External Squeeze Test During Pediatric Laparoscopic Hernia Repair: a Novel On-Table Assessment to Ensure Complete Closure of Patent Processus Vaginalis

Background: In pediatric patients, recurrent inguinal hernia (IH) after laparoscopic repair mostly occurs secondary to incomplete closure of the patent processus vaginalis (PPV). The "external squeeze test" (EST) is a simple on-table assessment tool to check completeness of closure of PPV during laparoscopic IH repair. Patients and methods: A review of effectiveness of EST and recurrence of IH was carried out at our institution from December 2007 to December 2017. Closure of PPV was achieved with creation of purse string over pre-peritoneal fascia of the deep inguinal ring with avoidance of important structures; EST was then performed, that is, a gentle squeeze on the scrotum or labia majora while the telescope remains focused at the pursed area. If the closure was incomplete, EST would result in escape of CO2 from within the scrotum or labia back into the peritoneal cavity, visualized as air bubbles internally and taken as a positive EST. A complete closure of PPV would not produce any bubbles internally upon external pressure; this would be taken as a negative EST. All patients had 1- to 12-month follow-up. Results: A total of 874 PPVs were repaired. EST was performed in 870 PPVs (99.5%). There were five recurrences of PPVs consistent with recurrent IH (0.57%); one was in a patient with negative EST, attributed to a slipped ligature; the other four did not have EST performed (p<0.000000). All the recurrences were re-repaired laparoscopically. Conclusion: EST is a simple, useful on-table assessment tool which significantly detects completeness of closure of PPV which may prevent recurrence of IH. We highly recommend EST in pediatric laparoscopic hernia repair, especially in large PPV.