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Robert M. Crowell

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Robert M. Crowell and Yngve Olsson

✓ Impairment of microvascular filling was demonstrated in relation to focal cerebral ischemia in the monkey. Temporary or sustained middle cerebral artery (MCA) clipping was achieved with a microsurgical technique. Animals were sacrificed by perfusion with a carbon black suspension. Brains were fixed in formalin, and the extent of microvascular carbon filling was estimated grossly and microscopically. In most animals, MCA occlusion of 2 hours to 7 days produced diminished filling in small vessels in the MCA territory of supply. The impairment of filling was most pronounced in the deep subcortical structures but also affected the cortex in some animals. Temporary and sustained occlusion of equal duration produced roughly equivalent areas of abnormal filling. The impairment of vascular filling tended to be more extensive with increasing duration of occlusion. Hypotension during MCA occlusion caused almost total non-filling of the microvasculature in the entire MCA territory. Impaired filling of vascular channels may play a role in the pathogenesis of some clinical cerebrovascular diseases.

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Robert M. Crowell and Yngve Olsson

✓ Anastomosis of the superficial temporal artery (STA) to a middle cerebral artery (MCA) branch was completed about 2 hours after occlusion of the MCA root in 20 dogs. Occlusion of the MCA root without bypass grafting was performed in 11 control animals. All dogs were evaluated clinically. Two days to 3 months (usually 2 weeks) after surgery, STA catheter angiograms were made and the animals sacrificed by perfusion fixation. The brains were evaluated pathologically. Animals with patent or occluded STA-MCA bypass grafts fared better both clinically and pathologically than the controls. Hemorrhagic infarction and blood-brain barrier damage were common in untreated dogs and uncommon in treated animals. STA-MCA bypass grafts rarely led to occlusion of intrinsic collateral blood supply to the brain. The data suggest that prompt STA-MCA branch anastomosis might lead to restoration of neurological function and parenchymal structural integrity in certain patients with acute middle cerebral artery occlusion.

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Robert M. Crowell and James G. Wepsic

✓ Two teen-age male cousins with hereditary multiple exostoses developed cord compression secondary to chondrosarcoma. The clinical presentation, diagnostic work-up, surgical treatment, pathological findings, and postoperative course are described in each patient.

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Wesley Y. Yapor and Robert M. Crowell

✓ Two cases of saccular intracranial aneurysms arising from the superior hypophyseal artery take-off from the internal carotid artery are presented. The angiographic findings and technical details of the operative approach are discussed. Particular attention is focused on the use of fenestrated angled clips.

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James L. Stone, Terry Lichtor and Robert M. Crowell

✓ A patient with trigeminal neuralgia caused by a tortuous and ectatic vertebrobasilar artery is presented. He was treated with microvascular decompression using a fine silicone sling sutured to the dura over the petrous pyramid. The technical details are described.

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Andrea L. Halliday, Christopher S. Ogilvy and Robert M. Crowell

✓ True intracranial arteriovenous fistulas are rare. The authors report a case of a direct fistula between the intracranial portion of the vertebral artery and the lateral medullary venous system. The patient initially presented with a subarachnoid hemorrhage. An open surgical approach with clip obliteration of the lesion was used. The anatomy of this lesion and its surgical management are described.

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John A. Anson, Mabel Koshy, Lawrence Ferguson and Robert M. Crowell

✓ The neurological complications of sickle-cell disease include cerebral infarction and intracerebral hemorrhage; subarachnoid hemorrhage (SAH) has been infrequently reported. Among 325 patients with sickle-cell disease followed at the University of Illinois between 1975 and 1989, 11 cases of SAH were identified. Aneurysms were found in 10 of these patients, three of whom had multiple aneurysms. All of the patients had some degree of anemia and nine underwent craniotomy without hematological or neurological complications. From this review it appears that SAH is not uncommon in sickle-cell disease patients and tends to occur at a younger age and with smaller aneurysm size than in the general population. With proper perioperative management, including exchange transfusions to reduce the proportion of hemoglobin S to less than 30%, these patients can undergo angiography and craniotomy without an increased incidence of complications. The techniques used in managing sickle-cell disease patients with SAH are discussed.

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Jafar J. Jafar, Walter S. Tan and Robert M. Crowell

✓ A patient harboring a cerebral arteriovenous malformation (AVM) underwent angiography in an attempt to embolize the AVM. During catheterization (and prior to embolization) he became hemiplegic and aphasia Angiography revealed a complete middle cerebral artery (MCA) occlusion by an embolus. The patient was treated with recombinant tissue plasminogen activator (t-PA), a thrombolytic agent. Restoration of MCA flow was achieved, and the patient recovered.

Immediately after MCA embolus, t-PA infusion may lead to thrombolysis and neurological recovery. The decision-making process as well as the risks associated with the use of t-PA are discussed.