Prediction of Intraoperative Urinary Collecting System Entry in Patients with Peripheral Renal Tumors Undergoing Partial Nephrectomy: Usefulness of Tumor-Centered Multiplanar Reconstruction.

ABSTRACT

OBJECTIVE: To assess the usefulness of tumor-centered multiplanar reconstruction (TC-MPR) for predicting intraoperative urinary collecting system (UCS) entry in patients with peripheral renal tumors undergoing partial nephrectomy (PN). METHODS: Dynamic computed tomography images of 50 peripheral cT1 renal tumors treated with laparoendoscopic PN were analyzed. TC-MPR generated a digital cross-sectional image showing the tumor center and the closest calyx on a same plane. Patients and tumor characteristics including the distance from the tumor margin to the closest calyx (MPR-distance), and the angle formed by 2 tangent lines from the closest calyx to the tumor (MPR-angle) were assessed. RESULTS: Intraoperative UCS entry was observed in 15 patients (30%). The patients who experienced intraoperative UCS entry had a higher RENAL score, wider MPR-angle, and shorter MPR-distance than those who did not (p = 0.04, p = 0.001, p < 0.001, respectively). Multivariate analysis identified MPR-angle as an independent factor for intraoperative UCS entry (p < 0.001). CONCLUSIONS: The spatial information assessed using TC-MPR serves as a predictive factor for intraoperative UCS entry during PN.