140 The benefit of laparoscopic partial nephrectomy in high body mass index patients

Objective: The aims of the present study were to evaluate the effect of body mass index on the surgical outcomes of open partial nephrectomy and laparoscopic partial nephrectomy, and to analyze whether higher body mass index patients may derive greater benefit from laparoscopic partial nephrectomy. Methods: We reviewed 110 patients who underwent open partial nephrectomy and 47 patients who underwent laparoscopic partial nephrectomy at our institution. We analyzed the data to determine what kind of factor would be associated with prolonged operative time, increased estimated blood loss and prolonged ischemic time, and compared the result of open partial nephrectomy with that of laparoscopic partial nephrectomy. Results: A statistically significant correlation was observed between body mass index and operative time or estimated blood loss in open partial nephrectomy. Multivariate analysis also demonstrated that body mass index was an independent predictor for prolonged operative time and higher estimated blood loss in open partial nephrectomy, but not in laparoscopic partial nephrectomy. In the normal body mass index group (body mass index , 25.0 kg/m 2 ), although mean operative time in the laparoscopic partial nephrectomy group was significantly longer than that in the open partial nephrectomy group, the difference was relatively small. In the high body mass index group (body mass index 25.0 kg/m 2 ), the mean operative time of the two groups was not statistically different. The estimated blood loss of open partial nephrectomy was significantly higher than that of laparoscopic partial nephrectomy in both groups. In both operative procedures, tumor size was an independent predictor for prolonged ischemic time in multivariate analysis. Conclusions: Body mass index was an independent predictor for prolonged operative time and higher estimated blood loss in open partial nephrectomy but not in laparoscopic partial nephrectomy. Laparoscopic partial nephrectomy was less influenced by body mass index and had a greater benefit, especially in high body mass index patients.