RESUMEN
Parent artery occlusion is a definitive treatment method for preventing rebleeding of dissecting aneurysms. We herein report a case of a ruptured distal posterior inferior cerebellar artery (PICA) dissecting aneurysm treated with internal trapping using n-butyl-2-cyanoacrylate (NBCA). A 65-year-old man visited our hospital with a complaint of headache and neck pain that began 1 week before his arrival. He had a history of spontaneous subarachnoid hemorrhage of unknown cause. Computed tomography of the brain revealed a small amount of subarachnoid hemorrhage, and distal subtraction angiogram showed a distal PICA dissecting aneurysm. We placed a guiding catheter in the left vertebral artery and an intermediate catheter in the PICA. A microcatheter was guided toward the proximal side of the aneurysm and was wedged into the parent artery. The dissecting aneurysm was treated with parent artery occlusion using 50% NBCA. The postoperative course was uneventful, and the patient was discharged 3 weeks after treatment without any neurological deficit. Parent artery occlusion with internal trapping using NBCA could be a safe and definitive treatment method for distal PICA dissecting aneurysms. Angiographical evaluation of the collateral network in the distal branch of PICA before embolization and wedged microcatheter technique in the parent artery are important for successful embolization using NBCA.
RESUMEN
OBJECTIVE: The characteristics, diagnosis, and preferred management strategies for distal posterior inferior cerebellar artery (PICA) aneurysms associated with cerebellar arteriovenous malformation (AVMs) are poorly understood. We present a case series with attention to aneurysm angioarchitecture, diagnostic imaging, treatment approaches, and a thorough review of the literature. With this information, we demonstrate a specific anatomical pattern for these aneurysms, an underreported need for conventional digital subtraction angiography (DSA) during evaluation, along with the utility of endovascular treatment with liquid embolic agents. METHODS: Neurosurgical patients from 2005 to 2016 were reviewed to identify PICA aneurysms along with distal PICA aneurysms. Details of their presentation, imaging studies, associated AVMs and treatment were recorded. A thorough literature search of previous case series and case reports of distal PICA aneurysms with and without associated small cerebellar AVMs was performed with PubMed and Google Scholar. RESULTS: Thirty-four patients with PICA aneurysms were identified at our institution, 12 of which were in a distal segment. All 12 of these patients underwent DSA as a part of their evaluation. Of the 12 patients with distal PICA aneurysms, 9 presented with subarachnoid hemorrhage and intraventricular hemorrhage. Five of these patients had a small occult cerebellar AVM. All nine patients presenting with a ruptured distal PICA aneurysm had a Fischer grade 4 subarachnoid hemorrhage. Of the five patients with a small occult cerebellar AVM, the AVM nidus was missed on computed tomography angiogram (CTA) interpretation but easily visualized with DSA. CTA followed by DSA with concurrent endovascular treatment was performed in 9 of the 12 patients with distal PICA aneurysms. Two of the 12 patients were treated with microsurgical clip ligation, and one mycotic aneurysm was identified and treated with antibiotics. Parent vessel sacrifice was used distal to the aneurysm in all 5 associated AVM cases with liquid embolic agents as well as AVM embolization in 3 of the 5 cases. Fifty-one well-described case reports of distal PICA aneurysms associated with small cerebellar AVMs have been reported in the literature. A total of 12 well-described case series of distal PICA aneurysms that comment on associated AVMs describe an associated small cerebellar AVM incidence of 4%-50%. In our case series, the incidence of an associated small cerebellar AVM with a distal PICA aneurysm was 42%. CONCLUSIONS: In cases of distal PICA aneurysms, there is a frequent association of a small cerebellar AVM. In our series, CTA was an inadequate diagnostic study to identify the associated AVM, and DSA was necessary to definitely visualize the AVM nidus. Endovascular treatment of the aneurysm and AVM with the use of liquid embolic agents was a feasible and useful management strategy.
