Obesity in percutaneous nephrolithotomy. Is body mass index really important?

To evaluate the influence of obesity in the results of percutaneous nephrolithotomy (PCNL) in terms of efficacy and safety and to evaluate other aspects such as fluoroscopy time, radiation exposure, total operative time, hemoglobin loss, hospital stay, and the need of auxiliary procedures.

We evaluated prospectively all the PCNLs performed at our institution between 2011 and 2012. A series of perioperative and postoperative details were recorded in our database. The patients were distributed in 4 groups using World Health Organization's classification of body mass index (BMI): normal weight, ≤ 25 kg/m(2); overweight, 25-29.9 kg/m(2); obese, 30-39.9 kg/m(2); and morbidly obese, ≥ 40 kg/m(2). Modified Clavien classification was used for reporting the complications. Results were compared between the groups using the chi square and multivariate logistic regression tests.

A total of 255 procedures were performed between January 2011 and December 2012. Overall stone clearance was 76.3% and complication rate using the modified Clavien grading system was 31.4%. No statistical differences in terms of complication rate and stone free rate were noted between the 4 groups. Total operative time and radiation doses increase along with BMI. No difference was found in fluoroscopy time, failure to gain access, hospital stay, or need for auxiliary procedures.

Obesity does not increase complications in PCNL, and the efficacy of the technique is similar to normal weight patients with appropriate expertise. Total operative time and radiation exposure increase along with BMI, putting patients at risk.