The impact of body mass index on the outcomes of retrograde intrarenal stone surgery.

Objective: To compare the outcomes of using retrograde intrarenal surgery (RIRS) for treating renal stones among normal weight, overweight, and obese patients.

Materials And Methods: From December 2008 to March 2012, 207 patients who underwent RIRS were included in the study. Patients were categorized into 3 groups according to their body mass index (BMI): normal weight <25 kg/m(2) (group 1), overweight 25-29.9 kg/m(2) (group 2), and obese ≥30 kg/m(2) (group 3). We compared the 3 groups with regard to preoperative characteristics, operative parameters, and postoperative outcomes.

Results: There were no significant differences in age, gender, or renal stone parameters (size, localization, laterality, multiplicity) among the 3 groups. The mean stone sizes were 18.6 ± 7.1 mm in group 1, 16.9 ± 7.0 mm in group 2, and 18.5 ± 8.4 mm in group 3 (P = .365). The stone-free rates (SFRs) of a single procedure for the groups were 79.0%, 77.9%, and 75.5% for groups 1, 2, and 3, respectively (P = .897). After additional treatments, the final SFR for the groups increased to 85.2%, 84.4%, and 81.6% for groups 1, 2, and 3, respectively (P = .861). We did not find any significant differences among the groups with regard to the operation times, complication rates, and hospital length of stay (LOS). Major complications were not observed either during or after the operations.

Conclusion: Our study demonstrates that the outcomes of RIRS for treating renal stones are similar in overweight and obese patients when compared with patients who are of normal weight. Therefore, these patients can be treated safely and successfully with RIRS.