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CHAPTER 23  Multidisciplinary Assessment of Patients with Chronic Pain

A general medical history that addresses issues such as weight loss or fevers should alert the physician to the possibility that a patient is symptomatic because of a disease such as an neoplasm or infection. 8,9 If symptoms appear to be the result of injury, what is the nature of the injury? 1. Neurologic injuries. The physician needs to be alert to clin- ical evidence of a cervical radiculopathy or a myelopathy. Evidence for these possibilities is obtained from the pa- tient’s history (e.g., pain and paresthesias into an extrem- ity in a segmental distribution) and a careful neurologic examination. Electrodiagnostic studies can provide addi- tional evidence regarding the presence of a cervical radic- ulopathy 10 ; MRI scans can provide evidence of anatomic compromise of nerve roots or the cervical spinal cord. 11–14 2. Major skeletal injuries. When a history of significant trauma is elicited, radiologic studies are needed to rule out the possibility that a patient has a spinal fracture or a ligamentous injury severe enough to yield instability. 14–16 Although these major skeletal injuries are often accom- panied by spinal cord injury or radiculopathy, 17 they may occur among individuals who are neurologically intact. 18 3. Other musculoskeletal injuries (axial spinal pain). The overwhelming majority of patients with chronic neck pain do not have evidence of a neurologic injury or a major skeletal injury but present with localized axial cer- vical spine pain that suggests a musculoskeletal injury or with pain in a pattern suggesting referral from a joint in the cervical spine. 19,20 These patients are often very diffi- cult to evaluate medically because there are no physical examination findings or diagnostic tests that unequivo- cally identify the structural basis of axial cervical spine pain. In this ambiguous situation, it is important for the examining physician to be aware of the structures that might underlie a patient’s symptoms. a. Ligamentous injuries. Ligaments abound in the cer- vical spine, so pain felt to be ligamentous in origin could stem from various structures. The ligaments most often proposed as causes of axial cervical spine pain are the alar ligament, the posterior longitudinal ligament, and the facet joint capsular ligaments. 15,21,22 Because ligaments are critical to the stability of the cer- vical spine, severe damage to them is often assessed by looking for instability. Most commonly, this gross in- stability is associated with major skeletal injuries and is diagnosed in emergency room settings. A more subtle type of ligamentous abnormality has been postulated to be identifiable based on an abnormal MRI signal from ligaments, such as high signal intensity on proton attenuation–weighted high-resolution MRI. In princi- ple, these signal abnormalities could reflect ligamen- tous injuries that cause pain but are not severe enough to cause instability. Some investigators have reported that ligamentous injuries identified by abnormal MRI signals play a significant role in whiplash injuries and that the severity of self-reported disability among peo- ple with these injuries correlates with the severity of the MRI signal abnormalities. 23–25 However, longitu- dinal studies on whiplash patients as well as research on asymptomatic people and ones with neck pain sec- ondary to cervical degenerative conditions rather than injury suggest that the MRI signals that some inves- tigators have interpreted as indicators of ligamentous injuries should actually be considered normal variants or indicators of cervical degenerative disk disease. 26–28 b. Disk pathology. It is widely accepted that cervical disk herniations can cause radiculopathies. But a more con- troversial issue is whether pathology of cervical disks

can cause axial cervical spine pain and, if so, how such discogenic pain can be diagnosed and treated. Some in- vestigators have proposed that cervical discogenic pain does occur and that it can be diagnosed via discogra- phy—a procedure in which imaging is performed after injection of contrast dye into a cervical disk and the pain response of the patient is assessed during injection of the dye and just after follow-up injection of a local anesthetic. The presence of an abnormal discogram, de- fined on the basis of some combination of the morphol- ogy of a disk and the pain responses of a patient during the procedure, is viewed as an indication that the disk accounts for the patient’s pain and that a cervical spinal fusion is the appropriate definitive treatment. 29 The ev- idence supporting discography as a means of identify- ing cervical discogenic pain is weak, with some reviews concluding that there is no compelling evidence to sup- port its use 30,31 and others specifically recommending against its use. 32 Skepticism regarding cervical spine discography is bolstered by research on lumbar spine discography. This research has demonstrated a high false-positive rate for discography, a tendency for psy- chosocially stressed people to have an especially high false-positive rate, and failure of spinal fusion based on discography results to produce satisfactory results. 29,33 Although dueling literature reviews make it somewhat difficult to reach any definite conclusions about cervi- cal discogenic pain, 34 a reasonable conclusion is that although discogenic pain is biologically plausible, 31 no technology currently exists to demonstrate its presence in an individual patient or to provide treatment based on its suspected presence. c. Facet joint injury. Bogduk and colleagues 35–37 have as- serted that facet joint injuries often underlie persistent cervical pain and have pioneered techniques for iden- tifying painful facet joints on the basis of patients’ reports of symptoms during injection procedures de- signed to provoke or palliate pain. Using these tech- niques, they have reported that approximately 70% of individuals with persistent neck pain following motor vehicle collisions have pain mediated by one or more of the cervical facet joints. Equally important, they have demonstrated that when patients diagnosed with facet joint–mediated pain receive injections (facet neurotomies) designed to denervate the affected facet joint, approximately 70% experience prolonged symp- tom relief. 37,38 More recent research has supported the importance of facet joint pathology in whiplash pain, although the frequency was reported as 29% rather than 70%. 39 As with discography, prominent teams of reviewers have reached opposite conclusions about the prevalence of facet joint–mediated pain, the va- lidity of the diagnostic procedures used to diagnose this kind of pain, and the efficacy of invasive therapies to treat it. 30,32 It is beyond the scope of this chapter to try to resolve the discrepant assessments of facet joint–mediated whiplash pain, although we believe the evidence supporting it is more impressive than the evi- dence supporting discogenic pain. d. Muscle pain. Opinions about the prevalence and sig- nificance of muscle pain in chronic axial neck pain are, if anything, more divided than opinions about dis- cogenic pain or pain associated with facet joint or liga- mentous injury. Most investigators of muscle pain use the language and concepts developed by Travell and Simons, 40 who popularized the term myofascial pain and emphasized its importance as a cause of persistent musculoskeletal pain. Proponents of myofascial pain