World Neurosurg
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The need for new and objective indexes for the neuroradiologic follow-up of brain tumors and for monitoring the effects of antiangiogenic strategies in vivo led us to perform a technical study on four patients who received computerized analysis of tumor-associated vasculature with ultra-high-field (7 T) magnetic resonance imaging (MRI). The image analysis involved the application of susceptibility weighted imaging (SWI) to evaluate vascular structures. ⋯ The qualitative changes of the intratumoral SWI patterns during a period of 4 weeks were quantified with the fractal dimension. Because SWI patterns are also related to the presence of vascular structures, the quantification of their space-filling properties with fractal dimension seemed to be a valid tool for the in vivo neuroradiologic follow-up of brain tumors.
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The authors present the outcome of radical surgical removal of giant acoustic neuromas. ⋯ Total removal of large acoustic neuroma can be achieved by retrosigmoid approach with acceptable morbidity and no mortality. Preoperative neurologic symptoms recovered after surgery in most cases. Facial function preservation was possible in the majority of cases. Even in large tumors, hearing preservation should be attempted if the patient has useful hearing preoperatively.
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Ventriculostomy complications are well documented in the literature. We report the first known example of an arteriovenous fistula created during passage of a ventriculostomy catheter for the treatment of hydrocephalus. ⋯ This is the first reported case of a pial arteriovenous fistula from a ventriculostomy catheter. The formation of a fistula can occur from trauma to cortical arteries and veins at the pial entry site. Although rare, vascular injury and subsequent fistula formation may form in patients in whom catheter tract hemorrhages occur after catheter placement.
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Case Reports
Dorsolateral prefrontal cortex transcranial magnetic stimulation and electrode implant for intractable tinnitus.
Tinnitus is a distressing symptom that affects up to 15% of the population; no satisfactory treatment exists. We present a novel surgical approach for the treatment of intractable tinnitus based on electrical extradural stimulation of the dorsolateral prefrontal cortex via an electrode implant. Tinnitus can be considered an auditory phantom phenomenon similar to deafferentation pain in the somatosensory system. It is characterized by gamma-band activity in the frontal cortex that can be visualized with the use of electroencephalography, magnetoencephalography, and functional magnetic resonance imaging (fMRI). ⋯ Focal extradural electrical stimulation of the dorsolateral prefrontal cortex at the area of cortical plasticity is capable of suppressing contralateral tinnitus partially. TMS might be a possible method for noninvasive studies of surgical candidates for implantation of stimulating electrodes for tinnitus suppression.