Lumbosacral Discogenic Pain Syndrome Workup

Updated: Aug 19, 2016
  • Author: Robert E Windsor, MD, FAAPMR, FAAEM, FAAPM; Chief Editor: Craig C Young, MD  more...
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Workup

Laboratory Studies

Laboratory evaluation is primarily used to identify underlying inflammatory, infectious, neoplastic, or nonspinal causes of low back pain. Such studies may include CBC, rheumatologic screening, and neuroendocrine testing.

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Imaging Studies

MRI is the best noninvasive test for detecting IDD. Note, however, that the relationship between MRI depicted IDD and low back pain remains poorly understood. [7]

Generally, MRI demonstrates degenerative changes within the disc, such as annular fissures and reduced signal intensity, indicative of reduced water content. These changes, of course, are not specific for IDD, although discs with IDD do demonstrate degenerative changes. The difficulty is differentiating between a pathologically degenerate disc and a physiologically aging one.

The most specific MRI hallmark for IDD is the high-intensity zone (HIZ). This is a high-intensity signal, usually at the posterior apex of an annular fissure. The significance of the HIZ in regard to discogenic low back pain is still controversial. Aprill and Bogduk initially described the HIZ and reviewed a subset of 41 patients who were also evaluated with CT discography. In this study, the presence of the HIZ was strongly correlated to concordant pain. However, a study by Horton and Daftari involving 63 discs in 25 patients did not support a high correlation of the HIZ with concordant provoked pain.

Gadolinium-DTPA enhanced MRI is also being proposed as a viable alternative, showing a signal flare at the site of granulation tissue within a healing or healed full-thickness tear. [8]

Discography is the criterion standard for detecting IDD. It is somewhat invasive but is the only tool for accurately demonstrating whether a disc is painful or not. However, the efficacy of discography is controversial, and proper interpretation requires knowledge of the pathologic condition, an in-depth appreciation of the patient, and proper technique.

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