Magnetically Guided 3-Dimensional Virtual Neuronavigation for Neuroendoscopic Surgery: Technique and Clinical Experience

OBJECTIVE: The authors have developed a novel intraoperative neuronavigation with 3-dimensional (3D) virtual images, a 3D virtual navigation system, for neuroendoscopic surgery. The present study describes this technique and clinical experience with the system. METHODS: Preoperative imaging data sets were transferred to a personal computer to construct virtual endoscopic views with image segmentation software. An electromagnetic tracker was used to acquire the position and orientation of the tip of the neuroendoscope. Virtual endoscopic images were interlinked to an electromagnetic tracking system and demonstrated on the navigation display in real time. Accuracy and efficacy of the 3D virtual navigation system were evaluated in a phantom test and on 5 consecutive patients undergoing neuroendoscopic surgery. RESULTS: Virtual navigation views were consistent with actual endoscopic views and trajectory in both phantom testing and clinical neuroendoscopic surgery. Anatomic structures that can affect surgical approaches were adequately predicted with the virtual navigation system. The virtual semitransparent view contributed to a clear understanding of spatial relationships between surgical targets and surrounding structures. Surgical procedures in all patients were performed while confirming with virtual navigation. In neurosurgery with a flexible neuroscope, virtual navigation also demonstrated anatomic structures in real time. CONCLUSION: The interactive method of intraoperative visualization influenced the decision-making process during surgery and provided useful assistance in identifying safe approaches for neuroendoscopic surgery. The magnetically guided navigation system enabled navigation of surgical targets in both rigid and flexible endoscopic surgeries.