Ruth E. Bristol, Felipe C. Albuquerque, Cameron McDougall and Robert F. Spetzler
✓Although many arachnoid cysts are discovered incidentally and require no intervention, a small subset has been known to rupture. Note that rupture can occur either spontaneously or in association with trauma. Based on a review of the literature on ruptured arachnoid cysts, it appears that patients with middle fossa cysts are more likely to experience symptomatic traumatic rupture than those with cysts in other locations. Middle fossa cysts are more commonly associated with hemispheric subdural collections and hematomas than are any other cysts. The authors report on two representative cases illustrating the distinct presentation, imaging characteristics, and management of these cysts.
Louis J. Kim, Felipe C. Albuquerque, Cameron McDougall and Robert F. Spetzler
Recurrent aneurysms of the anterior circulation that are distal to the anterior communicating artery (ACoA) but proximal to the callosomarginal–pericallosal bifurcation can pose a treatment challenge. The authors present one such case, in which the patient was treated with pericallosal artery–pericallosal artery (PerA–PerA) side-to-side bypass, followed by endovascular obliteration of the proximal A2 parent vessel. This patient, in whom an ACoA aneurysm had been treated with clip ligation 5 years previously, presented with a new, mid-A2, right-sided aneurysm with the out-flow artery arising from the dome of the lesion.
The treatment plan included two steps: an interhemispheric transcallosal approach for PerA–PerA side-to-side anastomosis; and endovascular coil embolization of the right A2 branch feeding the aneurysm. Postprocedure angiography demonstrated no ipsilateral aneurysm filling and excellent bilateral distal outflow from the anterior cerebral artery (ACA).
The use of PerA–PerA side-to-side bypass for the treatment of an ACA aneurysm, followed by parent vessel occlusion, offers an elegant solution for the treatment of A2 aneurysms that are not amenable to stand-alone clip ligation or coil occlusion. Such combined methods are invaluable in the management of complex cerebral aneurysms.