A new approach to computer-aided spine surgery: fluoroscopy-based surgicalnavigation

A new computer-based navigation system for spinal surgery has been designed . This was achieved by combining intraoperative fluoroscopy-based imaging u sing conventional C-arm technology with free-hand surgical navigation princ iples. Modules were developed to automate digital X-ray image registration. This is in contrast to existing computed tomography-(CT) based spinal navi gation systems, which require a vertebra-based registration procedure. Cros s-referencing of the image intensifier with the surgical object allows the real-time image-interactive navigation of surgical tools based on one singl e registered X-ray image, with no further image updates. Furthermore, the s ystem allows the acquisition and real-time use of multiple registered image s, which provides an advanced multi-directional control (pseudo 3D) during surgical action. Stereotactic instruments and graphical user interfaces for image-interactive transpedicular screw insertion have been developed. A de tailed validation of the system was performed in the laboratory setting and throughout an early clinical trial including eight patients in two spine c enters. Based on the resulting data, the new technique promises improved ac curacy and safety in open and percutaneous spinal surgery.