Surgical Results of 32 Foramen Magnum Meningiomas with a Special Reference to Vascular Complications

Objective: Surgical treatment for foramen magnum meningiomas (FMMs) is fraught with challenges. In this study, we aimed to review our surgical technique and operative results of FMMs with an emphasis on vascular complications.

Methods: Thirty patients harboring FMMs underwent surgery by the senior author (JHL) at the Cleveland Clinic between 1993 and July 2011. Clinical data on age, gender, pre- and postoperative neurological deficits, surgical approach, complications, and the follow-up results were reviewed.

Results: Mean age was 50.3 years (range, 27–87 years), and male/female ratio was 11/21. The most common clinical symptoms were headache and neck ache (46.9%), numbness/paresthesia (31.3%), unstable gait (18.8%), weakness (18.8%). Seven patients (21.9%) were asymptomatic. Preoperative neurological examination showed decreased sensation (31.3%), motor weakness (18.8%), ataxic gait (18.8%), and cranial nerve (IV, VI,VII, XI-XII) dysfunction (18.8%). The neurological examination was unremarkable in 18 patients (56.3%). The average tumor size was 3.4 cm (range, 1.5–6.0 cm). In 22 patients (69.0%), the tumor was anterolateral. Transcondylar approach was used in 89.2% of anterior, lateral, or anterolateral FMMs. Transposition of the vertebral artery was not performed in any case. Gross total resection was achieved in 75% of all cases. Cranial nerve injury was observed in eight patients (25.0%). Three patients had neurological deficits due to brainstem ischemia (9.4%). Mean follow-up was 48 months, and 90% of patients have been free from recurrence or regrowth.

Conclusions: Although a satisfactory resection can be achieved for FMMs utilizing meticulous skull base techniques, anterior or anterolateral FMMs carry significant surgical risks of cranial nerve injury and brainstem ischemia. The likelihood of cranial nerve recovery is favorable in time even when multiple lower cranial nerves are involved. However, ischemic injury of the brainstem due to occlusion of the vertebral, anterior spinal arteries, and/or medullary perforators may lead to fatal medical complications and unfavorable outcome.