Linear bearing device as a solution for optical navigation of fine needle procedures

BACKGROUND: Optical navigation of needles < 1 mm diameter remains a challenging task. Bending of these tools is the limiting factor. OBJECTIVE: To use a conventional optical navigation system for interventional fine needle procedures. MATERIALS AND METHODS: A novel custom-made device was constructed to guide the needle in the direction of the planned trajectory. Accuracy of this device was analyzed with two setups (A = ballistic gelatin; B = used pork meat). For both setups, a Plexiglas cube with integrated Plexiglas reference arrays was used. Metal targets of 1 mm diameter were placed in the center. Images were acquired using a 3D fluoroscope connected to a conventional optical navigation system. After trajectory planning, ten navigated injections were performed freehand and with the linear bearing device for each setup. A 3D scan was performed to measure the distance between contrast medium and metal target after each injection. RESULTS: Freehand navigation with a needle of 0.9 mm in diameter was not accurate with either setup (Setup A: mean 33.4 mm; range, 3-63 mm; Setup B: mean 40.1 mm; range, 12-75 mm). Linear bearing navigation was significant more precisely (Setup A: mean 0.7 mm; range, 0-0.75 mm; Setup B: mean 0.29 mm, range 0-1.3 mm) than freehand navigation. CONCLUSION: The linear bearing device reduced all bending. Optical fine needle navigation was accomplished with precision comparable to electromagnetic navigation. This device may provide useful for minimally-invasive clinical applications. Follow-up studies should compare electromagnetic and optical navigation systems in the same setup.