Biomechanical determinants of 8-mm robotic port-site hernia: the impact of torque exposure and operative duration.

Trocar-site hernia (TSH) is an uncommon but clinically significant complication following minimally invasive surgery. While traditionally associated with larger trocar diameters, hernias at 8-mm robotic port sites have been increasingly reported. The potential role of robotic arm torque and cumulative mechanical stress in facial failure remains poorly defined. To evaluate clinical and biomechanical predictors of 8-mm robotic port-site hernia using a risk -modeling framework, with a particular focus on robotic torque exposure and operative duration. A simulated cohort of 9,482 virtual patients undergoing robotic urologic surgery was generated using clinically plausible distribution derived from published literature and surgical experience. Key exposure variables included a modeled torque exposure score, excessive torque events, and extensive ProGrasp torqueing. Additional variables included body mass index (BMI), frailty index, operative time, and port location. Multivariable logistic regression models were constructed to identify factors associated with hernia formation within modeled datasets. Within the simulated cohort, 8-mm port-site hernia was strongly associated with both clinical and biomechanical factors. Independent predictors included BMI > 30 kg/m² (OR 66.28, p < 0.001), frailty index ≥ 81 (OR 19.47, p < 0.001), and operative duration > 180 min (OR 6.14, p < 0.001). Biomechanical variables demonstrated strong associations, including torque exposure score (OR 1.07 per unit increase, p < 0.001) and excessive torque events (OR 9.15, p < 0.001). Extensive ProGrasp torqueing emerged as the strongest predictor (OR 165.80, p < 0.001). Male sex was associated with reduced risk (OR 0.10, p < 0.001). The predictive model demonstrated good discrimination (AUC ≈ 0.80). In this risk-modeling study, increased torque exposure and prolonged operative duration were strongly associated with 8-mm port-site hernia within a simulated biomechanical framework. These findings support the hypothesis that mechanical stress at the trocar interface may contribute to fascial failure. However, given the modeled nature of the dataset and lack of direct measurement, these results should be interpreted as hypothesis-generating and require validation in prospective clinical studies.