Cerebrospinal fluid flow in an animal model of noncommunicating syringomyelia.

OBJECTIVE The source of fluid and the mechanism of cyst enlargement in syringomyelia are unknown. It has been demonstrated that cerebrospinal fluid (CSF) normally flows from the subarachnoid space through perivascular spaces and into the spinal cord central canal. The aim of this study was to investigate whether this flow continues during cyst formation in an animal model of syringomyelia and to determine the role of subarachnoid CSF flow in this model. METHODS The intraparenchymal kaolin model of noncommunicating syringomyelia was established in 78 Sprague-Dawley rats. Horseradish peroxidase was used as a tracer to study CSF flow at 1 day, 3 days, 1 week, and 6 weeks after kaolin injection. CSF flow was studied at 0, 10, and 30 minutes after horseradish peroxidase injection into the cisterna magna or thoracic subarachnoid space. RESULTS The central canal became occluded at the level of the kaolin injection and at one or more rostral levels. Segments of the central canal isolated between occlusions gradually dilated, and axonal retraction balls were detected in the surrounding white matter. There was a partial blockage of subarachnoid CSF flow at the site of the kaolin injection, both in a rostral-caudal direction and in a caudal-rostral direction. Horseradish peroxidase was detected at all time points, in a distinctive pattern, in perivascular spaces and the central canal. This pattern was seen even where segments of the central canal were isolated and dilated. CONCLUSION In this animal model, noncommunicating syringes continue to enlarge even when there is evidence that they are under high pressure. There may be an increase in pulse pressure rostral to the block of subarachnoid CSF flow, causing an increase in perivascular flow and contributing to syrinx formation. The source of fluid in noncommunicating syringomyelia may be arterial pulsation-dependent CSF flow from perivascular spaces into the central canal.

[1]  T. Milhorat,et al.  Stenosis of central canal of spinal cord in man: incidence and pathological findings in 232 autopsy cases. , 1994, Journal of neurosurgery.

[2]  T H Shawker,et al.  Pathophysiology of syringomyelia associated with Chiari I malformation of the cerebellar tonsils. Implications for diagnosis and treatment. , 1994, Journal of neurosurgery.

[3]  T. Milhorat,et al.  Pathological basis of spinal cord cavitation in syringomyelia: analysis of 105 autopsy cases. , 1995, Journal of neurosurgery.

[4]  W. Gardner,et al.  The varying expressions of embryonal atresia of the fourth ventricle in adults: Arnold-Chiari malformation, Dandy-Walker syndrome, arachnoid cyst of the cerebellum, and syringomyelia. , 1957, Journal of neurosurgery.

[5]  Christopher J. Brown,et al.  Arterial pulsation-dependent perivascular cerebrospinal fluid flow into the central canal in the sheep spinal cord. , 1997, Journal of neurosurgery.

[6]  O. R. Blaumanis,et al.  Evidence for a ‘Paravascular’ fluid circulation in the mammalian central nervous system, provided by the rapid distribution of tracer protein throughout the brain from the subarachnoid space , 1985, Brain Research.

[7]  O. R. Blaumanis,et al.  Rapid solute transport throughout the brain via paravascular fluid pathways. , 1990, Advances in neurology.

[8]  J. Miller,et al.  Noncommunicating syringomyelia following occlusion of central canal in rats. Experimental model and histological findings. , 1993, Journal of neurosurgery.

[9]  Christopher J. Brown,et al.  Evidence for rapid fluid flow from the subarachnoid space into the spinal cord central canal in the rat , 1996, Brain Research.

[10]  T. Milhorat,et al.  Clinicopathological correlations in syringomyelia using axial magnetic resonance imaging. , 1995, Neurosurgery.

[11]  The distending force in the production of communicating syringomyelia. , 1969, Lancet.

[12]  S. Heptinstall,et al.  RANDOMISED DOUBLE-BLIND PLACEBO-CONTROLLED TRIAL OF FEVERFEW IN MIGRAINE PREVENTION , 1988, The Lancet.

[13]  H. Abe,et al.  Experimental model of posttraumatic syringomyelia: the role of adhesive arachnoiditis in syrinx formation. , 1994, Journal of neurosurgery.