Background Surgical treatment of foramen magnum meningiomas is challenging because of the proximity to critical vascular and neural structures such as the medulla and lower cranial nerves. In addition to the morbidity and mortality associated with surgery, complete resection is not always feasible. Gamma knife radiosurgery may provide a safe alternative or adjuvant to surgery after neural decompression. Objective To evaluate the feasibility, efficacy and safety of the treatment of meningiomas involving the foramen magnum by gamma knife radiosurgery. Material and Methods Between December 2007 and April 2016, 23 patients with meningiomas involving foramen magnum were treated by gamma knife radiosurgery. Of these, 18 patients were available for follow up. There were 17 females and one male. The mean age at the time of gamma knife treatment was 51 years (36–71 years). Nine patients had previous surgery (5 were residual tumors after surgery and 4 were a tumor recurrence). Twenty-two sessions were performed for 18 tumors (4 tumors were volume-staged). The mean target volume was 5.2 cc (0.7–13.5 cc) and the mean dose was 10.7 Gy (10–12 Gy). Results The mean follow up was 35 months (12–88 months). One died 5 years after treatment from comorbidity. The tumors remained stable in 13 (72%), regressed in 4 (22%) and progressed in one (6%). The overall tumor control was 94%. Seventeen patients were symptomatic before treatment and one was accidentally discovered. Clinical improvement was observed in 8 patients (44%), while remaining patients were clinically stable. No patients suffered adverse radiation effects. Conclusion Gamma knife radiosurgery appears to be an effective and safe treatment option for meningiomas involving the foramen magnum. It can be utilized as an adjuvant to surgery or as a primary treatment in small tumors and in larger tumors in patients with comorbidities, using volume-staging technique. |
