Article
Vertebral aneurysms and associated anomalies of the posterior circulation
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Authors
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A. Harati
- Neurosurgical Department, Helsinki University Hospital, Finnland; Neurosurgical Department, Klinikum Dortmund
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H. Lehto
- Neurosurgical Department, Helsinki University Hospital, Finnland
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J. Satopää
- Neurosurgical Department, Helsinki University Hospital, Finnland
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R. Kivisaari
- Neurosurgical Department, Helsinki University Hospital, Finnland
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M. Niemelä
- Neurosurgical Department, Helsinki University Hospital, Finnland
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J. Hernesniemi
- Neurosurgical Department, Helsinki University Hospital, Finnland
| Published: | June 4, 2012 |
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Outline
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Objective: Because vertebral aneurysms are relatively rare, their specific anatomic features and associated anomalies have been reported mainly in small series or case reports. In the current series we assessed anomalies of the posterior circulation in 62 patients with vertebral aneurysms.
Methods: All radiological data were analyzed in digital form. The VA and PICA were defined as dominating if the diameter on one side was > 0,5 mm respectively > 0,3 mm. Otherwise they were considered as equal. Additionally, we searched for anomalies such as aberrant vertebral artery, aberrant PICA, a vertebral artery terminating in PICA, duplication of the PICA, persistent trigeminal or hypoglossal artery. Besides the anomalies we evaluated fetal distribution.
Results: 35 (56%) aneurysms were located on the left side and 27 (44%) on the right side. Left sided aneurysms presented significantly more often with hemorrhage. In general both the mean diameter of the left vertebral artery and the left PICA were larger than the right VA and the right PICA. The mean diameter of the vertebral artery with an associated aneurysm was also larger. 36 patients (59%) had normal anatomic conditions with two VAs and two PICAs. However equal distribution of both VAs and both PICAs together was present in only 12 patients (19%). Aberrant or hypoplastic right vertebral artery was seen in five patients (8%) and aberrant or hypoplastic right PICA was seen in nine patients. A vertebral artery terminating into the PICA was present in three patients (5%) on the right side. The left vertebral artery was dominant in 31 patients (50%); the right VA was dominant in 12 patients (19%). Equal size of the VA was found in 19 cases (31%). The side of the aneurysm was significantly associated with the dominance of the vertebral artery and the PICA especially on the right side (p < 0,001). A fetal distribution of the posterior communicating artery was present in 14%. We had no case of duplication of the PICA and no case of persistent fetal trigeminal or hypoglossal artery.
Conclusions: The vertebrobasilar system is more prone to demonstrate developmental anomalies or variants that can frequently be of clinical significance in the genesis of vascular pathology. Hypoplasia and aplasia of the vertebral artery and the PICA were present in varying degrees. These findings are important for both endovascular and surgical treatment of these lesions, especially in case of parent artery occlusion with or without revascularization.
