Imperforate anus: US determination of the type with infracoccygeal approach

Prediction of anorectal malformations with bladder-neck/urethral-prostatic fistula using classification and regression tree analysis

BACKGROUND

The anorectal malformations (ARMs) with bladder-neck/urethral-prostatic fistula in males are the most complex groups in ARMs. It is essential to diagnose them effectively before the primary operation for both surgical modalities and future functional prognosis can be quite different from other types. Our study aimed to develop a classification and regression tree (CART) model for the prediction of ARMs with bladder-neck/urethral-prostatic fistula.

METHODS

A total of 132 newborns with ARMs were included retrospectively and randomly assigned to the training sample and test sample in a 3:1 ratio. The pouch-perineum distance of ultrasound (PPDU), the pouch-perineum distance of invertogram (PPDI), and the rectum gas above the coccyx (RGAC) on the invertogram were hypothesized can serve as individual predictors. The CART analysis was used to determine the best combination of candidate predictors. The model's performance was assessed by the area under the receiver operating characteristic curve (AUC) and validated in the test sample.

RESULTS

All three individual predictors were included in the CART model to predict the ARMs with bladder-neck/urethral-prostatic fistula in the derivation cohort with the following test characteristics (95% CI): sensitivity 75.6% (60.1 to 86.6); specificity 88.9% (76.7 to 95.4); AUC 0.909 (0.854 to 0.965). The model's predicted accuracy was validated in the test cohort (AUC = 0.883). In all 132 subjects, the AUC of the tree model was significantly superior to that of the best individual index: PPDU (0.901 vs. 0.819; p = 0.005).

CONCLUSIONS

A predictive model that consists of PPDU, PPDI, and RGAC may be useful in predicting ARMs with bladder-neck/urethral-prostatic fistula.

Internal fat prolapse from ischiorectal fossa masquerading as currarino syndrome

Pelvic magnetic resonance imaging (MRI) is the latest addition to already existing tools for evaluation of anorectal malformation (ARM). It provides detailed information about pelvic floor musculature as well as position of rectal pouch. However, lack of knowledge about normal pelvic floor anatomy can lead to misinterpretation of pelvic MRI which can create confusion and change in approach for surgery. A 14-month-old male child with diagnosis of ARM was evaluated with pelvic MRI. There was finding of abnormal protrusion of fat through the ischiorectal fossa which was misinterpreted as Currarino syndrome which created confusion immediately before posterior sagittal anorectoplasty. Pelvic MRI is highly informative while evaluating a case of ARM. However, a detailed knowledge of pelvic floor anatomy is mandatory to avoid wrong interpretation and misdiagnosis.

Comparison of diagnostic accuracy for fistulae at ultrasound and voiding cystourethrogram in neonates with anorectal malformation

BACKGROUND

Recently, it has been reported that anorectal malformation with rectourethral fistula in male neonates can be managed by primary neonatal reconstruction without colostomy. To prevent urethral injury during anorectoplasty, the fistula's location is important. To date, the use of voiding cystourethrograms to determine the presence and location of fistulas in neonates with anorectal malformations has not been studied.

OBJECTIVE

To compare the accuracy of ultrasound (US) and voiding cystourethrogram for determining the presence and location of fistulas in neonates with anorectal malformation.

MATERIALS AND METHODS

We included 21 male neonates with anorectal malformation with rectourethral fistula (n=16), rectovesical fistula (n=1) or no fistula (n=4) who underwent US and voiding cystourethrogram preoperatively on the day of surgery. Fistula imaging was classified into three grades (0-2), and grades 1-2 were considered fistula positive. We compared the imaging-based location of the fistula with surgical findings.

RESULTS

US performed significantly better than voiding cystourethrogram for determining the presence of fistulas (area under the receiver operating characteristic curve, 0.90 vs. 0.71, respectively; P=0.044) (diagnostic accuracy 85.7%, 95% confidence interval [95% CI] 63.7-97.0% and 52.4%, 95% CI 29.8-74.3%, respectively). In cases with fistulas detected by either modality, the accuracy of locating the fistula by US was 50.0% (95% CI 24.7-75.3%) and by voiding cystourethrogram was 100% (95% CI: 59.0-100%).

