Using methylene blue for perioperative localization of the hydrocele sac in boys

Background : Ligation of a patent processus vaginalis via the inguinal approach is the standard operative technique for the treatment of hydroceles in infants and children. Although a simple technique, identification of the processus vaginalis can be difficult even for the experienced surgeon.
Aims : To investigate the use of methylene blue in the perioperative identification of the patent processus vaginalis in a group of children presenting with hydrocele.
Materials and Methods : Twenty consecutive patients with hydrocele between the ages of 1 and 9 years were recruited for the study. Methylene blue 0.3-0.5 ml was injected slowly into the hydrocele fluid through the scrotal wall after aspiration, followed by routine ligation of the hydrocele track.
Results : The track of the processus vaginalis was clearly visualized in 17 (85%) of the patients, while in 3 (15%) patients no track could be seen, the hydrocele being localized to the tunica vaginalis. There were no cases of inadvertent testicular injury and there was no intraoperative complication. No patient reacted in any abnormal way to the methylene blue.
Conclusion : The technique helps in the identification of a patent processus vaginalis when it is present. It may be useful in cases where difficulty in identification of the hydrocele tract is anticipated in a child.