Introduction

Complete occlusion of the bilateral vertebral artery (VA) can cause vertebrobasilar ischemia when the posterior communicating artery or other collaterals are poorly developed. Revascularization is mandatory in patients with

recurrent ischemia, despite administering maximal medical treatment. We describe a case of successful revascularization that was achieved using an occipital artery (OA) to distal extracranial VA bypass in a patient with bilateral proximal

vertebral artery occlusion.

Case report

A 71-year-old man was admitted during September, 2007 because of horizontal diplopia, dysarthria, right hemiparesis and an ataxic gait. He had been taking antiplatelet medication (aspirin 100mg and clopidogrel 75mg daily) for

three years due to infarction of the right superior cerebellar artery and bilateral posteroinferior cerebellar artery territories. The contrast enhanced magnetic resonance angiography and bilateral subclavian angiograms showed

complete occlusion at the second segment of the right VA and at the origin of the left VA (Fig. 1). The left distal VA was reconstituted by using collaterals from the deep cervical arteries, and only the distal portion of the basilar artery was observed to receive a blood supply through the posterior

communicating artery. Perfusion was severely reduced in the cerebellum and brain stem (Fig. 2). We performed a left OA to left distal VA bypass (Fig. 3)

by mobilizing the OA of the external carotid artery and anastomosing it end-to-side to the VA at the C1-2 level. At his 1-year follow-up, the bypass was widely patent and perfusion CT showed no abnormality in the posterior

circulation, other than in the previous infarction area (Fig. 4). Furthermore, the patient’ dysarthria disappeared and the patient was able to walk with a cane after bypass surgery. Heremains under observation and has not experienced recurrent

symptoms due to vertebrobasilar insufficiency for 2 years.

Discussion

To the best of our knowledge, there is only one previous report on endovascular treatment for complete occlusion of the extracranial VA.6) Endovascular revascularization has become more common because balloon angioplasty with stenting is relatively feasible for treating stenosis of an extracranial VA and this has been shown to produce good

initial angiographic results.1)5)9)12)13) However, unlike stenosis, endovascular recanalization has two major risks in the cases of complete extracranial VA occlusion, namely, vessel

perforation or rupture by a guide wire or a balloon, respectively, and intracranial embolization of debris during recanalization. Furthermore, in addition to the procedural risks, the long-term patency of balloon angioplasty with stent placement for proximal extracranial VA is

disappointing because the procedure has always been associated with restenosis at rates varying from 11.1 to 66.7%.3)10-12) Moreover, a study of the long-term outcome of angioplasty and stent placement in symptomatic VA stenosis showed no benefit for performing endovascular treatment over medical treatment.4) In contrast, surgical revascularization of the distal

extracranial VA has been used for decades as a therapeutic option in the posterior circulation, and its excellent longterm outcome is well known.2)8) The largest series of distal

VA reconstruction revealed a patency rate of 89.3% and a significant vertebrobasilar symptom-free rate of 94% at 5 years.8) However, the mortality and stroke rates during the

early postoperative period were relatively high (2.0% and 1.4%, respectively). A high risk of postoperative stroke was mainly observed in the patient subgroup that requires combined internal carotid artery and distal VA reconstruction. These risks can be reduced by creating a

bypass to the distal extracranial VA using the external carotid artery (ECA), or its branch as the donor. In fact, several authors have reported no morbidity or mortality in the cases that were treated using an ECA or OA to a distal extracranial VA bypass.2)7-8) Bypass surgery has recently become an uncommon neurosurgical procedure. However, carotid triangle surgery such

as carotid endarterectomy is one of the most common operations in neurosurgery, and the VA at the C1~2 level is relatively superficial as compared with the other segments, and so

anastomosis between the ECA and VA can be easily performed. For these reasons, revascularization of the distal extracranial VA with bypass should be considered as a treatment option in patients with recurrent vertebrobasilar insufficiency.

Conclusion

OA to distal extracranial VA bypass is useful when the VA is occluded at its origin or proximal portion in patients with a history of medically refractory ischemic events in the vertebrobasilar territory. In this era of balloons and stents,

we suggest that this technique has a role to play in thetreatment of bilateral proximal vertebral artery occlusion.

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