Bilateral vertebral artery dissection (VAD) is often related to sudden mechanical injury of the arteries such as that following direct trauma or rotational forces. The natural course of bilateral VAD is variable, from recanalisation to fatal subarachnoid haemorrhage.1 We report a patient with bilateral VAD and favourable clinical course due to adequate carotid haemodynamic compensation despite progressive vertebrobasilar insufficiency.

In February 2007, a 42-year-old man presented with acute, stabbing neck pain, radiating to his occipital area and persisting for 5 days after performing yoga exercises while standing on his head. He showed no neurological deficit except for limited neck motion due to pain. Serial magnetic resonance angiography (MRA) 5, 12, and 19 days later revealed progressive bilateral VAD with consequent vertebrobasilar flow insufficiency (Fig 1). Cerebral angiography 25 days after this dissection revealed compensated retrograde filling of the basilar artery (Fig 2). The MRA taken 50 days after dissection showed much more aggravated steno-occlusive changes in the entire vertebrobasilar circulation (Fig 3). Unlike the progressive deterioration of vertebrobasilar circulation, the patient’s neck pain gradually resolved without neurological deficit.

Cerebral angiography performed after the first three MRA studies showed nearly complete occlusion of the vertebral arteries just distal to the bilateral posterior inferior cerebellar artery. This protected the patient against neurological deficit. It is unclear why the fourth MRA at 1 month later showed further deterioration of vertebra-basilar circulation. The potential explanation for this finding may be related to the increased compensatory carotid artery flow through the collateral circulation. The presence of adequate haemodynamic compensation from the carotid artery territory constitutes an important positive prognostic factor of the low-flow ischaemia in a patient with bilateral VAD.1 2

Funaki et al3 reported that serial MRA could be of great use to monitor restorative bilateral VAD haemodynamics. In contrast, our patient showed progressive deterioration of vertebrobasilar circulation. This suggests that the haemodynamic status of bilateral VAD can variably alter, so serial MRA can help monitor the progression of dissection in some patients.2

The present case suggests that the haemodynamics of bilateral VAD are variable and adequate haemodynamic compensation may constitute a positive prognostic factor.

Concept or design: BD Ku.
Acquisition of data: All authors.
Analysis or interpretation of data: All authors.
Drafting of the manuscript: BD Ku.
Critical revision of the manuscript for important intellectual content: All authors.

All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.

The authors have disclosed no conflicts of interest.

The authors would like to thank Harrisco (www.harrisco.com) for the English language review.

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

This study was conducted in accordance with the principles outlined in the Declaration of Helsinki.

1. de Bray JM, Penisson-Besnier I, Dubas F, Emile J. Extracranial and intracranial vertebrobasilar dissections: diagnosis and prognosis. J Neurol Neurosurg Psychiatry 1997;63:46-51. Crossref

2. Bacci D, Valecchi D, Sgambati E, et al. Compensatory collateral circles in vertebral and carotid artery occlusion. Ital J Anat Embryol 2008;113:265-71.

3. Funaki T, Oshimoto T, Wataya T, et al. Bilateral vertebral artery dissection and its chronological changes detected by MR angiography: a case report [in Japanese]. No To Shinkei 2004;56:247-50.