Innovative 3D method predicts surgery outcomes by calculating Real Contact Surface of renal tumor.

The Contact Surface Area (CSA) is a predictor for peri-operative parameters and represent the contact area between the tumor and the respective organ. Nowadays, a precise method for calculating CSA is yet to be found in the literature. We tested a new CSA calculation method as a predictor of intra-operative parameters in robot assisted partial nephrectomy (RAPN). The study population consisted of all consecutive patients treated with RAPN at a single high-volume European institution (between 2020 to 2023; 82 patients). We proposed a new method to measure the real value of CSA using an algorithm that leverages the geometry of kidneys and tumors obtained from 3D reconstruction. These reconstructions were obtained using the certified medical software Materialized Mimics InPrint. Peri-operative parameters of patients were recorded in an anonymous database. We explored the correlation between RCSA, CSA of Hsieh (HCSA), PADUA and R.E.N.A.L. scores with peri-operative parameters using Spearman correlation. Furthermore, we examined which of RCSA, PADUA and R.E.N.A.L. score better describes the intra-operative parameters, Warm Ischemia Time (WIT), Operating Time (OT), and Estimated Blood Loss (EBL) using Receiver Operating Characteristic (ROC) curve analysis. Multivariable linear regression analyses were performed. We observed a significant correlation between RCSA and WIT, OT and EBL. Moreover, RCSA outperformed both the PADUA and R.E.N.A.L. score as demonstrated in the ROC curve analysis. In ROC analysis was chosen a threshold for each of the parameters: for WIT 20 minutes, for OT 180 minutes and for EBL 200 mL. At multivariable regression analysis, RCSA emerged as the only independent predictor for WIT, OT and EBL (B=0.39 & p=0.03, B=0.35 & p=0.01, B=0.48 & p<0.001, respectively). Our original and effective 3D RCSA calculation method was favorably associated to intra-operative surgical outcomes. As compared to PADUA and RENAL score, our calculated RCSA represented a better predictor of intra-operative parameters. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee of Policlinico San Martino of Genova gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data generated for this analysis were from anonymized database. The code for the analyses will be made available upon request.