Abstract
We reviewed the risk for peri-operative stroke after skull base surgery in patients with pre-existing internal carotid artery (ICA) occlusion caused by tumor involvement, aneurysm or other processes. Eight operations in 7 patients on the ipsilateral side and 3 operations on the contralateral side of ICA occlusion were carried out in such patients. Two of there patients suffered a perioperative stroke due to unexpected hypotension during or after the operation. Since this experience, we have developed a protocol to evaluate these patients, and perform prophylactic cerebral revascularization.
From the retrospective review of our cases, the patient with ICA occlusion who has the following features should be considered for revascularization. 1. Young patients who are at risk for occurrence of tumor or aneurysm on the contralateral side. 2 Elderly patients with arteriosclerotic disease or other risk factors such as hypertension or smoking, because they have less ability to dilate their blood vessels. 3 The clinical history shows ischemic symptoms, and/or there is evidence of minor stroke on MRI or CT scan. 4. Low cerebral blood flow on Xenon CT scan (Xe/CT) (under 30ml/100g/min) and/or no response, or paradoxical response after acetazolamide (Diamox) test. 5. Poor collateral channels on angiography. 6. The hemisphere is mainly supplied through collateral vessels that will be potentially sacrificed or occluded by the operation. 7. In the case of contralateral ICA occlusion to the operation side, there is a significant risk of ICA injury. 8. Biologically, the tumor is non-angiogenic or hypovascular, because a hypervascular tumor will be expected to increase the blood supply of tumor itself as well as supplied hemisphere from collateral channels.
