Objectives: To demonstrate the feasibility of safe resection of anterior foramen magnum meningiomas
through an endoscopic-assisted posterior midline suboccipital subtonsillar approach.
Design: Illustrating the surgical steps and outcome of this approach.
Setting: Evidence of CSF cleft between the tumor and brainstem/spinal cord on T2Wi MRI and
homogeneous contrast enhancement. Semi-sitting positioning with extensive electrophysiological
neuromonitoring and transesophageal echocardiogram. Preoperative tracheotomy can be
considered in cases of preoperative dysphagia/respiratory distress. A standard midline
incision with bilateral suboccipital craniotomy and C1-laminotomy is performed. After
partial resection and elevation of the tonsils, tumor is debulked unilaterally around
the lower cranial nerves and the vertebral artery, devascularized from the clival
dura, and then dissected from the brainstem. Endoscopic-assisted removal of its anterior
portion follows. The same procedure is repeated from the opposite site for the contralateral
portion, before approaching the purely anterior part with endoscope assistance.
Participants: Four consecutive patients.
Main Outcome Measures: Grade of tumor resection and outcome (mRS).
Results: Clinical outcome and grade of resection are comparable to other series of patient
treated with other foramen magnum approaches.
Conclusion: Anterior foramen magnum meningiomas can be safely removed through this relatively
faster midline approach with bilateral exposure of lower CNs and vertebral arteries
and lower approach-related morbidity (no condyle drilling). The surgical corridor
is created by the tumor during debulking reducing need for brain retraction and the
removal of the anterior dural attachment coagulated under the microscope is verified
and completed endoscopically with pituitary curettes (Simpson II).
