T2-based magnetic resonance genitography in children with complex anorectal malformations: experience at a tertiary pediatric hospital in Latin America.

In children with anorectal malformations (ARMs), it is essential to have a diagnostic imaging method that helps with the evaluation of the internal anatomy. In patients with a persistent cloaca, an ARM variant, in which the measurement of the urethral channel and common channel determines surgical management, there are multiple options for imaging. Magnetic resonance imaging (MRI) is an excellent method for this purpose, from which accurate measurements of channel length can be obtained. Additionally, the use of volumetric/isotropic sequences allows multiplanar reformatting. We present our experience with pelvic MRI and intracavitary non-paramagnetic contrast (MR genitography). This method uses volumetric T2-weighted images and the instillation of saline solution as a contrast agent to distinguish the common channel, length of the urethra, anatomy of the vagina, and presence and location of the rectal fistula. We believe this technique to be particularly useful for those working in settings with limited MRI resources.

The comparison of magnetic resonance and fluoroscopic imaging options in the preoperative assessment of boys with anorectal malformations and a colostomy.

BACKGROUND: In recent decades, magnetic resonance imaging (MRI) has gained prominence as a standard diagnostic method for preoperative assessment in patients with anorectal malformations and a colostomy, with the potential to replace the classic fluoroscopic distal pressure colostogram (FDPC). Three MRI techniques are available: MRI-distal pressure colostogram with gadolinium (MRI-DPCG) or saline (MRI-DPCS) instillation into the colostomy and native MRI without colostomy instillation. OBJECTIVE: To evaluate and compare the diagnostic accuracy of MRI (native MRI, MRI-DPCG and MRI-DPCS) in the preoperative workup of boys with an anorectal malformation and a colostomy and to compare it to FDPC. MATERIALS AND METHODS: Sixty-two boys with preoperative MRI using one of the three approaches and 43 with FDPC met the inclusion criteria for this retrospective study. The presence and localization of rectal fistulas according to the Krickenbeck classification were evaluated and compared with intraoperative findings. RESULTS: The accuracy of fistula detection for MRI in general (regardless of the technique), MRI-DPCS, MRI-DPCG, native MRI and FDPC was 95% (59/62, P<0.001), 100% (12/12, P=0.03), 100% (30/30, P<0.001), 85% (17/20, P=0.41) and 72% (31/43, P=0.82), respectively. The accuracy of describing fistula type in patients with a correctly detected fistula using these methods was 96% (45/47, P<0.001), 100% (9/9, P<0.001), 100% (23/23, P<0.001), 87% (13/15, P<0.001) and 67% (13/21, P=0.002), respectively. CONCLUSION: MRI is a reliable method for detecting and classifying fistulas in boys with an anorectal malformation and a colostomy and can be considered the modality of first choice for preoperative workup.

Preoperative fistula diagnostics in male anorectal malformations after colostomy: a single-center experience.

BACKGROUND: Accurate preoperative fistula diagnostics in male anorectal malformations (ARM) after colostomy are of great significance. We reviewed our institutional experiences and explored methods for improving the preoperative diagnostic accuracy of fistulas in males with ARMs after colostomy. METHODS: A retrospective analysis was performed on males with ARMs after colostomy admitted to our hospital from January 2015 to June 2022. All patients underwent magnetic resonance imaging (MRI) and high-pressure colostogram (HPC) before anorectal reconstruction. Patients with no fistula as diagnosed by both modalities underwent a voiding cystourethrogram (VCUG). General information, imaging results and surgical results were recorded. RESULTS: Sixty-nine males with ARMs after colostomy were included. Age at the time of examination was 52 ~ 213 days, and the median age was 89 days. The Krickenbeck classification according to surgical results included rectovesical fistula (n = 19), rectoprostatic fistula (n = 24), rectobulbar fistula (n = 19) and no fistula (n = 7). There was no significant difference in the diagnostic accuracy between MRI and HPC for different types of ARMs. For determining the location of the fistula, compared to surgery, HPC (76.8%, 53/69) performed significantly better than MRI (60.9%, 42/69) (p = 0.043). Sixteen patients diagnosed as having no fistula by MRI or HPC underwent a VCUG, and in 14 patients, the results were comfirmed. However, there were 2 cases of rectoprostatic fistula that were not correctly diagnosed. CONCLUSION: High-pressure colostogram has greater accuracy than MRI in the diagnosis of fistula type in males with ARMs after colostomy. For patients diagnosed with no fistula by both methods, VCUG reduces the risk of false-negative exclusion, and rectoprostatic fistula should be considered during the operation.

