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
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 ReportsWire tethering or 'bowstringing' as a long-term hardware-related complication of deep brain stimulation.
Widely reported long-term complications following implantation of deep brain stimulation (DBS) hardware include breakage of electrode leads, internal pulse generator (IPG) failure, skin erosions and infection. Here we report on a rarely described problem that arises from formation of scar tissue adhesions around the DBS extension wire(s). Over time, this scar tissue can become tight and pronounced, protruding noticeably beneath the skin ('bowstringing' in reference to its tight bow-like appearance) and leading to significant limitation of movement and discomfort. We term this 'wire tethering'. ⋯ Wire tethering, or 'bowstringing', is an underrecognized complication of DBS hardware implantation often necessitating surgical revision. The possible etiology of wire tethering is discussed as well as suggestions for its avoidance.
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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.
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Stereotact Funct Neurosurg · Jan 2009
Avoiding abducens nerve palsy during the percutaneous balloon compression procedure.
The main purpose of this study is to underline the factors which are likely to increase the risk of a sixth nerve injury after percutaneous balloon compression of the gasserian ganglion. ⋯ The anatomic position and the shape of the inflated balloon represent key factors in determining the procedure's benefit or risk of complications.