Reliability of Preoperative Inguinal Sonography for Evaluating Patency of Processus Vaginalis in Pediatric Inguinal Hernia Patients

Background: Among childhood illnesses requiring surgery, inguinal hernia is the most common entity. Pediatric inguinal hernia has been traditionally operated through a small incision in the inguinal region. Contralateral metachronous inguinal hernia has been the topic of discussion in pediatric surgeon's domain for a long time. Many studies have been conducted to prevent it from occurring. Although patency of processus vaginalis is known to be the cause of metachronous inguinal hernia, it is difficult to know the status of contralateral processus vaginalis preoperatively when the patient is non-symptomatic. Recently, the introduction of laparoscopic surgery has facilitated the observation and surgery of contralateral inguinal hernia during scheduled surgery of unilateral hernia repair while the processus vaginalis is intact. The standard treatment for inguinal hernia is herniotomy. Laparoscopic inguinal hernia repair has not been widely applied in Korea. The objective of this study was to analyze the accuracy of preoperative sonography results of inguinal lesion on the contralateral side in patients that needed laparoscopic operation of inguinal hernia. Methods: Data of 107 patients who received laparoscopic inguinal hernia repair and evaluation by preoperative ultrasonography at Dongguk University Ilsan Hospital from 2011 to 2015 were analyzed. Results: Preoperative sonography for inguinal lesion had a sensitivity of 20.5%, a specificity of 95.2%, a positive predictive value of 75%, and a negative predictive value of 63.2%. Its accuracy was 64.5%. A total of 107 patients had no inguinal hernia recurrence or metachronous contralateral inguinal hernia. Conclusion: Ultrasonography performed prior to traditional pediatric herniotomy is not enough for accurate diagnosis of patency of processus vaginalis in our retrospective study. Multicenter prospective study is needed to estimate accuracy of sonographic diagnosis for patency of processus vaginalis.