10/3 Ultrasound based non-invasive referencing of bone structures

		Minimally invasive spine surgery.

Intra-operative continuous tracking of the surgical object allows to establish a reference coordinate frame located at the object of interest, a process known as "referencing". Referencing may be achieved in three ways: rigid fixation of an articulated arm, rigid fixation of a marker, or imaging of the surgical object using a device that is itself tracked. The later category is certainly the best regarding reduced invasiveness. In recent years, several such systems have been proposed, for example using endoscopy with structured light or 2D B-mode ultrasound. But so far no appropriately accurate (error < 0.5mm) minimally invasive or even non-invasive referencing technique is available.

In this subproject we focus on solving the fully non-invasive referencing of a rigid anatomical structure using tracked ultrasound, specifically for spine surgery (vertebro/kyphoplasty), in which the fixation of a marker is more invasive than the intervention itself, and overall patient motion is minimal. Additionally, the use of shape estimation, ultrasound referencing, ultrasound registration and navigation will eliminate the need for fluoroscopy. This subproject will develop the clinical module for vertebro/kyphoplasty, as well as generate, in collaboration with subproject 4, the appropriate vertebral models.