Distal intracranial artery pseudoaneurysm causing subdural hematoma: An illustrative case and a systematic review

Abstract

Background: Pseudoaneurysm arising from the distal segment of an intracranial artery is a rare cause of subdural hematoma (SDH). We report a patient diagnosed with a pseudoaneurysm of a cortical branch of the distal anterior cerebral artery (ACA) during planned middle meningeal artery embolization for SDH and present a systematic review to summarize the present literature.

Methods: A systematic literature search was conducted across EMBASE, MEDLINE, CINAHL, the Cochrane Library, and Scopus to identify studies reporting SDH due to pseudoaneurysms in the terminal intracranial artery segments. Details regarding clinical presentation, management, and outcomes were extracted.

Results: Twenty patients from the 18 retrospective studies and the patient from the present report were included in the review. The mean age of the patients was 49.4 years; 80.9% of the patients were males. A history of nonpenetrating head trauma was present in 11 (52.4%) patients. The most common presenting symptoms were hemiparesis and altered mental status. Catheter angiography established the diagnosis in the majority of the patients (85.7%). Angiography was performed due to a clinical/radiological suspicion for a pseudoaneurysm in 6 (28.5%) patients. In the majority of the patients (66.7%), angiography was performed for a different indication. Middle cerebral artery (15 patients, 71.4%) was the most common location of the pseudoaneurysm, followed by ACA, posterior cerebral artery, and posterior inferior cerebellar artery. Pseudoaneurysm was treated surgically in 14 patients (66.7%) and by endovascular modalities in 5 patients (23.8%). One patient undergoing endovascular treatment required surgical evacuation of SDH. The majority of the patients in both treatment groups (surgical - 72.7%, endovascular - 80%) recovered without severe disability (modified Rankin Scale ≤ 4).

Conclusion: Pseudoaneurysms of distal segments of intracranial arteries are a very rare cause of SDH. A high index of suspicion is required for their identification. While a definitive diagnosis requires catheter angiography, indications to perform angiography in SDH are unclear. Pseudoaneurysms with SDH can be treated safely with both microsurgical and endovascular modalities. Microsurgery has the advantage of draining SDH at the same time. The relative efficacy of different treatment approaches and the indications for each are not yet defined.

Keywords: Endovascular; Microsurgery; Pseudoaneurysm; Subdural hematoma; Trauma.

Figure 1:

Computed tomography head and magnetic resonance imaging brain-T1 sequence showing left frontotemporoparietal subdural hematoma (blue arrows). (a) CT head, (b) MRI brain T1 sequence

Figure 2:

Cerebral angiogram showing pseudoaneurysm (arrows) arising from a frontal cortical branch of the A4 segment of the anterior cerebral artery. Pseudoaneurysm shows delayed filling (beginning in the late arterial phase) and delayed washout during different phases of the angiogram, which are seen classically in a pseudoaneurysm. (a) Early arterial phase, (b) late arterial phase, (c) capillary phase, (d) early venous phase, (e) late venous phase, (f) selective arterial injection of the parent artery.

Figure 3:

Pseudoaneurysm formation with layered fibrin clotting products, recanalized lumen, and an absence of a true vessel wall (Movat trichrome, ×200).

Figure 4:

The preferred reporting items for systematic reviews and meta-analyses flowchart for selection of studies.

Figure 5:

Modalities of treatment used for pseudoaneurysms. Excision repair involved excision of the pseudoaneurysm and repair of the parent artery, whereas trapping/parent vessel sacrifice involved parent artery sacrifice with or without excision of pseudoaneurysm. Bypass was not performed for any of the patients undergoing trapping/parent vessel sacrifice.