V08-11: 3D digital reconstruction of renal model to improve preoperative planning of robot assisted partial nephrectomy
We report the preliminary experience with preoperative use of 3D digital reconstruction to guide the surgical approach to the renal masses and to the vascular anatomy of the kidney during Robot assisted partial nephrectomy (RAPN).
We prospectively enrolled 20 non-consecutive patients with clinical diagnoses of renal mass, submitted to RAPN at our institution. 3D virtual reconstruction of an anatomical model including the lesion, the renal parenchyma, the urinary collecting system (UCS) and vascular anatomy was employed. The complexity of the renal lesions was assessed using conventional imaging and the 3D model, according to PADUA and R.E.N.A.L. scores. The preoperative surgical plan to define the level of arterial clamping and the potential need of UCS suture was recorded by surgeon using a 2 points questionnaire, basing on conventional imaging, then re-determined after examination of the 3D reconstruction. The intraoperative effective clamping technique and the need of UCS suture after revision of the 3D virtual model, was compared with the preoperative plan based on conventional imaging using the McNemar correlation coefficient.
Overall, 16 (80%) and 4 (20%) of the tumours were clinical T1a and T1b stage, respectively. Mean (±SD) operative time was 166 (± 45) minutes and mean (±SD) Warm Ischemia Time was 10 (±3.4) minutes. No intraoperative and post-operative complications were observed. After revision of the 3D reconstruction, PADUA and R.E.N.A.L. scores were reassessed in 12 (60%) and 16 (80%) cases, respectively (all p?0.02). Basing on conventional imaging, the preoperative plan of arterial clamping was: no clamping in 4 (20%), clamping of the main artery in 12 (60%) and selective clamping in 4 (20%) cases. The 3D virtual model revision induced the surgeon to modify the clamping plan in 8 (40%) cases, towards a selective approach, resulting in no cases of unclamped approach, clamping of the main artery in 8 (40%) individuals and selective clamping in 12 cases (60%; p=0.01). Moreover, basing on conventional imaging the surgeon was suggested to consider UCS repair in 40% of cases before surgery, while the 3D-based intraoperative plan resulted in UCS suture in 20% of patients (p=0.07).
The use of 3D virtual models facilitated the preoperative knowledge of the tumour and changed the preoperative plan of arterial clamping in 40% of patients during RAPN toward a more selective clamping approach.