Are the Morphological Indices of the Vertebrobasilar System Heritable? A Twin Study Based on 3D Reconstructed Models

Prevalence of anatomical variations at the suboccipital (V3) segment of the vertebral artery: a systematic review

BACKGROUND AND OBJECTIVE

A recent meta-analysis on the incidence of iatrogenic injury to the VA has revealed that patients with variant anatomy are more prone to iatrogenic injury. Therefore, this review is designed to investigate the incidence of variations in the suboccipital component of the vertebral artery in different population groups according to the available literature.

METHODS

This systematic review was conducted according to PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). The review is based on a comprehensive and extensive search of PubMed, Google Scholar, and ResearchGate. The following search terms were used: "vertebral artery" AND "suboccipital segment" AND "anomalies/anatomical variations of the V3 segment." Reference lists of all extracted articles were also extensively searched for references to any further relevant publications.

RESULTS

A total of 17 papers met the inclusion criteria. The 17 studies corresponded to a total of 10,820 patients. A persistent first intersegmental artery was registered in 1.8% (197 out of 10,820) of the patients. Extradural PICA origin was observed in 1.6% (175 out of 10,820) of the patients. Fenestration was detected in 0.7% (72 out of 10,820) of the patients.

CONCLUSION

The authors summarize the incidence of vascular variation at the suboccipital segment of the VA in different population groups across the Asian, European, American, and African continents. Awareness of the extent of possible anatomical variation will help interpret radiographs, which will enhance the identification of vascular pathologies and reduce the risk of iatrogenic injury.

A scoping review of the discrepancies in the measurement of cerebral blood flow in idiopathic intracranial hypertension: oligemia, euvolemia or hyperemia?

BACKGROUND

The literature regarding the global cerebral blood flow (CBF) in idiopathic intracranial hypertension (IIH) is divergent leading to skepticism about the significance of blood flow to the disease's underlying pathophysiology.

METHODS

The purpose of the current paper is to perform a PRISMA scoping review of the literature describing the CBF in IIH. The review investigated the PUBMED and Scopus data bases looking at case mix, technique and the methodologies employed by the studies selected.

DISCUSSION

Many studies indicate that the flow in IIH is normal but others show the flow to be altered. These later studies show a range of flows from a reduction of 20% to an increase of 50% compared to control values. Obesity is a common finding in IIH and is known to reduce CBF, anemia occurs in approximately 20% of IIH patients and is a potent cause of an increased CBF. Thus, variations in case mix may have a significant effect on the final outcome in those studies which are underpowered. The varying techniques which have been used to estimate CBF have differing strengths and weaknesses which may also have a bearing on the outcome. Some papers have significant confounding methodological issues.

CONCLUSIONS

This review suggests each of the variables investigated are responsible for the divergent CBF findings in IIH.