Plantar infrared thermography measurements and low back pain intensity

Objective: To study the skin temperature disorders in low back pain (LBP) patients compared with reference persons without LBP and to evaluate the relationship between pain intensity and other clinical signs and temperature abnormalities. Methods: Sixty-five patients with unilateral chronic LBP with or without referred nonradicular leg pain (29 men and 36 women; age range, 30-51 years) and 20 reference persons without LBP (7 men and 13 women; age range, 30-49 years) participated in this study. The pain level was recorded by the use of a visual analog scale (0-100). Questionnaires and a series of spinal mobility tests (the modified Schober, straight leg-raising test, finger-floor distance, side bending) were used. Thermographic images of the low back area and legs (anterior, lateral, and posterior surfaces and the plantar surfaces of feet) were taken with an infrared video camera. Results: The temperature changes in the plantar surface correlated with LBP intensity. The pain levels differed in the groups with the different types of temperature changes. There were significant lower extremity regional skin temperature alterations (at least 1 regional interside difference more than 0.3 degrees C) in most cases both in LBP patients and in reference persons, but plantar interside temperature difference was significantly higher in LBP patients. Conclusion: Temperature changes of the plantar surface seem to be connected with LBP intensity. Temperature measurements may be useful as an adjunctive physiological test in the evaluation and documentation of autonomic dysfunction in LBP patients.