Suboccipital Craniectomy for an Anterior Foramen Magnum Meningioma-Optimization of Resection Using Intraoperative Augmented Reality: 2-Dimensional Operative Video.

Foramen magnum meningiomas represent a challenge in skull base surgery because they frequently implicate the lower cranial nerves, brainstem, and posterior cerebral circulation, including the anterior spinal arteries.1 The use of virtual reality allows for surgical rehearsal based on patient-specific anatomy, thus increasing the surgeon's confidence and assists with bone opening planning by generating navigation-integrated templates.2,3 In this 2-dimensinal operative video, the authors demonstrate the importance of augmented reality (AR) template for the resection of a large intradural anterior foramen magnum meningioma in a 68-year-old patient. Preoperative MRI and virtual reality were used to delineate and define the extent of the tumor, as well as its relationship with nearby vital structures. The lesion measured 4.5 by 2 by 3 cm in the craniocaudal, anteroposterior and transverse axes, respectively, and was causing significant mass effect on the brainstem and spinal cord. Both vertebral arteries had a very close relationship with the tumor. After performing a bilateral craniectomy with a right side far lateral extension, debulking started at the inferior and continued toward the middle portion of the tumor. The most challenging part of the operation was to identify and protect the anterior spinal arteries, for which the AR-assisted preview of the surgical microscope proved of paramount importance. Following the heads-up display of the AR, the lateral portion of the tumor, which was adherent to the ventral surface of the vertebral artery, and then the uppermost portion of the tumor were removed, achieving a gross total resection. Appropriate consent was obtained. Images at 4:10 used with permission. Left from Matsushima T,4 ©2015; Right from Dhandapani et al,5 ©2014.