Influence of Psychological Variables on the Diagnosis of Facet Joint Involvement in Chronic Spinal Pain
From: Pain Physician 2008; 11:145-160
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.
Among the multiple structures responsible for pain emanating from the spine, facet or zygapophysial joints have been described as common structures. Consequently, facet joint interventions have increased substantially over the years in the United States, in multiple settings. Due to the inability of physical examination, clinical symptoms, radiologic evaluation, and nerve conduction studies to provide a reliable diagnosis of facet joint pain, controlled diagnostic blocks are considered the only means of reliable diagnosis of facet joint pain. Consequently, in accordance with the criteria established by the International Association for the Study of Pain, based on the controlled diagnostic blocks of facet joints, facet joints have been implicated as responsible for spinal pain in 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, utilizing the same IASP criteria, false-positive rates varying from 27% to 63% in the cervical spine, 42% to 58% in the thoracic spine, and 17% to 50% in the lumbar spine have been demonstrated.
Several reasons exist for these false-positive results including technical aspects, amount of local anesthetic, sedation, and, importantly, multiple psychological variables. The specificity of the effect of cervical and lumbar facet joint blocks has been demonstrated in controlled trials. Minimal effects of sedation were shown in the cervical and lumbar spine if strict criteria were utilized. In addition, a lack of influence of psychological factors on the validity of controlled diagnostic local anesthetic blocks of facet joints was demonstrated in the lumbar spine. Similarly, multiple other variables have also been evaluated. Psychological variables such as depression, anxiety, and excessive somatic symptoms are recognized as actively contributing to a patient’s perception of pain. Unrecognized and untreated psychopathology has been shown to interfere with the successful management of chronic pain and patient rehabilitation and has also been shown to be predictive of poor surgical outcomes. Further, psychopathology can serve to propitiate pain related dysfunction. A diagnosis of depression correlates with increased pain and anxiety decreases a patient’s pain threshold and tolerance. Emotional distress has been linked to physical symptoms through autonomic arousal and vigilance or somatic amplification, and anxiety and depression have been associated with the magnification of medical symptoms. It is well known that psychopathology affects treatment and outcomes. Even then, the influence of psychological factors on diagnosis and outcomes has not been well studied.
There is extensive evidence associating chronic pain with psychopathology including a host of studies showing that depression and anxiety are highly prevalent among persons with chronic pain. In samples evaluating chronic pain patients, rates of current major depression and anxiety ranged from 15% to 59%, significantly higher than the rate of 5% to 10% in persons without pain found in the general population. In addition, major depression is also frequently reported in association with somatization. The prevalence of somatization disorder ranges from 0% to 97%. Studies conducted in interventional pain management settings have shown a prevalence of somatization disorder of 20% to 34%.
This evaluation was undertaken to study the influence of psychopathology, namely depression, generalized anxiety disorder, and somatization, and combinations thereof, on the ability of controlled, comparative local anesthetic blocks to accurately identify facet joint pain and false-positive rates with a single block.
The primary findings of this study illustrate the significant prevalence of psychopathology in patients with chronic spinal pain but with no influence of the psychological variables of major depression, generalized anxiety disorder, somatization disorder, or a combination of any of these variables on the prevalence of facet joint pain based on controlled, comparative local anesthetic blocks in the thoracic and lumbar regions with a prevalence ranging from 29% to 40% in the thoracic spine and 25% to 34% in the lumbar spine. However, in patients with chronic neck pain utilizing controlled, comparative local anesthetic blocks, the prevalence of cervical facet joint pain was significantly higher in patients with major depression compared to those without major depression, and combined major depression and generalized anxiety disorder. There were no significant differences noted in the categories of generalized anxiety disorder, somatization disorder, and various other combinations in the cervical spine. The results of false-positive rates with a single diagnostic block also mirrored the prevalence rates with significant differences noted in patients with major depression compared to those without major depression (39% vs. 55%), and combined major depression and generalized anxiety disorder, whereas in both the thoracic and lumbar regions, and all other combinations and categories, there were no significant differences.
