Anterior Inferior Cerebellar Artery Aneurysm: Saccular Non-ruptured Aneurysm of the Premeatal Segment of the Anterior Inferior Cerebellar Artery, Treated with Flow Diverter Implantation into the Basilar Artery, with Complete Aneurysm Occlusion, Preservation of the Parent Artery, and Good Clinical Outcome
- 49 Downloads
A 43-year-old female patient who presented with hearing loss was found to have a small saccular aneurysm of the left anterior inferior cerebellar artery (AICA) arising at its origin from the basilar artery (BA). The aneurysm was treated with endovascular implantation of a Pipeline Embolization Device (PED) flow diverter into the BA, jailing the origin of the AICA and thus reducing the inflow into the aneurysm sac. The postoperative course was uneventful and the hearing loss remained stable. Angiographic follow-up examinations at 6 and 12 months confirmed complete occlusion of the aneurysm. Implantation of a flow diverter into the BA appears to be a viable option in the treatment of proximal AICA aneurysms, as conventional deconstructive techniques in the treatment of these aneurysms can cause severe neurologic deficit. Flow diversion is also technically more straightforward than stent- or balloon-assisted coil occlusion. The various technical options for the treatment of AICA aneurysms are the main topic of this chapter.
KeywordsAnterior inferior cerebellar artery (AICA) Flow diverter Posterior fossa aneurysm Pipeline Embolization Device (PED) Slipstream effect
A 43-year-old female patient presented with hearing loss. The attending otorhinolaryngologist obtained cranial MRI and non-contrast computed tomography (NCCT) which demonstrated a proximal dilatation of the left AICA.
The primary goal of the treatment was to prevent aneurysm growth and rupture, the latter causing subarachnoid hemorrhage (SAH), without compromising the BA, its pontine branches, or the AICA. Surgical access to this area was considered very difficult. Simple coil occlusion of the aneurysm was judged to have high risk for AICA occlusion. Catheterization of the left AICA with the aim of inserting a self-expanding stent or a (low-profile) flow diverter was considered hazardous. The only viable alternative was either conservative management or an indirect impact on the aneurysm by the implantation of a flow diverter into the BA, taking advantage of the so-called slipstream effect (i.e., the hemodynamic effect on an aneurysm as a result of flow diverter stent insertion without covering the aneurysm neck).
Procedure, 08.09.2011: endovascular treatment of an incidental aneurysm arising from the proximal left AICA with a Pipeline Embolization Device flow diverter implanted into the BA
Anesthesia: general anesthesia: 10,000 IU unfractionated heparin (Riveparin, Rivero) IV
Premedication: 1× 100 mg ASA (Aspirin, Bayer Vital) PO daily and 1× 75 mg clopidogrel (Troken, Laboratorio Bagó) PO daily, both started 5 days prior to the intervention
Access: right femoral artery, 7F sheath (Terumo); guide catheter: Fargo Plus (Balt Extrusion); microcatheter: Marksman 0.027" (Medtronic); microguidewire: Transend 0.014" (Stryker).
Implant: Pipeline Embolization Device 4.5/16 mm (Medtronic)
Duration: 1st–12th DSA run: 40 min; fluoroscopy time: 26 min.
Postmedication: 1× 100 mg ASA PO daily for life and 1× 75 mg clopidogrel PO daily for 6 months
The procedure was well-tolerated, and the patient was discharged home 2 days later without any new neurological deficit. There was no progression of the hearing loss, which remained stable at the 3-year follow-up.
Approximately 15% of all intracranial aneurysms occur in the posterior circulation; however, aneurysms of the AICA represent only 0.1–0.5% of all intracranial aneurysms (Mizushima et al. 1999). Locksley (1966) reports that only 2 AICA aneurysms out of 6368 aneurysms were studied. AICA aneurysms have a female preponderance. SAH is the clinical manifestation of AICA aneurysms in more than 70% of cases; however, neuropathies of the Vth, VIth, VIIth, and VIIIth cranial nerve may also occur. Saccular aneurysms are more frequent (>60%) than fusiform vessel dilatations (Lv et al. 2016). The most frequent aneurysm location reported by Lv et al. (2016) was the meatal segment (44%), followed by the premeatal segment (34%), with only 21% of the aneurysms located in the postmeatal segment.
In the vast majority of published cases of treated AICA aneurysms, a good clinical outcome (mRS 0–2) was achieved (Lv et al. 2016).
In conclusion, simple coil occlusion and flow diverter implantation into the BA are viable options for the treatment of proximal AICA aneurysms adjacent to the BA. For distal AICA aneurysms, selective coil occlusion can be performed if the anatomy is favorable (i.e., sufficient diameter and straight course of the parent vessel). PVO is the remaining endovascular option and can be achieved by coil insertion, particularly in the treatment of postmeatal aneurysms.
- Kanamori F, Kawabata T, Muraoka S, Kojima T, Watanabe T, Hatano N, Seki Y. Ruptured partially thrombosed anterior inferior cerebellar artery aneurysms: two case reports and review of literature. Nagoya J Med Sci. 2016;78(4):517–22. https://doi.org/10.18999/nagjms.78.4.517.CrossRefPubMedPubMedCentralGoogle Scholar
- Kikkawa Y, Suzuki K, Teranishi A, Tachikawa T, Kurita H. Ruptured intrameatal anterior inferior cerebellar artery aneurysm associated with obstructed internal auditory artery in a patient with sudden hearing loss and vertigo. Acta Neurochir. 2018; https://doi.org/10.1007/s00701-018-3771-x.CrossRefGoogle Scholar
- Rhoton AL. The cerebellar arteries. In: Rhoton AL, editor. Rhoton’s cranial anatomy and surgical approaches. Philadelphia: Lippincott Williams and Wilkins; 2007. p. 476–83.Google Scholar
- Srinivasan VM, Ghali MGZ, Reznik OE, Cherian J, Mokin M, Dumont TM, Gaughen JR, Grandhi R, Puri AS, Chen SR, Johnson JN, Kan P. Flow diversion for the treatment of posterior inferior cerebellar artery aneurysms: a novel classification and strategies. J Neurointerv Surg. 2018;10(7):663–8. https://doi.org/10.1136/neurintsurg-2017-013427.CrossRefPubMedGoogle Scholar