Renal tumour invasion index as a novel anatomical classification predicting urological complications after partial nephrectomy

Abstract Objective. The goal of anatomical classification systems (ACSs) is to assess renal tumour complexity and predict surgical complications. However, the present ACSs may include some relatively unimportant components and may be complicated to use. This study introduces the invasion depth of the renal tumour divided by the parenchymal thickness, called the renal tumour invasion index (RTII), as a novel ACS and compares it with previous ACSs in predicting urological complications after partial nephrectomy. Material and methods. This retrospective single-institution study assessed 280 consecutive patients subjected to a planned partial nephrectomy. The main outcome was perioperative 30-day urological complications. RTII was compared with the PADUA (preoperative aspects and dimensions used for an anatomical) classification score, RENAL (radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior and location relative to polar lines) nephrometry score and C (centrality) index...