Stereotactic and functional neurosurgery
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Stereotact Funct Neurosurg · Jan 1999
Comparative StudyA comparison of single fraction radiosurgery tumor control and toxicity in the treatment of basal and nonbasal meningiomas.
Between July 1993 and October 1997, 107 patients with 118 meningiomas were treated with Gamma Knife radiosurgery (GKRS). The most frequent site of tumor origin was the skull base (54%). The mean tumor diameter and volume were 2.5 cm and 9.4 cm3, respectively. ⋯ Deteriorating peritumoral edema associated with symptoms was observed in 1 of 49 (2%) skull-base tumors and in 4 of 39 (10%) non-basal tumors, without associated tumor growth. (p=0.l5 and 0.234 respectively, z-test). Stereotactic radiosurgery can achieve acceptable tumor control with low morbidity in the treatment of most meningiomas. However, when the tumor is nonbasal, the potential morbidity from peritumoral edema should be recognized and other treatment options considered, such as adjuvant surgery, partial fractionated irradiation or stereotactic radiotherapy.
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Stereotact Funct Neurosurg · Oct 1998
Preservation of hearing in acoustic neuromas treated by gamma knife surgery.
138 acoustic schwannomas were treated by Gamma Knife surgery from July 1992 to May 1994. Cases with neurofibromatosis were excluded because of differences in the patterns of growth and development of tumors in these cases. ⋯ No correlation was found between hearing preservation and tumor volume, central and marginal dose and number of shots. Gamma Knife surgery seems to be superior to microsurgery with regard to preservation of useful hearing.
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Stereotact Funct Neurosurg · Oct 1998
Gamma knife radiosurgery for the treatment of trigeminal neuralgia.
One hundred and ten patients with trigeminal neuralgia were treated with the Gamma Knife using a single isocenter, the 4 mm secondary collimator helmet and a radiosurgical dose maximum of 70 or 80-Gy. The isocenter was placed at the trigeminal sensory root adjacent to the pons as identified on stereotactic MRI scans. Follow-up periods range from 4-49 months (mean 19.8 months). ⋯ Three patients (2.7%) developed delayed loss of facial sensation following treatment, but no other complications of any kind were noted. We believe that Gamma Knife radiosurgery is the safest and most effective form of treatment which is currently available for trigeminal neuralgia. We recommend early radiosurgical treatment of trigeminal neuralgia once the diagnosis is clearly established.
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Stereotact Funct Neurosurg · Jan 1998
The effect of LINAC stereotactic radiosurgery on epilepsy associated with arteriovenous malformations.
Reduction of seizures associated with arteriovenous malformations (AVMs) following radiosurgery has been reported. This investigation assessed the effect of LINAC radiosurgical treatment of AVMs on the associated epilepsies correlated to AVM location, size, seizure type, and postradiosurgical thrombosis. Of 100 patients with AVMs, 33 presented with seizures (11 generalized tonic-clonic seizures, 8 simple partial seizures, and 14 complex partial seizures with or without secondary generalization). ⋯ Radiosurgery was most effective for generalized tonic-clonic and complex partial seizures. There was no statistically significant correlation between reduction in epilepsy and original AVM size. Four of 5 patients without thrombosis became seizure-free, suggesting that structural or biochemical alterations of epileptogenic neurons following radiosurgery may reduce epileptogenicity.
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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.