Planning and simulation of neurosurgery in a virtual reality environment

OBJECTIVE: To report our experience with preoperative neurosurgical plannin g in our stereoscopic virtual reality environment for 21 patients with intr a- and extra-axial brain tumors and vascular malformations. METHODS: A neurosurgical planning system called VIVIAN (Virtual Intracrania l Visualization and Navigation) was developed for the Dextroscope, a virtua l reality environment in which the operator reaches with both hands behind a mirror into a computer-generated stereoscopic three-dimensional (3-D) obj ect and moves and manipulates the object in real time with natural 3-D hand movements. Patient-specific data sets from multiple imaging techniques (ma gnetic resonance imaging, magnetic resonance angiography, magnetic resonanc e venography, and computed tomography) were coregistered, fused, and displa yed as a stereoscopic 3-D object. A suite of 3-D tools accessible inside th e VIVIAN workspace enabled users to coregister data, perform segmentation, obtain measurements, and simulate intraoperative viewpoints and the removal of bone and soft tissue. RESULTS: VIVIAN was used to plan neurosurgical procedures primarily in diff icult-to-access areas, such as the cranial base and the deep brain. The int raoperative and virtual reality 3-D scenarios correlated well. The VIVIAN s ystem substantially contributed to surgical planning by 1) providing a quic k and better understanding of intracranial anatomic and abnormal spatial re lationships, 2) simulating the craniotomy and the required cranial base bon e work, and 3) simulating intraoperative views. CONCLUSION: The VIVIAN system allows users to work with complex imaging dat a in a fast, comprehensive, and intuitive manner. The 3-D interaction of th is virtual reality environment is essential to the efficient assembly of su rgically relevant spatial information from the data derived from multiple i maging techniques. The usefulness of the system is highly dependent on the accurate coregistration of the data and the real-time speed of the interact ion.