Stent-Assisted Coiling of Aneurysm in a Persistent Primitive Lateral Vertebrobasilar System

Persistence of Primitive Lateral Basilovertebral Anastomosis with a Ruptured Posterior Inferior Cerebellar Artery Aneurysm: A Case Report

Posterior inferior cerebellar artery (PICA) variations are well recognized; however, their mechanisms have not been well understood. Primitive lateral basilovertebral anastomosis (PLBA) was described in 1948 by Padget and is one of the embryological transient longitudinal channels in the hindbrain. This study reports a PICA aneurysm associated with PLBA. A 48-year-old man presented with subarachnoid hemorrhage. Cerebral angiography showed a 3.6-mm fusiform aneurysm with a bleb of the left PICA just at the origin of the PICA from the vertebral artery. Furthermore, a direct anterior inferior cerebellar artery (AICA)-PICA anastomosis parallel to the basilar artery was revealed. This direct anastomosis between the AICA and PICA is explained by the partial persistence of PLBA. Variations in the three cerebellar arteries and vertebrobasilar junction can be caused by persistence of PLBA.

Vascular supply of the hindbrain: Basic longitudinal and axial angioarchitecture

The basic pattern of arterial vascularization is highly conserved across vertebrates and develops under neuromeric rules. The hindbrain has an angioarchitecture that is homologous to that of the spinal cord, and the hindbrain vascular system can be analyzed at the longitudinal and axial structures. During development, there are two main longitudinal arteries: the longitudinal neural artery and primitive lateral basilovertebral anastomosis. This review discusses the basic pattern of the blood supply of the hindbrain, the development of vascularization, and the anatomical variations, with a special reference to the embryological point of view of two main longitudinal anastomoses (longitudinal neural artery and primitive lateral basilovertebral anastomosis). The formation of commonly observed variations, such as fenestration and duplication of the vertebrobasilar artery, or primitive trigeminal artery variant, can be explained by the partial persistence of the primitive lateral basilovertebral anastomosis. Understanding the pattern and the development of the blood supply of the hindbrain provides useful information of the various anomalies of the vertebrobasilar junction and cerebellar arteries.