CONCLUSION

US accurately detected, but did not accurately locate, fistulas in neonates with anorectal malformation. When planning primary neonatal reconstruction of anorectal malformation without colostomy, voiding cystourethrogram could provide additional information about fistula location.

EFSUMB Recommendations for Gastrointestinal Ultrasound Part 3: Endorectal, Endoanal and Perineal Ultrasound

This article represents part 3 of the EFSUMB Recommendations and Guidelines for Gastrointestinal Ultrasound (GIUS). It provides an overview of the examination techniques recommended by experts in the field of endorectal/endoanal ultrasound (ERUS/EAUS), as well as perineal ultrasound (PNUS). The most important indications are rectal tumors and inflammatory diseases like fistula and abscesses in patients with or without inflammatory bowel disease (IBD). PNUS sometimes is more flexible and convenient compared to ERUS. However, the technique of ERUS is quite well established, especially for the staging of rectal cancer. EAUS also gained ground in the evaluation of perianal diseases like fistulas, abscesses and incontinence. For the staging of perirectal tumors, the use of PNUS in addition to conventional ERUS could be recommended. For the staging of anal carcinomas, PNUS can be a good option because of the higher resolution. Both ERUS and PNUS are considered excellent guidance methods for invasive interventions, such as the drainage of fluids or targeted biopsy of tissue lesions. For abscess detection and evaluation, contrast-enhanced ultrasound (CEUS) also helps in therapy planning.

Comparison Between the Pouch-Perineum Distance in Neonates With a Low-Type Anorectal Malformation With and Without an Opened Fistula: Pitfall of Measuring the Pouch-Perineum Distance on Sonography

OBJECTIVE

An anorectal malformation (ARM) in neonates requires urgent surgery, with the type of surgery being dependent on the type of malformation (low, intermediate, or high). Distal rectal pouch and perineum (pouch-perineum) distance is reported to be useful for differentiating the type of ARM; however, the impact of an opened fistula on pouch-perineum distance is not well known. The purpose of this study was to evaluate the difference in pouch-perineum distance between neonates with a low-type ARM with and without an opened fistula.

METHODS

We included 24 neonates with low-type ARM who underwent sonography before surgery. Eight neonates already had an opened fistula before sonography, and 16 did not. The pouch-perineum distance was measured using the perineal approach. Mann-Whitney U and Spearman's correlation coefficient tests were used for statistical analysis.

RESULTS

The mean pouch-perineum distance in all neonates with a low-type ARM was 8.3 ± 2.9 mm. The pouch-perineum distance was substantially longer for an ARM with than without an opened fistula (10.6 ± 3.4 mm vs. 7.1 ± 1.7 mm; P = .02). No appreciable correlation was identified between the pouch-perineum distance and the postnatal day of examination (ρ = -.23, P = .26) or birth weight (ρ = .15, P = .47).

CONCLUSION

The pouch-perineum distance is substantially longer in neonates with an ARM with an opened fistula than in those without an opened fistula. Caution should be exercised by the sonographic examiner in evaluating pouch-perineum distance in neonates with an opened fistula to prevent an incorrect surgical procedure based on misdiagnosis of the type of ARM.

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

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).

Anorectal malformations: Role of MRI in preoperative evaluation

PURPOSE

To evaluate the spectrum of magnetic resonance imaging (MRI) findings in pediatric patients with anorectal malformation (ARM) and compare the accuracy of MRI and distal cologram (DC) findings using surgery as reference standard.

MATERIALS AND METHODS

Thirty pediatric patients of age less than 14 years (19 boys and 11 girls) with ARM underwent preoperative MRI. MRI images were evaluated for the level of rectal pouch in relation to the pelvic floor, fistula, and development of sphincter muscle complex (SMC). Associated spinal and other anomalies in lumbar region and pelvis were also evaluated. DC was done in 26 patients who underwent colostomy. Ultrasound of abdomen and pelvis was also done for associated anomalies.

