Neurosurg Focus
-
Pneumosinus dilitans (PSD) is enlargement of the sinuses of the skull base and is frequently seen with meningiomas. Identifying PSD on imaging can assist with operative planning and preparation. Meningiomas associated with PSD are not more commonly high grade, and complete resection is frequently possible.
-
Olfactory groove meningiomas represent 10% of intracranial meningiomas and arise in the midline of the anterior cranial fossa along the dura of the cribriform plate and planum sphenoidale. Hyperostosis of the adjacent underlying bone is common, and further extension into ethmoid sinuses and nasal cavity can occur in 15%-25% of cases. Radical tumor resection including the involved dural attachment and underlying hyperostotic bone offers the best chance of a Simpson Grade I resection to minimize recurrence. ⋯ In addition, we discuss the advantages, limitations, patient selection, and complications of this approach. We specifically highlight our technique for multilayer reconstruction of large anterior skull base dural defects using fascia lata and acellular dermal allograft supplemented by bilateral vascularized pedicled nasoseptal flaps. Three new cases of endoscopically resected olfactory groove meningiomas are also presented.
-
Some patients develop communicating hydrocephalus after meningioma surgery, and this can develop into a serious clinical condition. However, this has rarely been addressed in the literature. Therefore, the authors sought to determine predictive patient variables for the occurrence of postoperative hydrocephalus following skull base meningioma surgery. ⋯ In this study, the incidence of communicating postoperative hydrocephalus was almost twice as high in patients with skull base lesions as in patients with meningiomas in other locations. Patient age, duration of surgery, duration of hospital stay, tumor volume, postoperative infection, and preoperative embolization were associated with the occurrence of hydrocephalus. In the statistical prediction model, patient age and duration of surgery were the most significant predictors of postoperative hydrocephalus after skull base meningioma surgery.
-
The standard surgical treatment for meningiomas is total resection, but the complete removal of skull base meningiomas can be difficult for several reasons. Thus, the management of certain meningiomas of the skull base--for example, those involving basal vessels and cranial nerves--remains a challenge. In recent reports it has been suggested that somatostatin (SST) administration can cause growth inhibition of unresectable and recurrent meningiomas. The application of SST and its analogs is not routinely integrated into standard treatment strategies for meningiomas, and clinical studies proving growth-inhibiting effects do not exist. The authors report on their experience using octreotide in patients with recurrent or unresectable meningiomas of the skull base. ⋯ Although no case of tumor regression was detected on MR imaging, the study results indicated that SST analogs can arrest the progression of unresectable or recurrent benign meningiomas of the skull base in some patients. It remains to be determined whether a controlled prospective clinical trial would be useful.
-
Case Reports
Quantitative and qualitative 5-aminolevulinic acid-induced protoporphyrin IX fluorescence in skull base meningiomas.
Complete resection of skull base meningiomas provides patients with the best chance for a cure; however, surgery is frequently difficult given the proximity of lesions to vital structures, such as cranial nerves, major vessels, and venous sinuses. Accurate discrimination between tumor and normal tissue is crucial for optimal tumor resection. Qualitative assessment of protoporphyrin IX (PpIX) fluorescence following the exogenous administration of 5-aminolevulinic acid (ALA) has demonstrated utility in malignant glioma resection but limited use in meningiomas. Here the authors demonstrate the use of ALA-induced PpIX fluorescence guidance in resecting a skull base meningioma and elaborate on the advantages and disadvantages provided by both quantitative and qualitative fluorescence methodologies in skull base meningioma resection. ⋯ Fluorescence-guided resection may be a useful adjunct in the resection of skull base meningiomas. The use of a quantitative intraoperative probe to detect PpIX concentration allows more accurate determination of neoplastic tissue in meningiomas than visible fluorescence and is readily applicable in areas, such as the skull base, where complete resection is critical but difficult because of the vital structures surrounding the pathology.