Stereotactic and functional neurosurgery
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Stereotact Funct Neurosurg · Jan 1997
Positron emission tomography during motor cortex stimulation for pain control.
We studied regional changes in cerebral flood flow (rCBF) in 9 patients undergoing motor cortex stimulation (MCS) for pain control. Significant increase in rCBF was observed in the lateral thalamus ipsilateral to MCS probably reflecting corticothalamic connections from motor/premotor areas. Subsignificant increases were observed in the anterior cingulate, left insula and upper brainstem. ⋯ Our results support a model of MCS action whereby activation of thalamic nuclei directly connected with motor and premotor cortices would entail a cascade of synaptic events in other pain-related structures, including the anterior cingulate and the periaqueductal gray. MCS could influence the affective-emotional component of chronic pain by way of cingulate activation, and lead to descending inhibition of pain impulses by activation of the brainstem. Such effects may be obtained only if thalamic activation reaches a 'threshold' level, below which the analgesic cascade would not be successfully triggered.
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From January 1, 1986, to June 30, 1996, 240 patients were operated on for trigeminal neuralgia: 182 patients were treated by thermocoagulation of the gasserian ganglion after Sweet and 58 patients by decompression of the trigeminal nerve after Janetta. In the thermocoagulation group, followed up for 6 months to 10 years 95.2% of the cases showed freedom from pain, in the Janetta operation group, followed up for 6 months to 6 years 98.5% showed freedom from pain. Thermocoagulation is the preferred therapy, especially in older patients in whom general anesthesia is risky, while the Janetta operation is the therapy of choice in younger patients.
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Stereotact Funct Neurosurg · Jan 1997
Can neuronavigation contribute to standardization of selective amygdalohippocampectomy?
Tailored selective amygdalohippocampal resections seem to be an interesting application for neuronavigation. The accuracy of freehand frameless neuronavigation was assessed in 28 patients for its ability to determine the hippocampal resection length, as compared to postoperative MRI. ⋯ The discrepancy is explained by an anterior-posterior component of brain collapse in a tilted head. Horizontal positioning of the head or navigational marking prior to the occurrence of brain collapse may overcome the problem.
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Stereotact Funct Neurosurg · Jan 1997
Microvascular decompression and percutaneous rhizotomy in trigeminal neuralgia.
We analyzed 417 patients with trigeminal neuralgia who underwent microvascular decompression (MVD; n = 146) or percutaneous procedures, i.e. radiofrequency rhizotomy (RFR; n = 235) and glycerol rhizotomy (GR; n = 36) between March 1973 and December 1996. MVD and RFR showed the highest rates of initial pain relief (MVD 96.5%; RFR 92.3%; GR 82.8%). ⋯ We concluded that MVD is the treatment of choice for tolerant younger patients and should be recommended for patients who desire no sensory deficit. We also determined that radiofrequency rhizotomy is the procedure of choice for patients in whom MVD failed.
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Stereotact Funct Neurosurg · Jan 1996
Trigeminal neuralgia radiosurgery: the University of Pittsburgh experience.
The results of Gamma Knife stereotactic radiosurgery in the management of 51 patients who had typical trigeminal neuralgia were evaluated at the University of Pittsburgh. In all cases, a 4-mm isocenter was targeted at the proximal nerve at the root entry zone. The target dose varied from 60 to 90 Gy. ⋯ A maximum radiosurgery dose > or = 70 Gy was associated with a significantly greater chance for complete pain relief. Using magnetic resonance imaging stereotactic targeting, the proximal trigeminal nerve is an appropriate anatomic target for radiosurgery. Gamma Knife radiosurgery is a useful additional surgical approach in the management of medically or surgically refractory trigeminal neuralgia.