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.

First trimester lower abdominal cysts as early predictor of anorectal malformations.

INTRODUCTION: Prenatal ultrasound diagnosis of anorectal malformations (ARMs) is challenging and often missed as direct visualization of the anal sphincter is not routinely performed, plus the technique is operator-dependent and inaccurate, also in expert hands. Other indirect signs, such as rectosigmoid overdistension or intraluminal calcifications, are occasionally present in late pregnancy. The detection of a cyst of the lower abdomen in the first trimester may be an early sign of ARM. Here we reported our experience and a review of the literature of such cases. MATERIAL AND METHODS: Isolated cases of lower abdomen cysts encountered in the first trimester at the Prenatal Diagnosis Unit during the last 5 years were retrieved and compared with those found in literature. Post-natal clinical data were analyzed to check the presence and type of malformations. RESULTS: A total of three cases of lower abdomen cysts were found in our center and 13 in literature. In our case series all the cysts spontaneously regressed and were no longer visible since the second trimester of pregnancy, while in literature this was reported in only 4 out of 13 cases. ARM was confirmed in all patients at birth or post-mortem. CONCLUSIONS: The finding of a lower abdomen cyst during the first trimester of pregnancy could be an early predictive sign of ARM, even if it disappears during pregnancy. In these cases, we suggest mentioning to the parents the possibility of an ARM during the counseling and to refer the couple to a Colorectal Center.

Detection and Management of Tethered Cord in Anorectal Malformation: A Survey of Pediatric Neurosurgeons in the United States.

INTRODUCTION: The reported prevalence of tethered spinal cord in patients with anorectal malformations (ARMs) ranges from 9% to 64%. Practice patterns surrounding the diagnosis and management of tethered cord (TC) are suspected to vary, with consideration to the type of spine imaging, adjunct imaging modalities, what patients are offered surgical intervention, and how patients are followed after detethering. We sought to determine what consensus, if any, exists among pediatric neurosurgeons in the USA in terms of diagnosis and management of TC and, specifically, patients with TC and ARM. METHODS: A survey was sent to members of the American Society of Pediatric Neurosurgeons (ASPN). Members of the ASPN received an email with a link to an anonymous REDCap survey that asked about their experience with detethering procedures, indications for surgery, diagnostic tools used, and follow-up protocols. RESULTS: The survey was completed by 93 of the 192 ASPN members (48%). When respondents were asked about the total number of all simple filum detetherings they performed annually, 61% (N = 57) indicated they perform less than 10 for all TC patients. Ninety-three percent (N = 87) of neurosurgeons performed these procedures in patients with simple filum TC and ARM patients (TC + ARM) specifically. When asked about prophylactic detethering in those with a confirmed diagnosis of low-lying conus and with a filum fatty terminale, 59.1% (N = 55) indicated they would offer this to TC + ARM patients regardless of their age. Regarding preoperative workup for simple filum detethering, all respondents indicated they would order an MRI in both TC and TC + ARM patients, with a minority also requiring additional testing such as urodynamics, neurodevelopmental assessments, and anorectal manometry for both groups. When following patients postoperatively, almost all respondents indicated they would require clinical neurosurgical follow-up with a clinic visit (100% in all simple filum TC patients, 98.9% in fatty filum/low-lying conus TC + ARM patients), but there was wide variation in the use of other tools such as urological testing, neurodevelopmental assessment, and anorectal manometry. DISCUSSION/CONCLUSIONS: A wide variety of diagnostic criteria and indication for procedural intervention exists for management of TC patients with and without ARM. Further studies are needed to determine outcomes. Prospective protocols need to be developed and evaluated to standardize care for this patient population and determine best practices.

