EAU 2018: Which Role Does the Intraoperative Ultrasonography Have in a Nephron-Sparing Surgery Setting?

Copenhagen, Denmark (UroToday.com) Preservation of renal function is the main feature of nephron-sparing surgery. In the setting of evaluation of renal function prior and after partial nephrectomy (PN), renal scintigraphy (RS) and volumetric assessment (VA) have gained popularity due to the more precise estimation of effective renal function allowed before and after PN. At the time of PN, the use of intraoperative ultrasonography (US) is a worldwide used procedure, but no definitive answers have been published, on whether it results in any advantage.

The aim of the study was to understand the role of intraoperative US during PN, based on functional data obtained by renal scintigraphy (RS) and software-calculated volume data, as assessed on CT-scan.

Consecutive patients who were diagnosed with a renal mass suitable for PN were prospectively enrolled. Demographics, intraoperative (including the use of intraoperative US) and postoperative variables were collected. Specifically, for this study, all patients underwent RS and VA prior and after PN (90 days postoperatively). RS Split renal function (SRF) and Effective Renal Plasma Flow (ERPF) were calculated prior to and after PN. For VA, CT-scan images were elaborated by a dedicated Software for 3D segmentation according to the “growing region” strategy by two dedicated radiologists. ROI were designed on the renal parenchymal slices, then a semi-automatic method based on voxels density calculated the parenchymal volume. 

Fifty-one patients who consecutively underwent PN by minimally-invasive approach were analyzed. Median ERPF and volume drops were 24% and 14%, respectively. Intraoperative US was performed in 27 cases (52.9%). Kolmogorov-Smirnov test showed a significantly higher volume loss when intraoperative US was not performed   (-9.9 ± 14.3 vs -18.8 ± 16.1%) (p < 0.025). Conversely, no significant difference was found in ERPF drop (-27.7 ± 14.8 vs -21.5 ± 19.2, US yes vs US no, respectively), regardless if US was performed or not (p>0.10).

In this preliminary experience, the data showed that more renal parenchyma is preserved when intraoperative US is performed. This should sponsor the routine use of intraoperative US, together with its known advantages. On the other hand, no influence on renal function was found. It is possible that the larger amount of renal parenchyma preserved does not translate to a clinically relevant advantage. In any case, further studies are needed to draw definitive conclusions.

Presented by: Porpiglia F,  San Luigi Gonzaga Hospital, Dept. of Urology, Orbassano, Italy

Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre, twitter: @GoldbergHanan at the 2018 European Association of Urology Meeting EAU18, 16-20 March, 2018 Copenhagen, Denmark