UroToday.com — September 22, 2018

Presented by: Fumiya Hongo – Department of Urology, Kyoto Prefectural University of Medicine, Japan

Authors: Fumiya Hongo, Atsuko Fujihara, Yuta Inoue, Nomura Takeshi, Tsukasa Narukawa, Yasuyuki Naitoh, and Osamu Ukimura – Department of Urology, Kyoto Prefectural University of Medicine, Japan

Written by: Dr. Shlomi Tapiero, Department of Urology, University of California-Irvine, medical writer for UroToday.com. at the 36th World Congress of Endourology (WCE) and SWL, Paris, France.

As part of the preoperative plan prior to partial nephrectomy, the surgeon must have a cognitive 3D image of the kidney, its vessels, and most importantly, the tumor shape and its location. When the tumor is exophytic it is usually clearly visible and well defined. However, some tumors (e.g. small, completely endophytic tumors) present a surgical challenge and intraoperative B-mode Doppler ultrasound (US) does not always clearly delineate the tumors and its margins. Professor Hongo from Kyoto University in Japan presented how he overcomes this challenge with contrast-enhanced intraoperative Doppler US during robotic partial nephrectomy.

The contrast medium, Sonazoid, consists of billions of microscopic spheres and is administered intravenously. The microspheres are smaller than capillaries but do not leak from blood vessels. Sonazoid reflects ultrasonic waves and the microspheres produce a well detected acoustic signal. It is therefore ideal for hypervascular tumors such as clear cell carcinoma. Contrast-enhanced doppler US was used in five patients when the tumor margin was unclear to the surgeon on conventional B-mode US. In these cases, injection of Sonazoid produced a well visible rim of blood vessels around the tumor, and allowed the surgeon to proceed safely with the procedure. In addition, it assisted in selective clamping of the arteries supplying the tumor as it clearly confirmed ischemia of the tumor area.

In conclusion, intraoperative contrast-enhanced Doppler US was a useful adjunct tool in robotic partial nephrectomy, when tumors had unclear margins on conventional B-mode US. Of note, Sonazoid is contraindicated in patients with egg allergy and is associated with a low incidence of side effects such as diarrhea, albuminuria, and neutropenia.