Abstract
The surgical management of solid renal tumors has evolved from removing the entire kidney in radical nephrectomy to only removing the tumor and preserving the remaining healthy kidney tissue in partial nephrectomy. The indications for partial nephrectomy have also expanded from individuals with imperative indications (e.g., solitary kidney, bilateral tumors, or high renal insufficiency risk) to all individuals whenever technically feasible, independent of tumor size. 1,2 This is the result of compelling evidence that partial nephrectomy offers a 19% advantage to patients in terms of better renal function and overall survival. 3 Robotic technology has had a revolutionary impact on urologic oncology surgery. As more complex tumors with higher nephrometry scores, such as more endophytic, large, and hilar tumors, are being resected, the need for a detailed portrayal of medical imaging has become even more crucial. This is important especially for hilar tumors given the variable anatomy of the renal hilum and the tumor itself, the proximity of the collecting system, and the complex reconstruction required.
The authors report utilizing an intelligent/interactive qualitative and quantitative analysis (IQQA) three-dimensional (3D) reconstruction technique during minimal invasive partial nephrectomy that aims to aid in selective ischemia, accurate localization, and resection of renal hilar tumors. The platform uses 3D reconstructed virtual imagery with manipulation capability for preoperative planning and guidance at the time of partial nephrectomy. The authors should be commended for reporting their clinical experience incorporating this image segmenting technology for the management of 26 patients with hilar renal tumors. In conclusion, they reported that IQQA offered accurate localization, complete resection, and fewer perioperative complications as a benefit for hilar tumors. However, several aspects that present barriers to the application of this technology should be noted.
First, this technology is not novel. Several authors have described platforms using 3D reconstruction imagery with manipulation capability at the time of partial nephrectomy. 4 –7 The authors do report using a commercially available Food and Drug Administration-approved technology that adds merit to their argument for the utility of this platform. However, the additional costs for acquiring the software were not mentioned in their article and accordingly may impact accessibility to most surgeons.
Second, for an accurate portrayal of renal anatomy especially segmental arterial and venous branches all patients received computed tomographic angiography preoperatively. This form of imaging utilizes a higher concentration contrast agent compared with standard contrast-enhanced imaging, thus is more expensive, poses an additional risk of kidney injury, and maybe only limited to patients with normal renal function. Moreover, it is important to emphasize that the processing and rendering of scans obtained in the Digital Imaging and Communications in Medicine format is often performed manually, which are subject to significant operator variability. 8 The process also mandates a significant real-time interaction between the radiologist (or in this case the laboratory technicians) and the urologist for adjustment and confirmation of the 3D model.
Third, despite the encouraging clinical data in the 26 patients reported with an average warm ischemia time of 24.3 minutes, estimated blood loss of 156 mL, selective ischemia in 54.8% of cases, negative surgical margins, and a relatively low complication rate, this remains a single arm single surgeon single center feasibility study. Claiming superiority to a nonmatched cohort of patients performed almost a decade ago at another institution is unjustified and the authors are encouraged to continue their efforts with the completion of their own comparative study.
The authors present compelling data of their experience with image guidance technologies incorporated into the robotic console during complex partial nephrectomy cases. This report, like its predecessors, utilizes patient-specific virtual segmentations as an external reference of comparison for the surgeon and in some cases can be manually superimposed onto exposed vital structures in the operative field, but these still remain a far cry from a genuine real-time surgical navigation and guidance system. The development of an automated system that can accurately register and superimpose these virtual segmentations on the in vivo intraoperative field for a targeted dissection would be a game-changing shift in the era of surgical navigation technologies.