855 Prospective assessment of the adherent perinephric fat in partial nephrectomies - predictors and impact on peri-operative outcomes

543 Background: The surgical complexity of partial nephrectomy (PN) can be partly anticipated using renal morphometric scores that do not consider patient related issues such as obesity or perirenal fat. Our primary objective was to prospectively assess the predictive factors for adherent perinephric fat (APF) and its impact on the onset of complications. The secondary objective was to correlate the surgical appraising with the histological reality of APF. Methods: Fifty consecutive patients undergoing robotic or open PN were prospectively included from November 2014 to March 2015. The previously published Mayo adhesive probability score (MAP score) was calculated and compared to the per-operative surgical assessment of APF using a 0 to 3 scale (APF being defined by a score ≥ 2). Fat was analyzed histologically for fibrosis (HES staining and picrosirius red) and inflammatory infiltrate of macrophages (immunohistochemistry using anti-CD68 antibody). Results: APF was present in 18 patients (36%), with no im...