Neurosurg Focus
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Arterial hypotension and intracranial hypertension are detrimental to the injured brain. Although artificial elevation of cerebral perfusion pressure (CPP) has been advocated as a means to maintain an adequate cerebral blood flow (CBF), the optimal CPP for the treatment of severe traumatic brain injury (TBI) remains unclear. ⋯ For these reasons, a more useful approach may be to consider the optimal CPP in an individual patient at any given time, rather than having an arbitrary goal applied uniformly to all patients. Important information for optimizing CBF is provided by monitoring intracranial pressure in combination with assessment of the adequacy of CBF by using global indicators (for example, jugular oximetry), supplemented when appropriate by local data, such as brain tissue oxygen tension.
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The St. Louis Carotid Occlusion Study demonstrated that ipsilateral increased O2 extraction fraction (OEF) (Stage II hemodynamic failure) measured by positron emission tomography (PET) is a powerful independent risk factor for subsequent stroke in patients with symptomatic complete carotid artery (CA) occlusion. The ipsilateral ischemic stroke rate at 2 years has been shown to be 5.3% in 42 patients with normal OEF and 26.5% in 39 patients with increased OEF (p = 0.004). ⋯ The primary endpoint will be all strokes and death occurring between randomization and the 30-day postoperative cut off (with an equivalent period in the nonsurgical group), as well as subsequent ipsilateral ischemic stroke developing within 2 years. It is estimated that 186 patients will be required in each group. Assuming that 40% of PET scans will demonstrate increased OEF, this will require enrolling 930 clinically eligible individuals.
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The role of cerebral revascularization remains unclear in symptomatic occlusive cerebrovascular disease refractory to medical therapy. Despite the disappointing findings of the Cooperative Study on Extracranial-Intracranial Bypass, a subpopulation of patients with ischemic cerebrovascular disease and poor hemodynamic reserve may benefit from extracranial-intracranial (EC-IC) bypass. The authors reviewed the records of 65 patients who underwent 71 EC-IC bypass procedures at their institution over the past 6 years. ⋯ Although the Cooperative Study failed to show benefit from this treatment modality, the authors have continued to perform EC-IC bypass in certain cases. Carefully selected individuals with occlusive cerebrovascular disease and persistent ischemic symptoms refractory to maximal medical therapy appear to benefit from cerebral revascularization.
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An aging population will require that surgeons increasingly consider operative intervention in elderly patients. To perform this surgery safely will require an understanding of the factors that predict successful outcomes as well as complications. ⋯ Surgery in patients older than age 75 years can be conducted safely and with similar outcome rates as in younger patients. The Charlson Weighted Comorbidity Index score and operative time were predictive of the risk of complications.
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Comparative Study
Evaluation of factors predicting accurate resection of high-grade gliomas by using frameless image-guided stereotactic guidance.
Frameless image-guided stereotaxy is often used in the resection of high-grade gliomas. The authors of several studies, however, have suggested that brain shift may occur intraoperatively and result in inaccurate resection. To determine the usefulness of frameless stereotactic image-guided surgery of high-grade gliomas, the authors correlated factors predictive of brain shift, such as tumor size, periventricular location, and patient age (as an indicator of brain atrophy) with the extent of resection. ⋯ Frameless image-guided stereotactic techniques can be reliably used for accurate resection of high-grade gliomas when the tumor is less than 30 ml in volume and not adjacent to the ventricular system. In cases involving tumors larger in volume or located near the ventricles, intraoperative ultrasonography or MR imaging updates should be considered.