How does visceral obesity affect surgical performance in laparoscopic radical nephrectomy?

Objective: In a previous study, we described the relationship between operating time and obesity, particularly visceral obesity, in laparoscopic surgery. Operating time in laparoscopic surgery is affected by the experience and technique of the surgeon. Here, we investigated whether a difference in the surgeon's experience affects the operating time for laparoscopic radical nephrectomy in patients with visceral obesity. Methods: From January 2006 to February 2012, 167 laparoscopic radical nephrectomies were performed at our institution. Visceral fat areawas measured at the level of the umbilicus using computed tomography. A visceral fat area ≥ 100 cm² was used as the definition of visceral obesity. All laparoscopic radical nephrectomies were performed by six surgeons. Two of the six surgeons perform 50 cases or more laparoscopic surgeries every year and they were defined as the expert group. We analyzed the relationships between clinical findings, methods, surgeon experience, body mass index or visceral fat area and operating time. Results: The expert and non-expert surgeons performed 77 and 90 laparoscopic radical nephrectomies, respectively, and the median operating timewas 167.0 ± 44.0 and 227.5 ± 60.6 min. Twenty-five patients underwent laparoendoscopic single-site nephrectomy by the expert surgeons. For all surgeons, visceral obesity was a significant factor for prolonged operating time. Multivariate analysis showed that visceral obesity and clinical T stage were independent risk factors for prolonged operating time for the non-expert surgeons [P = 0.004, hazard ratio (HR):5.15, P = 0.037, HR:10.41]. However, for the expert surgeons, clinical T stage was the only independent risk factor for prolonged operating time (P = 0.039, HR:4.33). Conclusion: Visceral obesity was a factor of prolonged operating time in laparoscopic radical nephrectomy. The non-expert surgeons were particularly affected by visceral obesity.