Assessment of a mini stereotactic guidance system for percutaneous focal liver tumour ablation

Percutaneous liver tumour ablation is becoming the preferred treatment option for patients ineligible for surgery. Percutaneous insertion of ablation applicator is often assisted by ultrasound (US) as it provides real-time visualization of subcutaneous anatomy and needle advancement. However, US-guided approach often requires multiple needle repositioning, leading to increased risk of tumour seeding and patient harm. Surgical Navigation Systems (SNS) have the potential to mitigate these limitations of the US-guided approach by providing additional visual and mechanical support. In this paper, we present a SNS comprising a mini stereotactic, patient-attached, mechanical needle guider with virtual reality (VR) visualization to facilitate needle positioning. We present a preliminary user trial comparing traditional US needle guidance puncture against our Mini-SNS. Nineteen (19) non-experts performed two randomized needle insertions into a designated tumour in a custom liver phantom. Preparation time, insertion time, total procedural time, needle repositioning, and final needle tip (tracked and virtual) position were recorded and analyzed. The Mini-SNS results show a reduction in insertion time compared to the traditional approach, without significant difference in the total procedure time. Compared to the traditional manual US-guided method, our SNS improves needle tip placement accuracy from 17mm to less than 10 mm. The number of repositioning was significantly reduced using the Mini-SNS, being just 3 in times total compared to an average of 8 times per user using the traditional approach. These initial findings suggest that the Mini-SNS enhances efficiency in needle punctures, with reduced insertion time and repositioning, supporting its potential to minimize patient harm.