RESULTS

Overall accuracy of MRI and DC to detect the exact level of rectal pouch including cloacal malformation was 93.33% and 76.9% respectively. MRI and DC could correctly identify presence or absence of fistula in 76.6% and 76.9% cases respectively. MRI and DC correctly identified the anatomy of fistula in 76% and 65% cases respectively. On MRI, correlation of development of levator ani and puborectalis with the level of rectal pouch as found on surgery was significant (P = 0.008; 0.024 respectively). Subjective assessment of sphincter muscle development on MRI correlated well with the surgical assessment [P = 0.019 and 0.016 for puborectalis and external anal sphincter (EAS) respectively]. Lumbosacral spine anomalies were present in 33.3% of patients and were most common in high type of ARM. Vesicoureteric reflux and renal agenesis were the most common renal and urinary tract anomalies and were present in 40% of cases.

CONCLUSION

MRI allows reliable preoperative evaluation of ARM and should be considered as a complementary imaging modality for preoperative imaging in ARM.

Distance Between the Distal Rectal Pouch and Perineum in Neonates of Low-Birth Weight With Imperforate Anus

This study was to evaluate the correlation between birth weight and the distance between distal rectal pouch and perineum (P-P distance) and to determine a cutoff value for P-P distance to diagnose low-type imperforate anus in neonates with low-birth weight (LBW).We included 15 neonates with LBW (mean weight, 2012 ± 470 g; range, 906-2452 g) and imperforate anus (surgically confirmed: 11 low type and 3/1 intermediate/high type), who underwent ultrasonography on the day after birth. Type of imperforate anus was defined based on the International Classification of Anorectal Anomalies. The P-P distances on ultrasonograms were measured. Pearson correlation coefficient test and receiver operating characteristic curve were used for statistical analyses.Among all 15 neonates, nonsignificant correlation was observed between the birth weight and P-P distance (r = 0.36; P = 0.18). Mean P-P distance was 9.0 ± 6.6 mm (range, 1.0-24.0 mm) in all neonates, 5.7 ± 2.8 mm (range, 1.0-11.0 mm) in the 11 neonates with low-type imperforate anus, and 18.3 ± 9.1 mm (range, 14.0-24.0 mm) in the 4 neonates with intermediate-/high-type imperforate anus. Using cutoff P-P distance of 12.5 mm, sensitivity and specificity for diagnosis of low-type imperforate anus were 100% (11/11) and 100% (4/4), respectively.In conclusion, nonsignificant correlation was observed between P-P distance and birth weight, and cutoff P-P distance to diagnose low-type imperforate anus was 12.5 mm. Despite the very small sample size in our study, and only 4 neonates with intermediate-/high-type imperforate anus, these findings are important because surgical management whether transperineal anoplasty or diverting colostomy is decided based on the type of imperforate anus, and P-P distance to diagnose the type of imperforate anus was feasible even in neonates with LBW.

Diagnostic Accuracy of Sonography for Detection of a Fistula on the Birth Day in Neonates With an Imperforate Anus: Comparison of Diagnostic Performance Between Suprapubic and Perineal Approaches

OBJECTIVES

To evaluate the diagnostic accuracy of sonography for detection of an internal fistula on the birth day in neonates with an imperforate anus and to compare the diagnostic performance between the suprapubic and perineal approaches.

METHODS

We included 46 neonates with an imperforate anus (29 low type and 17 intermediate/high type) who underwent sonography by both the suprapubic and perineal approaches on the birth day. Thirty-nine neonates had internal fistulas, and 12 did not, as surgically proven. Two blinded radiologists evaluated the suprapubic and perineal sonograms for the presence of the internal fistula in consensus. A final diagnosis of the internal fistula was determined on the basis of the findings of both approaches. A receiver operating characteristic analysis was used to compare the diagnostic performance for detection of an internal fistula between the suprapubic and perineal approaches.

RESULTS

The sensitivity, specificity, and accuracy of the final diagnosis based on the findings of suprapubic, perineal, and both approaches were 52.9%, 79.4%, and 79.4%; 75.5%, 75.5%, and 75.5%; and 58.7%, 78.3%, and 78.3%, respectively. The diagnostic performance of the perineal approach was significantly better than that of the suprapubic approach (P < .0001).

