Stereotactic and functional neurosurgery
-
Stereotact Funct Neurosurg · Jan 2009
Parasagittal transinsular electrodes for stereo-EEG in temporal and insular lobe epilepsies.
Direct invasive EEG recordings of the insula - due to its particular anatomical position, deeply seated between both opercula - can only be performed with intracerebral electrodes. To date, the technique most commonly used for insular stereoelectroencephalography (SEEG) is the orthogonal-transopercular electrode approach with the Talairach methodology. We propose another technique utilizing MRI with transinsular parasagittal electrodes and a posterior entry point. This avoids passing through the opercula and sylvian vessels running over the insular surface. ⋯ We report a novel technique for insular SEEG with parasagittal electrodes, parallel to the insular cortex, with an entry point at the parieto-occipital junction. This technique is based entirely on use of MRI, and avoids passing through the opercula and sylvian vessels.
-
Stereotact Funct Neurosurg · Jan 2009
Analysis of factors associated with volumetric data errors in gamma knife radiosurgery.
Gamma knife (GK) surgery is an important part of the treatment armamentarium for benign and malignant brain tumors. In general, quantitative volumetrical analysis of the tumor on neuroimaging studies is the most reliable method of assessment of the tumor's response and is critical for accurate dose planning. This study evaluated various factors contributing to volumetric data error of tumors treated with GK radiosurgery. ⋯ Volume discrepancies existed between those volumes computed by the PGK-WS and volumes determined by laser scanning. The volumetric data errors were reduced through the acquisition of more slices through the phantom and a more spherical morphology of the phantom. Relatively few system volume errors were observed between those by the PGK-WS and PACS except for a significant discrepancy for the irregular surface phantom. For the rectangular-shaped phantom, the volumetric data errors were significantly related to slice orientation of measurement. When measuring the tumor response in GK radiosurgery or follow-up, an error of as large as 20% is possible for irregularly shaped object and with MRIs using
-
Stereotact Funct Neurosurg · Jan 2009
Case ReportsThalamic deep brain stimulation for midbrain tremor secondary to cystic degeneration of the brainstem.
Tremor resulting from damage to midbrain structures is poorly understood and often difficult to treat. The authors report a case of cystic degeneration of the brainstem with resultant Holmes-like tremor which was successfully treated using a stimulating electrode placed in the contralateral ventralis intermedius nucleus (VIM) of the thalamus. ⋯ Deep brain stimulation is an effective and safe intervention for tremor of unusual etiology. Electrode placement should be based on an understanding of the structure-function relationships underlying the various and distinct types of tremor.
-
Stereotact Funct Neurosurg · Jan 2009
Comparative StudyPrognostic factors of subthalamic stimulation in Parkinson's disease: a comparative study between short- and long-term effects.
Bilateral subthalamic nucleus deep brain stimulation (STN-DBS) has been shown to have long-term benefits in Parkinson's disease (PD). Through analyzing different variables, this study identified prognostic factors for the short- and long-term effects of STN-DBS. ⋯ The prognostic factors for STN-DBS benefit were different for short- and long-term follow-ups. Good prognostic factors for long-term STN-DBS for PD patients were good cognitive function and tremor dominance. Poor prognostic factors were related to older age and non-dopaminergic-responsive axial disability.
-
Stereotact Funct Neurosurg · Jan 2009
Clinical TrialSpectral analysis of field potential recordings by deep brain stimulation electrode for localization of subthalamic nucleus in patients with Parkinson's disease.
Spectral analysis of local field potential (LFP) recorded by deep brain stimulation (DBS) electrode around the subthalamic nucleus (STN) in patients with Parkinson's disease was performed. ⋯ A spectral power analysis of LFP recording by DBS electrode helps with the final confirmation of the dorsal and ventral borders of the STN of Parkinson's disease in DBS implantation surgery.