Does the use of monopolar energy as the preferred mode of dissection effectively reduce seroma formation in laparoscopic total extra peritoneal hernioplasty? A prospective double-blinded randomized control trial

Introduction: Seroma is a commonly encountered sequela after hernia repair. Tremendous effort has been spent to investigate the effective way to prevent this "complication" including the modification of surgical technique, use of per-peritoneal drainage, etc. There were debates about the use of monopolar diathermy versus blunt dissection in laparoscopic TEP in the prevention of seroma formation. This randomized study aims to compare the effects of using 2 techniques in laparoscopic TEP on pre-peritoneal drain output and seroma formation.

Method: From 1.9.2018 to 30.9.2019, all male and female patients presented with the first occurrence, unilateral inguinal hernia anticipated for laparoscopic TEP were enrolled into the study after informed consent. Patients were randomized into "monopolar dissection preferred" (MDP) group and "blunt dissection-preferred" (BDP) group just before commencing of operation after general anesthesia. Surgeons were instructed to use monopolar energy as main dissection method for the whole operation if possible (MDP), whereas blunt dissection is the preferred choice in BDP group, but the use of monopolar energy was allowed if needed. Total energy time was measured by a specially designed homemade device attaching to the monopolar pedals as accurate as to millisecond (ms). Pre-peritoneal drains were inserted for drainage and removed 23 h after operation. Drainage output, total operating time, energy time, clinical and ultrasonic seroma sizes at day 1, day 6, 1-month post operations, recurrence are compared between 2 groups.

Results: A total of 103 patients where included. There was no significant difference in age, gender, co-morbidities, side of hernia, mean defect size, operating time, fixation adjuncts, or postoperative stay. The drain volume in BDP group is 71.13 ± 31.42 mL while it in MDP group is 56.36 ± 21.46 mL. The MDP group had significantly fewer drain output at 23 h post operation (p = 0.007) and lower seroma incidence on days 6 (p = 0.036). Overall incidence of seroma formation was 12% on postoperative day 1, 11% on postoperative day 7. No statistically differences in postoperative pain score or complications were observed at the first week, 1- and 3-months' post operation. There was no correlation with energy time to the drain output. No recurrence was found in subsequent follow-up.

Conclusion: Pre-peritoneal drainage is clinically safe in laparoscopic totally extra-peritoneal hernioplasty and can effectively reduce the size and incidence of seroma. The seroma formation can be further reduced by appropriate use of monopolar energy as preferred dissection approach in lap TEP. Due to limitation in measuring the actual energy time, the result should be further validated by randomized multi-centers trial on its potential benefit in hernia repair by a more accurate measuring device on energy used.