Imaging of anorectal malformations: where are we now? Abdominal imaging task force of the European Society of Paediatric Radiology.

Anorectal and cloacal malformations are a broad mix of congenital abnormalities related to the distal rectum and anus. Confusion exists between all the forms in this large and heterogeneous group. The spectrum includes everything from anal stenosis, ventral anus, anal atresia (with and without fistula) and the full spectrum of cloacal malformations. Imaging in these conditions is done through the whole armamentarium of radiologic modalities, with very different imaging strategies seen across the centres where these conditions are managed. In 2017, the European Society of Paediatric Radiology (ESPR) abdominal imaging task force issued recommendations on the imaging algorithm and standards for imaging anorectal malformations. This was followed by further letters and clarifications together with an active multispecialty session on the different imaging modalities for anorectal malformations at the 2018 ESPR meeting in Berlin. Through this paper, the abdominal task force updates its guidelines and recommended imaging algorithm for anorectal malformations.

Levator ani asymmetry and deviation in high-type anorectal malformation evaluated by magnetic resonance imaging.

INTRODUCTION: The levator ani (LA) complex in high-type imperforate anus (H-IA), low-type imperforate anus (L-IA), and Hirschsprung's disease (HD) patients as controls were documented using magnetic resonance imaging (MRI) and compared for symmetry. MATERIALS AND METHODS: Mean left:right LA thickness ratio (LA ratio), and deviation of the LA from the pubococcygeal line (PCL; LA angle) were calculated from thin-slice MRI images (axial 2 mm, coronal 2 mm, and sagittal 3 mm) of the puborectalis and pubococcygeus taken parallel to the PCL under sedation in H-IA (n=14), L-IA (n=16), and HD (n=9). RESULTS: MRI scans were performed between January 2018 and June 2021. LA were significantly thinner in H-IA (1.78±0.46 mm) compared with L-IA (2.97±0.55 mm) and controls (2.87±0.32 mm), p<0.0001. LA ratio was significantly lower in H-IA (0.71±0.15) compared with L-IA (0.93±0.04), and controls (0.91±0.06), p<0.0001. Mean LA-angle was significantly different in H-IA, 10.8° (range 6°-19°), versus L-IA and controls, both zero degrees (range 0°-5°), p<0.0001, respectively. CONCLUSIONS: LA was confirmed to be significantly asymmetric in H-IA. Because outcome of surgical repair involving a midline incision, such as posterior sagittal anorectoplasty could be impaired, pediatric surgeons are advised to plan surgical intervention for H-IA carefully and appropriately.

Diffusion tensor imaging in anorectal malformations: a pilot study for the evaluation of lumbosacral plexus.

INTRODUCTION: Neurogenic bladder with anorectal malformations (ARM) is a well-known yet understudied topic. Diffusion tensor imaging (DTI) is a special usage of MRI that can evaluate peripheric nerves. The aim of this study is to evaluate the lumbosacral plexuses of patients with ARM using DTI. PATIENTS AND METHODS: Patients with ARM willing to participate were included. Patient files were reviewed, a questionnaire was made, and DTI was performed. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were computed for the right and left lumbosacral plexuses. RESULTS: There were 18 patients and 12 controls. Groups were similar in terms of sex (p = 0.232) and age (p = 0.853). There was a significant difference only for ADC of the left plexus. There was visible asymmetry in tractographies and DTI parameters of two patients with severely deformed pelvises (image 1) but also in another patient with a normal sacrum. In addition, despite asymmetry, FA and ADC were similar to controls also in these patients. CONCLUSION: This is the first study presenting quantitative data about the lumbosacral plexus in ARM. We think the most interesting finding of this study was observing the normal values even in the patients with severely malformed sacrum which is yet to be validated with further studies.

