Correlation between Pain Scale and Infrared Thermogram in Lumbar Disc Herniations

ABSTRACT

Back pain and radiating leg pain due to compression of the nerve root by the lumbar disc herniation are subjective symptoms. Objective evaluation of pain site and severity is important for the diagnosis and the treatment. We evaluate the correlation between the severity of pain and the temperature changes in the patients of lumbar disc herniations using infrared thermograms. 174 consecutive patients who underwent operation or chemonucleolysis for single level unilateral disc protrusion with ipsilateral leg pain were included in this study. Subjective pain was divided four groups(Group I: mild pain, Group II: moderate pain, Group III: severe pain, Group IV: intractable pain). Thermal differences of each group were as follows: Group I was 0.26degreesC, Group II was 0.39degreesC, Group III was 0.60degreesC and Group IV was 0.98degreesC. Disc protrusions were divided three groups. Thermal differences of each group were as follows; mild protrusion group was 0.52degreesC, moderate protrusion group was 0.79degreesC and severe protrusion group was 0.95degreesC. Duration of symptom was divided four groups and each thermal differences were as follows: under 2 months was 0.87degreesC, 2 to 6 months was 0.71degreesC, 6 to 12 months was 0.50degreesC and more than 12 months was 0.47degreesC. All these data were statistically significant in p<0.01. In conclusion, infrared thermal imaging can demonstrate the subjective pain objectively. The discogenic pain is the more severe, or the disc herniation is the more protruded, or the symptom duration is the shorter, the thermal difference between the both legs is the more significantly prominent. Thermal difference between both legs is a useful pain scale in the herniated lumbar disc patients. Infrared thermal imaging is effective in the evaluation of lumbar discogenic pain.