Peer-Review ReportOccipital Artery–Posterior Inferior Cerebellar Artery Bypass for the Treatment of Aneurysms Arising from the Vertebral Artery and Its Branches
Introduction
The vertebral artery (VA) and posterior inferior cerebellar artery (PICA) are uncommon sites for intracranial aneurysms; <0.5%–3% of all intracranial aneurysms occur in this area (38). At the VA and PICA, there is a high incidence of both dissecting and fusiform aneurysms. Yamaura et al. (47) reported that 28% of intracranial aneurysms that occur at the VA and PICA are dissecting aneurysms and 13% are atherosclerotic fusiform aneurysms. Treatment of intracranial aneurysms of the VA and PICA is very difficult because of their location at the skull base near the brainstem and their unusual shapes.
Nonetheless, these difficult cases should be treated for the following reasons. The presenting clinical symptoms of patients who have intracranial aneurysms arising from the VA and PICA are subarachnoid hemorrhage (SAH) and brainstem ischemia 21, 23, 38, 46, 47. In addition, the rupture and rebleeding rates of these nonsaccular posterior circulation aneurysms are high. Mizutani et al. (29) reported that 71% of nonsaccular posterior circulation aneurysms rupture before treatment, and rebleeding occurs within 24 hours in 40.5% of these ruptured aneurysms. Saccular aneurysms of the posterior circulation, including the VA and PICA, tend to rupture more frequently than aneurysms of the anterior circulation 1, 43, 44. Finally, cranial nerve palsy occurs more frequently at the VA and PICA than in other locations 10, 47.
An aneurysm at the VA including the VA-PICA junction and one arising from the PICA have different characteristics. However, both types have a point of similarity in that they can diminish or obstruct the blood flow through the PICA during treatment. Multidisciplinary approaches including bypass surgery may be helpful in the treatment of these aneurysms. In the present study, we report our experience of 7 cases of an intracranial aneurysm located at the VA and its branches, including the PICA and an unusual collateral artery, that were treated with aneurysm trapping combined with distal revascularization.
Section snippets
Materials and Methods
We retrospectively reviewed patients who were treated for intracranial aneurysms arising from the VA and its branches, including the PICA and an unusual collateral artery, at our institution from January 2009 to December 2012. Patients were assessed according to the following inclusion criteria: 1) bypass treatment performed for intracranial aneurysms arising at the VA and its branches; 2) use of the occipital artery (OA) as the donor graft and the PICA as the recipient artery; and 3) all cases
Illustrative Case 1
A 45-year-old man (Case No. 2) was admitted to another hospital with a sudden severe headache. CT showed a diffuse SAH and intraventricular hemorrhage in the fourth ventricle. TFCA revealed a fusiform dissecting aneurysm in the fourth segment of the right VA just below the VA-PICA junction (Figure 1A); its longest length was 16.1 mm, and the largest diameter was 6.0 mm. The patient underwent stent-assisted coil embolization (Figure 1B). However, TFCA revealed coil compaction and recanalization
Revascularization for Treatment of Aneurysms Arising from the VA Involving the VA-PICA junction
Since the development of endovascular techniques, many aneurysms that arise from the VA involving the VA-PICA junction are treated using these methods 2, 11, 36. However, incomplete obliteration after endovascular treatment may occur to try to keep distal PICA flow. In addition, even if a residual aneurysm is not immediately noted after endovascular treatment, hemodynamic stress could induce coil compaction and recanalization of the aneurysm. Lv et al. (27) reported incomplete treatments in
Conclusions
We provide a retrospective review of 7 cases of intracranial aneurysms arising from the VA and its branches. These aneurysms are uncommon, and a standard treatment protocol is not yet fully established. On the basis of our experiences and previous reports, an OA-PICA bypass with trapping of the aneurysm is a viable option for the treatment of complex intracranial aneurysms arising from the VA and its branches. This procedure can result in total obliteration of the aneurysms, preventing
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2022, World NeurosurgeryCitation Excerpt :The PICA-PICA bypass was more commonly used because an OA graft was not required. The complex course of the OA through the suboccipital muscles makes the harvest more complicated.1-7 Several techniques of OA harvest were proposed.
Subarachnoid Hemorrhage Due to Rupture of Vertebral Artery Dissecting Aneurysms: Treatments, Outcomes, and Prognostic Factors
2021, World NeurosurgeryCitation Excerpt :When the contralateral VA is hypoplastic and when the dissected segment contains the posterior inferior cerebellar artery (PICA) origin or the anterior spinal artery, neither internal nor surgical trapping is appropriate because the parent artery must be preserved. Such VADAs have been treated with surgical VA trapping with an occipital artery (OA)–PICA bypass,11,12 coil embolization with a neck-bridging stent,13-16 overlapping multiple stents,17 or flow diverter.18-20 Treatment decisions must take into account the positional relationship between the VADA and the PICA and the morphology of the contralateral VA or the posterior communicating artery.
Rerupture Following Flow Diversion of a Dissecting Aneurysm of the Vertebral Artery: Case Report and Review of the Literature
2020, World NeurosurgeryCitation Excerpt :The construct demonstrated compaction with recanalization of the aneurysm after 9 months, so the authors performed an OA-PICA bypass with proximal clip occlusion of the right PICA using a far lateral approach followed by endovascular trapping of the dissected segment of the VA 2 days after surgery. This technique resulted in a good outcome at 6-month follow-up.38 Czabanka et al39 introduced a VA-PICA bypass with radial artery interposition graft and trapping of the aneurysm as an alternative to PICA-PICA and OA-PICA bypass for hemorrhagic dissecting aneurysms that cannot be treated with endovascular occlusion.
Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.