Percutaneous nephrolithotripsy in the morbidly obese patient.

From 1989 to 1995, 530 patients underwent percutaneous nephrolithotripsy, of which 93 were identified as morbidly obese. A retrospective study was performed comparing results of nephrolithotripsy in patients with near normal ideal body weight versus those patients considered morbidly obese. Outcome parameters measured included size, configuration, and number of calculi, location and number of access sites required, stone-free rates, operative time, number of ancillary procedure, hospital stay, and complications. Stone number was similar between the normal weight and morbidly obese groups; however, the morbidly obese group had smaller stones treated percutaneously. Operative time was similar between the two groups if a single access was required, but then was significantly higher in the morbidly obese group if multiple access sites were necessary. Stone-free rates were not statistically different between normal weight versus obese patients (89% vs. 82%). However, hospital stay was longer (3.5 days vs. 4.4 days) and the overall rate of complications was higher (16% vs. 37%) in the morbidly obese group compared to normal weight group.