We recommend the standard retrosigmoid approach for treating small to medium aneurysms involving the lower two-thirds of the clivus or distal AICA aneurysms. Cranial base approaches are recommended for large or giant aneurysms or for those proximal to the emergence of the AICA from the basilar trunk. Hypothermic cardiac arrest facilitates dissection of giant aneurysms. Endovascular treatment is a useful adjunct for treating residual aneurysms but did not provide definitive treatment in any of our patients.

Endovascular therapy is a feasible, safe, and effective treatment in patients with proximal and distal PICA aneurysms, providing excellent patient outcomes and adequate protection against rehemorrhage. The long-term incidence of aneurysm recanalization appears to be high, especially in distal aneurysms, and requires careful angiographic follow-up.