DISSECTING ANEURYSMS OF THE BASILAR ARTERY

TEN PATIENTS (six men and four women; mean age, 40 yr) with spontaneou s dissection of the basilar artery are reported. Clinically, six were admitted with subarachnoid hemorrhage (SAH) and four were admitted wit h brain stem ischemia. Angiography demonstrated string sign in four pa tients, pearl reaction in four, double lumen in one, and arterial ecta sia with mural retention of contrast medium in one. Magnetic resonance imaging was performed in two patients. Follow-up angiograms or magnet ic resonance angiography in six patients showed spontaneous healing in two patients, improvement in two, progression in one, and no change i n one. Nine patients were treated medically, and one underwent selecti ve intravascular occlusion of the dissecting aneurysm. One patient die d after further SAH, two remain severely disabled, three have residual neurological deficit, and four are in good clinical condition. The mo st interesting observations in this series include a relatively good c ourse in a substantial number of patients and low further bleeding pot ential after SAH, the late ''globular'' evolution, which may be favora ble for reconstructive treatment, and the diagnostic value of associat ed computed tomographic/angiographic findings. Surgical options in bas ilar dissection are very poor; in some reported cases, wrapping has be en tried with disappointing results. In light of the possibility of sp ontaneous healing or improvement, wrapping should be reserved for only those patients with recurrent SAH or angiographic progression of the dissection.