One of the primary findings of this study is the higher prevalence (43% vs 30%) of cervical facet joint pain and lower incidence false-positive rates (39% vs 55%) in patients with major depression, compared to patients without major depression is in contrast to the diagnosis of facet joint pain in the thoracic and lumbar regions. For the thoracic and lumbar regions, since there were no significant differences, it is assumed that psychopathology has no influence on the diagnosis of the prevalence rate or the false-positive rate with controlled, comparative local anesthetic blocks. Similarly, for cervical facet joint pain diagnosis, other psychological variables or combinations had no influence except for major depression and major depression when combined with generalized anxiety disorder only, whereas no other combinations of psychopathological disorder resulted in significant differences. The results of this study therefore do not support the common assumptions that psychopathology may interfere with the successful diagnosis of chronic spinal pain by means of reduction of a patient’s pain threshold and tolerance due to anxiety. Further, the results also do not show interference in the diagnosis of somatic amplification nor anxiety as associated with magnification of medical symptoms. The previous results of lumbar discography findings as described by Carragee et al were not confirmed in this study. Further, depression was the only significant variable, and then only in the cervical spine, which is difficult to explain and needs to be evaluated carefully in larger trials.
Depression, generalized anxiety disorder, and somatization, or combinations thereof are complex psychological issues. While the value of a diagnosis of depression and generalized anxiety disorder is well accepted, the validity of somatization disorder is questioned. A diagnosis of somatization should meet all the criteria described in the DSM-IV-TR. Major depression is a frequently reported condition in patients suffering with spinal pain, either independently or in association with somatization and generalized anxiety disorder. Studies have shown that major depression and generalized anxiety disorder are commonly seen in patients suffering with chronic pain, even among those on antidepressant and/or anti-anxiety therapy. It has been shown that a DSM-IV-TR criteria-based questionnaire evaluation incorporated into the overall pain management intake questionnaire, along with a short clinical interview is a reliable means of assessing depression and anxiety in patients suffering with chronic pain. For somatization disorder, the DSM-IV-TR criteria are the available standard.
The presence of psychological issues (psychopathology), according to some, has been described as being similar to the diagnosis of chronic pain syndrome, which is a complex condition composed of physical, psychological, emotional, and social components. Both chronic pain and chronic pain syndrome are defined in terms of duration and persistence of the sensation of pain, even though the chronic pain syndrome, as opposed to chronic pain, has the added component of certain recognizable psychological and socioeconomic influences with characteristic psychological and sociological behavioral patterns that distinguish the 2 conditions. While psychological problems are extremely common, chronic pain syndrome is not a common phenomenon. It has been shown in the literature that in matched samples of pain-free individuals compared to chronic pain groups, there were significantly higher prevalence rates of anxiety and depressive disorders in the chronic pain groups.
It has been a common assumption that patients with psychological or emotional factors are not amenable to accurate diagnosis and respond poorly to surgical and interventional techniques. However, there is no convincing evidence that chronic spinal pain develops secondary to psychopathology nor that response to treatment is hindered significantly based on psychopathology. The literature has shown that physical factors have been found to predict the outcome in lumbar surgery and there is a growing body of evidence indicating that psychosocial factors may also have a significant influence on the outcome of lumbar surgery. Carragee found psychological screenings were most useful for those patients with lesser degrees of disc pathological findings, longer disability, and confounding economic issues. However, there is no significant research available related to interventional techniques except that some studies have shown that psychological issues improve simultaneously with decreased physical pain and improvement in functional status.
The current study may be criticized for its retrospective nature and the controlled diagnostic blocks and their reliability and validity. The retrospective nature of the study essentially confirms previous results and thus provides external validity of the primary findings. Further it also provides initial results for the cervical and thoracic spine, thus, further randomized controlled trials may be performed.
Facet joints have been shown to be a source of chronic spinal pain by means of diagnostic techniques of known reliability and validity. Controlled diagnostic blocks are performed to diagnose facet joint pain by blocking the medial branches of the dorsal rami that innervate the target joint. Relief of pain demonstrates that a joint is the source of the pain. The true responses are determined by performing controlled blocks, either in the form of placebo injection or normal saline or more commonly in the form of comparative local anesthetic blocks on 2 separate occasions, when the same joint is anesthetized using local anesthetics with different durations of action.
The results noted in this study confirm the previous results of a lumbar facet study on the role of psychological factors in the lumbar spine and also in the diagnosis of discogenic pain with provocation discography. The results also provide the basis for evaluation in the thoracic spine. However, caution must be exercised in patients with major depression with chronic neck pain even though the results were similar in all other patients with generalized anxiety disorder and/or somatization disorder without depression.
The study may also be criticized for the type of psychological evaluation performed. The psychological evaluation was performed by utilizing the criterion standard which is used for all other tests, namely DSM-IV-TR.
Caution must be exercised in the interpretation of these results as they are only applicable in patients utilizing controlled, comparative local anesthetic blocks based on IASP criteria. Further, the results need to be confirmed in further evaluations with larger population samples, preferably in controlled evaluations.
