Age-Related Prevalence of Facet-Joint Involvement in Chronic Neck and Low Back Pain
From: Pain Physician 2008; 11:67-75
Background: Spinal pain is common in all age groups. While the research has focused primarily on incidence and prevalence in younger working adults, there is evidence that spinal pain is one of the most frequent complaints in older persons and is responsible for functional limitations. While facet arthrosis is a common radiographic finding, which has been suggested to be a potential cause of spinal pain, nearly 10% of all adults show signs of degeneration by the time they reach age 30. Radiographic changes of osteoarthritis have been shown to be equally common in patients with and without low back or neck pain. The studies of low back pain have shown the prevalence of facet joint involvement to be approximately 15% to 45%. However, age related prevalence of facet joint neck pain has not been studied. Objective: To assess age-related prevalence and false-positive rates of facet-joint involvement in chronic spinal pain using controlled comparative local anesthetic blocks.
Design: Retrospective analysis of 424 patients, divided into 6 groups based upon age (Group I: aged 18 – 30 years, Group II: aged 31 – 40 years, Group III: aged 41 – 50 years, Group IV: aged 51 – 60, Group V: 61 – 70 years, and Group VI: greater than 70 years of age).
Results: The prevalence of cervical facet joint-related pain was the lowest (33%) in Group VI and highest (42%) in Group I. False-positive rates for cervical facet joint blocks ranged from 39% (Group III) to 58% (Group V) with an overall false-positive rate of 45%. The prevalence of facet joint involvement in lumbar spinal pain ranged from 18% (in Group II) to 44% (in Group IV), with significant differences noted when Group II and Group III were compared to other groups and with higher rates in Group V.
Conclusion: This study demonstrated a variable age-related prevalence of facet joint pain in chronic low back pain, whereas in the cervical spine it was similar among all the age groups.
This retrospective evaluation of patients with chronic non-specific spinal pain involving the cervical and/or lumbar regions demonstrated a prevalence of facet-joint involvement of 35% to 42%, in patients with neck pain, with false-positive rates of 40% to 56%. The prevalence of facet-joint involvement was 18% to 44% in the lumbar spine, with false-positive rates ranging from 30% to 64% across age groups. These results illustrate that while minor differences exist (e.g. differences in the cervical region with Group IV), the prevalence of facet-joint involvement in neck and low back pain is relatively similar in young, middle- aged, and older patients.
These results differ from those of previous studies that showed a significantly higher prevalence of facet joint-related pain in the elderly. Despite this, the present study reaffirms that involvement of the facet joint(s) is a major cause of chronic spinal pain in both the cervical and lumbar regions. Moreover, this is the first study to provide age-related prevalence of facetjoint involvement in cervical spinal pain. As well, while arthrosis has been most commonly reported at L4/5 facet joints, the present study revealed that facet-joint involvement appears to frequently occur at both the L4/5 and L5/S1 levels.
Facet joints have been shown to be a source of chronic spinal pain by means of diagnostic techniques of known reliability and validity utilizing criteria established by IASP. Blocks of facet joints are performed to test the hypothesis that the target joint is a source of the patient’s pain and the joint is anesthetized generally by the facet joint blocks of the nerves that innervate the target joint. Consequently, painful joints are identified by true-positive responses by means of controlled diagnostic blocks, generally with controlled comparative local anesthetic blocks utilizing 2 local anesthetics on 2 separate occasions anesthetizing the same joint. Further, the value and validity of medial branch blocks and comparative local anesthetic blocks in the diagnosis of facet joint pain has been demonstrated. In addition, specifically in the elderly, there are no clinical features or diagnostic imaging studies that can determine whether a facet joint is painful or not, leading us to depend on controlled diagnostic blocks as the only available reliable tool in the diagnosis of chronic spinal pain.
This study may be criticized for a small number of patients in certain groups after allocating them into 6 groups. Further, rationale of allocation into 6 groups may be questioned as we do not have any specific evidence of radiologic changes or prevalence of facet joint pain based on changes in every 10 years. However, this allocation appeared to be better than simply demarcating the patient’s above and below 65 years of age even though it consequently resulted in a small proportion of patients in certain age groups. Since the basic sample is large, we believe that the results are appropriate and accurate in providing information with regards to age-related prevalence of facet joint pain.
