Document Detail


A laboratory model of shunt-dependent hydrocephalus. Development and biomechanical characterization.
MedLine Citation:
PMID:  3572499     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study was designed to determine whether implanting shunts in hydrocephalic cats produced the same biomechanical changes as have previously been found in children with shunts. Neuraxis volume-buffering capacity (pressure-volume index: PVI) and the resistance to the absorption of cerebrospinal fluid (CSF) were determined before and 3 weeks after placing shunts in 16 hydrocephalic cats. Intracranial pressure (ICP) was monitored for at least 6 hours after the shunts were occluded. The brains were perfused in vivo and removed to assess the size of the ventricles. The mean PVI of the hydrocephalic cats was 3.6 +/- 0.2 ml (+/- standard error of the mean) before the shunts were placed. Three weeks after adequate shunt function was first established, the mean PVI decreased to 1.1 +/- 0.1 ml and was similar to values determined in control animals. Prior to shunt placement, the resistance to the absorption of CSF was 28.4 +/- 4.5 mm Hg/ml/min and did not vary with ICP. This parameter changed after shunting and increased as a function of ICP (r = 0.87, p less than 0.001). At ICP's below 20 mm Hg, the resistance to the absorption of CSF was 65.0 +/- 18.0 mm Hg/ml/min but increased to 220.0 +/- 40.5 mm Hg/ml/min when determined at ICP's above 20 mm Hg. Corroborating evidence for this linkage of resistance to the absorption of CSF to ICP was found in the inexorable rise of ICP during the 6 hours of monitoring after the shunts were occluded. After shunt placement, the ventricles were normal in size in 12 cats and slightly enlarged in four. The biomechanical profile and pressure response to shunt occlusion in this laboratory model resembles that previously described in shunt-dependent children. As in humans, shunt placement in hydrocephalic cats results in normalization of the PVI and a linkage of the resistance to the absorption of CSF to ICP. The significance of these changes as they relate to shunt dependency is discussed.
Authors:
A Fried; K Shapiro; F Takei; I Kohn
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of neurosurgery     Volume:  66     ISSN:  0022-3085     ISO Abbreviation:  J. Neurosurg.     Publication Date:  1987 May 
Date Detail:
Created Date:  1987-06-05     Completed Date:  1987-06-05     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0253357     Medline TA:  J Neurosurg     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  734-40     Citation Subset:  AIM; IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Biomechanics
Cats
Cerebrospinal Fluid Shunts*
Disease Models, Animal
Equipment Failure
Hydrocephalus / physiopathology*,  surgery
Intracranial Pressure
Grant Support
ID/Acronym/Agency:
NSI-EA 1 K07 00769-01/NS/NINDS NIH HHS

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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