CONCLUSIONS

The diagnostic accuracy of sonography for detection of an internal fistula on the birth day exceeded 75% in neonates with an imperforate anus, and sonography on the birth day is feasible. The perineal approach had superior diagnostic performance over the suprapubic approach. Thus, when evaluating an internal fistula by sonography, we recommend using the perineal approach in addition to the suprapubic approach.

Sonography for an Imperforate Anus: Approach, Timing of the Examination, and Evaluation of the Type of Imperforate Anus and Associated Anomalies

This systematic review outlines the role of sonography in an imperforate anus. The diagnostic performance for type of imperforate anus is superior on the day after birth than that on the day of birth by using the pouch-perineum distance. Three approaches can be used (suprapubic, infracoccygeal, and perineal). The pouch-perineum distance, fistula location, and relationship between the puborectalis muscle and distal rectal pouch are useful for classifying the type of imperforate anus. However, the pouch-perineum distance measured has an overlap between the low and high/intermediate types of imperforate anus. Sonography can be useful for some of the associated anomalies and helpful for surgeons in some cases.

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

OBJECTIVES

To compare the diagnostic accuracy for the low-type imperforate anus between prone cross-table radiography and sonography.

METHODS

We included 20 neonates with imperforate anus: 13 with a surgically proven low type and 7 with an intermediate or high type. The distance between the distal rectal pouch and the perineum (pouch-perineum distance) was measured by both sonography and prone cross-table radiography. A previously established pouch-perineum distance of 10 mm was used as the cutoff for diagnosis of a low-type imperforate anus. The fistula location was also determined with sonography. We then compared the diagnostic accuracy of the imaging methods for a low-type imperforate anus using the cutoff value of the pouch-perineum distance alone and both the cutoff value of the pouch-perineum distance and fistula location. The McNemar test was used for statistical analysis.

RESULTS

With the use of only the pouch-perineum distance, the diagnostic accuracy for the low-type imperforate anus based on sonographic measurements was comparable with the accuracy achieved by prone cross-table radiographic measurements (60.0% [12 of 20] versus 45.0% [9 of 20]; P = .625). With the use of the pouch-perineum distance and fistula location, the diagnostic accuracy of sonography was significantly better than the accuracy of prone cross-table radiography (90.0% [18 of 20] versus 45% [9 of 20]; P = .012).

CONCLUSIONS

The diagnostic accuracy of sonography for the low-type imperforate anus based on both the pouch-perineum distance and fistula location is better than that of prone cross-table radiography. If the pouch-perineum distance on prone cross-table radiography is greater than 10 mm, a sonographic examination to determine the fistula location could be recommended.

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

OBJECTIVES

To evaluate changes in the distance between the distal rectal pouch and the perineum (pouch-perineum distance) from the birth day to the next day and to determine which day is better for diagnosis of a low-type imperforate anus in neonates.

METHODS

We reviewed medical records at our hospital from May 2003 to August 2015 and identified 9 neonates with a radiographically and surgically proven low-type imperforate anus and 9 with high/intermediate types of imperforate anus who had undergone sonography on both the birth day and the next day before the first surgical treatment. The sonograms were reviewed to measure the pouch-perineum distance at both examinations. The Wilcoxon signed rank sum test and a receiver operating characteristic curve analysis were used for the statistical analyses.

RESULTS

The pouch-perineum distance on the next day (mean ± SD, 9.37 ± 4.89 mm; range, 2.1-20.9 mm) was significantly shorter than on the birth day (15.75 ± 6.67 mm; range, 8.1-37.2 mm; P = .001). The receiver operating characteristic analysis showed significantly better diagnostic performance (P < .001) of the pouch-perineum distance on the next day (area under the curve, 0.864) versus the birth day (0.420) for the low-type imperforate anus.

CONCLUSIONS

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.

Sonographic Determination of Type in a Fetal Imperforate Anus

OBJECTIVES

The purpose of this study was to determine the type of an imperforate anus by using sonography in the prenatal period.

