Stereotactic and functional neurosurgery
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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
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Stereotact Funct Neurosurg · Jan 2009
CT/MR image fusion in the postoperative assessment of electrodes implanted for deep brain stimulation.
Stereotactic postoperative imaging is essential for verification of the position of electrodes implanted for deep brain stimulation (DBS). MRI offers superior visualisation of the DBS targets relative to CT, but previous adverse incidents have heightened concerns about risks of postoperative MRI. Preoperative MRI fused with postoperative CT offers an alternative method for evaluating electrode position, but before this method can be clinically applied, the image registration accuracy must be established. The purpose of this study was to quantitatively assess the accuracy of three different image registration and fusion methods. ⋯ CT/MRI fusion provides a safe, practical technique for postoperative identification of DBS electrodes.
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Stereotact Funct Neurosurg · Jan 2009
Dorsal root entry zone lesions for phantom limb pain with brachial plexus avulsion: a study of pain and phantom limb sensation.
Lesions in the dorsal root entry zone (DREZ) have been shown to be significantly effective in relieving the pain of brachial plexus avulsion (BPA), but they have a limited effect on phantom limb pain (PLP). There is still the question remaining of whether DREZ lesions are effective in treating PLP in cases of BPA. ⋯ DREZ lesions are effective in the treatment of PLP with BPA. Alteration in PLS after the surgery may be a predictive factor for good pain relief. The good response of PLP patients with BPA to DREZ lesions suggests that an evaluation of the cervical dorsal roots should be conducted in patients with post-traumatic PLP.
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Stereotact Funct Neurosurg · Jan 2009
Case ReportsSimultaneous use of functional tractography, neuronavigation-integrated subcortical white matter stimulation and intraoperative magnetic resonance imaging in glioma surgery: technical note.
The importance of preserving function during glioma surgery cannot be overemphasized. There are a number of techniques utilized including functional MRI, direct electrophysiological monitoring and functional neuronavigation to maximize and safely resect gliomas. ⋯ Combining these technologies will enhance the safety and efficacy of glioma surgery. This is the first report in the literature where we successfully combine both functional neuronavigation and subcortical stimulation, using a single probe to safely resect a recurrent glioblastoma.
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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.