Patent processus vaginalis in adults who underwent robot-assisted laparoscopic radical prostatectomy: Predictive signs of postoperative inguinal hernia in the internal inguinal floor

Objective: To evaluate the risk for postoperative inguinal hernia according to the presence of patent processus vaginalis in an adult population. Methods: Medical records of 205 patients who underwent robot-assisted laparoscopic radical prostatectomy from May 2007 to November 2011 were reviewed. Age, prostate-specific antigen, prostate volume, body mass index, operative time and history of previous abdominal surgery were evaluated. The existence of patent processus vaginalis was also evaluated for the development of postoperative inguinal hernia. Results: Postoperative inguinal hernia occurred in 20 out of 410 (4.9%) groins (17/205 patients; 8.3%), and patent processus vaginalis was observed in 49 out of 410 (11.9%) groins. In the normal groin group, inguinal hernia occurred in seven out of 361 (1.9%) groins. However, in the patent processus vaginalis group, it occurred in 13 out of 49 (26.5%) groins. On univariate analysis using Cox proportional hazards model, age, body mass index, history of previous abdominal surgery and patent processus vaginalis were significant risk factors. Among them, patent processus vaginalis significantly increased the risk of postoperative inguinal hernia in multivariate analysis (hazard ratio 22.37). In the patent processus vaginalis group, inguinal hernia developed at 12.9±9.2months after robot-assisted laparoscopic radical prostatectomy and 15±7.4months in the normal groin group. Inguinal hernia-free ratios were significantly lower in the patent processus vaginalis group than the normal groin group (P<0.001). Conclusions: The existence of patent processus vaginalis represents an important risk factor for postoperative inguinal hernia in adults. Urologists should consider the possibility of postoperative inguinal hernia when patent processus vaginalis is observed during surgery.