Document Detail

Intramedullary pressure in syringomyelia: clinical and pathophysiological correlates of syrinx distension.
MedLine Citation:
PMID:  9361064     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: The pathophysiological effects of syrinx distension are incompletely understood. Although it is generally assumed that the accumulation of fluid within syrinx cavities can contribute to neurological dysfunction, there are no reports describing intramedullary pressure in syringomyelia. The purpose of the current study was to measure syrinx pressures in patients with progressive clinical deterioration and to correlate these data with neurological deficits and intraoperative physiological findings. METHODS: Intramedullary fluid pressure was measured manometrically in 32 patients undergoing syrinx shunting procedures. The data were correlated with syrinx morphology, intraoperative somatosensory evoked potentials, laser Doppler measurements of local spinal cord blood flow (six patients), and neurological findings before and after syrinx decompression. RESULTS: Syrinx pressures recorded under atmospheric conditions ranged from 0.5 to 22.0 cm H2O (mean = 7.7 cm). There was a significant elevation of the cardiac pulse (mean = 0.7 cm H2O) and the respiratory pulse (mean = 1.1 cm H2O) that was consistent with raised cerebrospinal fluid pressure. Syrinx pressures decreased to subatmospheric levels after surgical drainage. In 18 of 24 patients with predrainage somatosensory evoked potential abnormalities, syrinx decompression produced a consistent reduction of N20 latencies (mean change = 0.49 ms +/- 0.094 SE right, P = 0.002; 0.61 ms +/- 0.089 SE left, P = 0.001) and a similar but less consistent increase in N20 amplitudes (mean change = 0.17 mV +/- 0.103 SE right, P = 0.115; 0.31 mV +/- 0.097 SE left, P = 0.027). Measurements of local spinal cord blood flow revealed very low baseline values (mean = 12.2 arbitrary units +/- 13.9 standard deviation), which increased to intermediate levels (mean = 144.7 arbitrary units +/- 42.6 standard deviation) after syrinx decompression. Patients with syrinx pressures greater than 7.7 cm H2O tended to have more rapidly progressive symptoms, exhibited greater improvements after shunting, and had a higher incidence of postoperative dysesthetic pain. CONCLUSION: The current study is the first to measure intramedullary pressure in a human disease. Evidence is presented that distended syringes are associated with varying levels of raised intramedullary pressure that can accentuate or induce neurological dysfunction by the compression of long tracts, neurons, and the microcirculation. Symptoms referrable to raised intramedullary pressure are potentially reversible by syrinx decompression.
T H Milhorat; A L Capocelli; R M Kotzen; P Bolognese; I M Heger; J E Cottrell
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Neurosurgery     Volume:  41     ISSN:  0148-396X     ISO Abbreviation:  Neurosurgery     Publication Date:  1997 Nov 
Date Detail:
Created Date:  1997-12-22     Completed Date:  1997-12-22     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7802914     Medline TA:  Neurosurgery     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1102-10     Citation Subset:  IM    
Department of Neurosurgery, State University of New York Health Science Center at Brooklyn, USA.
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MeSH Terms
Cerebrospinal Fluid Pressure*
Child, Preschool
Evoked Potentials, Somatosensory
Follow-Up Studies
Laser-Doppler Flowmetry
Median Nerve / physiopathology
Middle Aged
Monitoring, Intraoperative
Neurologic Examination
Regional Blood Flow
Spinal Cord / blood supply*
Syringomyelia / physiopathology*,  surgery*
Time Factors
Treatment Outcome
Comment In:
Neurosurgery. 1998 Jun;42(6):1403   [PMID:  9632209 ]
Neurosurgery. 1998 Jul;43(1):188-9   [PMID:  9657211 ]
Neurosurgery. 1998 Sep;43(3):648-9   [PMID:  9733328 ]

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