The Enigma of Basilar Artery Dissections Secondary to Vasospasm following Subarachnoid Hemorrhage; Exploration of the Unknown Effect of Superior Cervical Ganglia: A Preliminary Experimental Study.

BACKGROUND: Life-threatening basilar artery dissection (BAD) can be seen following subarachnoid hemorrhage (SAH), but it is not clear whether subarachnoid hemorrhage causes dissection, or not. This study aims to investigate the relationship between, degenerative changes in the superior cervical ganglia and the dissection rate of the basilar artery. MATERIAL AND METHOD: In this article, after three weeks of experimental SAH, animals were decapitated. 18 rabbits were divided into three groups, according to their vasospasm indexes. The basilar arteries were examined by anatomical and histopathological methods. RESULTS: Basilar dissection with high vasospasm index value (VSI>3) was detected in six animals (G-I, n=6); severe basilar edema and moderate vasospasm index value (VSI>2.4) in seven rabbits (G-II, n=7) and slight vasospasm (VSI<1.5) index value in five subjects (G-III, n=5) was detected. The degenerated neuron densities (n/mm3) of the superior cervical ganglia were detected as 12±4 in G-I, 41±8 in G-II; and 276±78 in G-III. The dissected surface values/lumen values were calculated as (42±1)/(64±11) in G-I; (21±6)/(89±17) in G-II; and (3±1)/(102±24) in G-III. If we look at these ratios as a percentage: 62%in G-I, 23% in G-II, and 5% in G-III. CONCLUSION: Inverse relationship between the degenerated neuron densities (n/mm3) of the superior cervical ganglia and the dissected surface values basilar artery was observed. The common knowledge is that basilar artery dissection may lead to SAH, however, this study indicates that SAH is the cause of basilar artery dissection.