Advanced virtual endoscopy for endoscopic transsphenoidal pituitary surgery

OBJECTIVE: Virtual endoscopy (vE) is the navigation of a camera through a virtual anatomical space that is computationally reconstructed from radiological image data. Inside this three-dimensional space, arbitrary movements and adaptations of viewing parameters are possible. Thereby, vE can be used for noninvasive diagnostic purposes and for simulation of surgical tasks. This article describes the development of an advanced system of vE for endoscopic transsphenoidal pituitary surgery and its application to teaching, training, and in the routine clinical setting. METHODS: The vE system was applied to a series of 35 patients with pituitary pathology (32 adenomas, three Rathke's c left cysts) operated endoscopically via the transsphenoidal route at the Department of Neurosurgery of the Medical University Vienna between 2004 and 2006. RESULTS: The virtual endoscopic images correlated well with the intraoperative view. For the transsphenoidal approach, vE improved intraoperative orientation by depicting anatomical landmarks and variations. For planning a safe and tailored opening of the sellar floor, transparent visualization of the pituitary adenoma and the normal gland in relation to the internal carotid arteries was useful. CONCLUSION: According to our experience, vE can be a valuable tool for endoscopic transsphenoidal pituitary surgery for training purposes and preoperative planning. For the novice, it can act as a simulator for endoscopic anatomy and for training surgical tasks. For the experienced pituitary surgeon, vE can depict the individual patient's anatomy, and may, therefore, improve intraciperative orientation. By prospectively visualizing unpredictable anatomical variations, vE may increase the safety of this surgical procedure.