Background/purpose: For over 50 years there has been debate over how to manage the contralateral groin in children who present with a unilateral inguinal hernia. Many preoperative and intraoperative tools to diagnose a contralateral patent processus vaginalis or true inguinal hernia have been described. In 1992 laparoscopy was introduced as a new diagnostic test. Although multiple series have assessed this new tool, none of them have been able to statistically show that laparoscopy is effective in assessing the contralateral groin. By combining all published studies and using the technique of meta-analysis, intraoperative laparoscopy can be shown to be effective in diagnosing a contralateral patent processus vaginalis in children undergoing unilateral inguinal herniorrhaphy.
Methods: All available studies of children with a unilateral hernia who had exploration of the contralateral groin by laparoscopy were reanalyzed. Sensitivity and specificity of laparoscopy was determined using open exploration or development of a metachronous hernia as the gold standard.
Results: Nine hundred sixty-four patients were suitable for analysis. A contralateral hernia was seen on laparoscopy in 376 patients. All of these patients underwent open contralateral exploration. A patent processus vaginalis or true hernia sac was found in 373. The sensitivity of laparoscopy was 99.4% (95% confidence interval 97.87 to 99.91). Five hundred eighty-eight patients had a laparoscopy with negative results. Sixty-two of these patients then had open contralateral exploration. In one case, a patent processus vaginalis was found; the other 61 patients underwent exploration with negative results. In the remaining 526 laparoscopy-negative patients, follow-up (1 month to 3 years) was used to see if a contralateral hernia developed. A metachronous hernia developed in one of the 526 patients. The specificity of laparoscopy was 99.5% (95% confidence interval 98.39 to 99.87). Laparoscopy added an average of 6 minutes to the surgical time and was accurate regardless of the technique. There were two minor complications related to laparoscopy and no deaths.
Conclusions: Laparoscopy may be the ideal tool to diagnose a contralateral patent processus vaginalis intraoperatively. It is sensitive, specific, fast, and safe. Although the presence of a patent processus does not imply that the patient will go on to develop a metachronous hernia, identifying and ligating a patent processus should certainly prevent the development of an indirect inguinal hernia.