facet, lumbar spinal stenosis model

A retrospective CT scan and medical record review [ 1. The Prevalence of Asymptomatic Cervical and Lumbar Facet Arthropathy: A Computed Tomography Study] of 50 patients with no history of spinal pathology used a four-point scale to grade the severity of evident arthritis and found that arthritic spinal changes were frequently evident—even in asymptomatic patients. The incidence of these changes corresponded positively with aging and was more prevalent in scans of the lower lumbar spine.

What’s at Stake?

Chronic neck and lower back pain affect between 66 and 84 percent of the U.S. population and is responsible for approximately 87 billion dollars of lost income and medical expenses annually—a figure that is only surpassed by the yearly wage loss and expenditures on diabetes and heart disease.

Diagnosing CNP and LBP is problematic due to the number of possible factors—including dysfunction of the intervertebral discs (IVD’s), facet joints, spinal nerve roots, ligaments, and muscles surrounding the spine— that can contribute to these disorders.

Some studies have indicated that facet arthropathy, rather than nerve root irritation, cause axial neck and back pain. The increase of CNP and chronic LBP in aging populations may be associated with a progressive degeneration of the IVDs that subsequently increases facet joint loading and creates favorable conditions for the development of facet arthritis. Facet joint blocks by injection have been shown to be ineffective in providing symptomatic relief in up to 90 percent of patients diagnosed via CT scan in previous studies. This suggests that scan observations alone may provide prevalent false positive results and therefore cannot be a reliable diagnostic tool.

Disc replacement may alleviate pain and restore spinal fluidity of motion, but the presence of facet joint arthritis is considered a contraindication to this surgical procedure. Understanding more about facet joint arthritis can assist practitioners in developing effective treatment plans for LBP and CBP patients—including the determination of which patients may be ill-suited for IVD replacement. This study of asymptomatic patients was conducted with the aim of understanding the prevalence of facet joint arthritis to help quantify the percentage of patients for whom facet injections are ineffective.

The Study

An approved review of archived CT scans of 100 total non-spinal patients was conducted using scans of 500 cervical facet joints from 50 subjects and 500 lumbar facet joints from an additional 50 subjects. All of the patient subjects’ medical records and scans were previously analyzed and evaluated as spinally asymptomatic for the purpose of this study.

The images were each graded and evaluated by an orthopedic spinal surgeon, neuroradiologist, and trained medical student on an independent basis. An additional three observers with separate clinical backgrounds also conducted a review of the facet joints to ensure no bias existed due to training backgrounds of the first group. The severity of facet joint arthritis symptoms were graded and statistical analysis was applied across different subject age groups. An average of all groups was then calculated using a coefficient.

The Results

Cervical Data

Of the 500 cervical facet joints from 50 patient subjects studied, asymptomatic cervical facet joint arthritis was evident in more than 33 percent of the scans. Nearly 60 percent of these patients showed only mild narrowing of the joint space and irregularities. About half of the subjects over the age of 40 demonstrated signs of arthritic changes. There were fewer “normal” or non-degenerated facet joints in patients in the aging (over 45) subject population. The prevalence of degenerative changes increased at all cervical levels in the aging subjects.

In all age groups, greater changes occurred more prevalently in the caudal spine area. At the C6-C7 spinal level, 78 percent of patients over-40 demonstrated facet joint arthritis. At the C2-C3 level, however, only 29 percent of the patients of the over-40 age group showed arthritic changes.

Lumbar Data

Thirty-seven percent of the patient subjects in the lumbar data group demonstrated asymptomatic lumbar facet joint arthritis, and up to 2/3 of these subjects showed grade 1 changes. As with the cervical data set, the lumbar set demonstrated a positive correlation with aging (over 45) and arthritic changes and degeneration of the facet joints. Caudal levels (L5-S1, for example) were more likely to show increased arthritic degeneration compared to cephalad levels. Only 12 percent of the patients over 50 years old showed changes at the L1-L2 levels, while 54 percent demonstrated these changes at the L5-S1 level.

Lumbar Spinal Stenosis Model

Conclusion

This study found a statistically significant positive correlation between aging and asymptomatic arthritic changes and degeneration of the facet joints of patients over the age of 45. These changes were evident at all spinal levels but were most prevalent in the lumbar facet joints and the C2-C3 and C6-C7 levels of the caudal spine. Approximately one third of the patient population in this study were found to have evident facet joint arthritic changes that were asymptomatic and associated with aging. When considering motion-preserving spinal implants, the age of the patient should be considered, as the treatment may not be as effective in patients over the age of 45, who are more likely to have or develop asymptomatic facet joint arthritis—a contraindication of the implant procedure.

 

 

 

 

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