Increased intra-abdominal fat predicts perioperative complications following minimally invasive partial nephrectomy

Objective: To evaluate the anthropometric measurements of body mass index, outer-abdominal fat (OAF) and intra-abdominal fat (IAF) for their utility in predicting perioperative complications following minimally invasive partial nephrectomy. Methods: We retrospectively reviewed the clinical data of patients who underwent a laparoscopic or robotic partial nephrectomy between August 2006 and July 2012 by a single surgeon. Measurements of OAF and IAF were obtained from preoperative cross-sectional imaging available through our institution's imaging archive. Preoperative clinical parameters, including BMI, OAF and IAF, were evaluated for associations with postoperative complications, operative time and length of hospital stay. Results: In total, 257 patients underwent a minimally invasive partial nephrectomy during the study period. Of these patients, 195 (75.9%) had preoperative scans available for analysis of OAF and IAF. A total of 52 (26.7%) patients experienced a Clavien grade I-IV complication within 30 days of surgery, 18 (34.6%) of which were grade III-IV. No patient experienced a grade V complication. On multivariate analysis, only increasing IAF (OR 1.05 [95% CI 1.02-1.09], P = .005) was associated with grade I-IV complications, while IAF (OR 1.05 [95% CI 1.00-1.10], P =.04) and intermediate to high tumor complexity (OR 5.31 [95% CI 1.47-19.17], P =.01) were associated with grade III-IV complications. BMI, OAF and IAF were not found to be independently associated with operative time or length of hospital stay. Conclusion: IAF is independently associated with complications following minimally invasive partial nephrectomy. With further validation, this measurement may prove useful in the preoperative risk stratification of patients with small renal masses.