Image-Guidance for Non-Anatomical Liver Resections: An ex-vivo Study

Abstract

Introduction: Non-anatomical resections of liver tumors are becoming more popular because they spare a larger portion of healthy liver parenchyma. However, the lack of anatomical landmarks to follow during the resection process makes them technically more challenging than anatomical resections. Image-guidance systems have been introduced to provide additional guidance, but are rarely used due to their inaccuracy, time-effort and complexity in usage and setup. Therefore, we have designed a new navigation approach that renders a surgical plan intra-operatively in real time using only navigated ultrasound. Method: The ultrasound based navigation approach comprises the following steps:i)scanning the surface using the navigated ultrasound,ii)marking the tumor location and size on a midsection ultrasound image,iii)specifying a resection shape and a safety margin to create an optimal surgical plan. In this study, we evaluated this method in an ex-vivo porcine model by three experienced hepatobiliary surgeons with respect to R0 resection status. Results: In 22 out of 23 resections an R0 resection (margin > 1mm) was achieved (95.7%) with a median resection margin of 5.9 mm (IQR 3.5 - 7.7 mm). There was a difference between the surgeons in terms of resection margin with operators 1,2 and 3 having 7.8 mm, 4.15 mm and 5.1 mm median resection margin respectively (p = 0.054). Conclusions: This navigation approach could represent a useful tool for intra-operative guidance in non-anatomical resection alongside conventional ultrasound guidance. A clinical pilot trial with 10 patients is currently in planning and will start beginning of 2020.