Study of Renal and Kidney Tumor Vascularization Using Data from Preoperative Three-dimensional Arteriography Prior to Partial Nephrectomy.

BACKGROUND: In a cadaveric model with healthy kidneys, it has recently been highlighted that a single renal segment could be supplied by one or more arterial branches originating from an artery supplying another segment. OBJECTIVE: To demonstrate occurrences of anatomical variations of renal vascularization and to analyze vascularization of renal tumors. DESIGN, SETTING, AND PARTICIPANTS: This prospective monocentric study included all patients treated for a renal tumor between May 2015 and June 2017 by laparoscopic partial nephrectomy after superselective tumor embolization in a hybrid operating room. INTERVENTION: Three-dimensional renal and tumoral arteriography with cone-beam computed tomography scan was performed, coupled with preoperative cross-sectional imaging. This procedure provided an accurate vascular anatomical mapping of the kidney and allowed further analysis of tumor vascularization. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Relation between anatomical variations of the vascularization and perioperative data was assessed. A χ2 test or Fisher's test was used for qualitative variables, and a Student t test was used for quantitative variables. RESULTS AND LIMITATIONS: Out of the 60 patients included, only 25 (42%) presented a standard vascular subdivision. In 26 patients (43%), tumors were supplied by more than one branch and in 20 patients (33%), there was a branch supplying the tumor from another segment. In these cases of multiple or multi-segmental tumor vascularization, tumor size, operative duration, and duration of embolization were significantly higher than in the case of standard vascularization. These complex tumors were more often located at the upper pole of the kidney or at the junction of the anterior and posterior vascular territories of the kidney. Limitations of this study include the low number of patients and its monocentricity. CONCLUSIONS: This study confirms that renal vascularization frequently differs from Graves' reference model and that tumor vascularization can depend on several segmental branches. This vascular complexity explains surgical difficulties and must be taken into consideration when segmental arterial clamping is considered during partial nephrectomy. PATIENT SUMMARY: We studied renal and tumor vascularization using three-dimensional preoperative arteriography data on tumor kidneys. We have shown that there is great variability in renal vascularization and that tumors can be vascularized branches that originate from an artery leading to another segment. This vascular complexity explains surgical difficulties and must be taken into consideration when segmental arterial clamping is considered during partial nephrectomy.