Changes in the Distance Between the Distal Rectal Pouch and Perineum From the Birth Day to the Next Day in Neonates With an Imperforate Anus

Abstract

The pouch-perineum distance was shorter on the next day than on the birth day, and the diagnostic performance of the pouch-perineum distance on the next day was significantly superior to that on the birth day for the diagnosis of a low-type imperforate anus. We recommend sonography on the next day in neonates with an imperforate anus when possible.

Comparison of Diagnostic Accuracy for the Low‐Type Imperforate Anus Between Prone Cross‐Table Radiography and Sonography

“…We report a 40% false‐negative rate for the diagnosis of a low‐type imperforate anus when using only the pouch‐perineum distance on sonography. It has been reported that meconium is produced after birth in neonates with an imperforate anus as well as in healthy neonates . Therefore, the possibility exists that we could not accurately determine the rectal mucosal position as the base of the pouch because of a collapse of the rectal mucosa on the day of birth.…”

“…Therefore, the possibility exists that we could not accurately determine the rectal mucosal position as the base of the pouch because of a collapse of the rectal mucosa on the day of birth. Actually, the diagnostic performance for the type of imperforate anus according to the pouch‐perineum distance has been reported to be worse on the day of birth day than on the day after birth . Sonographic examinations performed both on the day of birth and the day after birth were included in our study, which might have accounted for the high false‐negative rate of sonography.…”

“…All sonograms were obtained by using a real‐time scanner with a high‐resolution 9–15‐MHz linear transducer (LOGIQ 7, E9, and S8; GE Healthcare, Waukesha, WI) via longitudinal scanning by a suprapubic approach, as previously described by Donaldson et al and Hosokawa et al The neonates were examined in the supine position without specific preparation, and a marker indenting the anal dimple helped identify the skin level. Grayscale images were obtained by 1 of 4 board‐certified diagnostic radiologists (10, 15, 15, and 25 years of experience).…”

“…Care was taken not to press or indent the skin or to diminish the pouch‐perineum distance . The diagnostic performance of the pouch‐perineum distance on the day after birth is reported to be superior than that on the day of birth . Therefore, if the neonate had been examined by sonography both on the day of birth and on the day after birth, the pouch‐perineum distance on the day after birth was used.…”

“…Prone cross‐table radiography should be performed 20 to 24 hours after the initial examination to allow time for intraluminal pressure in the rectal pouch to increase . Previous studies have shown that sonography is useful for classifying the imperforate anus type both by establishing the distance between the distal rectal pouch and the perineum (pouch‐perineum distance) and by establishing the location of the fistula . However, to the best of our knowledge, there have been no reports comparing the accuracy of diagnosing the imperforate anus type by using prone cross‐table radiography versus sonography.…”