This prospective case series analyzed patients who underwent indocyanine green (ICG) fluorescent lymphography during open inguinal hernia repair. The aim of this study was to investigate the association between ICG leakage and postoperative hydroceles in patients who underwent inguinal hernia repair.

Data were analyzed from 40 patients who underwent primary open hernia repair between October 2020 and June 2021 (44 cases in total). Hydroceles were categorized into two types: symptomatic and “ultrasonic” (detected only by ultrasound imaging).

In the univariate analysis, hernia type (p = 0.044) and ICG leakage (p = 0.007) were independent risk factors for postoperative ultrasonic hydroceles. Additionally, mesh type (p = 0.043) and ICG leakage (p = 0.025) were independent risk factors for postoperative symptomatic hydroceles. In the multivariate analysis, ICG leakage (p = 0.034) was an independent risk factor for postoperative ultrasonic hydroceles.

ICG leakage after inguinal hernia repair was independently associated with postoperative ultrasonic and symptomatic hydroceles. These findings suggest a relationship between lymphatic vessel injury and the incidence of postoperative hydroceles.