Stereotactic and functional neurosurgery
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Stereotact Funct Neurosurg · Jan 2007
Clinical TrialHypofractionated stereotactic radiotherapy using intensity-modulated radiotherapy in patients with one or two brain metastases.
A small fraction of patients with 1-2 brain metastases will not be suitable candidates to either surgical resection or stereotactic radiosurgery (SRS) due to either their location or their size. The objective of this study was to determine the local control, survival, patterns of relapse and the incidence of brain injury following a course of hypofractionated stereotactic radiotherapy while avoiding upfront whole brain radiation therapy (WBRT) in this subgroup of patients. ⋯ The preliminary results of hypofractionated SRS are comparable to both surgery and SRS data for solitary brain metastases in terms of local control and overall survival with acceptable morbidity in this cohort of unfavorable patients.
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Stereotact Funct Neurosurg · Jan 2007
Case ReportsHistopathology of radiation necrosis with severe peritumoral edema after gamma knife radiosurgery for parasagittal meningioma. A report of two cases.
Gamma knife radiosurgery (GKS) has been an effective treatment for meningiomas. Nevertheless, it still has certain risks. We present 2 cases of parasagittal meningioma after GKS complicated with radiation necrosis and peritumoral edema. The results of histologic examination are discussed. ⋯ After radiosurgery peritumoral edema tends to occur in meningiomas with a parasagittal position. Radiation necrosis, infiltration of inflammatory cells, and radiation injury to the vasculature causing hyalinization of blood vessels are suggested as the underlying histopathology.
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Stereotact Funct Neurosurg · Jan 2006
Long-term outcomes of bilateral subthalamic nucleus stimulation in patients with advanced Parkinson's disease.
In patients with advanced Parkinson's disease (PD), deep brain stimulation (DBS) of the subthalamic nucleus (STN) has been shown to improve motor function and decrease medication requirements in the short term. However, the long-term benefits of DBS are not yet established. ⋯ In this cohort of subjects with advanced PD, bilateral STN stimulation improved 'off' medication motor function, reduced time spent in the medication-off state and reduced medication requirements for up to 4 years after surgery. We conclude that STN DBS is an effective long-term therapy for selected patients with advanced PD.
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Stereotact Funct Neurosurg · Jan 2006
Clinical TrialDirect effect of subthalamic nucleus stimulation on levodopa-induced peak-dose dyskinesia in patients with Parkinson's disease.
We examined the direct effect of deep brain stimulation of the subthalamic nucleus (STN-DBS) on levodopa-induced peak-dose dyskinesia in 45 patients with Parkinson's disease (PD) without reducing the levodopa dosage during the early period after surgery. In 8 patients (18%), the dyskinesia was quickly attenuated by bipolar stimulation in an experimental trial (5 min) with the contacts placed within the area above the STN. In contrast, bipolar stimulation using contacts placed within the STN itself tended to provoke or exacerbate the dyskinesia, indicating that dyskinesia could be inhibited by stimulation of the areas above the STN rather than the STN itself. ⋯ In the area above the STN, pallidothalamic, pallidosubthalamic and subthalamopallidal fibers are densely distributed. It appears that stimulation of these fibers may cause effects similar to thalamic or pallidal DBS and therefore inhibit peak-dose dyskinesia. Bipolar STN-DBS with contacts placed within the area above the STN as an anode appears to represent a useful option for controlling both the cardinal symptoms of PD and peak-dose dyskinesia at the same time.
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Stereotact Funct Neurosurg · Jan 2006
Comparative StudyConventional MRI is inadequate to delineate the relationship between the red nucleus and subthalamic nucleus in Parkinson's disease.
An understanding of the relationships between the anterior commissure-posterior commissure line (AC-PC), the subthalamic nucleus (STN), and red nucleus (RN) is imperative if these structures are to be used for targeting in deep brain stimulation. Currently, these relationships are incompletely understood and difficult to assess using conventional MRI. We examined the location and relationships of the STN and the RN to the AC-PC line and to each other in order to provide a greater understanding of their utility when targeting the STN, and the consistency of these anatomic relationships when examined using conventional MRI. ⋯ Although recent studies imply that the RN can be used as a relatively consistent marker for the position of the STN, the present data suggest otherwise. These data indicate that a single targeting method may be inadequate given the resolution of conventional MRI, and that it is imperative to use multiple anatomical measurements when targeting the STN for deep brain stimulation in Parkinson's disease.