Computed tomography–evaluated features of spinal degeneration: prevalence, intercorrelation, and association with self-reported low back pain
Received 4 April 2009; received in revised form 21 August 2009; accepted 28 October 2009. published online 14 December 2009.
Abstract
Background context
Although the role of radiographic abnormalities in the etiology of nonspecific low back pain (LBP) is unclear, the frequent identification of these features on radiologic studies continues to influence medical decision making.
Purpose
The primary purposes of the study were to evaluate the prevalence of lumbar spine degeneration features, evaluated on computed tomography (CT), in a community-based sample and to evaluate the association between lumbar spine degeneration features. The secondary purpose was to evaluate the association between spinal degeneration features and LBP.
Study design
This is a cross-sectional community-based study that was an ancillary project to the Framingham Heart Study.
Sample
A subset of 187 participants were chosen from the 3,529 participants enrolled in the Framingham Heart Study who underwent multidetector CT scan to assess aortic calcification.
Outcome measures
Self-report measures: LBP in the preceding 12 months was evaluated using a Nordic self-report questionnaire. Physiologic measures: Dichotomous variables indicating the presence of intervertebral disc narrowing, facet joint osteoarthritis (OA), spondylolysis, spondylolisthesis, and spinal stenosis and the density (in Hounsfield units) of multifidus and erector spinae muscles were evaluated on CT.
Methods
We calculated the prevalence of spinal degeneration features and mean density of multifidus and erector spinae muscles in groups of individuals with and without LBP. Using the χ2 test for dichotomous and t test for continuous variables, we estimated the differences in spinal degeneration parameters between the aforementioned groups. To evaluate the association of spinal degeneration features with age, the prevalence of degeneration features was calculated in four age groups (less than 40, 40–50, 50–60, and 60+ years). We used multiple logistic regression models to examine the association between spinal degeneration features (before and after adjustment for age, sex, and body mass index [BMI]) and LBP, and between all degeneration features and LBP.
Results
In total, 104 men and 83 women, with a mean age (±standard deviation) of 52.6±10.8 years, participated in the study. There was a high prevalence of intervertebral disc narrowing (63.9%), facet joint OA (64.5%), and spondylolysis (11.5%) in the studied sample. When all spinal degeneration features as well as age, sex, and BMI were factored in stepwise fashion into a multiple logistic regression model, only spinal stenosis showed statistically significant association with LBP, odds ratio (OR) (95% confidence interval [CI]): 3.45 [1.12–10.68]. Significant association was found between facet joint OA and low density of multifidus (OR [95% CI]: 3.68 [1.36–9.97]) and erector spinae (OR [95% CI]: 2.80 [1.10–7.16]) muscles.
Conclusions
Degenerative features of the lumbar spine were extremely prevalent in this community-based sample. The only degenerative feature associated with self-reported LBP was spinal stenosis. Other degenerative features appear to be unassociated with LBP.
aClinical Epidemiology Research and Training Unit, Boston University School of Medicine, Boston, MA 02118, USA
bDivision of Research, New England Baptist Hospital, 125 Parker Hill Ave., Boston, MA 02120, USA
cDepartment of Orthopaedic Surgery, New England Baptist Hospital, 125 Parker Hill Ave., Boston, MA 02120, USA
dDepartment of Radiology, Boston University School of Medicine, 820 Harrison Ave., Boston, MA 02118, USA
Corresponding author. Department of Physical Therapy, Recanati School for Community Health Professions, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel.
FDA device/drug status: not applicable.
Author disclosures: LK (research support, Arthritis Foundation Postdoctoral Grant); DHK (consulting fees, Medtronic, DePuy, Stryker, Zimmer, Synthes; research support, New England Baptist Hospital); AG (stock ownership, Synarc; President, BICL, LLC); DJH (research support, Donjoy, Wyeth, Merck, Pfize, Stryke).
Supported by the National Heart, Lung and Blood Institute's Framingham Heart Study contract (No. N01-HC-25195) for the recruitment, enrollment, and examination of the Offspring and Third Generation cohorts and the imaging by computed tomography scan.
ABSTRACT