Can intracranial vertebral artery hypoplasia be an etiopathogenetic factor for Barré–Lièou syndrome other than arcuate foramen? A retrospective clinical study and review of literature

Abstract

AIM: To investigate the co-occurrence of the arcuate foramen (AF) variation of atlas and intracranial vertebral artery (V4) hypoplasia and, therefore, to understand the pathophysiology of Barr?????Li??ou syndrome (BLS). The AF localizes on the vertebral artery (VA) sulcus posterior to the atlas and has incomplete and complete types. Complete-type AF can exert pressure on the VA that passes through it, resulting in vertebrobasilar insufficiency finding, a BLS component. By the surgical decompression of VA at the AF level, complaints could be decreased in some cases. However, a reliable theory regarding BLS has not yet been established; therefore, the cases that do not respond to AF decompression have not been fully elucidated. We assumed that V4 hypoplasia that accompanies AF might be the main factor in the pathophysiology of BLS. MATERIAL and METHODS: Cervical computed tomography and magnetic resonance angiography images of 139 patients aged 14???88 years with head and neck pain and dizziness were retrospectively evaluated. RESULTS: Of the patients, 19.4% exhibited complete AF and 32.4% exhibited VA hypoplasia (VAH); 10% of the patients with VAH had accompanying contralateral complete AF variation. There was no significant relationship between complete AF and contralateral and ipsilateral VAHs (right side: p=0.527 and p=0.433, respectively; left side: p=1.000 and p=0.740, respectively). CONCLUSION: Our findings indicate that V4 hypoplasia is not the main factor of BLS pathophysiology. Furthermore, the rarity of the relationship suggests why some cases do not respond to decompressive surgery.