Advertisement

Neurosurgical Review

, Volume 29, Issue 4, pp 251–264 | Cite as

Unraveling the riddle of syringomyelia

  • Dan GreitzEmail author
Review

Abstract

The pathophysiology of syringomyelia development is not fully understood. Current prevailing theories suggest that increased pulse pressure in the subarachnoid space forces cerebrospinal fluid (CSF) through the spinal cord into the syrinx. It is generally accepted that the syrinx consists of CSF. The here-proposed intramedullary pulse pressure theory instead suggests that syringomyelia is caused by increased pulse pressure in the spinal cord and that the syrinx consists of extracellular fluid. A new principle is introduced implying that the distending force in the production of syringomyelia is a relative increase in pulse pressure in the spinal cord compared to that in the nearby subarachnoid space. The formation of a syrinx then occurs by the accumulation of extracellular fluid in the distended cord. A previously unrecognized mechanism for syrinx formation, the Bernoulli theorem, is also described. The Bernoulli theorem or the Venturi effect states that the regional increase in fluid velocity in a narrowed flow channel decreases fluid pressure. In Chiari I malformations, the systolic CSF pulse pressure and downward motion of the cerebellar tonsils are significantly increased. This leads to increased spinal CSF velocities and, as a consequence of the Bernoulli theorem, decreased fluid pressure in narrow regions of the spinal CSF pathways. The resulting relatively low CSF pressure in the narrowed CSF pathway causes a suction effect on the spinal cord that distends the cord during each systole. Syringomyelia develops by the accumulation of extracellular fluid in the distended cord. In posttraumatic syringomyelia, the downwards directed systolic CSF pulse pressure is transmitted and reflected into the spinal cord below and above the traumatic subarachnoid blockage, respectively. The ensuing increase in intramedullary pulse pressure distends the spinal cord and causes syringomyelia on both sides of the blockage. The here-proposed concept has the potential to unravel the riddle of syringomyelia and affords explanations to previously unanswered clinical and theoretical problems with syringomyelia. It also explains why syringomyelia associated with Chiari I malformations may develop in any part of the spinal cord including the medullary conus. Syringomyelia thus preferentially develops where the systolic CSF flow causes a suction effect on the spinal cord, i.e., at or immediately caudal to physiological or pathological encroachments of the spinal subarachnoid space.

Keywords

Cerebrospinal fluid Chiari 1 malformation Hydrocephalus Hydromyelia Intramedullary pulse pressure theory MRI Pathophysiology Posttraumatic syringomyelia Pulse pressure Spinal cord Syringomyelia Venturi effect 

Notes

Acknowledgements

This article was supported by The Foundation for Medical Imaging in Memory of Erik Lysholm (Stiftelsen för Medicinsk Bildering till Erik Lysholms Minne).

The author declares no potential conflicts of interest concerning this article.