Cysto-Vaginoscopy of a 3D-Printed Cloaca Model: A Step toward Personalized Noninvasive Preoperative Assessment in Patients with Complex Anorectal Malformations.

INTRODUCTION: For the classification of the complexity of cloacal malformations and the decision on the operative approach, an exact anatomical assessment is mandatory. To benefit from using three-dimensional (3D)-printed models in preoperative planning and training, the practicability of these models should be guaranteed. The aim of this study was to evaluate the quality and feasibility of a real-size 3D-printed cloaca model for the purpose of cysto-vaginoscopic evaluation. MATERIALS AND METHODS: We performed a 3D reconstruction and printed a real-size, rubber-like 3D model of an infant pelvis with a cloacal malformation and asked invited pediatric surgeons and pediatric urologists to perform a cysto-vaginoscopy on the model and to complete a brief questionnaire to rate the quality and feasibility of the model and to indicate whether they would recommend the model for preoperative planning and training. RESULTS: Overall, 41 participants rated the model quality as good to very good (M = 3.28, standard deviation [SD] = 0.50, on a scale from 1 to 4). The model was rated as feasible for preoperative training (M = 4.10, SD = 0.75, on a scale from 1 to 5) and most participants (85.4%) would recommend the model for preoperative training. The cysto-vaginoscopy of the model was considered as a valid training tool for real-life cases and improved the confidence on the anatomy of a cloaca. CONCLUSION: The results of our study indicate that patient-specific 3D-printed models might be a useful tool in the preoperative evaluation of complex anorectal malformations by simulation of cysto-vaginoscopy with an excellent view on anatomical structures to assess the whole spectrum of the individual cloacal malformation. Our model might be a valuable add-on tool for specialty training in pediatric colorectal surgery.

Perineal ultrasound in infants with anteriorly displaced anus: A new decision-making tool for the surgeon?

BACKGROUND: Anteriorly displaced anus (ADA) is defined as anterior displacement of the anus toward the perineum. Early radiologic characterization is a crucial step in guiding the first-line management. OBJECTIVE: The objective of this study was to assess the urethra-to-anus distance (UAD) on perineal ultrasound in female infants under the age of 3 months with anteriorly displaced anus and to retrospectively determine a cut-off to guide the indications for surgery. MATERIALS AND METHODS: Perineal ultrasound was performed prospectively in female infants under the age of 3 months with determination of the UAD, during screening for congenital hip dislocation. Determinations of the UAD on perineal ultrasound and pelvic MRI were performed for anteriorly displaced anus in girls between 2011 and 2018. RESULTS: 230 patients were included, of whom 173 were in the control group, with 52 examinations performed for anteriorly displaced anus and 5 examinations performed for vestibular anus. The mean UAD for infants under the age of 3 months was: 22.9 mm (±1.7) in healthy infants, 21.4 mm (±2.4) in infants with non-operated ADA, 17.5 mm (±1.8) in infants with operated ADA, and 10.8 mm (±1.3) in infants with anorectal malformation (ARM). A statistically significant difference was observed between the control group and the ARM group (p = 0.0001) and between the control group and the operated ADA group (p = 0.0001). The mean UAD for infants over the age of 3 months was: 25.5 mm (±4.1) in infants with non-operated ADA and 26 mm (±3) in infants with operated ADA. CONCLUSION: A urethra-to-anus distance of less than 17 mm appears to be a cut-off for anteriorly displaced anus in anorectal malformations.

Correlation between the lateral and anteroposterior sacral ratios in anorectal malformations.

