A method for fluoroscopy based navigation system to assist needle insertion concerning reduced radiation exposure for endoscopic disc surgery

Endoscopic disc surgery requires a process of inserting a guide-needle to the target lumbar disc. And the insertion path is manually planned by drawing lines on the patient´s skin while monitoring the fluoroscopic view of the lumbar. Such operative procedure inevitably exposes both surgeon and patient to the fluoroscopic radiation emitted from c-arm for a long time. To reduce the radiation exposure time, this study proposes a computer assisted operative planning method implemented by using computer vision and computer graphics theory. This method calculates the 3 -dimensional path line of guide-needle from multiple triangular planes. Triangular planes can be obtained by analyzing 2-dimensional images of patient´s disc in 3 different angles from rotationally movable c-arm. Additionally, a method of guiding robot´s control based on the 3-dimensional needle path was developed by implementing the Hand-eye (end-effector and camera) calibration. Hand-eye calibration method calculates the geometric transformation matrix between the c-arm coordinate system and base of guidance robot coordinate system. The proposed system was then tested for its accuracy.