Histopathologic Changes in Oculomotor Nerve and Ciliary Ganglion in Aneurysmatic Compression Injuries of Oculomotor Nerve

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.

The role of sympathectomy on the regulation of basilar artery volume changes in stenoocclusive carotid artery modeling after bilateral common carotid artery ligation: an animal model

BACKGROUND

Stenoocclusive carotid artery disease causes important histomorphologic changes in all craniocervical vasculatures, such as luminal enlargement, vascular wall thinning, elongation, convolutions, and aneurysm formation in the posterior circulation. Although increased pressure, retrograde blood flow, and biochemical factors are described in the pathogenesis of vascular remodelisation, the vasoregulatory role of the autonomic nervous system has not been investigated thus far. We investigated the relationship between the sympathetic nervous system and the severity of histomorphologic alterations of basilar arteries after bilateral common carotid artery ligation (BCCAL).

MATERIAL AND METHODS

This study was conducted on 21 rabbits. The rabbits were randomly divided into three groups: baseline group (n = 5), sympathectomy non-applied group (SHAM; n = 8), and sympathectomy applied group (n = 8) before bilateral common carotid artery ligation. Permanent ligation of the prebifurcations of the common carotid arteries was performed to replicate stenoocclusive caroid artery disease. Basilar artery volumes were measured after ligation. Volumes of the basilar arteries were estimated by stereologic methods and compared between groups.

RESULTS

Luminal enlargement, wall thinning, elongation, convolutions, and doligoectatic configurations were detected in the majority of basilar arteries. The mean basilar arterial volume was 4.27 ± 0.22 mm3 in the baseline group; 5.28 ± 0.67 mm(3) in the SHAM group, and 8.84 ± 0.78 mm3 in the study group. The severity of basilar enlargement was significantly higher in the study group compared with the SHAM (p < 0.005) and baseline groups (p < 0.001).

CONCLUSIONS

Sympathectomy causes basilar artery enlargment, which is beneficial for maintaining cerebral blood flow; however, it also causes wall thinning, elongation, convolution, and aneurysm formation, which may be hazardous in stenoocclusive carotid artery disease. Sympathectomy can prevent new vessel formation and hyperthyrophic changes at the posterior circulation. Neovascularisation is not detected adequately in sympathectomised animals.

Histopathological changes in ciliary ganglion of rabbits with subarachnoid hemorrhage

The histopathological changes in the ciliary ganglia due to subarachnoid hemorrhage were investigated. Subarachnoid hemorrhage was produced by infusing autologous blood to the cisterna magna of rabbits. The number of neurons in the ganglia was evaluated with physical dissector method. Comparing with controls, a statistically significant increase in the number of degenerated neurons in subarachnoid hemorrhage group was noted. It is considered that the loss of trophic effect from the presynaptic supply of ciliary ganglion via the preganglionic fibers of oculomotor nerve could alter the structure of the ganglion through the anterograde transneuronal degeneration process in subarachnoid hemorrhage.