Affiliations: [a] Trauma Department, Hannover Medical School, Hannover, Germany | [b] Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, USA | [c] Orthopaedic Department, University Hospital Basel, Basel, Switzerland
Abstract: 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.
