Objective: A qualitative review of the scientific literature on thermographic instrumentation for detecting neuromusculoskeletal abnormalities of the spinal column was made. Electronic infrared instrumentation (telethermography), liquid crystal thermography and various hand held devices were scrutinized in terms of reliability and comparison with other diagnostic tests (e.g. computed tomography, myelography, electromyography, magnetic resonance imaging).
Data Sources: A Medline literature search was performed from 1966 through 1990. English language material was retrieved using the following key words: thermography and spine, spinal injuries, cervical vertebrae, thoracic vertebrae, lumbar vertebrae, sacroiliac joint, lumbosacral region, back or neck. The Index to Chiropractic Literature was also reviewed. The categories of skin temperature and thermography were scrutinized. Chapters of texts and unpublished works were not incorporated.
Study Selection: Studies involving the comparison of thermographic findings with those of other tests were the primary focus of the review. Case reports, as well as the use of thermography as an outcome measure, were also studied. Interexaminer reliability studies are reported.
Data Extraction: The study populations are characterized as well as blinding procedures, if any. The authors’ statistical work, if applicable, is presented and criticized.
Data Synthesis: Relatively few reliability studies exist for thermography. Emphasis has been on validity studies that compare the results of the thermogram with other reference tests. There has been a general lack of high-quality research design (e.g., blinding) throughout the thermographic literature base. The sensitivity of the various thermographic instrumentation has shown encouraging results, although this must be tempered with the generally poor design of many studies. Specificity, in contrast, has shown mixed results. The review indicated telethermography to be a sensitive diagnostic procedure for detecting abnormalities, such as disc protrusion, of the lumbar and cervical spine. Liquid crystal thermography effectiveness is difficult to determine due to the paucity of blinded investigations, although normative data for the cervical spine and upper extremities is present. Literature on the various hand-held instruments has revealed moderate levels of examiner reliability for infrared devices, with less information available for thermocouple instruments. Normative data for hand-held instruments is absent.
Conclusion: Continued investigation is needed in the area of thermographic research in light of the paucity of blinded and/or controlled investigations. More sensitive neurophysiological and anatomical measures must be used when comparing the results from thermography. The lack of an available gold standard for comparing thermographic findings has been problematic. Future research should focus on thermography as a non-invasive outcome measure and interpreter reliability.