References

  1. 1.
    Bering EA Jr (1962) Circulation of the cerebrospinal fluid. Demonstration of the choroid plexuses as the generator of the force for flow of fluid and ventricular enlargement. J Neurosurg 19:405–413PubMedGoogle Scholar
  2. 2.
    Carpenter PW, Berkouk K, Lucey AD (2003) Pressure wave propagation in fluid-filled co-axial elastic tubes. Part 2: Mechanisms for the pathogenesis of syringomyelia. J Biomech Eng 125:857–863PubMedCrossRefGoogle Scholar
  3. 3.
    Chang HS, Nakagawa (2003) Hypothesis on the pathophysiology of syringomyelia based on simulation of cerebrospinal fluid dynamics. J Neurol Neurosurg Psychiatry 74:344–347PubMedCrossRefGoogle Scholar
  4. 4.
    Chang HS, Nakagawa H (2004) Theoretical analysis of the pathophysiology of syringomyelia associated with adhesive arachnoiditis. J Neurol Neurosurg Psychiatry 75:754–757PubMedCrossRefGoogle Scholar
  5. 5.
    Cserr HF, Ostrach LH (1974) Bulk flow of interstitial fluid after intracranial injection of blue dextran 2000. Exp Neurol 45:50–60PubMedCrossRefGoogle Scholar
  6. 6.
    Dandy WE, Blackfan KD (1914) Internal hydrocephalus. An experimental, clinical and pathological study. Am J Dis Child 8:406–481Google Scholar
  7. 7.
    Davis C, Symon L (1989) Mechanisms and treatment in post-traumatic syringomyelia. Br J Neurosurg 3:669–674PubMedCrossRefGoogle Scholar
  8. 8.
    Edgar R, Quail P (1994) Progressive post-traumatic cystic and non-cystic myelopathy. Br J Neurosurg 8:7–22PubMedCrossRefGoogle Scholar
  9. 9.
    Ellertsson AB, Greitz T (1969) Myelocystographic and fluorescein studies to demonstrate communication between intramedullary cysts and the cerebrospinal fluid space. Acta Neurol Scand 45:418–430PubMedCrossRefGoogle Scholar
  10. 10.
    Ellertsson AB, Greitz T (1970) The distending force in the production of communicating syringomyelia. Lancet 1:1234PubMedCrossRefGoogle Scholar
  11. 11.
    Feigin I, Ogata J, Budzilovich G (1971) Syringomyelia: the role of edema in its pathogenesis. J Neuropathol Exp Neurol 30:216–232PubMedCrossRefGoogle Scholar
  12. 12.
    Fischbein NJ, Dillon WP, Cobbs C, Weinstein PR (1999) The “presyrinx” state: a reversible myelopathic condition that may precede syringomyelia. Am J Neuroradiol 20:7–20PubMedGoogle Scholar
  13. 13.
    Gardner WJ, Angel J (1958) The mechanism of syringomyelia and its surgical correction. Clin Neurosurg 6:131–140PubMedGoogle Scholar
  14. 14.
    Gardner WJ (1965) Hydrodynamic mechanism of syringomyelia: its relationship to myelocele. J Neurol Neurosurg Psychiatry 28:247–259PubMedCrossRefGoogle Scholar
  15. 15.
    Greitz D (1991) Notes on the driving forces of the CSF circulation with special emphasis on the piston action of the brain. In: du Boulay G, Molyneux A, Moseley I (eds) Proceedings of the XIV Symposium Neuroradiologicum. Springer, Berlin Heidelberg New York. Neuroradiology 33(Suppl 2):178–181Google Scholar
  16. 16.
    Greitz D, Wirestam R, Franck A, Nordell B, Thomsen C, Ståhlberg F (1992) Pulsatile brain movement and associated hydrodynamics studied by magnetic resonance phase imaging. The Monro-Kellie doctrine revisited. Neuroradiology 34:370–380PubMedCrossRefGoogle Scholar
  17. 17.
    Greitz D (1993) Cerebrospinal fluid circulation and associated intracranial dynamics. A radiologic investigation using MR imaging and radionuclide cisternography. (Thesis). Acta Radiol 34(Suppl 386):1–23Google Scholar
  18. 18.
    Greitz D, Franck A, Nordell B (1993) On the pulsatile nature of the intracranial and spinal CSF-circulation demonstrated by MR imaging. Acta Radiol 34:321–328PubMedCrossRefGoogle Scholar
  19. 19.
    Greitz D, Hannerz J, Rähn T, Bolander H, Ericsson A (1994) MR imaging of cerebrospinal fluid dynamics in health and disease. On the vascular pathogenesis of communicating hydrocephalus and benign intracranial hypertension. Acta Radiol 35:204–211PubMedGoogle Scholar
  20. 20.
    Greitz D (1995) CSF-flow at the craniocervical junction: increased systolic and diastolic pressure gradients as the cause of cystic cord lesions. In: Kenéz J (ed) Imaging of the craniocervical junction. Edizione del Centauro, Udine Milano, pp 19–23Google Scholar
  21. 21.
    Greitz D, Jan Hannerz J (1996) A proposed model of cerebrospinal fluid circulation: Observations with radionuclide cisternography. Am J Neuroradiol 17:431–438PubMedGoogle Scholar
  22. 22.
    Greitz D, Greitz T, Hindmarsh TV (1997) A new view on the CSF-circulation with the potential for pharmacological treatment of childhood hydrocephalus. Acta Paediatr 86:125–132PubMedCrossRefGoogle Scholar
  23. 23.
    Greitz D, Greitz T (1997) The pathogenesis and hemodynamics of hydrocephalus. A proposal for a new understanding. Int J Neuroradiol 3:367–375Google Scholar
  24. 24.
    Greitz D, Ericson K, Flodmark O (1999) Pathogenesis and mechanics of spinal cord cysts: a new hypothesis based on magnetic resonance studies of cerebrospinal fluid dynamics. Int J Neuroradiol 5:61–78Google Scholar
  25. 25.
    Greitz D (2004) Radiological assessment of hydrocephalus: new theories and implications for therapy. Neurosurg Rev 27:145–165; ReviewPubMedGoogle Scholar
