Neurosurgery
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Meningiomas arising primarily within the internal auditory canal (IAC) are notably rare. By far the most common tumors that are encountered in this region are neuromas. We report a series of eight patients with meningiomas of the IAC, analyzing the clinical presentations, surgical management strategies, and clinical outcomes. ⋯ Although intrameatal meningiomas are quite rare, they must be considered in the differential diagnosis of intrameatal mass lesions. The clinical symptoms are very similar to those of vestibular schwannomas. A radiological differentiation from vestibular schwannomas is not always possible. Surgical removal of intrameatal meningiomas should aim at wide excision, including involved dura and bone, to prevent recurrences. The variation in the anatomy of the faciocochlear nerve bundle in relation to the tumor has to be kept in mind, and preservation of these structures should be the goal in every case.
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Comparative Study Clinical Trial
Pressure autoregulation and positron emission tomography-derived cerebral blood flow acetazolamide reactivity in patients with carotid artery stenosis.
Testing autoregulation is of importance in predicting risk of stroke and managing patients with occlusive carotid arterial disease. The use of small spontaneous changes in arterial blood pressure and transcranial Doppler (TCD) flow velocity can be used to assess autoregulation noninvasively without the need for a cerebrovascular challenge. We have previously described an index (called "Mx") that achieves this. Negative or low positive values (<0.4) indicate intact pressure autoregulation, whereas an Mx greater than 0.4 indicates diminished autoregulation. The objective of this study was to compare acetazolamide reactivity of positron emission tomography (PET)-derived cerebral blood flow (CBF) with Mx in patients with carotid arterial disease. ⋯ The measurement of Mx offers a noninvasive, safe technique for assessing abnormalities of pressure autoregulation in patients with carotid arterial disease.
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Clinical Trial
Peripheral stimulation for treatment of trigeminal postherpetic neuralgia and trigeminal posttraumatic neuropathic pain: a pilot study.
Trigeminal neuropathic pain (TNP) after facial trauma or herpes zoster infection is often refractory to treatment. Peripheral nerve stimulation has been used to treat occipital neuralgia; however, efficacy in controlling facial TNP or postherpetic neuralgia is unknown. A retrospective case series of patients who underwent subcutaneous placement of stimulating electrodes for treatment of V(1) or V(2) TNP secondary to herpetic infection or facial trauma is presented. ⋯ Peripheral nerve stimulation of the supraorbital or infraorbital branches of the trigeminal nerve is an effective method for relief of TNP after facial trauma or herpetic infection. A prospective trial using this novel approach to treat these disorders is thus warranted.
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Case Reports Clinical Trial
Intraoperative Doppler to measure cerebrovascular resistance as a guide to complete resection of arteriovenous malformations.
Intraoperative color Doppler ultrasound has been used to locate arteriovenous malformations (AVMs). We describe the use of spectral Doppler to measure flow resistance and resistive index (RI) of vessels around the nidus to distinguish feeding arteries from en passant and normal vessels. This is particularly helpful in small AVMs and aids in the identification of normal vessels and completeness of resection by ruling out persistent low RI flow. ⋯ Intraoperative duplex Doppler allowed more accurate localization of the AVM nidus. RI of the vessels around the AVM helped to distinguish vessels feeding the AVM from en passant vessels. Furthermore, comparison of pre-resection and postresection RI accurately indicated the completeness of resection.
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There are several lines of evidence suggesting that matrix metalloproteinases (MMPs), particularly MMP-9, are involved in the pathogenesis of intracranial aneurysms. Some studies have demonstrated that genetic variants in the promoter region of the MMP-9 gene are associated with aneurysms. We performed a case-control study to investigate whether single-nucleotide polymorphisms (SNPs) within the coding region of the MMP-9 gene might affect the development of intracranial aneurysms. ⋯ SNPs of the coding region and the 3' untranslated region of the MMP-9 gene are not associated with intracranial aneurysms in Caucasians.