Document Detail

Spinal Cord Intramedullary Pressure in Cervical Kyphotic Deformity: A Cadaveric Study.
MedLine Citation:
PMID:  21289583     Owner:  NLM     Status:  Publisher    
ABSTRACT: Study Design. In vitro cadaveric study of cervical spinal cord intramedullary pressure (IMP) in kyphotic deformity.Objective: To define the relationship between cervical spinal kyphotic deformity and spinal cord intramedullary pressure.Summary of Background Data. Previous studies of asymptomatic volunteers have revealed that the greatest variation in regional sagittal neutral upright spinal alignment occurs in the cervical spine with "normal" alignment ranging up to +15 to +20° kyphosis. We sought to determine if IMP changes in response to increasing cervical kyphosis.Methods. In eight fresh-frozen cadavers, a progressive kyphotic deformity was created. Cadavers were positioned sitting with cervical lordosis, head stabilized using a skull clamp. The C1 posterior arch was removed, dura opened, and 3 pressure sensors were advanced caudally to C7, C4-C5, and C2 within the cord parenchyma. A step-wise kyphotic deformity was then induced by sequentially releasing and retightening the skull clamp while distracting posterior short segment rods and closing anterior segmental osteotomies. After each step, fluoroscopic images and pressure measurements were obtained. The C2-C7 Gore angle and horizontal displacement of the odontoid plumb line relative to C7 (C2-C7 SVA) were measured.Results. Minor IMP increases of 2-5 mm Hg were observed at one or more spinal cord levels in 1 of 8 cadavers when the Gore angle < +7.5° and in 3 of 8 cadavers when the Gore angle was > +7.5° and < +21°. At Gore angles exceeding +21, ΔIMP progressively increased at one or more spinal cord levels in 8 of 8 cadavers. Gore angles ranging from +21° to +78° resulted in statistically significant increases in IMP ranging to > 50 mm Hg, as did C2-C7 SVA > +75 mm. ΔIMP did not correlate with segmental spinal canal diameter (stenosis).Conclusions. Cervical lordosis and kyphosis less than +7.5° resulted in no meaningful increase in IMP. Minor cervical kyphosis measuring +7.5° to +21° resulted in 2 to 5 mm Hg increases in IMP. As the cervical kyphotic deformity exceeded +21°, IMP increased significantly. ΔIMP with spinal alignment may help explain the wide range of "normal" cervical neutral upright sagittal alignment in studies of asymptomatic individuals and may help further define cervical kyphotic deformity.
Albert Chavanne; David B Pettigrew; Jeffrey R Holtz; Neal Dollin; Charles Kuntz
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-2-1
Journal Detail:
Title:  Spine     Volume:  -     ISSN:  1528-1159     ISO Abbreviation:  -     Publication Date:  2011 Feb 
Date Detail:
Created Date:  2011-2-3     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7610646     Medline TA:  Spine (Phila Pa 1976)     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
1 The UC Neuroscience Institute: Department of Neurosurgery, University of Cincinnati College of Medicine, Mayfield Clinic and Spine Institute, Cincinnati, Ohio 2 Department of Medical Education, University of Cincinnati College of Medicine, Cincinnati, Ohio.
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