  26. 26.
    Greitz T, Ellertsson AB (1969) Isotope scanning of spinal cord cysts. Acta Radiol Diagn 8:310–320Google Scholar
  27. 27.
    Häckel M, Benes V, Mohapl M (2001) Simultaneous cerebral and spinal fluid pressure recordings in surgical indications of the Chiari malformation without myelodysplasia. Acta Neurochir 143:909–918CrossRefGoogle Scholar
  28. 28.
    Hall P, Turner M, Aichinger S, Bendick P, Campbell R (1980) Experimental syringomyelia: the relation between intraventricular and intrasyrinx pressures. J Neurosurg 52:812–817PubMedGoogle Scholar
  29. 29.
    Heiss JD, Patronas N, DeVroom HL, Shawker T, Ennis R, Kammerer W, Eidsath A, Talbot T, Morris J, Eskioglu E, Oldfield EH (1999) Elucidating the pathophysiology of syringomyelia. J Neurosurg 91:553–562PubMedGoogle Scholar
  30. 30.
    Iskandar BJ, Quigley M, Haughton VM (2004) Foramen magnum cerebrospinal fluid flow characteristics in children with Chiari I malformation before and after craniocervical decompression. J Neurosurg (Pediatrics 2) 101:169–178Google Scholar
  31. 31.
    Josephson A, Greitz D, Klason T, Olson L, Spenger C (2001) A spinal sac constriction model supports the theory that induced pressure gradients in the cord cause edema and cyst formation. Neurosurgery 46:636–646CrossRefGoogle Scholar
  32. 32.
    Klekamp J, Volkel K, Bartels CJ, Samii M (2001) Disturbances of cerebrospinal fluid flow attributable to arachnoid scarring cause interstitial edema of the cat spinal cord. Neurosurgery 48:174–186PubMedCrossRefGoogle Scholar
  33. 33.
    Klekamp J (2002) The pathophysiology of syringomyelia - historical overview and current concept. Acta Neurochir 144:649–664CrossRefGoogle Scholar
  34. 34.
    Klekamp J, Samii M (2002) Syringomyelia: diagnosis and treatment. Springer, Berlin Heidelberg New YorkGoogle Scholar
  35. 35.
    Koyanagi I, Iwaski I, Hida K, Houkin K (2005) Clinical features and pathomechanisms of syringomyelia associated with spinal arachnoiditis. Surg Neurol 63:350–356PubMedCrossRefGoogle Scholar
  36. 36.
    Ljunggren B, al Refai M, Sharma S, Fodstad H, Hutchings R (1992) Functional recovery after near complete traumatic deficit of the cervical cord lasting more than 24 hours. Br J Neurosurg 6:375–380PubMedCrossRefGoogle Scholar
  37. 37.
    Levine DN (2004) The pathogenesis of syringomyelia associated with lesions at the foramen magnum: a critical review of existing theories and proposal of a new hypothesis. J Neurol Sci 220:3–21PubMedCrossRefGoogle Scholar
  38. 38.
    Milhorat TH, Capocelli AL, Kotzen RM, Bolognese P, Heger IM, Cotrell JE (1997) Intramedullary pressure in syringomyelia: clinical and pathophysiological correlates of syrinx distension. Neurosurgery 41:1102–1110PubMedCrossRefGoogle Scholar
  39. 39.
    Oldfield EH, Muraszko K, Shawker TH, Patronas N (1994) Pathophysiology of syringomyelia with Chiari 1 malformation of cerebellar tonsils. J Neurosurg 80:2–15Google Scholar
  40. 40.
    Ozawa H, Matsumoto T, Ohashi T, Sato M, Kokubun S (2001) Comparison of spinal cord gray matter and white matter softness: measurement by pipette aspiration method. J Neurosurg (Spine 2) 95:221–224Google Scholar
  41. 41.
    Ozawa H, Matsumoto T, Ohashi T, Sato M, Kokubun S (2004) Mechanical properties and function of the spinal pia mater. J Neurosurg (Spine 1) 1:122–127CrossRefGoogle Scholar
  42. 42.
    Quigley MF, Iskandar B, Quigley ME, Nicosia M, Haughton V (2004) Cerebrospinal fluid flow in foramen magnum: temporal and spatial patterns at MR imaging in volunteers and in patients with Chiari I malformation. Radiology 232:229–236PubMedCrossRefGoogle Scholar
  43. 43.
    Rennels ML, Gregory TF, Blaumanis OR, Fujimoto K, Grady PA (1985) 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. Brain Res 326:47–63PubMedCrossRefGoogle Scholar
  44. 44.
    Samii M, Klekamp J (1994) Surgical results of 100 intramedullary tumors in relation to accompanying syringomyelia. Neurosurgery 35:865–873PubMedCrossRefGoogle Scholar
  45. 45.
    Stoodley MA, Brown SA, Brown CJ, Jones NR (1997) Arterial pulsation-dependent perivascular cerebrospinal fluid flow into the central canal in the sheep spinal cord. J Neurosurg 86:686–693PubMedCrossRefGoogle Scholar
  46. 46.
    Williams B (1969) The distending force in the production of “communicating syringomyelia”. Lancet 2:189–193PubMedCrossRefGoogle Scholar
  47. 47.
    Williams B (1981) Simultaneous cerebral and spinal fluid pressure recordings. 2. Cerebrospinal dissociation with lesions at the foramen magnum. Acta Neurochir 59:123–142CrossRefGoogle Scholar
  48. 48.
    Williams B (1986) Progress in syringomyelia. Neurol Res 8:130–145PubMedGoogle Scholar
  49. 49.
    Wolpert SM, Bhadelia RA, Bogdan AR, Cohen AR (1994) Chiari I malformations: assessment with phase-contrast velocity MR. Am J Neuroradiol 15:1299–1308PubMedGoogle Scholar

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Department of Neuroradiology and MR Research CenterKarolinska University HospitalStockholmSweden

Personalised recommendations