V2158: Intra-operative ultrasonography using miniature drop-type ultrasound probe manipulated by surgeon during robot-assisted partial nephrectomy

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Introduction and Objectives
Conventional flexible laparoscopic ultrasound (US) probe or drop-type finger-sized US probe have been used for US guidance during robotic-assisted partial nephrectomy (RAPN). However, disadvantage of the flexible US probe included limited angulations, and requirement of additional assistant to manipulate US probe, while the size of drop-type finger-sized US probe may be suboptimal. We evaluated the utility of miniature US probe (Hitachi Aloka Medical Ltd. CT, USA) manipulated by console surgeon.

Methods
Ten patients with age (61 years), median body mass index (27.7), tumor size (3.5 cm), C-index (1.6), RENAL score (8) and PAUDA score (8) were enrolled, including 6 cases of zero-ischemia partial nephrectomy. Mini probe was designed as ?gdrop-type?h to be manipulated by robotic arm with a flexible cord through the laparoscopic port. The size was 9?~16?~6 mm in diameter, and multi-frequency from 5 to 13 MHz was available, to allow various penetration of US. Intra-operative US data was transferred to the da Vinci console to provide the real-time US image shown directly to surgeon in parallel to the surgical view in the Tile-pro display.

Results
9 renal cell carcinomas and 1 angiomyolipoma were dissected with negative margin in all cases (100%). The median time to use intra-operative use of the mini probe was 3minutes. Based on the expert surgeon?fs rating for the utility of the probe, its utilities were excellent regarding 2 aspects as following: (a) visualization of tumor vascularity and peri-tumor vascularity, and (b) superiority in manipulation of the probe in comparison to the finger-size drop-type US probe. However, the optimal size of the drop-type US probe remained debatable, since the scanned area (9mm) of the miniature US probe seems too small to visualize the tumor margin in case of the tumor with larger diameter. Values of serum creatinine at the time of preoperative (1.18) and discharge (1.10) had no statistical difference (p=0.6).

Conclusions
To visualize anatomy beyond the endoscopic view such as tumor margin and feeding artery in console display using intra-operative drop-type US probe manipulated by console surgeon provided a new opportunity of image-guided RAPN. The optimal size of intra-operative drop-type US probe remained debatable.

Funding: none