Microsurgical Clipping Compared with New and Most Advanced Endovascular Techniques in the Treatment of Unruptured Middle Cerebral Artery Aneurysms: A Meta-Analysis in the Modern Era

Objective: Analyzing occlusion, complications rate, and clinical results in unruptured saccular middle cerebral artery aneurysms (MCAAs) comparing clipping with the most advance and newer endovascular techniques. Methods: We conducted a literature research from January 2009 to December 2018 to evaluate the efficacy and safety of microsurgical clipping or endovascular treatment with new devices (such as Flow-diverter or Woven EndoBridge) in patients with unruptured MCAAs. We extracted data involved: study and intervention features, occlusion rate; time of occlusion assessment; and clinical outcome. Results: A total of 29 studies and 1552 patients with unruptured saccular MCAAs were included in our analysis (464 patients included in the endovascular group, 1088 patients in the surgical group). Overall, the rate of long-term complete/near-complete occlusion was 78.1% (311/405, 95% confidence interval [CI], 69%-87.1%) and 95.7% (113/118, 95% CI, 92%-99.3%) after endovascular and surgical treatments, respectively (P = 0.001). The long-term complete occlusion rate was 60% (153/405, 95% CI, 45%-74%) and 95% (112/118, 95% CI, 90%-98%) after endovascular and surgical treatments, respectively (P = 0.001). The overall rate of treatment-related complications was 5.6% (33/464, 95% CI, 3.6%-7.7%) and 2.9% (37/1088, 95% CI, 0.8%-5%) among the endovascular and surgical groups, respectively (P = 0.001). Endovascular treatments were associated with higher rates of good neurologic outcome (283/293 [97%], 95% CI, 95%-98% vs. 570/716 [84%], 95% CI, 67%-98%; P = 0.001). No difference was found for the mortality (3/464 [1.5%], 95% CI, 0.4%-2.6% vs. 1/1088, 95% CI, 0.1%-0.6%; P = 0.5). Conclusions: Treatment-related complication and mortality are comparable among these techniques and the risk of aneurysm rupture seems very low for both strategies. The endovascular approach seems to increase the probability of good functional outcome after treatment, compared with surgery.