Surgical Navigation Improves Renal Parenchyma Volume Preservation in Robot-Assisted Partial Nephrectomy: A Propensity Score Matched Comparative Analysis

PURPOSE: We investigated the relationship between the surgical navigation system and postoperative parenchyma preservation volume, and assessed the feasibility of image guided surgery in robot-assisted partial nephrectomy. MATERIALS AND METHODS: We developed surgical navigation with registration between real-time endoscopic images using 3-dimensional virtual reality models for robot-assisted partial nephrectomy. Surgical outcomes of 44 (nonsurgical navigation group) and 102 (surgical navigation group) patients between June 2013 and December 2018 were retrospectively analyzed. To adjust for potential baseline confounders propensity score matching (1:1) was performed. Renal parenchymal preservation rate and extraparenchymal volume with a tumor including functional and oncological outcomes ("trifecta" defined as warm ischemia time of less than 25 minutes, no complications and negative surgical margins; "pentafecta" defined as trifecta plus greater than 90% preservation of estimated glomerular filtration rate at 12 months postoperatively and chronic kidney disease up staging) were evaluated using volumetric analysis and compared. RESULTS: After matching, 42 patients were allocated to each group. No significant differences in baseline characteristics; complications; and intraoperative, trifecta and pentafecta outcomes were observed between the 2 groups. Pathological T stages were significantly different between the groups (T1a/T1b/T2a or more 25/10/7 in the nonsurgical navigation group vs 35/7/0 in the surgical navigation group, p=0.003). Extraparenchymal volumes and parenchyma volume preservation rates were significantly higher in the surgical navigation group (21.4 vs 17.2 ml, p=0.041 and 83.5% vs 90.0%, p=0.042, respectively). Surgical navigation was positively associated with improved parenchyma preservation volume (p=0.003). CONCLUSIONS: Surgical navigation preserves renal parenchyma in robot-assisted partial nephrectomy and may contribute to improvement in postoperative renal function.