Prospective Evaluation of the Association of Adherent Perinephric Fat with Perioperative Outcomes of Robotic-assisted Partial Nephrectomy

Objective To prospectively analyze the association of adherent perinephric fat (APF) with perioperative outcomes of robotic-assisted partial nephrectomy (RAPN). Methods We analyzed 100 consecutive RAPNs performed by a single experienced surgeon and defined APF as the necessity of subcapsular renal dissection to mobilize the kidney and isolate the renal tumor for RAPN. Our primary analysis focused on comparing perioperative outcomes, including operative time, warm ischemia time, estimated blood loss, postoperative complications, length of stay, and margins, ischemia, and complications score between patients with and without APF. To control the probability of obtaining a false-positive finding at 5% after the numerous statistical comparisons that were performed, we used a Bonferroni correction for multiple comparisons, after which P values of ≤.0042 were considered to be statistically significant. Results Thirty patients (30%) had APF. Presence of APF was not significantly associated with blood loss, warm ischemia time, hospital stay, postoperative complications, or margins, ischemia, and complications score. We noted some evidence of longer operative times in patients with APF compared with those without APF (median, 223 vs199 minutes; P =.026); however, this was not significant after adjustment for multiple comparisons. In multivariate analysis, we noted stronger evidence of associations with increased operative time for RENAL score (P <.001) and body mass index (P =.020) than for the presence of APF (P =.32). Conclusion APF may be associated with slightly longer operative times but does not appear to affect perioperative complications or outcomes.