Trigeminal control of cranio-facial vasomotor response: I. Histamine test in patients with unilateral gasserian ganglion lesions.

It has been hypothesized that the trigeminal system may control vasomotor changes and pain in vascular headaches. In this study, headache was induced by an intravenous injection of histamine in 37 patients with trigeminal rhizotomy and in 12 controls. The vasomotor response to histamine was studied with facial telethermography. The headache in patients with trigeminal lesions differed, in a prevalence of unilateral localization contralaterally to the operated side (21 patients), from that in controls. No relationship was found between the hypoesthesia caused by the operation and the prevalence of unilateral headache. A statistically significant correlation (p less than 0.001) was found between unilateral absence of headache and decreased vasomotor response on the operated side. These reactions occurred more in patients who underwent thermocoagulation than in patients who underwent retro-gasserian rhizotomy. Thus the gasserian ganglion seems to control the cranio-facial vasomotor response and the headache through a vascular pathway, acting on cerebral arteries, which differs from the sensory pathway.