European Spine Journal

, Volume 17, Issue 8, pp 1049–1056 | Cite as

Biomechanical effect of different lumbar interspinous implants on flexibility and intradiscal pressure

  • Hans-Joachim WilkeEmail author
  • J. Drumm
  • K. Häussler
  • C. Mack
  • W. -I. Steudel
  • A. Kettler
Original Article


Interspinous implants are used to treat lumbar spinal stenosis or facet joint arthritis. The aims of implanting interspinous devices are to unload the facet joints, restore foraminal height and provide stability especially in extension but still allow motion. The aim of this in vitro study was to compare four different interspinous implants––Colfex, Wallis, Diam and X-Stop––in terms of their three-dimensional flexibility and the intradiscal pressure. Twenty-four human lumbar spine specimens were divided into four equal groups and tested with pure moments in flexion/extension, lateral bending and axial rotation: (1) intact, (2) defect, (3) after implantation. Range of motion and the intradiscal pressure were determined.In each implant-group the defect caused an increase in range of motion by about 8% in lateral bending to 18% in axial rotation. Implantation had similar effects with all four implants. In extension, Coflex, Wallis, Diam, and X-Stop all overcompensated the instability caused by the defect and allowed about 50% of the range of motion of the intact state. In contrast, in flexion, lateral bending and axial rotation the values of the range of motion stayed about the values of the defect state. Similarly the intradiscal pressure after implantation was similar to that of the intact specimens in flexion, lateral bending and axial rotation but much smaller during extension. All tested interspinous implants had a similar effect on the flexibility: they strongly stabilized and reduced the intradiscal pressure in extension, but had almost no effect in flexion, lateral bending and axial rotation.


Lumbar spine Interspinous implant Biomechanics Flexibility Intradiscal pressure 



The authors gratefully acknowledge Paradigm Spine for financial support.


  1. 1.
    Amundsen T, Weber H, Nordal HJ, Magnaes B, Abdelnoor M, Lilleas F (2000) Lumbar spinal stenosis: conservative or surgical management?: A prospective 10-year study. Spine 25(11):1424–1435 (discussion 1435–1436)CrossRefPubMedGoogle Scholar
  2. 2.
    Christie SD, Song JK, Fessler RG (2005) Dynamic interspinous process technology. Spine 30(16 Suppl):S73–S78CrossRefPubMedGoogle Scholar
  3. 3.
    Fujiwara A, Tamai K, An HS, Kurihashi T, Lim TH, Yoshida H, Saotome K (2000) The relationship between disc degeneration, facet joint osteoarthritis, and stability of the degenerative lumbar spine. J Spinal Disord 13(5):444–500CrossRefPubMedGoogle Scholar
  4. 4.
    Guehring T, Unglaub F, Lorenz H, Omlor G, Wilke HJ, Kroeber MW (2006) Intradiscal pressure measurements in normal discs, compressed discs and compressed discs treated with axial posterior disc distraction: an experimental study on the rabbit lumbar spine model. Eur Spine J 15(5):597–604CrossRefPubMedGoogle Scholar
  5. 5.
    Höjer S, Krantz M, Ekström L, Kaigle A, Holm S (1999) A microstructure based fiberoptic pressure sensor for measurements in lumbar intervertebral discs. Proc SPIE (in revision) 3570:115–122CrossRefGoogle Scholar
  6. 6.
    Kettler A, Liakos L, Haegele B, and Wilke HJ (2007) Are the spines of calf, pig and sheep suitable models for pre-clinical implant tests? Eur Spine J 16(12):2186–2192CrossRefPubMedPubMedCentralGoogle Scholar
  7. 7.
    Lindsey DP, Swanson KE, Fuchs P, Hsu KY, Zucherman JF, Yerby SA (2003) The effects of an interspinous implant on the kinematics of the instrumented and adjacent levels in the lumbar spine. Spine 28(19):2192–2197CrossRefPubMedGoogle Scholar
  8. 8.
    Minns RJ, Walsh WK (1997) Preliminary design and experimental studies of a novel soft implant for correcting sagittal plane instability in the lumbar spine. Spine 22(16):1819–1825 (discussion 1826–1827)CrossRefPubMedGoogle Scholar
  9. 9.
    Schmoelz W, Huber JF, Nydegger T, Dipl I, Claes L, Wilke HJ (2003) Dynamic stabilization of the lumbar spine and its effects on adjacent segments: an in vitro experiment. J Spinal Disord Tech 16(4):418–423CrossRefPubMedGoogle Scholar
  10. 10.
    Simotas AC, Dorey FJ, Hansraj KK, Cammisa F Jr (2000) Nonoperative treatment for lumbar spinal stenosis. Clinical and outcome results and a 3-year survivorship analysis. Spine 25(2):197–203 (discussions 203–204)CrossRefPubMedGoogle Scholar
  11. 11.
    Swanson KE, Lindsey DP, Hsu KY, Zucherman JF, Yerby SA (2003) The effects of an interspinous implant on intervertebral disc pressures. Spine 28(1):26–32CrossRefPubMedGoogle Scholar
  12. 12.
    Turner JA, Ersek M, Herron L, Deyo R (1992) Surgery for lumbar spinal stenosis. Attempted meta-analysis of the literature. Spine 17(1):1–8CrossRefPubMedGoogle Scholar
  13. 13.
    Whitesides TE Jr (2003) The effect of an interspinous implant on intervertebral disc pressures. Spine 28(16):1906–1907 (author reply 1907–1908)CrossRefPubMedGoogle Scholar
  14. 14.
    Wilke HJ, Wenger K, Claes L (1998) Testing criteria for spinal implants: recommendations for the standardization of in vitro stability testing of spinal implants. Eur Spine J 7(2):148–154CrossRefPubMedPubMedCentralGoogle Scholar
  15. 15.
    Wilke HJ, Neef P, Caimi M, Hoogland T, Claes LE (1999) New in vivo measurements of pressures in the intervertebral disc in daily life. Spine 24(8):755–762CrossRefPubMedGoogle Scholar
  16. 16.
    Wilke HJ, Rohlmann F, Neidlinger-Wilke C, Werner K, Claes L, Kettler A (2006) Validity and interobserver agreement of a new radiographic grading system for intervertebral disc degeneration: part I. Lumbar spine. Eur Spine J 15(6):720–730CrossRefPubMedGoogle Scholar
  17. 17.
    Wiseman CM, Lindsey DP, Fredrick AD, Yerby SA (2005) The effect of an interspinous process implant on facet loading during extension. Spine 30(8):903–907CrossRefPubMedGoogle Scholar
  18. 18.
    Zindrick MR, Wiltse LL, Widell EH, Thomas JC, Holland WR, Field BT, Spencer CW (1986) A biomechanical study of intrapeduncular screw fixation in the lumbosacral spine. Clin Orthop 203:99–112PubMedGoogle Scholar

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Hans-Joachim Wilke
    • 1
    Email author
  • J. Drumm
    • 2
  • K. Häussler
    • 1
  • C. Mack
    • 1
  • W. -I. Steudel
    • 2
  • A. Kettler
    • 1
  1. 1.Institute of Orthopaedic Research and Biomechanics (Director: L. Claes)University of UlmUlmGermany
  2. 2.Department of NeurosurgerySaarland University HospitalHomburgGermany

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