The added value of perfusion volumes implementation in 3D virtual models for the planning of robotic partial nephrectomy: comparative analysis with the old generation 3D imaging

Introduction: The increased incidence of renal cancer has led to the development of innovative 3D virtual models with the aim of facilitating nephron-sparing surgery (NSS) by allowing the evaluation of kidney perfusion zones through the division of the kidney parenchyma into anatomical portions based on artery morphology and proximity and offering personalized surgical approach based on the patient’s specific anatomical characteristics and tumor location. Objective: The main objective of this single-center prospective comparative study is to assess the role of a new generation of 3D virtual models implemented with perfusion volumes algorithm in influencing perioperative and functional outcomes after robotic partial nephrectomy compared with older generation studies lacking perfusion volume. Materials and Methods: All patients diagnosed between December 2019 and December 2022 with a solitary, organ confined renal mass and eligible for robot-assisted nephron-sparing surgery were enrolled to this study. Patients underwent contrast-enhanced CT scans with four phases (unenhanced, corticomedullary, nephrographic, and urographic phases) three months prior to surgery. Patients with anatomical abnormalities such as horseshoe or ectopic kidney as well as patients with outdated preoperative imaging or inadequate imaging quality were excluded from the study. Results: In total 333 patients were enrolled to the study of which 217 underwent RAPN with standard 3DVM guidance while 116 experienced the new perfusion 3DVMs. Both groups were comparable both for patient and tumor features with a minor difference in terms of BMI which was slightly in favor of the standard 3DVM group (25.1 for standard 3DVM group vs 25.8 for perfusion 3DVM group). Median operative time was comparable between the groups (90 vs 91 min, p=0.7). A super-selective clamping was performed in 67.5% of the patients of the perfusion group and 37.3% of patients in the standard group. A higher rate of third order artery clamping was recorded in the perfusion group (42/77 vs 26/81 p 0.004). Clamping strategy failure from selective to global was seen in 5 perfusion group patients (4.3%) and in 26 standard group patients (11.9%) (p 0.02). Concerning intraoperative complications only 1 was recorded in the perfusion 3DVM group (0.9%) and 2 in the standard 3DVM group (0.9%) but in terms of postoperative complications there was no significant difference. The median change in ERPF rate was higher in standard 3DVM group (-18.9%) than perfusion 3DVM group (-10.69%). Therefore, a significant loss of renal function, defined as a change in ERPF exceeding 20%, was recorded in 16/82 (19.5%) standard group patients and 3/51 (5.8%) perfusion group patients (0.04). It was confirmed that the use of perfusion 3DVM is the only protective factor against a significant loss of renal function (OR 0.27; 95%CI: 0.14-0.53, p<0.001). In contrast, the choice of an enucleoresection instead of pure enucleation was found as the only factor significantly promoting the occurrence of a renal function decline (OR 5.34; 95%CI: 1.54-18.59, p=0.008). Conclusions: The results of the study indicate that the use of new generation perfusion 3DVMs provide functional advantages in terms of preservation of kidney function with respect to the standard 3DVM counterpart which instead lacks important vascular details.