3D renal modeling has been shown to be a useful adjunct to surgical planning and education. 3D printed models are frequently studied but 3D printing comes with challenges including cost and difficulty representing complex intrarenal anatomy. Interactive virtual 3D modeling reduces cost compared to 3D modeling while rendering high complexity. Previous investigations on the use of 3D modeling for minimally invasive partial nephrectomy have focused on perioperative outcomes and surgical planning.10,11 There is less evidence regarding the use of virtual 3D models for trainee and patient education.
This study showed that use of a cost-effective and detailed virtual 3D model was associated with significant improvements in patients’ understanding of the kidney itself, their disease, the procedure, and the associated risks and benefits. This demonstrates the utility of a virtual interactive model to accomplish what has been previously shown with 3D printed models.6 The model was perceived as helpful (> 9 out of 10) by both patients and providers across all assessed domains of counseling. These findings indicate that the model likely improved health literacy. As has been discussed in a prior similar study on 3D printed models, higher health literacy has been shown to correlate with better patient outcomes.6,12
Although a previous study found that 3D printed model improved trainee confidence in the planned surgical approach, this was not observed in this study.6 Surveys were typically filled out by senior trainees who were well-prepared for the cases and had collaboratively reviewed the available cross-sectional imaging. Senior trainees may find review of the conventional imaging to be sufficient to establish confidence in the proposed surgical approach and specific patient anatomy.
We felt that the model was particularly helpful for retroperitoneoscopic single-port cases. Especially in the single port cases, where renal manipulation and global anatomic perspective are more challenging to achieve, the model was felt to aid in operative confidence. While the results were not statistically significant, there was a trend toward significance in improvement of trainee confidence in the proposed operative approach in retroperitoneoscopic cases regardless of platform and for single port cases specifically when compared to transperitoneal and XI cases respectively.
To our knowledge, this is the first 3D modeling study that has involved a significant proportion of SP retroperitoneoscopic partial nephrectomy. Due to the heterogeneity that this introduced in operative time, mass complexity, and surgical approach, we did not feel that an analysis of perioperative metrics or comparison to a historical control cohort, as has been performed in similar studies, would provide a comparable control. We acknowledge that our institution was early in our experience with the SP platform. Nevertheless, further studies specifically investigating 3D model usage in single port robotic surgery can be considered.
The protocol used in this most recent study allows for cost improvement. A 3D printed model technique was previously investigated at our institution to create cost-effective models at a material cost of $30–50 per model. 6 This study did not consider additional 3D printing-related labor costs incurred for computer-aided design and print processing/assembly (approximately $200 and $40 respectively), bringing the true cost to produce a physical 3D printed model to about $270–290 per model based on our previously published protocol. Additionally, the previous study protocol included the segmentation of four discrete structures in each case (renal parenchyma, renal artery, renal vein, and tumor/pathology). This study’s protocol aimed for a higher level of model specificity including segmentation of seven structures (renal parenchyma, renal artery, renal vein, tumor/pathology, medulla, collecting system, ureter) and additional fine structures, as relevant and differentiable (ex. smaller arteries/veins supplying the pathology) without needing to consider printability of these fine structures. This increased detail likely translated to an increase in segmentation time (5 hours in this study vs 2 hours in the prior study) although the segmentation staff were different and the studies were not designed to correlate complexity and segmentation time. In the current protocol, eliminating the physical model may preserve much of the benefit, while reducing the cost and complexity of execution. By eliminating the design, 3D printing, and assembly of a physical model, we gained a time benefit and could create models for cases closer to the scheduled surgery.
This study has other important limitations. Creation of virtual models, although cost-effective compared to printed models, incurs costs including labor to perform segmentation. While model development algorithms have not yet met the necessary precision threshold, this process could be automated in the future. Additionally, all trainees completing surveys were staff of the institution administering the study, which may have created response bias. Since the model was shown the day of surgery, the counseling with conventional imaging and then the model was iterative, which may have improved post-model survey results, in part, from repetition.