Foramen magnum meningiomas: experiences in 114 patients at a single institute over 15 years.

BACKGROUND: Although there has been great development in the anatomical understanding and operative techniques for skull base tumors, controversy still exists regarding the optimal surgical strategies for the FMMs. We report clinical and radiologic features as well as the surgical findings and outcome for patients with FMM treated at our institution over the last 15 years.

METHODS: We reviewed 114 consecutive cases of FMM operated between May 1993 and June 2008 in the neurosurgery department at Beijing Tiantan Hospital.

RESULTS: There were 68 female and 46 male patients (mean age, 52.3 years; range, 28-76 years). Foramen magnum meningiomas were classified as anterior (80 cases), anterolateral (24 cases), and posterolateral (10 cases). Mean duration of symptoms was 11.7 months (ranging from 1.5 to 240 months). Cervico-occipital pain (80.7%) and headache and dizziness (42.1%) were the most common presenting symptoms. The preoperative KPS was 72.5 +/- 8.3. Mean maximum diameter of the tumors on MRI was 3.35 cm (range, 1.5-4.7 cm). Posterior midline approach was performed in 10 cases, far-lateral retrocondylar approach in 97 cases, and extended far-lateral approach in 7 cases. Gross total resection was achieved in 86.0% of patients and subtotal resection in 14.0%. Surgical mortality was 1.8%. Follow-up data were available for 93 patients, with a mean follow-up of 90.3 months (range, 1-180 months), of which 59 (63.4%) lived a normal life (KPS, 80-100).

CONCLUSION: Our experience suggests that most anterior and anterolateral FMMs can be completely resected by a far-lateral retrocondylar approach without resection of the occipital condyle. Complete resection of the tumor should be attempted at the first operation. Postoperative management of FMM is important for the prognosis.