European Spine Journal

, Volume 16, Issue 12, pp 2159–2165 | Cite as

StabilimaxNZ® versus simulated fusion: evaluation of adjacent-level effects

  • Manohar M. PanjabiEmail author
  • Gweneth Henderson
  • Yue James
  • Jens Peter Timm
Original Article


Rationale behind motion preservation devices is to eliminate the accelerated adjacent-level effects (ALE) associated with spinal fusion. We evaluated multidirectional flexibilities and ALEs of StabilimaxNZ® and simulated fusion applied to a decompressed spine. StabilimaxNZ® was applied at L4–L5 after creating a decompression (laminectomy of L4 plus bilateral medial facetectomy at L4–L5). Multidirectional Flexibility and Hybrid tests were performed on six fresh cadaveric human specimens (T12–S1). Decompression increased average flexion–extension rotation to 124.0% of the intact. StabilimaxNZ® and simulated fusion decreased the motion to 62.4 and 23.8% of intact, respectively. In lateral bending, corresponding increase was 121.6% and decreases were 57.5 and 11.9%. In torsion, corresponding increase was 132.7%, and decreases were 36.3% for fusion, and none for StabilimaxNZ® ALE was defined as percentage increase over the intact. The ALE at L3–4 was 15.3% for StabilimaxNZ® versus 33.4% for fusion, while at L5–S1 the ALE were 5.0% vs. 11.3%, respectively. In lateral bending, the corresponding ALE values were 3.0% vs. 19.1%, and 11.3% vs. 35.8%, respectively. In torsion, the corresponding values were 3.7% vs. 20.6%, and 4.0% vs. 33.5%, respectively. In conclusion, this in vitro study using Flexibility and Hybrid test methods showed that StabilimaxNZ® stabilized the decompressed spinal level effectively in sagittal and frontal planes, while allowing a good portion of the normal rotation, and concurrently it did not produce significant ALEs as compared to the fusion. However, it did not stabilize the decompressed specimen in torsion.


Pedicle Screw Spinal Fusion Artificial Disc Follower Load Spine Specimen 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



We gratefully acknowledge a gift from Applied Spine Technology, New Haven, CT, USA which made this research possible.


  1. 1.
    Abumi K, Panjabi MM, Kramer KM, et al (1990) Biomechanical evaluation of lumbar spinal stability after graded facetectomies. Spine 15:1142–1147PubMedCrossRefGoogle Scholar
  2. 2.
    Ames CP, Acosta FL Jr, Chamberlain RH, Larios AE, Crawford NR (2005) Biomechanical analysis of a newly designed bioabsorbable anterior cervical plate. Invited submission from the joint section meeting on disorders of the spine and peripheral nerves, March 2005. J Neurosurg Spine 3:465–470PubMedCrossRefGoogle Scholar
  3. 3.
    Andersson GB (1999) Epidemiological features of chronic low-back pain. Lancet 354:581–585PubMedCrossRefGoogle Scholar
  4. 4.
    Cunningham BW, Lewis SJ, Long J, et al (2002) Biomechanical evaluation of lumbosacral reconstruction techniques for spondylolisthesis: an in vitro porcine model. Spine 27:2321–2327PubMedCrossRefGoogle Scholar
  5. 5.
    Cunningham BW, Lowery GL, Serhan HA, et al (2002) Total disc replacement arthroplasty using the AcroFlex lumbar disc: a non-human primate model. Eur Spine J 11(Suppl 2):S115–S123PubMedGoogle Scholar
  6. 6.
    Dmitriev AE, Cunningham BW, Hu N, et al (2005) Adjacent level intradiscal pressure and segmental kinematics following a cervical total disc arthroplasty: an in vitro human cadaveric model. Spine 30:1165–1172PubMedCrossRefGoogle Scholar
  7. 7.
    Erulkar JS, Grauer JN, Patel TC, Panjabi MM (2001) Flexibility analysis of posterolateral fusions in a New Zealand white rabbit model. Spine 26:1125–1130PubMedCrossRefGoogle Scholar
  8. 8.
    Goel V, Grauer J, Patel T, et al (2005) Effects of charite artificial disc on the implanted and adjacent spinal segment mechanics using a hybrid testing protocol. Spine 30:2755–2764PubMedCrossRefGoogle Scholar
  9. 9.
    Hilibrand AS, Robbins M (2004) Adjacent segment degeneration and adjacent segment disease: the consequences of spinal fusion? Spine J 4:190S–194SPubMedCrossRefGoogle Scholar
  10. 10.
    Kotani Y, Cunningham BW, Abumi K, et al (2005) Multidirectional flexibility analysis of cervical artificial disc reconstruction: in vitro human cadaveric spine model. J Neurosurg Spine 2:188–194PubMedGoogle Scholar
  11. 11.
    Luo X, Pietrobon R, Sun SX, Liu GG, Hey L (2004) Estimates and patterns of direct health care expenditures among individuals with back pain in the United States. Spine 29:79–86PubMedCrossRefGoogle Scholar
  12. 12.
    Nibu K, Panjabi MM, Oxland T, Cholewicki J (1997) Multidirectional stabilizing potential of BAK interbody spinal fusion system for anterior surgery. J Spinal Disord 10:357–362PubMedCrossRefGoogle Scholar
  13. 13.
    Panjabi MM (1988) Biomechanical evaluation of spinal fixation devices: I. A conceptual framework. Spine 13:1129–1134PubMedCrossRefGoogle Scholar
  14. 14.
    Panjabi MM (2007) Hybrid multidirectional test method to evaluate spinal adjacent-level effects. Clin Biomech 22(3):257–265CrossRefGoogle Scholar
  15. 15.
    Panjabi MM, Malcolmson G, Teng E, Tominaga Y, Henderson G (2006) Hybrid adjacent-level testing of lumbar Charite discs versus fusions. Spine 32:959–966CrossRefGoogle Scholar
  16. 16.
    Patwardhan AG, Havey RM, Carandang G, et al (2003) Effect of compressive follower preload on the flexion-extension response of the human lumbar spine. J Orthop Res 21:540–546PubMedCrossRefGoogle Scholar
  17. 17.
    Schlegel JD, Smith JA, Schleusener RL (1996) Lumbar motion segment pathology adjacent to thoracolumbar, lumbar, and lumbosacral fusions. Spine 21:970–981PubMedCrossRefGoogle Scholar
  18. 18.
    Yoshimoto H, Ito M, Abumi K, et al (2004) A retrospective radiographic analysis of subaxial sagittal alignment after posterior C1-C2 fusion. Spine 29:175–181PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Manohar M. Panjabi
    • 1
    Email author
  • Gweneth Henderson
    • 1
  • Yue James
    • 1
  • Jens Peter Timm
    • 1
  1. 1.Biomechanics LaboratoryYale University, Orthopaedics and RehabilitationNew HavenUSA

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