Magnetic Resonance Evaluation Of Anorectal Malformation Cases Treated By Posterior Sagittal Anorectoplasty

OBJECTIVES: Pelvic MRI is a useful tool for assessing patients with anorectal malformations before and after operation. The images obtained after PSARP can be reviewed for quality and shape of the sphincter muscle, position of the rectum, shape of the sacrum, and associated pelvic abnormalities related to the initial operation. These were then correlated with the clinical status of the patient during follow-up after colostomy closure. MATERIALS AND METHODS: Twenty six male patients with intermediate or high anorectal malformation were included in the study between January 2012 to December 2013. The findings thus obtained in the MRI were correlated clinically with the Kelley's scoring system. RESULTS: A total of 26 post-PSARP patients were included in the study. Eighteen of them were also selected for clinical correlation after colostomy closure. According to MRI findings, 2 patients had good degree of development of the pelvic floor muscles, 11 of them had fair amount of muscles and the rest 13 of them had significantly thinned out muscles. Four patients showed well-developed external sphincter muscle, 15 of them were having fair degree of development and in the rest 7 of them it was poorly-developed. Our study also showed that only 3 patients were showing symmetrical development of the sphincter complex whereas in the rest 23 of them it was asymmetrical. Eighteen patients had centrally-placed pulled-through rectum, whereas in the rest 8 of them the colon was located away from the center of the sphincter complex. Sixteen patients had mesenteric fat inadvertently pulled along with the bowel during PSARP; and in this same study, 58% of our patients were also having associated anomalies detected by MRI. On clinical correlation, it was found that external sphincter muscle and fat interposition play an important role in the overall clinical status of the patients after colostomy closure. CONCLUSION: Pelvic MRI is a useful tool for assessment of anorectal malformation after PSARP. Our study shows that development of the external sphincter muscle and the presence of mesenteric fat interposition has significant impact on the overall clinical status of the patient; however, other factors like operative technique and muscle innervations may also play important role in the overall continence of the patients. KEYWORDS: Anorectal malformation, MRI.