A high rate of recanalization and clinical improvement can be observed in patients with ischemic stroke using low-dose thrombolytic agents with adjunctive mechanical disruption of clot. Moreover, this strategy may reduce the risk of intracerebral hemorrhage observed with thrombolytics.

Endovascular management of extracranial arterial dissection continues to evolve. Current experience shows that this treatment option is safe and technically feasible. Prospective randomized trials compared with medical management are needed to further elucidate the role of stenting.

Tentorial DAVMs are aggressive lesions that require prompt total angiographic obliteration. Disconnection of the venous drainage from the fistula may be accomplished with transarterial embolization to the venous side, transvenous embolization, or surgical disconnection of the fistula. We think that extensive nidal resections carry more risk and are unnecessary. We do not think there is a role for stereotactic radiosurgery in the treatment of these lesions.

Intraoperative rupture of an intracranial arterial aneurysm can dramatically interrupt a deliberate microsurgical procedure and jeopardize the patient's chances for a favorable outcome. Intraoperative rupture occurred in 58 of 307 (19%) consecutive aneurysm procedures done at The University of Texas Health Science Center. Rupture occurred during three specific periods: early or predissection in 7%, dissection in 48%, and clip application in 45%. Outcome after rupture during the predissection interval was poor, with only 1 of 4 patients surviving. Aneurysmal rupture during dissection could be attributed to blunt dissection techniques in 75% of the cases and to sharp subarachnoid dissection in 25%. The outcome was favorable in only 50% of the patients sustaining blunt dissection errors, whereas all patients sustaining intraoperative rupture during sharp dissection recovered well. Rupture during clip application was attributed to incomplete dissection in 65%, poor clip application in 31%, and a mechanical clip failure in 1 case. Eighty-eight per cent of the patients who underwent uneventful operative procedures had favorable outcomes, whereas only 62% of the patients suffering intraoperative rupture recovered well. The use of sharp microsurgical techniques with a systematic contingency plan for dealing with sudden hemorrhage and the judicious use of temporary clips should minimize the adverse effect of intraoperative rupture on overall management morbidity and mortality.

Infratentorial arteriovenous malformations represent only some 5-7% of malformations in major series. Since 1977 thirty-two patients with intracranial, intradural malformations of the brain stem or cerebellum have been evaluated by the Division of Neurological Surgery of The University of Texas Health Science Center at Dallas. Thirty of these patients have undergone surgical treatment. Twenty-three patients presented with intracranial hemorrhage which was recurrent in eleven cases. Nine patients were evaluated due to progressive brain stem or cerebellar deficits. A history of progressive deficits was unusual in the group that presented with hemorrhage and a prior or subsequent hemorrhage was rare in the patients initially evaluated due to progressive deficits. Seventeen of these malformations were located in the vermis, seven within the cerebellar hemisphere, two in the tonsil, two in the cerebellar-pontine angle, and four within the brain stem. Operative intervention was directed at primary resection in fifteen cases, staged resection in seven cases, embolization and resection in five cases, and evacuation of hematoma in three patients. Operative mortality in this surgical series was 7% with significant morbidity in 13%. Application of modern microsurgical techniques to the removal of arteriovenous malformations of the posterior fossa may result in improvement over the natural history of the disease process, especially in those patients who present with hemorrhage.