A novel preoperative evaluation technique for partial nephrectomy: three-dimensional extended renal tumor plane

Objective: To develop a three-dimensional (3D) image based extended tumor plane technique for robotic-assisted partial nephrectomy (RAPN).

Methods: We prospectively enrolled patients with a local renal tumor for RAPN between March 2019 and Mar 2022. 3D virtual model was reconstructed based on the computed tomography urography. The tumor plane was extended equidistantly (10 mm) to form a virtual plane. According to the relationship between the extended plane and the collection system, patients are divided into those with no collecting system involvement, renal medulla involvement, and renal calyx involvement. The primary endpoint was trifecta achievement, which was defined as warm ischemic time ≤ 25 min, negative surgical margins, and no major perioperative complications.

Results: This study enrolled a total of 215 patients. The median preoperative aspects and dimensions used for an anatomical (PADUA) score was 9 (6-15). The average warm ischemic time was 21.64 ± 9.35 min. Postoperative complications occurred in 26 (12.1%) patients, of whom 14 (6.5%) classified as major complication. The number of cases with trifecta failure was 1 (5.3%) in the no involvement group, 28 (20.6%) in the renal medullary involvement group, and 24 (40.0%) in the renal calyx involvement group (p < 0.001). Logistic regression indicated that renal calyx involvement was a risk factor for trifecta failure (OR = 2.639, 95% confidence interval [1.268-5.492], p = 0.009).

Conclusions: The extended tumor plane based on three-dimensional images can is useful for the evaluation of RAPN. Determining whether the extended plane involves the collecting system, particularly the renal calyx, may impact the achievement of trifecta.