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Robert F. Spetzler, Neil Martin, Mark N. Hadley, Richard A. Thompson, Elizabeth Wilkinson and Peter A. Raudzens

patients have developed paralysis of auto-regulation in the chronically under-perfused hemisphere. The removal of the obstructive carotid lesion causes focal hyperperfusion that manifests as migrainous headache, focal seizures, and intracerebral hemorrhage. These events may be analogous to the normal perfusion pressure breakthrough phenomenon that can accompany the removal of large cerebral arteriovenous malformations. 65, 67, 70 In both cases, chronically hypoperfused brain is suddenly exposed to a dramatic increase in perfusion. Postoperative neurological

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Vertebrobasilar insufficiency

Part 1: Microsurgical treatment of extracranial vertebrobasilar disease

Robert F. Spetzler, Mark N. Hadley, Neil A. Martin, Leo N. Hopkins, L. Philip Carter and James Budny

been observed as a rare consequence of chronic steal. 27, 55 Extracranial vertebral artery disease is still clinically important even though the risk of stroke is comparatively low. Vertebral artery lesions have a pronounced capacity to cause frequent TIA's. The repetitive occurrence of vertigo, diplopia, focal motor or sensory deficits, or dysarthria can be severely disabling. Our patients were significantly impaired by continuing attacks that often were precipitated by postural changes or moderate exertion despite anticoagulant or antiplatelet therapy. Surgery is

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The effect of nimodipine on intracranial pressure

Volume-pressure studies in a primate model

Mark N. Hadley, Robert F. Spetzler, Mary S. Fifield, William D. Bichard and John A. Hodak

, Roski RA, et al: Cerebral revascularization during barbiturate coma in primates and humans. Surg Neurol 17: 111–115, 1982 13. Spetzler RF , Selman WR , Weinstein P , et al : Chronic reversible cerebral ischemia: evaluation of a new baboon model. Neurosurgery 7 : 257 – 261 , 1980 Spetzler RF, Selman WR, Weinstein P, et al: Chronic reversible cerebral ischemia: evaluation of a new baboon model. Neurosurgery 7: 257–261, 1980 14. Steen PA , Newberg LA , Milde JH , et al : Nimodipine

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Daniele Rigamonti, Burton P. Drayer, Peter C. Johnson, Mark N. Hadley, Joseph Zabramski and Robert F. Spetzler

established preoperatively in only seven (44%) of 16 patients. 35 Chronic hemorrhage does not remain hyperdense on CT; therefore, it is often difficult to differentiate glioma or infarction from angioma by CT criteria alone. In our series, CT studies were negative in three instances and correctly identified only 14 of 27 lesions that were detected by MRI. The sensitivity of MRI increases the probability of detecting a cavernous malformation. Computerized tomography may occasionally miss even relatively large lesions ( Fig. 1 ) and is not sensitive enough to detect the

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The transoral approach to the superior cervical spine

A review of 53 cases of extradural cervicomedullary compression

Mark N. Hadley, Robert F. Spetzler and Volker K. H. Sonntag

deformities of the axis/skull base, or chronic traumatic dislocations of the dens. 1–3, 11, 14, 15, 19, 21–25 Extradural tumor masses have also been resected via the transoral approach with good results. 3, 4, 8, 11, 16, 17 Recent refinements in surgical techniques and intraoperative retraction have facilitated these procedures and low morbidity and mortality rates can be achieved. 3, 14, 21, 22, 24 Despite these advances, the procedure has not been widely accepted or employed. Infection and cerebrospinal fluid (CSF) fistulae remain major concerns among surgeons who

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Julian E. Bailes, Robert F. Spetzler, Mark N. Hadley and Hillel Z. Baldwin

: Disturbances of cerebrospinal fluid circulation during the acute stage of subarachnoid hemorrhage. Neurosurgery 12 : 435 – 438 , 1983 Dóczi T, Nemessányi Z, Szegváry Z, et al: Disturbances of cerebrospinal fluid circulation during the acute stage of subarachnoid hemorrhage. Neurosurgery 12: 435–438, 1983 11. Farrar JK Jr : Chronic cerebral arterial spasm. The role of intracranial pressure. J Neurosurg 43 : 408 – 417 , 1975 Farrar JK Jr: Chronic cerebral arterial spasm. The role of intracranial pressure. J Neurosurg

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Mark J. Cuffe, Mark N. Hadley, Guillermo A. Herrera and Richard B. Morawetz

glomerulus of the kidney. Patients with end-stage renal failure cannot excrete this protein, and contemporary dialysis systems cannot remove it from the bloodstream due to its large size. Beta 2-micro globulin serum levels have been found elevated as high as 60-fold in anuric patients undergoing chronic dialysis. 7, 20, 23 Infiltration of the vertebral bodies, discs, and spinal support structures occurs and leads to spinal instability in some of these patients. Clinicians who manage long-term dialysis patients, particularly those with vertebral column complaints, should

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Randolph C. Bishop, Karen A. Moore and Mark N. Hadley

cervical disc sequestration. J Neurosurg 72: 370–377, 1990 2. Broulik PD , Jaráb J : The effect of chronic nicotine administration on bone mineral content in mice. Horm Metab Res 25 : 219 – 221 , 1993 Broulik PD, Jaráb J: The effect of chronic nicotine administration on bone mineral content in mice. Horm Metab Res 25: 219–221, 1993 3. Brown MD , Malinin TI , Brown PB : A roentgenographic evaluation of frozen allografts versus autografts in anterior cervical spine fusions. Clin Orthop 119

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Jay M. Meythaler, Anne McCary and Mark N. Hadley

spasms occurring > 1/hr 4 spasms occurring > 10/hr reflex 0 reflexes absent 1 hyporeflexia 2 normal 3 mild hyperreflexia 4 3 or 4 beats clonus only 5 clonus Inclusion Criteria After the initial screening evaluation, patients were enrolled in the study if they met all of the following criteria: 1) they were between 10 and 75 years old; 2) they had a diagnosis of severe chronic spastic hypertonia in the lower extremities (although the upper extremities could also be involved) of at least 6

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Daniel K. Resnick, Tanvir F. Choudhri, Andrew T. Dailey, Michael W. Groff, Larry Khoo, Paul G. Matz, Praveen Mummaneni, William C. Watters III, Jeffrey Wang, Beverly C. Walters and Mark N. Hadley

the frequency of lumbar fusion procedures in the 1980s. Davis 3 observed that the age-adjusted rate of hospitalization for lumbar surgery and lumbar fusion increased greater than 33% and greater than 60%, respectively, from 1979 to 1990. Lumbar fusion has been described as a treatment of symptomatic degenerative disc disease, spinal stenosis, spondylolisthesis, and degenerative scoliosis. Lumbar fusion has been performed to treat acute and chronic low-back pain, radiculopathy, and spinal instability. As practitioners have become caught up in the excitement of