Introduction: Nearly 1-2% of MCA aneurysms have angiographic or anatomic features that preclude conventional microsurgical or endovascular reconstruction. Such complex aneurysms generally necessitate a deconstructive strategy, thus mandating surgical revascularization to replace blood flow.
Methods: All consecutive patients who underwent microsurgical or endovascular deconstruction of a complex MCA aneurysm between 2004 and 2017 were included. Charts were retrospectively reviewed and demographic, clinical, imaging, operative, and outcome data were recorded.
Results: Twenty-two patients, 13 women and 9 men with mean age 51 years (16-72), were identified. Aneurysm location: M1 in 6, MCA bifurcation in 9, M2 in 6, M3 in 1, left side in 13, right side in 9. Morphology: non-saccular in 12, saccular in 10, unruptured: 19, ruptured: 3. Mean size was 19 mm (5-60). Flow replacement: in situ MCA-MCA bypass in 8 (3 with concomitant STA-MCA), STA-MCA in 7, IMaxA-MCA in 5, reimplantation in 2. Aneurysm deconstruction: microsurgical in 13, endovascular in 5, combined in 4. All but one (95.5%) had technically successful bypass. Twenty (90.9%) had complete aneurysm obliteration, 2 had small remnants after embolization. One (4.5%) died from hemorrhagic venous infarction, none had permanent morbidity. Transient and/or minor postoperative complications occurred in 11 (50%): transient neurologic deficits in 4, small perianeurysmal infarcts in 3, cerebral edema requiring decompressive craniectomy in 3 (all following embolization of large or giant aneurysms), epidural hematoma requiring evacuation in 1. After a mean follow-up of 17 months (1-97), all 21 survivors had either stable or improved functional status with a patent bypass. One had aneurysm recanalization 1 year after coiling, requiring repeat embolization. All remaining patients had stable aneurysm occlusion at follow-up.
Conclusions: Microsurgery is the best treatment option for complex MCA aneurysms. Bypass skills are an absolute prerequisite for tackling those lesions. Cerebral edema remains a concern after endovascular deconstruction of large and giant aneurysms.
Patient Care: This is one of the very few studies out there that address the management of complex MCA aneurysms, a relatively rare but real problem that faces neurosurgeons in practice. This paper illustrates the various revascularization and deconstruction techniques, both microsurgical and endovascular, that can be used in the management of those challenging lesions. It will allow neurosurgeons to have better understanding of the challenges posed by those lesions, as well as the available treatment options.
Learning Objectives: 1. Recognize that complex MCA aneurysms generally require microsurgical or endovascular deconstruction for complete and durable occlusion.
2. Recognize that cerebral revascularization, i.e. bypass surgery becomes mandatory in this setting to replace blood flow in the deconstructed MCA territory.
3. Understand the different revascularization and deconstruction strategies that can be used in the management of comnplex MCA aneurysms.
4. Recognize the critical importance of cerebrovascular bypass skills for optimally managing these challenging lesions.
5. Recognize massive cerebral edema as a potential complication of large or giant aneurysm treatment, particularly after endovascular deconstruction.