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Differential intracranial pressure in patients with unilateral mass lesions

David D. Weaver, H. Richard Winn, and John A. Jane

✓ Four patients with unilateral mass lesions are presented in whom bilateral supratentorial subarachnoid pressures were continuously recorded. A significant pressure differential between the ipsi- and contralateral side was documented in each case. The possible relationship of this phenomenon to various factors involved in producing increased intracranial pressure, including cerebrospinal fluid flow dynamics, vascular reactivity, elasticity, and brain tissue pressure, are discussed. This study suggests that supratentorial subarachnoid pressure should be measured ipsilateral to the site of a focal mass lesion.

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Adverse impact of a calcium entry-blocker (verapamil) on intracranial pressure in patients with brain tumors

Robert F. Bedford, Ralph Dacey, H. Richard Winn, and Carl Lynch III

✓ In order to examine the effects of verapamil on intracranial pressure (ICP) in patients with compromised intracranial compliance, five hypertensive patients with supratentorial tumors were given verapamil, 5 mg intravenously, at the time of anesthesia induction. Within 4 minutes, ICP increased 67% from 18 ± 4 mm Hg (standard error) to 27 ± 5 mm Hg (p < 0.05), whereas mean arterial pressure decreased 20% from 111 ± 7 mm Hg to 89 ± 4 mm Hg (p < 0.05), and cerebral perfusion pressure (CPP) decreased 33% from 93 ± 11 mm Hg to 62 ± 6 mm Hg (p < 0.05). The increases in ICP responded promptly to hyperventilation and intravenous lidocaine (1.5 mg/kg). A control group of five hypertensive patients with supratentorial tumors received the same anesthetic agents without verapamil. In this group, ICP and CPP were unchanged. The authors conclude that calcium entry-blockers, such as verapamil, should be avoided in patients with compromised intracranial compliance unless ICP is being monitored and proper therapy for intracranial hypertension can be rapidly instituted.

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Intracranial Pressure Recording

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White Blood Cell Count and Mortality

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Acute cauda equina syndrome from a ruptured aneurysm in the sacral canal

Case report

Richard H. Schmidt, M. Sean Grady, Wendy Cohen, Sanford Wright, and H. Richard Winn

✓ The case is presented of a young woman with acute cauda equina syndrome from a ruptured aneurysm in the sacral canal. The lesion was associated with pathological enlargement of the lateral sacral arteries bilaterally, which presumably occurred to provide cross-pelvic collateral flow in response to the diversion of the right internal iliac artery for renal transplantation. The patient presented with signs and symptoms of spontaneous spinal epidural hemorrhage. The radiographic features of this lesion are described. In addition to angiography and partial embolization of the vascular supply, contrast-enhanced high-resolution computerized tomography was essential in the diagnosis and treatment of this unique aneurysm.

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Classification and regression trees (CART) for prediction of function at 1 year following head trauma

Nancy R. Temkin, Richard Holubkov, Joan E. Machamer, H. Richard Winn, and Sureyya S. Dikmen

✓ A cohort of 514 hospitalized head-injury survivors was identified based on their injury and 448 (87%) of them were followed for 1 year. Comprehensive neurobehavioral testing was performed 1 month and 1 year after injury.

The authors developed predictions of six neuropsychological and two psychosocial outcomes 1 year after head injury. Prediction trees are presented for verbal IQ, Halstead's Impairment Index, and work status at 1 year. Early predictors of neurobehavioral outcome in survivors are similar to previously reported predictors of mortality. Extent (both depth and length) of coma and age are the medical and demographic variables most predictive of late outcome. Adding 1-month scores substantially improves prediction of neuropsychological variables.

The classification and regression tree is a useful technique for predicting long-term outcome in patients with head injury. The trees are simple enough to be used in a clinical setting and, especially with 1-month scores, predictions are accurate enough for clinical utility.

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Toward a rational treatment of Chiari I malformation and syringomyelia

Richard G. Ellenbogen, Rocco A. Armonda, Dennis W. W. Shaw, and H. Richard Winn

In patients with Chiari I malformation with and without associated syringomyelia, aberrant cerebrospinal fluid (CSF) dynamics and a spectrum of posterior fossa pathological findings are demonstrated. In this study, the authors test the validity of using prospective cardiac-gated phase-contrast cine-mode magnetic resonance (MR) imaging to define the malformation, delineate its pathophysiology, and assist in implementing a rational treatment plan.

Eighty-five cases were prospectively analyzed using cine MR imaging. Sixty-five patients, adults and children, with symptomatic Chiari malformation, with and without syringomyelia, were surgically treated from 1990 to 1999. All patients underwent pre- and postoperative cine MR evaluation. Ten patients were treated after a previous surgical procedure had failed. To establish CSF flow characteristics and normative CSF profiles, 20 healthy volunteers were examined.

Compared with normal volunteers, in Chiari I malformation patients with and without syringomyelia, uniformly abnormal craniocervical junction CSF flow profiles were revealed. After intradural exploration, nearly all patients with Chiari I malformation experienced clinical improvement and CSF flow profiles, paralleling those of normal volunteers, were shown. In all patients in whom treatment had failed, abnormal preoperative CSF flow profiles, which correlated with suspected physiological abnormalities and the pathological findings noted at reoperation, were demonstrated.

Symptomatic Chiari I malformation is a dynamic process characterized by the impaction of the hindbrain in an abnormal posterior fossa. This compression obstructs the normal venting of CSF in and out of the craniocervical sub-arachnoid space, throughout the cardiac cycle. Therefore, decompression or enlargement of the posterior fossa to establish normal CSF pathways should be the primary goal of surgical intervention. Aberrant CSF flow appears to be only one aspect of the pathological condition found in patients with Chiari I malformation. Arachnoid scarring in the posterior fossa and selective vulnerability of the spinal cord may also be factors in the pathogenesis and maintenance of associated syringomyelia. Phase-contrast cine MR imaging is a useful tool in defining physiological and anatomical problems in patients with Chiari I and syringomyelia, and it can help guide an appropriate primary or salvage surgical therapy.

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Prevalence of asymptomatic incidental aneurysms: review of 4568 arteriograms

H. Richard Winn, John A. Jane, James Taylor, Donald Kaiser, and Gavin W. Britz

Object. The prevalence of unruptured cerebral aneurysms is unknown, but is estimated to be as high as 5%. The goal of this study was to determine the prevalence of asymptomatic incidental aneurysms.

Methods. The authors studied all cerebral arteriography reports produced at a single institution, the University of Virginia, between April 1969 and January 1980. A review of 3684 arteriograms demonstrated 24 cases of asymptomatic aneurysms, yielding a prevalence rate of 0.65%. The majority (67%) of the 24 patients harboring unruptured aneurysms were women. More than 90% of the unruptured aneurysms were located in the anterior circulation and in locations similar to those found in patients with ruptured aneurysms. Nearly 80% of the aneurysms were smaller than 1 cm in their greatest diameter. The frequency of asymmetrical unruptured aneurysms (0.6–1.5%) was constant throughout all relevant age ranges (35–84 years).

Conclusions. While keeping in mind appropriate caveats in extrapolating from these data, the prevalence rate of asymptomatic unruptured aneurysms found in the present study allows an estimation of the yearly rate of rupture of these lesions. The authors suggest that this yearly rate of rupture falls within the range of 1 to 2%.

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CT Enhancement Following Lobectomy

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Are Ruptured and Unruptured Aneurysms Different?