Improved ultrasound-based navigation for robotic drilling at the lateral skull base

Abstract

Sensitive structures of the lateral skull base demand for robotic procedures a higher precision than provided by standard navigation systems relying on CT scans. Keystone of our multisensor approach to improve accuracy is the use of ultrasound for local navigation. In this study we compare two different ultrasound techniques to measure human skull bone in vitro: (A) the classic echo technique and (B) a combination of “coded excitation” and “matched filter” Technique B showed to be very useful by improving accuracy and practical penetration depth of the ultrasound. Sound velocity showed to be highly variable in the specimens. We therefore suggest sound velocity measurements during surgery.