{'fraction_non_alphanumeric': 0.011979166666666667, 'fraction_numerical': 0.0010416666666666667, 'mean_word_length': 5.787985865724382, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Long-term results of extracranial to intracranial bypass for ischemic vascular disease.

MORE THAN A DECADE has passed since the first cases of extracranial to intracranial bypass in humans were reported. Since then improvement in microsurgical techniques and instruments has allowed for an array of microvascular procedures for establishing collateral flow to the brain in cases of ischemic disease. The most common of these is the superficial temporal artery to middle cerebral artery bypass. Other procedures for improving flow in the basilar circulation are being done with increasing frequency. These include occipital artery to posterior inferior cerebellar artery bypass, superficial temporal artery to superior cerebellar artery bypass and intracranial vertebral endarterectomy. Increasing experience with the surgical treatment of ischemic cerebral vascular disease should provide valuable information regarding the management of stroke and its prevention. Now that thousands of superficial temporal artery to middle cerebral artery bypasses have been done, it is important to look at current concepts as well as long-term results. Indications for this bypass procedure continue to be ischemic lesions in the carotid circulation inaccessible to conventional extracranial vascular techniques, such as endarterectomy. The most common angiographic indication is internal carotid artery occlusion, but a large number of patients with intracranial carotid artery stenosis and middle cerebral artery stenosis and occlusion are felt to be suitable candidates. Clinical indications include transient ischemic attacks and the presence of a reversible ischemic neurologic deficit. Certain selected patients with completed stroke, especially those with continued ischemic symptoms, are also candidates for the procedure. Patency rates in well-selected patients continue to be more than 90%. Morbidity and mortality figures