Accuracy Of Transperineal Sonography And Distal Loopogram In Determining Distal Rectal Pouch-Perineal Distance And Fistula On Anorectal Malformation Post Colostomy

Background : Imperforated anus is a congenital abnormality which is better known as anorectal malformation. The incidence of anorectal malformations is 1 in 4000 to 5000 live births. The incidence of anorectal malformations in Europe varies from 1.14 to 5.96 per 10,000 people and can change each year. The surgical approach in the management of anorectal malformations depends on the classification of anorectal malformations based on low, intermediate and high location. The distal loopogram or distal colostrography / colostrogram examination is an examination that is very important to determine the location of the distal rectum before definitive repair, but this examination has the disadvantage of using contrast and x-ray radiation. One alternative radiological examination that can be used for faster initial management is sonographic.


Introduction
Imperforated anus is a congenital abnormality which is better known as anorectal malformation. The incidence of anorectal malformations is 1 in 4000 to 5000 live births. The incidence of anorectal malformations in Europe varies from 1.14 to 5.96 per 10.000 people and can change every year. [1][2][3] Anorectal malformations comprise a wide spectrum of diseases, which can affect both boys and girls, and involve the distal anus and rectum as well as the urinary and genital tracts. Defects range from very small and easily treatable with an excellent functional prognosis, to complex, difficult to manage, often associated with other anomalies, and have a poor functional prognosis. [1][2][3] The results of research conducted at Sardjito Hospital by Pratomo in 1998Pratomo in -2003 reported that the ratio between male and female anorectal malformation patients was 21:19. Of the 93 cases, there were an estimated 34 cases of anorectal malformation each year. Most patients with anorectal malformations were male with a ratio of 23:14 cases. [4][5] Delay in the treatment of anorectal malformations can increase morbidity and mortality. Examination of the distal loopogram or distal colostrography / colostrogram is an examination that is very important to determine the location of the distal rectum before definitive repair. Distal colostrography with augmented pressure should be performed in all male and all women patients undergoing colostomy with cloaca. This examination provides information regarding the location of the fistula between the rectum and the genitourinary, the length of the colon available from the colostomy to the fistula site, the distance between the rectum and the anal dimple, and the rectum to the sacrum. However, there are major drawbacks to using ionizing contrast under fluoroscopy or still using X-ray imaging. The exposure of young infants to radiation continues to cause concern.
Although the absolute risk of radiation exposure from this procedure is minimal, there remains an even higher risk of cancer-related radiation injury in exposed children compared to adults. This is because children are more sensitive to radiation than adults because they are still growing and more actively dividing cells; their long life expectancy also increases the risk of radiation injury manifestations. In addition, the adjustment of radiation machines that do not fit their small body size can cause high radiation doses with the resulting cellular damage. One alternative radiological examination that can be used for faster initial management is sonographic examination. 1,7 Takahiro et al in 2016 stated that the sonographic diagnostic accuracy of low-type imperforate anus based on pouch-perineal distance and fistula location was better than cross-table radiographs. If the pouch-perineal distance on the cross-table radiograph is greater than 10 mm, sonographic examination to determine the location of the fistula may be recommended. Hans et al in 2007 also stated that transperineal sonography is feasible for all children without special preparation. The mean distance between the distal rectal sac and perineum in 22 infants with low imperforate anus was 10 ± 4 (SD) mm compared with a mean of 24 ± 6 mm in 34 infants with moderate or high anomalies (p <0.001). Transperineal sonographic sensitivity is 100%; All 34 cases of moderate or high imperforate anus were identified by a cutoff distance between the distal rectal sac and perineum of 15 mm. Hans also found sonography to have a specificity of 86% and an accuracy of 95% . [8][9][10] The importance of accurate investigations for initial management to prevent complications led the investigators to asses the diagnostic accuracy of distal loopogram and sonographic examinations with the transperineal approach to anorectal malformations.

Methods
This study was a diagnostic test study to assess the diagnostic accuracy of the distal The inclusion criteria were all post colostomy Anorectal Malformations patient, had never been manipulated, and were willing to participate in the study and signed an informed concern sheet. Exclusion criteria were patients who had PSARP operation and were not willing to be sampled.
Based on the calculation of the sample size with predetermined limits, the minimum sample size was 34 patients. If add the possibility of dropping out of 10%,so get a sample numbers with rounds of 37 patients.
The Gold Standard variable in this study was the intraoperative result and the predictor variable was the transperineal ultrasound examination and the Distal Loopogram examination.
Data were presented in 2x2 table form and analyzed using SPSS version 21 program.

General Characteristics
Based on gender, there were 10 male and 11 female. The mean age in months was 13 months, the youngest was 3 months and the oldest was 70 months.

Discussion
In this study, Transperineal Sonography has a very high accuracy value with a sensitivity of 100% and a specificity of 93.8% while the Loopogram has a sensitivity of 100% and a specificity of 68.8%. Although there is a significant difference between the distal rectum-perineal distance calculation with a difference of -0.38 ± 0.70 cm, these two methods are equally accurate in assessing the distal rectum and fistula distances. Examination of the distal loopogram or distal colostrography / colostrogram is an examination that is very important to determine the location of the distal rectum before definitive repair. Distal colostrography with augmented pressure should be performed in all male and all women patients undergoing colostomy with cloaca. This examination provides information regarding the location of the fistula between the rectum and the genitourinary, the length of the colon available from the colostomy to the fistula site, the distance between the rectum and the anal dimple, and the rectum to the sacrum. However, there are major drawbacks to using ionizing contrast under fluoroscopy or still using X-ray imaging. [1][2][3][4][5][6][7] Takahiro et al in 2016 stated that the sonographic diagnostic accuracy of low-type imperforate anus based on pouch-perineal distance and fistula location was better than cross- Complex genitourinary anomalies that can replace pouches can also be quickly recognized.
Ultrasound carries no radiation risk and is not as expensive as an MRI or CT scan. Using ultrasound, internal fistulas can be identified as well. Donaldson evaluated 18 children with imperforate anus using ultrasound mostly using a suprapubic approach, and in some cases via the perineum. Ultrasonography correctly predicted pocket location in all 12 children who had pocketlevel confirmation surgically or a distal colostogram. However, definitive surgery to confirm the placement of the pouch was performed only in one of the 7 cases with a P-P distance of more than 15 mm. In the study of Alehossein, et al, all examinations were carried out with a transperineal approach. Of our 23 cases, five children, the pouch to perineum (P-P) distance was less than 10mm.
All of these low lesions were safely treated by a simple perineal anoplasty (minimal posterior sagittal anorectoplasty; i.e. minimal PSARP) and were confirmed as low type. Seven children had P-P distance of 10-15 mm. In the follow up definitive surgery, 5 cases were intermediate and two cases were high. Eleven children had a P-P distance of more than 15 mm, of which ten cases were