Visceral Fat Volume and Inguinal Hernia After Robot-Assisted Radical Prostatectomy: A Three-Dimensional CT Analysis

Low body mass index has been reported as a risk factor for inguinal hernia after robot-assisted radical prostatectomy, but whether this association reflects reduced fat mass or reduced muscle mass remains unclear. This study aimed to determine which three-dimensional computed tomography-derived body composition parameter is associated with postoperative inguinal hernia.

We retrospectively analyzed 280 patients who underwent robot-assisted radical prostatectomy between February 2016 and January 2024 and had available preoperative non-contrast computed tomography images. Visceral fat volume, subcutaneous fat volume, and psoas muscle volume were quantified using three-dimensional analysis. Cox proportional hazards models were used to evaluate factors associated with postoperative inguinal hernia.

Inguinal hernia occurred in 23 patients (8%). Patients who developed inguinal hernia had lower BMI, visceral fat volume, and subcutaneous fat volume than those who did not, whereas psoas muscle volume did not differ significantly. In the multivariable visceral fat volume model, greater visceral fat volume was associated with a lower risk of inguinal hernia (HR per 1 000-cm³ increase, 0.597; 95% CI, 0.445-0.800; p < 0.001). In a model including both body mass index and visceral fat volume, visceral fat volume remained significant (HR, 0.626; 95% CI, 0.408-0.961; p = 0.032), whereas body mass index did not.

Lower visceral fat volume was associated with a higher risk of inguinal hernia after robot-assisted radical prostatectomy. These findings may provide insight into the body composition factors relevant to the previously reported association between low body mass index and postoperative inguinal hernia.