Construction and application of a three-dimensional vascular variation-based nephrometry scoring system for completely endophytic renal tumors.

Background: Completely endophytic renal tumors (CERT) pose significant challenges due to their anatomical complexity and loss of visual clues about tumor location. A facile scoring model based on three-dimensional (3D) reconstructed images will assist in better assessing tumor location and vascular variations.

Methods: In this retrospective study, 80 patients diagnosed with CERT were included. Forty cases underwent preoperative assessment using 3D reconstructed imaging (3D-Cohort), while the remaining 40 cases were assessed using two-dimensional imaging (2D-Cohort). Vascular variations were evaluated by ascertaining the presence of renal arteries > 1, prehilar branching arteries, and arteries anterior to veins. The proposed scoring system, termed RAL, encompassed three critical components: (R)adius (maximal tumor diameter in cm), (A)rtery (occurrence of arterial variations), and (L)ocation relative to the polar line. Comparison of the RAL scoring system was made with established nephrometry scoring systems.

Results: A total of 48 (60%) patients exhibited at least one vascular variation. In the 2D-Cohort, patients with vascular variations experienced significantly prolonged operation time, increased bleeding volume, and extended warm ischemia time compared with those without vascular variations. Conversely, the presence of vascular variations did not significantly affect operative parameters in the 3D-Cohort. Furthermore, the 2D-Cohort demonstrated a notable decline in both short- and long-term estimated glomerular filtration rate (eGFR) changes compared with the 3D-Cohort, a trend consistent across patients with warm ischemia time ≥ 25 min and those with vascular variations. Notably, the 2D-Cohort exhibited a larger margin of normal renal tissue compared with the 3D-Cohort. Elevated RAL scores correlated with larger tumor size, prolonged operation time, extended warm ischemia time, and substantial postoperative eGFR decrease. The RAL scoring system displayed superior predictive capabilities in assessing postoperative eGFR changes compared with conventional nephrometry scoring systems.

Conclusions: Our proposed 3D vascular variation-based nephrometry scoring system offers heightened proficiency in preoperative assessment, precise prediction of surgical complexity, and more accurate evaluation of postoperative renal function in CERT patients.