Occlusion angiography using intraoperative contrast-enhanced ultrasound scan (CEUS): a novel technique demonstrating segmental renal blood supply to assist zero-ischaemia robot-assisted partial nephrectomy.

Background: Recent innovations in technology and operative techniques have enabled safe performance of robot-assisted zero-ischaemia partial nephrectomy (PN), thus preventing the deleterious effect of warm ischaemia time.
Objective: To describe a novel technique of occlusion angiography using intraoperative contrast-enhanced ultrasound scan (CEUS) for zero-ischaemia robot-assisted PN (RAPN).
Design, Setting, and Participants: We used a prospective cohort evaluation of five patients who had imaging suspicious of renal cell carcinoma (RCC) treated at a single centre.
Surgical Procedure: We used computed tomography with three-dimensional reconstruction to identify renal arterial anatomy and its relationship to the tumour. Then, RAPN was performed with selective clamping and demonstration of a nonperfused segment of kidney (occlusion angiography) using intraoperative CEUS.
Outcome Measurements and Statistical Analysis: We prospectively collected data on baseline, perioperative, and postoperative parameters.
Results and Limitations: We describe the effects seen on ultrasound contrast administration. Contrast flare is seen in the segment of the kidney that is perfused. When selective clamping is performed, a watershed (line of demarcation) between the perfused and nonperfused segments of the kidney is clearly seen, allowing excision of the tumour in a relatively avascular plane and ensuring an adequate oncologic margin, when feasible. The mean age was 68.2 yr of age (range: 36-85), and the mean tumour size was 29.6mm (range: 20-42). The mean intraparenchymal extension of the tumour was 22.6mm (range: 12-30). Three tumours were located on the right kidney and two on the left. The mean blood loss was 420ml (range: 200-1000). The histology revealed clear cell RCC in two patients, oncocytoma in two patients, and type 1 papillary RCC in one patient. All the surgical specimens had negative surgical margins. The mean decrease in glomerular filtration rate was 8.4ml (range: 0-24). The mean follow-up was 6.4 mo (range: 5-8), with no evidence of recurrence in any patient. The only limitation in adopting this technique is the need for an intraoperative ultrasound probe with a CEUS mode. However, most specialists who perform minimally invasive surgery for small renal tumours believe that intraoperative ultrasound scan imaging is essential to achieving adequate resection margins.
Conclusions: Intraoperative CEUS can be a useful adjunct in determining whether zero-ischaemia RAPN is feasible by delineating the area of nonperfusion. This technique has several advantages over the currently available techniques, such as indigo carmine green and Doppler probes.
(Copyright © 2012 European Association of Urology. Published by Elsevier B.V. All rights reserved.)