Feasibility of laparoscopic partial nephrectomy in the obese patient and assessment of predictors of perioperative outcomes

INTRODUCTION: Partial nephrectomy is the gold standard for treatment of small renal masses. Our study compares outcomes for obese (body mass index [BMI] ≥30) and healthy (BMI <30) patients undergoing laparoscopic partial nephrectomy (LPN) with the intention of defining preoperative risk factors for complications and renal insufficiency in the obese. MATERIALS AND METHODS: We conducted a retrospective review of 187 consecutive patients who underwent LPN. We examined the association between BMI and postoperative complication, estimated blood loss (EBL), hospital length of stay, warm ischemic time (WIT), and postoperative renal function. We did similar analyses using the RENAL nephrometry score and the comorbidity status of the patients. RESULTS: We found no statistically significant increase in complications in obese (BMI ≥30) individuals relative to healthy (BMI <30) patients. The obese experienced approximately 100 cc more EBL (P = 0.0111). Patients experienced more complications if they had a Charlson comorbidity score ≥3 (P = 0.0065), an American Association of Anesthesiologists score ≥3 (P = 0.0042), or a history of diabetes mellitus (P = 0.0196). There was no association between RENAL nephrometry score and complication. However, patients with a score ≥8 experienced higher WIT (P = 0.0022), a greater decline in estimated glomerular filtration rate postoperatively (P = 0.0488), and an increased risk of developing chronic kidney disease ≥3 (P = 0.0065). CONCLUSIONS: Obese patients undergoing LPN are not at significantly increased risk of complication relative to nonobese patients. Comorbidity status and RENAL nephrometry score, independent of BMI, should be the main considerations of a patient's suitability for LPN.