Role of the trigeminal system on posterior communicating artery remodelization after bilateral common carotid artery ligation.

Objective: To examine whether or not there is a possible relationship between the neuron density of trigeminal ganglion (TGG) and the severity of posterior communicating artery (PComA) vasodilation values after permanent bilateral common carotid artery ligation (BCCAL).

Study Design: This study included 25 rabbits. Both the common carotid arteries of 20 rabbits were explored and denervated. Five animals served as controls. Permanent BCCAL was applied in 15 of the 20 rabbits, and the other 5 were used as the SHAM group without ligation. All animals were followed for 2 months and then sacrificed. Their brains and cranial nerves were extracted and fixed in 10% formalin solution. The relationship between PComA vasodilation values and TGG neuron densities were compared.

Results: Elongation, convolution and enlargement were detected in all the basilar arteries of all ligated animals and 2 from the SHAM group. On histopathogical examination vascular wall thinning, luminal enlargement, flattened inner elastic membrane, flattened vessel muscle cells, endothelial desquamation and intimal erosions were detected. An inverse relationship was discovered between the neuron density of TGG and the severity of PComA vasodilation index.

Conclusion: BCCAL may lead to important beneficial and hazardous histomorphological changes at the posterior communicating artery. The high neuron density of TGG may provide a beneficial effect by facilitating PComA enlargement via its vasodilatory properties for the increase of decreased cerebral circulation, although this situation may be hazardous for certain subjects with congenital or acquired cerebrovascular pathologies.