A Three-dimensional Renal Tumor Anatomy and Intrarenal Relationship Nephrometry (ADDD) for Robot-assisted Partial Nephrectomy : 3D-CT Based Nephrometry for RAPN

Objective: To develop a 3D scoring system of tumor anatomy and intrarenal relationship for assessing surgical complexity and outcomes of robot-assisted partial nephrectomy (RAPN).

Methods: We prospectively enrolled patients with a renal tumor who had a 3D model and underwent RAPN between Mar 2019 and Mar 2022. The ADDD nephrometry consisted of the contact surface area between tumor and parenchyma (A), the depth of tumor invasion into the renal parenchyma (D), the distance from tumor to the main intrarenal artery (D), and to the collecting system (D). The primary outcomes included perioperative complication rate and trifecta outcome (WIT ≤ 25 min, negative surgical margins, and no major complications).

Results: We enrolled a total of 301 patients. The mean tumor size was 2.93 ± 1.44 cm. There were 104 (34.6%) patients, 119 (39.5%) patients, and 78 (25.9%) patients in the low-, intermediate-, and high-risk groups, respectively. Each point increase in the ADDD score increased the risk of complications [hazard ratio (HR) 1.501]. A lower grade indicated a lower risk of failed trifecta (HR low group 15.103, intermediate group 9.258) and renal function damage (HR low risk 8.320, intermediate risk 3.165) compared to the high-risk group. The AUC of ADDD score and grade were 0.738 and 0.645 for predicting major complications, 0.766 and 0.714 for predicting trifecta outcome, and 0.746 and 0.730 for predicting postoperative renal function reservation.

Conclusion: The 3D-ADDD scoring system shows the tumor anatomy and its intraparenchymal relationships and has better efficacy in predicting surgical outcomes of RAPN.