Towards a hypermodern theory of meningioma surgery

Parasagittal meningiomas – literature review and a case report

Meningiomas are tumors that can develop anywhere along the neuraxis, but with increased concentration in some specific areas. Parasagittal meningiomas have the dural attachment on the external layer of the superior sagittal sinus (SSS) and invade the parasagittal angle displacing brain away from its normal position. Among meningiomas, the parasagittal location is the most common (22%). Taking into account their anatomic insertion along SSS, parasagittal meningiomas can have their dural attachment in the anterior, the middle or the posterior third of the SSS. Most frequently parasagittal meningiomas are located in the middle third of the superior sagittal sinus (between coronal suture and lambdoid suture). The clinical picture of parasagittal meningiomas depends on the tumor location along the SSS and so is the attitude towards ligation and reconstruction of the sinus. Controversial issues regarding surgical management of parasagittal meningiomas concerning leaving a tumor remnant that invades the SSS instead attempting total resection, or the attitude in the case of totally occluded segment of a sinus are summarized in this paper. The special care for the venous system is emphasized. The recurrence matter is also approached underlining the importance of adjuvant radiosurgery for the management of residual tumors. Results described in the main papers of the literature are reviewed. Conclusions are referring to the historical evolution regarding the surgical management of parasagittal meningiomas: aggressiveness of resection, sinus reconstruction, importance of adjuvant techniques: radiosurgery, endovascular surgery and to the importance of microsurgery and careful and meticulous planning of the approach in order to avoid interference with venous collaterals. A suggestive clinical case from the authors experience is presented.

The role of the basal cisterns in the development of posterior fossa skull base meningiomas

Meningiomas account for more than 30% of all intracranial brain tumors, with 25% of them originating somewhere along the skull base and about 20% of these located in the posterior fossa. The intimate relation of these tumors with neural and vascular structures make them difficult to treat, both surgically and nonsurgically. Their treatment is further hampered by the lack of definitive recommendations, which is partially due to the fact that there is no general accepted model of classification. The present report proposes a new concept of classification of posterior fossa skull base meningiomas, one that takes into account the intimate relation of these tumors with arachnoid structures, simplifies the overcrowded landscape of their systematization and can be extended to oher skull base locations.