Anatomy of the pontine arteries and perforators of the basilar artery in humans

Abstract

Cerebral blood flow constitutes a critical area of interest for neurologists, neurosurgeons, and interventional radiologists as a social burden related to ischemic stroke, hemorrhagic stroke, and vascular dementia is expected to intensify. There is a great need to develop new and effective therapies, therefore deepening understanding of cerebrovascular anatomy, physiology, and pathology is crucial. The main aim of the study was to develop a comprehensive classification of the pontine arteries considering their typology, relations to the cranial nerves, branching schemes, and superficial pontine blood supply areas. We prepared 100 anatomical specimens of the human brainstem with the basilar artery, the pontine arteries, and the terminal perforating arteries. With the use of microsurgical microscope, we analyzed morphometry of the basilar artery, origins, courses, and branching patterns of the pontine arteries as well as distribution of the terminal perforators in relation to pontine superficial vascular areas and the cranial nerves. Additionally, we studied presence of pontine branches of the superior cerebellar artery (SCA) and anterior inferior cerebellar artery (AICA). Repetitive branching patterns, origins, and courses led us to distinguish five types of the pontine arteries: type 1—the paramedian branches, type 2—the short circumflex branches, type 3—composition of the paramedian and the short circumflex branches, type 4—long circumflex branches, and type 5—median branches penetrating the pons along the basilar sulcus. Types 1, 2, and 4 were described in the literature previously, but the classification did not include the median branches (the most prevalent branches) and frequently occurring combinations of the types 1 and 2. There were seven pontine arteries on both sides on average that presented the following general pattern: the first pontine artery below the SCA is a type 4 vessel called the posterolateral pontine artery and it is followed by a type 2 vessel—the superolateral pontine artery; the next three arteries represent the types 1, 2, and 3 and supply most of the ventral pontine surface; the sixth artery—the anterolateral pontine artery—is a short circumflex branch and the seventh artery, originating below the AICA, represents long circumflex arteries. Occlusion of each of the abovementioned vessels relates to a specific pontine vascular syndrome. As explained by the phylogenesis and ontogenesis of the central nervous system, the pontine arteries are subject to variability. The SCA and the AICA took part in the pontine blood supply in 2.5% and 12.5% of cases, respectively, therefore neurovascular interventions involving the SCA, or the AICA may lead to pontine ischemia. Contact of the pontine arteries with the cranial nerves depends on the vessel type and origin location.

Basilar tip fenestration giving rise to Percheron’s and mesencephalic arteries

“…It is worth noting that the superior cerebellar arteries may also be involved in the vascularization of the pons. [7] Intracranial arteries fenestrations (defined as a vessel division and fusion after some distance) [8,9] are present in about 40% of people and the basilar artery is the second most common site (after the anterior communicating artery) [10]. However, fenestration of the basilar tip has never been described.…”

The Vertebrobasilar Trunk and Its Anatomical Variants: A Microsurgical Anatomical Study

“…Surgical intervention in this area is not only technically challenging but also poses significant risks due to the dense concentration of critical blood vessels and neural structures [ 23 ]. The vertebrobasilar system, which supplies the majority of the posterior fossa, including the cerebellum, brainstem, and related structures, is of particular interest due to its intricate anatomy and the potential for life-threatening complications if damaged [ 24 ].…”