METHODS

This retrospective study evaluated the fetal anus in all pregnant women, including low- and high-risk populations, between February 2010 and November 2013. High-type imperforate anuses were diagnosed by prenatal sonography when the anal sphincter muscles and anal canal mucosa were not visible. Low-type imperforate anuses were prenatally suspected when at least 1 of the following was present: (1) a small anus; (2) no visible anal mucosa; or (3) close location of the genitalia by the anus without a visible perineal body, particularly in a female fetus.

RESULTS

Among the 9499 fetuses, 41 were prenatally suspected of having an imperforate anus, and 32 were confirmed to have this disorder. During the same study period, there were 11 false-negative cases, for a diagnostic sensitivity rate of 74%. All 9 fetuses who were confirmed to have a normal anus were prenatally suspected of having a low-type imperforate anus. Among the 32 fetuses with a confirmed imperforate anus, 19 were confirmed to have a high or intermediate type and 13 to have a low type. The type in 3 fetuses was incorrectly determined prenatally.

CONCLUSIONS

Although an imperforate anus is not always diagnosed prenatally, its type can be determined by prenatal sonography.

Survey on the management of anorectal malformations (ARM) in European pediatric surgical centers of excellence

PURPOSE

Various management strategies for anorectal malformations (ARM) have been proposed. The aim of this study was to assess the current management in centers of excellence in Europe.

METHODS

An online survey on the pre- and post-operative concepts, surgical techniques, and the management of complications was sent to the representative experts of 28 selected European centers of pediatric surgery with special expertise in the treatment of ARM.

RESULTS

The survey was completed by 25 experts from 14 countries. To assess the level of the rectal pouch in newborns 60% of participants perform a prone cross-table X-ray and 52% ultrasound. If an ostomy is required, 84% create divided Peña stomas. Primary repair in the newborn period is performed in females with rectoperineal (92%), rectovestibular (60%), and no fistula (32%), and in males with rectoperineal (92%), rectourinary (17%) and no fistula (38%). For 68 % of surgeons, the PSARP is the preferred surgical approach for "low" malformations. Laparoscopically assisted pull-throughs are routinely performed by 48% of experts for ARM with bladderneck and 28% for rectoprostatic fistula. 88% perform postoperative dilations.

CONCLUSIONS

The management of ARM in Europe is very heterogeneous. High-quality clinical studies are needed to provide scientific evidence for the optimal treatment strategies.

Imperforate Anus With Renal Ectopia

This case study describes the sonographic findings of an infant born with an imperforate anus. Imperforate anus occurs in about 1 in 4000 to 5000 live births. It can be associated with VACTERL or VATER syndrome, which includes vertebral, anal, cardiac, tracheoesophageal, renal, and limb malformations. Prognosis depends on the level of the imperforate anus and the extent of the associated anomalies.

Transperineal sonography for determination of the type of imperforate anus

OBJECTIVE

The purpose of this study was to assess whether transperineal sonography is valid and accurate for discriminating the low (translevator) type of imperforate anus from the intermediate and high (supralevator) types. The distinction is critical in determination of the surgical approach.

MATERIALS AND METHODS

Fifty-six consecutively enrolled infants (0-90 days old) with imperforate anus underwent transperineal gray-scale sonography with a 12-MHz linear array transducer. The distance between the distal rectal pouch and the perineum was measured, and a cutoff distance for differentiating types of imperforate anus was identified. The sonographic findings were compared with the final diagnosis reached with radiographic and surgical findings.

RESULTS

Transperineal sonography was feasible in all children without specific preparation. The mean distance between the distal rectal pouch and the perineum in the 22 infants with low imperforate anus was 10 +/- 4 (SD) mm compared with a mean of 24 +/- 6 mm in the 34 infants with intermediate or high anomalies (p < 0.001). The sensitivity of transperineal sonography was 100%; all 34 cases of intermediate or high imperforate anus were identified with a cutoff distance between the distal rectal pouch and the perineum of 15 mm. The specificity of sonography was 86% and the accuracy, 95%.

CONCLUSION

Transperineal sonography is a valid and accurate noninvasive imaging technique for differentiating low and intermediate or high imperforate anus.