Inverse Association Between Basilar Artery Volume and Neuron Density in the Stellate Ganglion Following Bilateral Common Carotid Artery Ligation: An Experimental Study

Predictive role of trigeminal ganglion ischemia on scalp survival affected by temporal artery diameters: The first experimental study

Scalp arteries are mainly innervated by trigeminal, facial, and vagal nerves. The ischemic neurodegeneration of the trigeminal ganglion can impede scalp circulation via vasospasm-creating effects. This study was designed to investigate whether there is any link between the vasospasm index of deep temporal arteries and ischemic neuron densities of the trigeminal ganglion after subarachnoid hemorrhage. The study subjects included five normal control rabbits, six sham rabbits, and nine rabbits chosen from a formerly established experimental subarachnoid hemorrhage group created by cisternal homologous blood injection (0.75 mL). These rabbits, all male, were followed up for 3 weeks. The trigeminal ganglion and deep temporal artery vasospasm indexes were examined by stereological methods. Ischemic neuron densities of the trigeminal ganglion and vasospasm index values of deep temporal arteries were compared statistically. Postmortem examinations showed important vasospasms of deep temporal arteries, foramen magnum herniations, and neurodegeneration of the trigeminal ganglion. The mean vasospasm index values and degenerated neuron densities of the trigeminal ganglion were determined as 1.03 ± 0.13 and 10 ± 3/mm³ (p > 0.5) in the control group, 1.21 ± 0.18 and 35 ± 9/mm³ in the sham group (p < 0.005 for sham vs. control), and 2.54 ± 0.84 and 698 ± 134/mm³ in the experimental group (p < 0.0005 for sham vs. control and p < 0.00001 for study vs. control). There was an inverse relationship between the vasospasm index values and the degenerated neuronal density of the trigeminal ganglion. The high degenerated neuron density in the trigeminal ganglion had a facilitative effect on temporal artery vasospasm. Trigeminal ganglion neurodegeneration may promote temporal artery vasospasms after subarachnoid hemorrhage, which has not been previously mentioned in the literature.

Morphological Irregularity of Unruptured Intracranial Aneurysms is More Related with Aneurysm Size Rather Than Cerebrovascular Atherosclerosis: A Case-Control Study

Objective

It remains unclear whether irregular morphological features of intracranial aneurysms (IAs) are associated with atherosclerosis. We investigated the effect of cerebrovascular atherosclerosis stenosis (CAS) on irregular morphology of IAs.

Patients and Methods

This single-center case-control study included consecutive patients with IAs at our institution from September 2011 to September 2018. Cases were patients with irregular IAs, and age- and location-matched controls were patients with regular IAs. Conditional logistic regression models were used to assess the relationship between angiographic variables of CAS and aneurysmal irregularity.

Results

A total of 140 cases of irregular IAs and 140 controls were included in the analysis. Sixteen patients with irregular IAs (11.4%) and eleven patients with regular IAs (7.9%) had >50% parent artery stenosis; however, the differences were not statistically significant between these two groups. In addition, no significant between-group differences were observed in distributions of the cerebrovascular stenosis, number of arterial stenoses, and location of the stenosis. In the final adjusted conditional logistic regression model, only aneurysm size (≥7 mm) was significantly associated with irregular IA morphology (P = 0.022). Moreover, 89 cases of irregular IAs and 89 controls were included in the analysis of unruptured IAs (UIAs). In the final adjusted conditional logistic regression model, only aneurysm size (≥7 mm) was significantly associated with irregular UIA morphology (P = 0.020).

Conclusion

Our findings indicate that the morphological irregularity of unruptured intracranial aneurysms is more related with aneurysm size rather than cerebrovascular atherosclerosis. Further studies are needed to use prospective data to identify causative factors responsible for aneurysmal irregularity.