Image-Guided Surgery for Skull Base Meningiomas

Purpose: Skull base meningiomas invade and distort bony structures and may encase, displace, or extend into normal neural and vascular structures. Their treatment requires precise preoperative planning, intraoperative orientation by localization of anatomical landmarks, which may be disrupted by the lesion itself, and accurate identification of vital structures. The aim of this paper is to define the role of image-guided surgery (IGS) in the treatment of skull base meningiomas.

Method: From March 2000 to December 2006 we operated on 132 cases of skull base lesions with the aid of neuronavigation; 88 of these lesions were meningiomas. We describe our experience in the treatment of these lesions with the aid of IGS.

Result: Neuronavigation appears useful to define more accurately the best trajectory to the lesion, facilitating early identification of deeply located anatomic structures. Moreover, it allows identification of anatomic landmarks distorted or eroded by the meningioma, facilitating the identification of tumor boundaries and its dural implant. Because of their location, complex approaches are sometimes required to treat these lesions; in these cases IGS was particularly useful in reducing the approach-related morbidity.

Conclusion: Neuronavigation is ideal for the surgical treatment of skull base meningiomas, making surgical maneuvers safer and more effective. It also reduces morbidity and mortality. Moreover, brain shift, which is the most important limit of IGS in the treatment of intraparenchymal lesions, does not influence skull base procedures. In fact the lesions and distorted structures are in intimate relationship with bony structures and do not move as a consequence of CSF loss during surgery.

Neuronavigation remains an adjuvant tool which in no way replaces the neurosurgeon's experience and technical skills.