These two articles are reviewed together because the second is a commentary, appearing in the same journal, which places the first in appropriate context. It raises valid questions regarding the quest for diagnostic certainty for most, if not all, mechanical pain syndromes of the spine and extremities.

In the first article on MRI imaging and acute neck pain, Fryer and Adams examine the hypothesis that inflammation in or around the facet joints may be the source of acute unilateral axial neck pain. Five subjects, three women and two men between the ages of 18 and 50 who were otherwise healthy, were selected on the basis of acute onset (less than 48 hours) of unilateral, non-traumatic neck pain. The authors refer to this presentation as 'crick in the neck' or acute torticollis. Subjects were scanned with a 0.35 Tesla MRI unit. There were no MRI findings showing clear evidence of synovial effusion or inflammation around the facet joints of the cervical spine.

In addition, "Signs of muscle edema, altered alignment, disc and facet arthrosis, and spinal stenosis were noted, but these did not appear to be related to the symptomatic segmental level or side of pain". The authors concluded that: "The current case series failed to find any indication of inflammation in the deep spinal structures using MRI". They were also examined by palpation, with findings that "the side of focal tenderness was the same as the symptomatic side in all cases, and the segmental level identified as tender corresponded to the symptomatic region...in all subjects but one, who was unable to identify a localized region of most intense pain".

Fryer and Adams conclude that inflammation was either not present or that it was too subtle to image with their relatively low field strength magnet. Thus, they argue, their study cannot rule out inflammatory changes associated with acute neck pain. They found that: "Minor pathologies were detected in all subjects but were likely unrelated to the current presentation of pain or the findings on palpation". This is consistent with the broader literature on spine and extremity imaging in which abnormalities are commonly found but correlate poorly with symptoms. Degenerative changes seen in the current study were found on both sides, but the symptoms were unilateral.

This study has several weaknesses: There were only five subjects and the MRI field strength was weak. However, as Haldeman points out in his commentary, it is unlikely that adding more subjects would result in a different outcome since this is not the only study which has failed to find a strong correlation between common diagnostic tests and axial neck pain: "Virtually every clinical study that has compared more than one test in a group of patients has resulted in either no correlation or a small statistical but clinically insignificant correlation. A few examples include the failure of diagnostic blocks to correlate with C2-C3 segment axial rotation or local tenderness and the failure of MRI to correlate with discography."

Haldeman notes that: "For the past 50 years or more, spine care clinicians have been preoccupied, almost to the point of obsession, in their search for the single 'diagnosis', 'pathology', 'cause' or 'generator' of uncomplicated axial neck pain. There is no easier method to generate heated controversial debate than question the credibility of a clinician's favorite method of diagnosing the structure or pathology he or she believes is the source of the patient's pain and, therefore, likely to be amenable to whatever treatment the clinician is offering." Haldeman lists nearly 30 diagnostic procedures used in the quest to identify the pathology of uncomplicated spine pain, concluding that: "it is now possible to spend a great deal of time and thousands of dollars in the search for the structural source or pathological cause of the patient's pain. The question that repeatedly comes up is whether any of this testing is informative to the clinician or of benefit to the patient".

Haldeman describes four problems with current thinking about uncomplicated neck pain, and may apply as well to other spinal areas and to the extremities:

1. There is no agreed-upon gold standard for the diagnosis of neck pain. All the tests cited by Haldeman have high false positive rates and, without a gold standard, false negative rates are unknown.

2. There is no widely practiced and standardized assessment process across clinicians of different specialties.

3. There is no correlation between clinical findings and MRI findings for uncomplicated neck pain.

4. Diagnostic labeling of the patient with uncomplicated neck pain has not been shown to have a positive impact on prognosis or outcome.

On the contrary, there is some evidence that a specific diagnosis can negatively affect prognosis and, in most cases, treatments based on these diagnoses have only a modest impact on pain and disability. Haldeman argues for further research on clinical prediction rules in place of diagnostic labeling. He realistically notes that it is a 'pipe dream' to hope that spine care clinicians will suddenly standardize their myriad approaches, but he presents a strong case for changing the emphasis of future research away from diagnostic labeling and toward a more functional approach.

The principles of mechanical diagnosis and therapy (MDT) emphasize this functional approach while avoiding unhelpful or misleading diagnostic labeling for uncomplicated spinal and extremity pain. In addition, the proven reliability, validity and prognostic power of the MDT lumbar spinal assessment is evidence that a standardized approach already exists and merits further investigation, especially in relation to the cervical spine and extremities. In the latter case, evolving MDT clinician experience suggests that applying MDT principles to extra-spinal tissues may prove to have prognostic and therapeutic benefit as well, while at the same time avoiding the pitfalls of diagnostic labeling.

Cervical: Trials