A low subcutaneous fat mass is a risk factor for the development of inguinal hernia after radical prostatectomy

Purpose Inguinal hernia (IH) after radical prostatectomy (RP) is a complication that impairs quality of life; however, the factors contributing to IH after RP remain unclear. Therefore, we herein attempted to identify the factors responsible for the development of IH after RP. Methods We reviewed 622 patients who underwent laparoscopic or robot-assisted laparoscopic RP at our hospital between December 2011 and April 2020. The total fat area and visceral fat area were calculated at the level of the umbilicus using computed tomography, and the subcutaneous fat area (SFA) was calculated by subtracting the visceral fat area from the total fat area. The psoas muscle area was measured at the third lumbar vertebrae level using computed tomography to calculate the psoas muscle mass index, which is used in sarcopenia as an index of muscle mass. We investigated the risk factors for IH after laparoscopic or robot-assisted laparoscopic RP. Results IH developed in 88 patients (16.7%). Fifty-seven of these patients underwent hernia repair at our hospital, and 56 (98.2%) had indirect hernias. A multivariate analysis identified SFA (odds ratios: 0.383, p < 0.001) as an independent predictor for the development of IH. Two-year IH-free survival rates were 77.3% in the small SFA group (SFA < 123 cm 2 ) and 88.7% in the large SFA group (SFA ≥ 123 cm 2 ) ( p < 0.001). Conclusion Subcutaneous fat was associated with the development of IH, particularly indirect IH, after laparoscopic or robot-assisted laparoscopic RP. An indirect IH prevention technique needs to be considered, particularly for patients with less subcutaneous fat.