BACKGROUND: The sacral ratio has been used as a tool for evaluating sacral development in patients with anorectal malformations. Sacral ratios can be calculated by obtaining sacral radiographs in the anteroposterior (AP) and lateral planes. OBJECTIVE: The objective of the study was to determine the correlation and agreement in sacral ratio calculations. MATERIALS AND METHODS: In this single institution retrospective cohort study, we reviewed medical charts of all pediatric anorectal malformation patients treated between March 2014 and September 2018 who had both AP and lateral images of their sacrum. All sacral ratios were measured by three radiologists. Pearson's correlation coefficients and corresponding 95% confidence intervals (CIs) were used to assess the correlation between the AP and lateral radiographs. A weighted Kappa statistic was used to measure the agreement between how the AP and lateral sacral ratios categorized observations into risk groups. RESULTS: Our initial cohort consisted of 646 observations from patients with anorectal malformations who had radiographs obtained in both AP and lateral planes. We excluded all observations (n=76) where the radiographs were deemed to be inadequate or not appropriately centered to measure sacral ratio. For a given pair of measurements, the mean lateral sacral ratio was 0.07 units greater than the AP plane (95% CI 0.06-0.09, paired t-test P-value <0.0001). AP and lateral images had a moderate positive correlation (Pearson's r=0.76, 95% CI 0.73-0.79, P<0.0001) and moderate agreement in risk categorization (unweighted kappa = 0.60, P<0.0001). AP and lateral readings conducted by all three radiologists had excellent inter-rater reliability with intraclass correlations for AP and lateral sacral ratios of 0.88 and 0.84, respectively. CONCLUSION: Even though the AP and lateral sacral ratios had moderate positive correlation, the mean sacral ratio determined by images in the lateral plane was 0.07 units greater than the AP plane. AP and lateral sacral ratios concluded different risk categories relatively often. Future studies are needed to determine whether AP or lateral sacral ratios correlate better with continence in patients with anorectal malformations.

A novel combined enteroscopy and laparoscopy approach to prevent urethral complications in management of rectourethral fistula.

BACKGROUND: For the last 20 years, laparoscopy management of anorectal malformations (ARM) has been challenged due to the development of postoperative urethral diverticulum or injury caused by the imprecise transection of rectourethral fistulae, particularly rectobulbar fistulae situated deep in the pelvis. We have developed a combined approach of enteroscopy and laparoscopy for intraluminal incision of a rectourethral fistula. METHODS: We retrospectively reviewed 47 ARM patients who underwent surgical corrections using the combined approach between January 2019 and June 2020. Early postoperative and subsequent follow-up results were evaluated. RESULTS: The median follow-up period was 12 months. The average age at surgery was 3.18 ± 0.64 months. The mean operative time of a single-incision laparoscopic-assisted anorectoplasty (SILAARP) was 1.19 ± 0.29 h. The time for intraluminal incision of the fistula was shortened from 14 to 2 min. No patients underwent a conversion. The average postoperative hospital stay, time to full feeds and placement of an anal tube were 10 days, 1 day, and 5 days, respectively. No urethral diverticulum, urinary injury, wound infection, rectal retraction, anal stenosis or rectal prolapse was encountered in the cohort. CONCLUSIONS: The combined enteroscopy and laparoscopy approach offers precise management of rectourethral fistulae. It could effectively obviate urethral complications, eliminating the obstacles of laparoscopy application in the management of ARMs.

Assessment of sacral ratio in patients with anorectal malformations: Can magnetic resonance imaging replace conventional radiograph?

