Neurosurg Focus
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Petroclival meningiomas remain a formidable challenge for neurosurgeons because of their location deep within the skull base and proximity to eloquent neurovascular structures. Various skull base approaches have been used in their treatment, and deciding which is the optimal one remains controversial. Attempts at achieving gross- or near-total resections are associated with an increased rate of morbidity and mortality. As adjunctive treatment options such as stereotactic radiosurgery have been developed and become widely available, there has been a trend toward accepting subtotal resections in an effort to minimize neurological morbidity. This paper reviews a recent series of patients with petroclival meningiomas and highlights current management trends and important considerations useful in surgical decision making. ⋯ Achieving gross- or near-total resections of large petroclival meningiomas remains achievable and should be the primary goal of surgical treatment. A retrosigmoid craniotomy remains a workhorse surgical approach for most petroclival tumors of any size. Tumors that are medial to the internal auditory canal and span both middle and posterior cranial fossae are often best treated with a combined transpetrosal approach, which is especially true if there is a preoperative hearing deficit.
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WHO Grade II and III intracranial meningiomas are uncommon, but they portend a significantly worse prognosis than their benign Grade I counterparts. The mainstay of current management is resection to obtain cytoreduction and histological tissue diagnosis. The timing and benefit of postoperative fractionated external beam radiation therapy and stereotactic radiosurgery remain controversial. The authors review the stereotactic radiosurgery outcomes for Grade II and III meningiomas. ⋯ The current data for radiosurgery suggest that it has a role in the management of residual or recurrent Grade II and III meningiomas. However, better studies are needed to fully define this role. Due to the relatively low prevalence of these tumors, it is unlikely that prospective studies will be feasible. As such, well-designed retrospective analyses may improve our understanding of the effect of radiosurgery on tumor recurrence and patient survival and the incidence and impact of treatment-induced complications.
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Review Case Reports
Management of meningiomas involving the transverse or sigmoid sinus.
Meningiomas that invade the transverse or sigmoid sinuses are uncommon tumors that are challenging to treat surgically. Although the risk of recurrence is associated with the extent of resection, complete removal of meningiomas in these locations must be balanced with avoidance of venous outflow obstruction, which could cause venous infarction and significant neurological consequences. ⋯ When the tumor invades but does not completely obliterate a major venous sinus, however, opinions differ on whether to accept a subtotal resection or to open the sinus, perform a complete resection, and reconstruct the venous outflow tract. In this paper, the authors review the different strategies used to treat these lesions and provide illustrative case examples.
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The role of preoperative embolization in meningioma management remains controversial, even though 4 decades have passed since it was first described. It has been shown to offer benefits such as decreased blood loss and "softening of the tumor" during subsequent resection. However, the actual benefits remain unclear, and the potential harm of an additional procedure along with the cost of embolization have limited its use to a small proportion of the meningiomas treated. ⋯ The overall complication rate reported after treatment with preoperative meningioma embolization ranges from as high as 21% in some of the older literature to approximately 6% in recent literature describing treatment with newer embolization techniques. The evidence in the literature supporting the use of preoperative meningioma embolization is mainly from case series, and represents Level III evidence. Due to the lack of randomized controlled clinical trials, it is difficult to draw any significant conclusions on the overall usefulness of preoperative embolization during the management of meningiomas to consider it a standard practice.
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The purpose of this study was to evaluate patterns of failure after stereotactic radiosurgery (SRS) for meningiomas and factors that may influence these outcomes. ⋯ In this patient series, 12 Gy was the minimum sufficient margin dose for the treatment of meningiomas. Male sex is a risk factor for distant failure, whereas high-grade histology and multifocal disease are risk factors for local failure.