula Vulvar anus

Low anomalies Males: Anocutaneous fistula Female: Ano vestibular fistula

Various investigations in Anorectal anomalies Differentiate high , intermediate or low anomaly Presence of gas in the region of urinary bladder and vagina indicate underlying fistula. Invertogram RGU/MCU To confirm level of blind bowel pouch To demonstrate fistula Contrast studies Distal cologram Direct catheterisation

Various investigations in Anorectal anomalies USG Upper urinary tract congenital anomalies CT Bony/urinary abnormalities Demonstrate thickness of muscles-puborectalis sling and external anal sphincter ( deficiency leads to incontinence) MRI Better understanding the relationship between bowel with muscles in axial, coronal and sagittal planes

Objectives of Contrast study To confirm level of blind bowel pouch To confirm presence & level of fistula between Gastrointestinal & Genitourinary system. To see for associated bony abnormalities if present

Clinical history Procedure details A 4 year old male, operated case for imperforate anus (Transverse loop colostomy done). On clinical examination patient had associated cleft palate and hypospadias. Procedure details Study was done using diluted gastrograffin given through infant feeding tube in distal stoma of colostomy and serial radiographs were taken under fluoroscopic guidance.

Findings The rectum was abruptly narrowed proximal to pubococcygeal line Beaking of blind rectal pouch Acute backward angulation of posterior urethra Communicating fistulous tract between urethra and distal rectum The distal urethral opening in underside of glans penis The visualised sacral spine shows S2 hemivertebra and S4 butterfly vertebra

Acute backward angulation of posterior urethra communicating fistulous tract between urethra and distal rectum-rectoprostatic fistula

The rectum was abruptly narrowed proximal to pubococcygeal line with beaking of blind rectal pouch.

The visualised sacral spine shows S2 hemivertebra and S4 butterfly vertebra Anal site marker

Conclusion Distal loop cologram is useful study to confirm level of blind bowel pouch, presence and level of fistula between gastrointestinal & genitourinary system. Ano-rectal atresia is commonly associated with high rectourethral fistula in which Rectoprostatic fistula is common type. In skeletal anomalies, sacral bony abnormalities are common which can be demonstrated in plain radiograph.

References Stephens FD, Smith ED. Anorectal Malformation in Children Chicago; Year Book Medical Publishers, 1971. Wangensteen OH, Rice CO, Imperforate anus-a method of determining the surgical approach, Ann surg 1930; 92:77. Cremin BJ. The radiological assessment of anorectal anomalies, Clin Radiol 1971;22:239. Silverman F (Ed). Caffey’s Pediatric X-Ray Diagnosis (8th ed)Chicago: Year Book Medical Publishers 1985; 2:1863-73. Stephens FD, Smith ED, Paul NW. Anorectal malformation in children-update 1988. Birth defects 1988;24(4).