Foramen magnum meningiomas – experience with the posterior suboccipital approach

Abstract

The aim of this study is to analyse short- and long-term results after surgical treatment of foramen magnum meningiomas and to identify the possible advantages of the posterior suboccipital approach over lateral and anterior approaches. Between 1992 and 2006, 16 patients with foramen magnum meningiomas were operated on in our institution, and in all cases a posterior suboccipital approach was utilised with lateral extension of the bone opening according to the position of the tumour. In 14 patients, intraoperative monitoring of the lower cranial nerves was performed. Localisation of the tumours was ventral (3), ventrolateral (10), dorsal (1) and dorsolateral (2). Mean age of the patients was 61 years (ranging from 40 to 85 years). Preoperative and postoperative function was classified according to the McCormick scale. We found in eight patients a postoperative upgrading of at least one grade, in five patients an unchanged status and a deterioration in only two patients. Complete removal of the tumour was possible in 14 cases (Simpson 1-2). The follow-up period varied from 24 to 119 months (mean 43.5 months), during this time there were no recurrences. Removal of foramen magnum meningiomas can be performed safely today with the use of microsurgical techniques and intraoperative monitoring. In our experience, the posterior suboccipital approach is suitable for the majority of these tumours.

The far-lateral approach for foramen magnum meningiomas

“…The mean age of the patients with these lesions at the time of diagnosis is approximately 55 years old, 4,7,15,17,22,23,32,33,40,47,50 and they often mimic degenerative or demyelinating diseases such as cervical spondylosis, multiple sclerosis, and amyotrophic lateral sclerosis. 7,13,28,37,49 Such a prolonged-and often relapse and remitting-presentation explains the 30.8-month mean length of symptoms prior to diagnosis, even in the era of advanced neuroimaging.…”

“…A standard midline suboccipital craniectomy with an upper cervical laminectomy (C-1, occasionally C-2) is the preferred approach for most of the lesions originating posteriorly to the dentate ligaments. 8,17,22,37 The anterior approach for anterior or anterolateral FMMs, via transoral or transcervical routes, has been described for treatment of anteriorly located lesions, but never gained wide acceptance. 37,42 Common complications associated with anterior approaches include a higher risk of CSF leakage and infection.…”

“…17,19,22 The endoscopic extended endonasal approach has recently gained attention for treatment of anteriorly located FMMs. Despite their theoretical potential to minimize surgical morbidity, its actual clinical indications remain unclear.…”

“…Variations of the standard technique were described and included lateral occipital bone resection and/or C-1 and C-2 laminectomies. 6,22,26,28,31,37,48,49 This surgical approach proved adequate for lesions located posterior to the dentate ligament. However, anterior or anterolateral lesions were associated with increased surgical morbidity, due to medullary tissue retraction needed for adequate exposure.…”

Surgical Management of Skull Base Meningiomas – An Overview

“…These approaches not only involve pterional and orbitozygomatic craniotomies but also sub-occipital approaches, sometimes in combination with a petrosal approach (Bambakidis et al 2007;Kandenwein et al 2009;Samii & Gerganov 2008;Seifert 2010).…”