Influence of Psychological Variables on the Diagnosis of Facet Joint Involvement in Chronic Spinal Pain

Abstract

Background: Facet or zygapophysial joint pain is one of the common conditions responsible for chronic spinal pain. Controlled diagnostic blocks are considered the only means of reliable diagnosis of facet joint pain, due to the inability of physical examination, clinical symptoms, radiologic evaluation, and nerve conduction studies to provide a reliable diagnosis. The prevalence of facet joint pain has been established to be 15% to 45% of patients with low back pain, 39% to 67% of patients with neck pain, and 34% to 48% of patients with thoracic pain. However, using only a single block, false-positive rates of 27% to 63% in the cervical spine, 42% to 58% in the thoracic spine, and 17% to 50% in the lumbar spine have been reported. While there are multiple reasons for false-positive results, psychological variables may also contribute to false-positive results. A lack of influence of psychological factors on the validity of controlled diagnostic local anesthetic blocks of lumbar facet joints has been demonstrated. However, no such studies have been performed in the thoracic or cervical spine. Objective: To study the influence of psychopathology (depression, generalized anxiety disorder, and somatization individually or in combinations of multiple psychopathologic conditions) on the ability of controlled, comparative local anesthetic blocks to accurately identify facet joint pain and false-positive rates with a single block. Methods: Four hundred thirty-eight patients undergoing controlled, comparative local anesthetic blocks were included in the study. Patients were allocated based on their psychological profiles — each diagnostic group or combination was divided into distinct categories. Primary groups consisted of patients with major depression, generalized anxiety disorder, and somatization disorder. Combination groups consisted of 4 categories based on multiple combinations. All the patients were treated with controlled, comparative local anesthetic blocks either with 1% lidocaine or 1% lidocaine and 0.25% bupivacaine. A positive response was defined as at least an 80% reduction in pain and the ability to perform previously painful movements with appropriate relief with 2 separate local anesthetics. Results: The prevalence of facet joint pain in chronic spinal pain ranged from 25% to 40% in patients without psychopathology, whereas it ranged from 28% to 43% in patients with a positive diagnosis of major depression, generalized anxiety disorder, and somatization disorder, respectively, compared to 23% to 39% in patients with a negative diagnosis. Regional facet joint pain prevalence and false-positive rates were higher in the cervical region in patients with major depression. In the lumbar and thoracic regions, no significant differences were noted. Conclusion: This study demonstrated that, based on patient psychopathology, there were no significant differences among the patients either in terms of prevalence or false-positive rates in the lumbar and thoracic regions. A higher prevalence and lower false-positive rates in the cervical region were established in patients with major depression. Key words: Zygapophysial joint pain, facet joint pain, prevalence, false-positive rate, controlled comparative local anesthetic blocks, major depression, generalized anxiety disorder, somatization disorder