INTRODUCTION: In patients with anorectal malformations (ARM), the sacral ratio (SR) serves as an established predictive marker for functional prognosis and is derived from conventional radiographs. More recently, magnetic resonance imaging (MRI) has emerged as a diagnostic alternative for preoperative/baseline assessment of patients with ARM. With this study we aimed to evaluate if the SR could be reliable be measured from MRI images and if it correlated to SR measurements obtained from radiographs. METHODS: Two raters analyzed MRI data and conventional radiographs from thirty-one subjects (n = 17 with ARM; n = 14 controls). We calculated intra-class correlation coefficients (ICCs) to test inter-rater reliability and applied paired t-tests to examine if SR parameters from MRI were comparable with those from pelvic radiograph. We further computed Pearson's correlation coefficients to test the linear relationship between SR calculated from MRI and conventional radiographs. RESULTS: The ARM and control groups did not statistically differ in their age and weight on the day of the MRI scan. Reliability analysis revealed an excellent inter-rater agreement for SR from radiograph parameters with an intraclass correlation coefficient (ICC) of 0.94, respectively of 0.86 for MRI (frontal plane), and of 0.84 for MRI (sagittal plane). The correlation coefficient between SR calculated from the sagittal MRI and SR calculated from radiograph images was significant and high (r = 0.80, P < 0.001). The SRs from MRI images did not significantly differ from SRs from radiographs, but were also not statistically equivalent. CONCLUSION: Our results demonstrate that the SR can be derived from MRI images with good inter-rater reliability. The SR value is marginal higher when calculated on MRI, presumably due to inclusion of cartilaginous yet unossified structures.

Visualization of the fetal anus by prenatal ultrasound for the diagnosis of anorectal malformations: is it feasible?

PURPOSE: The goal of this study was to determine the feasibility of identifying the anal dimple (AD) on routine prenatal ultrasound. Using the presence, absence, appearance, and location of the anal dimple as an indirect sign for possible underlying anorectal malformations (ARM), we hypothesize that evaluation of the anal dimple as part of the fetal anatomic survey may increase the sensitivity in detecting less severe ARMs. METHODS: In a prospective longitudinal observational study, pregnant women who underwent prenatal ultrasound (US) at the Colorado Fetal Care Center between January 2019 and 2020 were enrolled. The variables recorded included gestational age, singleton versus multiple pregnancy, gender of the fetus, visualization of the AD, and reason for non-visualization of the AD. RESULTS: A total of 900 ultrasounds were performed, evaluating 1044 fetuses, in 372 different pregnant women. Gestational ages ranged from 16 to 38 weeks. The AD was visualized in 612 fetuses (58.6%) and not seen in 432 (41.4%). The two most common reasons for non-visualization were extremes in gestational age (n = 155; 36%) and fetal position (n = 152; 35.3%). The optimal gestational age range for AD visualization was 28-33 weeks + 6 days, with 78.1% visualization rate. CONCLUSION: Visualization of the anal dimple by ultrasound is feasible and may aid in the detection of less severe ARMs, ultimately impacting pregnancy management and family counseling. The optimal timing for anal dimple visualization is late second and third trimester.

A case of Currarino syndrome in an adult female presenting with refractory chronic constipation

No disponible

Contrast enhanced colostography: New applications in preoperative evaluation of anorectal malformations.

INTRODUCTION: Understanding details of anatomic relationships between the colon and surrounding structures is a critical piece of preoperative planning prior to surgical repair of anorectal malformations (ARMs). Traditional imaging techniques involve ionizing radiation, distention of the rectum with supraphysiologic intraluminal pressures, and sometimes require sedation. Recent developments in the field of contrast agents have allowed the emergence of an ultrasound-based technique that can avoid these requirements while continuing to provide high resolution structural information in three dimensions. METHODS: Fourteen children (13 male, 1 female, age 1-11 months) with ARMs underwent contrast enhanced colostography (ceCS) in addition to traditional preoperative imaging techniques to delineate anatomic relationships of pelvic structures. RESULTS: ceCS and traditional imaging yielded concordant anatomic information, including structural relationships and fistulous connections, in 10/14 patients (71%). ceCS detected fistulous connection in 2/13 patients (15%) that were not seen by traditional imaging. Ultrasonography failed to detect the fistulous connection in one patient. CONCLUSIONS: ceCS is a safe, effective and flexible method for defining important structural information in ARM patients. When compared with traditional methods, it provided equivalent or superior results 93% of the time and bears consideration as a standard tool in preoperative planning for this population. TYPE OF STUDY: Retrospective Comparative Study. LEVEL OF EVIDENCE: Level III.