O-armA®-based spinal navigation and intraoperative 3D-imaging: first experiences

Since the first use of instrument-tracking techniques in the early 1990s, image-guided technologies became a leading topic in all branches of spine surgery. Today, navigation is a widely available tool in spine surgery and has become a part of clinical routine in many centers for a large variety of indications. Spinal navigation may not only contribute to more precision during surgery, but it may also reduce radiation exposure and fluoroscopy time, with advantages not only for the patient but also for the operating room personnel. Different registration algorithms have been developed differing in terms of the type of image data used by the navigation system (preoperatively acquired computed tomography [CT] images, intraoperatively acquired fluoroscopy images) and the way virtual and physical reality is matched. There is a tendency toward a higher accuracy for 3D fluoroscopy-based registration algorithms. The O-arm(A (R)) represents a new flat-panel technology with the source and detector moving in a 360A degrees arc around the patient. In combination with the Stealth(A (R)) station system, navigation may start immediately after automated registration with already referenced instruments. After instrumentation, an additional scan may confirm intraoperatively the correct positioning of the instrumentation. The first experiences with the system are described in this paper.