Introduction: Perforators along the middle cerebral artery (MCA) M1 territory make the treatment of dissecting aneurysms exceptionally challenging. Management of these lesions ranges from observation to complex staged procedures requiring flow augmentation techniques.
Methods: Utilizing a neurovascular registry containing nearly 900 patient admissions from October 2008 through February 2013, we identified 13 patients with fusiform MCA-M1 aneurysms. Patient records were analyzed to assess patient demographics, presenting symptoms, co-morbidities, treatments, and outcomes.
Results: Medical records of 13 patients treated for MCA-M1 segment aneurysms were evaluated. Average patient age was 56 years and ranged from 22 to 73 years. The population was predominately female (69%). Unruptured aneurysm was the most frequent initial presentation (69%), followed by subarachnoid hemorrhage (15%) and stroke (15%). Subarachnoid hemorrhage patients were Hunt Hess grade III (n=1) and IV (n=1). Common co-morbidities included hypertension (77%), smoking (62%), and hyperlipidemia (46%). Two patients (15%) experienced regrowth after initial treatment and required further intervention.
Treatment was most often surgical (73%) and varied among four categories: observation only; simple surgical, including occlusion without parent vessel compromise; transitional, characterized by flow reversal using proximal occlusion or trapping; and maximal combined, defined as flow reversal with bypass to augment MCA distal circulation. Aneurysm management included wraps with or without clip (47%), bypass with stent, clip or occlusion (27%), coil and stent (13%), bypass with coil (7%), and observation (7%). Seven treatments (47%) were staged procedures.
Post-procedure complications included hydrocephalus (27%), vasospasm (20%), and seizures (20%). The 30-day mortality rate was 15% (n=2). The small sample size precludes statistical analysis of how type of treatment may relate to complications or mortality rates.
Conclusions: MCA-M1 dissecting aneurysms are challenging lesions that may require simple observation or aggressive staged interventions which reverse flow from the dissecting segment while preserving parent vessel lumen and distal perfusion.
Patient Care: Management of non-atherosclerotic fusiform dissecting M1-MCA aneurysms necessitate sophisticated or staged treatments due to complex anatomical, pathological, and hemodynamic features. Treatment strategies should be based on the type of symptoms at presentation, lesion size, radiologic appearance, location within the M1 segment, and risk accompanying the intervention.
Learning Objectives: • Assess alternate treatment strategies for M1 dissecting aneurysms
• Evaluate treatment options when considering combined staged treatments
• Anticipate treatment related complications