Ultrasound imaging of the anorectal malformation during the neonatal period: a comprehensive review

Abstract

Anorectal malformation (ARM) is classified as low, intermediate, or high; accurate diagnosis of the type during the early neonatal period is important to determine the appropriate initial surgical approach. This review assesses the role of ultrasound examination in the classification of ARM during the neonatal period, with a focus on landmarks on the sonogram, the approach used for sonography, and the optimal examination timing. The following three factors on the sonogram are used for the classification: location of the fistula, the distance between the distal rectal pouch and the anal dimple (perineum) (P-P distance), and the relationship between the puborectalis muscle and the distal rectal pouch. Three approaches can be used to evaluate ARM by ultrasonography, namely, suprapubic, perineal, and infracoccygeal approaches. Each approach has its own advantages and disadvantages. Optimal timing of the ultrasound examination is also important with respect to each factor to classify ARM. We have described the pitfalls of ultrasound in diagnosis of cases, namely ARM with Down syndrome (which tends to be without fistula), ARM with low birth weight, ARM with unusual location of fistula, ARM with opened fistula (where the P-P distance is unreliable), and cloacal malformation (variation of the high-type ARM).

Risk factors for anorectal and associated malformations in German children: A 10-year analysis

“…34 This has been also demonstrated by Jonker et al, who showed that the diagnosis was made at a later stage in mild forms of ARM such as a rectoperineal or vestibular fistula, and sometimes ARM remained completely unrecognized, as the only symptom was a chronic constipation. 35 Sharma et al, also observed a high incident of delayed diagnosis, especially among girls in developing countries (37). Our results confirm these findings, and we strongly support the implementation of an interdisciplinary approach with pediatric surgery consultation as a part of the initial examination in cases of unclear anogenital findings to improve outcome.…”

“…Twenty-five percent of our children had mild forms clinically suggestive of ARM which needed further imaging diagnostics to establish an ARM with certainty, which was similar to the findings of Hosokawa et al, 37 Often there are only mild symptoms like a tendency to constipation with a nearly normal anus. ARM must be ruled out through imaging diagnostics to avoid further complications, especially in girls.…”

Transperineal ultrasound to assess anal positioning in female neonates

“…Defining quality scores The criteria for the image quality were defined beforehand by senior radiologists (SR1, SR2) using the quality criteria defined by Son et al [3] and Hosokawaet al [12]: transperineal US was performed with a high-frequency linear array transducer (8 MHz or higher), with a thick coating of gel over the perineum to eliminate air artifacts. The midsagittal plane was identified by the presence of the pubic symphysis and urethra on the same image.…”

Incidence and diagnostic performance of ultrasound for perianal abscess or fistula‐in‐ano in pediatric patients with perianal inflammation

“…Transperineal ultrasound is used to evaluate anorectal diseases in neonates and infants 11–13 . To our knowledge, there have been no studies on the diagnostic performance of ultrasound for perianal abscesses and fistula‐in‐ano.…”

“…Transperineal ultrasound is used to evaluate anorectal diseases in neonates and infants. [11][12][13] To our knowledge, there have been no studies on the diagnostic performance of ultrasound for perianal abscesses and fistula-in-ano. This study aimed to describe the incidence and diagnostic performance of ultrasound for perianal abscess or fistula-in-ano in pediatric patients with perianal inflammation.…”