ANALYSIS OF SURGICAL COMPLICATIONS OF RENAL TUMOR ENUCLEATION WITH STANDARDIZED INSTRUMENTS AND EX- TERNAL VALIDATION OF PADUA CLASSIFICATION

Aim of the study To assess surgical results and morbidity of tumor enucleation (TE), and to evaluate their correlation with PADUA nephrometric score. Materials and methods We prospectively gathered data, including accurate analysis of tu- mor nephrometry, from 244 consecutive patients treated with TE for clinically localized renal cell carcinoma. All surgical results were collected, and perioperative complications were stratified for sever- ity according to Clavien system. Correlation between preoperative variables and surgical results/complications was assessed with uni- and multivariate analysis. Results Mean (range) tumor size was 3.6 (0.8-10.0) cm, and mean (range) warm ischemia time was 16.8 (5-35) min. Overall, perioperative complications occurred in 45 patients (18.4%), and of those 8 were medical (3.3%) and 37 were surgical (15.2%; 4 Clavien grade 1, 25 grade 2, and 8 grade 3) complications. Urine leakage rate was 2.0%. No grade 4/5 complications occurred in this series. At uni- variate analysis PADUA score, endophytic tumor growth, tumor di- ameter, involvement of UCS and renal sinus resulted associated with warm ischemia time. Discussion This study evaluated only patients treated with open surgery, but TE can also be done in laparoscopy and robotics, so the lack of these assessments can be a limitation of this study. Ourselves and oth- ers should validate PADUA classification for TE using different ap- proaches. Another potential drawback of this study is the validation of the PADUA score only, not evaluating other anatomical classifica- tions such as the C-Index [23] or R.E.N.A.L score [24]. Compared to C Index, we found PADUA score easier to assign, because it does not require a software for the cross-sectional imaging assessment. Furthermore, while considering the R.E.N.A.L. a satisfactory and simple system, we used PADUA score because it includes also the variable “relationship with renal sinus”, that we consider potentially related to the degree of complexity of NSS. Indeed, in our analysis the renal sinus involvement was the only anatomical variable who, by itself, resulted independently correlated to Clavien grade 3 surgi- cal complications. Conclusions The TE technique was associated with a 15.2% surgical complica- tion rate with a 3.3% reintervention rate (including ureteral stenting and superselective renal artery embolization). Tumor nephrometry and surgical indication resulted independent predictors of Clavien grade 3 complications. The PADUA score is a reliable tool to predict surgical results and morbidity of TE.