VASCULAR CONSIDERATIONS AND COMPLICATIONS IN CRANIAL BASE SURGERY

THE TECHNICAL EVOLUTION of cranial base surgery has resulted in approa ches that allow more radical surgical extirpation of complex cranial b ase lesions. Our service has extensively applied these cranial base ap proaches for lesions of the cranial base. A subgroup of 100 patients w ho had cranial base tumors involving potential manipulation or sacrifi ce of carotid arteries underwent 20-minute balloon test occlusions coo rdinated with vascular assessments consisting of a combination of the following: 1) four-vessel cerebral angiogram with compression studies; 2) occlusion transcranial Doppler ultrasonography; 3) occlusion singl e-photon emission computed tomography perfusion studies; and 4) xenon- 133 cerebral blood flow studies. Transient neurological deficits assoc iated with balloon test occlusion occurred in 7 of 100 patients (7%). Subsequently, 18 patients underwent permanent carotid occlusion by end ovascular detachable balloons. Delayed ischemic complications (>72 h) occurred in 4 of 18 (22%) patients. Additionally, a number of vascular complications not predicted by the balloon occlusion tests and vascul ar assessments were experienced. Repeat vascular assessments defined t he causes and guided treatment of ischemic patients. Ischemic complica tions were caused by hemodynamic insufficiency, embolization, vasospas m, radiation vasculopathy, and venous anomaly. Our experience leads us to believe that no vascular assessment exists today that can predict the occurrence of vascular complications accurately. The current enthu siasm for cranial base surgery must be tempered with the sober reality that management of cerebrovascular anatomy and physiology remain sign ificant limitations. Consideration of potential cerebrovascular compli cations is paramount to successful outcome and implementation of crani al base surgery.