Chapter 31 - Surgical Management of Tumors of the Foramen Magnum

Abstract

A broad range of intra- and extradural surgical pathologies may affect the foramen magnum (FM). Tumors represent almost 5% of spinal and 1% of intracranial neoplasms; they consist mostly of meningiomas, neurinomas, and chordomas. In the past, these lesions were approached posteriorly and eventually via the transoral route; however, the results of these techniques were disappointing. The introduction of computed tomography (CT) and magnetic resonance imaging (MRI) broadened our knowledge of the brain’s microanatomy and facilitated the development of microsurgical techniques and skull base approaches. Surgical treatment is the best approach to the treatment of tumors of the FM, especially meningiomas, schwannomas, neurofibromas, and chordomas. Most of these lesions can be removed using posterior approaches; however, when the tumors are situated anteriorly or anterolaterally, resection using traditional approaches becomes more difficult. The far lateral approach with or without condylar resection has the advantage of being combinable with the petrosal, retrosigmoid, and infratemporal approaches. It also enables the removal of most of these tumors, either intradural or extradural lesions. In recent years, the development of an expanded endoscopic endonasal approach has provided an excellent alternative to the treatment of ventral FM tumors. Although very few studies have been published, the results thus far are very promising.