Abstracts & Literature Review 2

Does Lumbar Facet Arthrosis Precede Disc Degeneration?

Jason David Eubanks, MD*; Michael J. Lee, MD†; Ezequiel Cassinelli, MD*; and
Nicholas U. Ahn, MD*
Clinical Orthopedics and Related Research
Number 464, pp. 184–189
© 2007 Lippincott Williams & Wilkins

JACO Editorial Reviewer: Dale G. Huntington, DC, FACO, FICC

Published: December, 2009
Journal of the Academy of Chiropractic Orthopedists
December 2009, Volume 6, Issue 4
Received: September 2009
Accepted: September 2009

The original article copyright belong s to the original publisher. This review is available from: http://www.dcorthoacademy.com © 2009 Huntington and the Academy of Chiropractic Orthopedists. This is an Open Access article which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

JACO Editorial Summary:

• This research article expands into greater depths of discovery in the stages of the degenerative process of the three joint vertebral complex composed of the intervertebral disc and facets. From the more than 3000 treated and dried specimens contained in the Hamann-Todd Osteological Collection, Cleveland Ohio 647 specimens were chosen. They represent individuals who died in Cleveland between 1893- 1938. Included in the study were 475 men and 172 women ranging in age from 17 to 93 years with a nearly bell – shaped distribution of ages for men and a larger proportion of younger ages in the female specimens.
• In the process of studying skeletal lumbar spines for another purpose, it became apparent that some young individuals showed marked facet osteophytosis (FO) in the absence of bony evidence of vertebral rim osteophytosis (VRO). This intriguing finding led the authors to question the commonly held belief that disc degeneration necessarily precedes facet arthrosis. In an era in which disc replacement surgery is being purported to save motion and avert further degeneration and, yet, is contraindicated in the presence of facet arthrosis, this issue has important implications within the orthopedic community.
• A power analysis was performed to determine the number of samples needed to arrive at a significant difference between the incidences of facet and end plate arthrosis. At the time of examination specific attention was not paid to the coexisting presence or absence of spondylolysis nor was the examiner blinded to the age of the specimens. Using a value of p< 0.05 and a power of 80%, it was estimated , for a 20% difference between the incidence of facet and end plate arthrosis, a sample size of 91 would be needed.
• Evaluation of FO and VRO using a grading scale ranging from 0 to 4, as suggested in the guidelines presented by Kettler and Wilke. Grade 0 = normal facet joints or vertebral end plates; Grade 1 = mild arthrosis with osteophytic reaction involving as much as 50% of the facet joint or vertebral end plates; Grade 2 = moderate arthrosis with osteophytic reaction involving 50% to 100% of the facet joint or vertebral end plates; Grade 3 = severe arthrosis with osteophytic reaction involving 100% of the facet joints or vertebral end plates with hypertrophic osteophytes bridging the joint space; Grade 4= complete ankylosis. The right and left facet joints of each lumbar level were graded independently. The prevalence and degree were analyzed using (0-4) of the FO and VRO by decade at each lumbar level using analysis of variance.For every decade examined the prevalence of FO was compared with the prevalence of VRO to determine the predominant, if any , site (facet versus disc) and level (L-1-L2 to L5-S1) of degeneration for any given age category.
• Specimens younger than 30 years had a greater prevalence of FO at the L-1-L2 and L2-L3 levels than corresponding VRO. These level-specific findings stood in contrast to the other age categories in which they observed no differences between FO and VRO at these levels. In the specimens 30 to 39 years of age, and increased prevalence of FO as compared with VRO appeared at L-4-L5. This level specific finding was particular to those specimens in their fourth decade of life when compared with all other age categories. Considerable FO ,in the absence of VRO, was noted in specimens as young as 21 years. By the fifth decade of life this trend for the early predominance of FO changed and VRO began to outpace FO. Specimens aged 40 to 49, 50 to 59, 60 to 69, and older than 70 years showed more marginal osteophytosis than FO and VRO within age groups closely paralleled one another with the important exception of the findings previously noted at L1-L2 and L2-L3 for the younger than 30 years specimens and the L4-L5 findings in the younger than 40 years specimens. After the comparative early spike in FO, followed by the shift to predominant VRO in the fifth decade, by the sixth decade of life,evidence of arthrosis in the functional units of the lumbar spine was nearly ubiquitous, with overall greater prevalence in the degenerative discs.

Editorial Comment: The commonly held belief that Lumbar disc degeneration precedes facet degeneration has been challenged by this expanded study. At the very least the facets are degenerating simultaneously and not merely after disc degeneration. This opens the door for further expanded investigation using serial imaging and autopsy analysis after death would provide the most satisfactory answers to these questions. However , such a study would be logistically difficult and financially prohibitive. These findings and questions are important to the chiropractic and medical orthopedists in patient evaluation and management along with the development of manual and surgical techniques.