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Stefan-Nikolaus Kroppenstedt, Michael Kern, Ulrich-Wilhelm Thomale, Gerd-Helge Schneider, Wolfgang Reinhardt Lanksch and Andreas Wilhelm Unterberg

critical threshold for exacerbation of primary brain damage has not been defined. Therefore, the effect of blood pressure reduction and elevation on contusion volume after controlled cortical impact injury (CCII) was studied. 11 Blood pressure was decreased by venous blood pooling in lower body portions by using hypobaric hypotension or elevated by administration of dopamine. 10, 15 Materials and Methods Controlled Cortical Impact Injury The experimental protocol was approved by the committee for animal research in Berlin, Germany. Sixty male Sprague—Dawley rats, each

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Christopher Reilly, Chris Amidei, Jocelyn Tolentino, Babak S. Jahromi and R. Loch Macdonald

investigated the role of these factors in relation to vasospasm, there are no studies in which the relationships between vasospasm and initial clot volume, clearance, and density have been examined simultaneously and quantitatively. Because larger volumes of clot might clear more slowly, a multivariate analysis would be needed to determine whether clot volume and clearance are independent factors associated with vasospasm. Clinical Material and Methods Patient Characteristics and Clinical Variables After approval of the protocol by the Institutional Review Board

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Michael Kosteljanetz

A n analysis of the relationship between intracranial pressure (ICP) and volume is essential for a better understanding of ICP dynamics, under both normal and hypertensive conditions. Various methods have been employed to study this relationship, most of which demand a volume perturbation of the cerebrospinal fluid (CSF) space. 11–13, 27 In an attempt to avoid fluid manipulations of the CSF space, some authors have analyzed the ICP pulse amplitude, 2, 4, 5, 25 because it has been suggested that the pulse amplitude is a measure of intracranial compliance or

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David S. Ditor, Sunil John, Jason Cakiroglu, Colin Kittmer, Paula J. Foster and Lynne C. Weaver

efficacy of neuroprotective or neuroregenerative strategies. Traditionally, many investigators have relied on histological techniques to estimate lesion size after experimental SCI, with the Cavalieri method being perhaps the most commonplace. 10–12 , 14 , 15 In brief, the Cavalieri method of lesion volume estimation involves serial sectioning of the injured spinal cord, either transversely or longitudinally, and then staining of the sections to differentiate the spared tissue from the lesion. The area of the lesion is then determined for each serial section, and the

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Letters to the Editor To The Editor Harold A. Wilkinson , M.D. Worcester, Massachusetts 804 805 In their article on intracranial volume-pressure relationships, Tans and Poortvliet state that “there is no general agreement on how to administer the bolus infusions…” for volume-pressure testing in the clinical situation (Tans JTJ, Poortvliet DCJ: Intracranial volume-pressure relationships in man. Part 2: Clinical significance of the pressure-volume index. J Neurosurg 59: 810–816, November, 1983). Their article

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Fred G. Barker II, William E. Butler, Sue Lyons, Ethan Cascio, Christopher S. Ogilvy, Jay S. Loeffler and Paul H. Chapman

designed to deliver 90% of the maximum dose at the arteriographically defined margins of the lesion. Dose inhomogeneities within the treatment volume were 10% or less. Doses were chosen according to the anticipated risk of brain necrosis, using Kjellberg's isocentile curves as the basis of predicted risk. 19 Definition of Variables and End Points Treatment dose is expressed as the maximum dose within the treatment volume, based on ionization chamber dosimetry. No correction has been made for relative biological effectiveness. Because the relative biological

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Victoria J. Williams, Jenifer Juranek, Karla K. Stuebing, Paul T. Cirino, Maureen Dennis, Robin M. Bowman, Susan Blaser, Larry A. Kramer and Jack M. Fletcher

from those in patients who had enlarged ventricles due to neuronal atrophy and in whom the caudate FA matched that in healthy individuals. In patients with chronic hydrocephalus, caudate diffusion rapidly returns to normal immediately after shunting. 29 Few studies have quantified the relationship between diffusion metrics and a stabilized subacute ventricular volume in individuals who underwent shunting. The Evans ratio is a commonly used clinical indicator of ventricular dilation, but volumetric measurements of the lateral ventricles in experimental hydrocephalus

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Lucia Schwyzer, Robert M. Starke, John A. Jane Jr. and Edward H. Oldfield

patients with acromegaly caused by GH-secreting tumors. We explored the possibility that if individual tumors have their own intrinsic level of GH production and if that level of GH production is homogeneous across the tumor, a comparison of GH levels before and after surgery would indicate the fraction of tumor that had been removed. Thus, a close correlation between tumor volume and hormone secretion in individual patients would permit calculation of the fraction of tumor removed by surgery, simply by measuring the postoperative GH levels. Methods We assessed

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Jaiho Chung, Sook Young Sim and Soo Han Yoon

attempted to ascertain whether cranial remodeling by a soft molding helmet is effective and safe by evaluating cranial growth and volume changes in an animal model. Materials and Methods The helmet used in this study consisted of a soft inner layer made of polyethylene foam and a hard outer layer made of ethylene vinyl acetate fused under high pressure. To minimize skin irritation and enhance ventilation, an additional layer of fine textile mesh was added to the inner foam layer. The helmet had an open top for ventilation ( Fig. 1 ). The size of the helmet was

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Robert S. Heller, Carlos A. David and Carl B. Heilman

periorbita when necessary. Reconstruction of the orbital rim and at least some of the lateral wall is then performed to restore the eye to a normal position and to prevent temporal depression. Surgeons planning to perform orbital wall reconstruction have the option of reconstructing the orbit to a larger-than-anatomical volume, anatomical volume, or smaller-than-anatomical volume. There are advantages and disadvantages to each, depending on the perceived effect of the pathology on the normal orbital contents and venous drainage of the orbit. In cases of long