GLYCEROL INJECTION INTO THE TRIGEMINAL GANGLION PROVOKES A SELECTIVE INCREASE IN HUMAN CEREBRAL BLOOD-FLOW

Fourteen patients suffering from idiopathic trigeminal neuralgia (refractory to medication) were treated by injection of glycerol into the trigeminal ganglion. The changes in cerebral blood flow (CBF) after glycerol injection were quantified by intravenous Xe-133 emission tomography. There was a significant 11% (P < 0.01) increase in ipsilateral CBF and an 8% (P < 0.05) increase in contralateral CBF 1 h after glycerol injection. The interhemispheric difference was significant (P < 0.05). The increase was significantly greater in the ipsilateral internal carotid territory, in the anterior cerebral artery and middle cerebral artery territories (superficial (P < 0.05), deep territories (P < 0.001)). We suggest that these changes are due to the release of substance P and/or calcitonin gene-related peptide, from terminals of the trigeminal-vascular system during glycerol injection.