Thrombosed aneurysms of the middle cerebral artery (MCA) usually show large dimension and complex morphology with neck sclerosis and perforating vessels originating from the sac. Only limited experiences from case reports or small mixed series including thrombosed aneurysms in different locations are available in literature. To systematically review all the pertinent literature, a comprehensive literature review with the search terms "MCA, aneurysm, and thrombosis" and a pooled analysis including our institutional series were performed. We evaluated demographics, ruptured status, aneurysm morphology, topography and size, thrombosis extension, treatment, complications, final occlusion rate, and clinical outcome at follow-up. Data were individually extracted for each patient and included in a pool for the statistical analysis. Forty-two articles published between 1992 and 2016 were selected, including a total of 115 patients. Most of thrombosed aneurysms were saccular (67.6%), large or giant (86.7%), and located at the MCA bifurcation (67.3%). The treatment of choice was surgery in more than 80% of cases compared with the endovascular techniques, though the overall percentage of complications reported in the two groups was similar and around 20% of cases. Clinical outcome was favorable in more than 85% of patients after treatment. This is the first systematic review focusing on treatment and outcome of thrombosed MCA aneurysms. Our data depict their main angioarchictectural and clinical characteristics, proving the feasibility of their treatment with good prognosis in a high percentage of patients. However, complication and mortality rates of about 20 and 3.5%, respectively, are not negligible.
Keywords: Clipping; Endovascular treatment; Intracranial aneurysms; MCA; Middle cerebral artery; Perianeurysmal edema; Thrombosed aneurysms.