Liquid crystal thermography. A new tool for evaluating low back pain.

Liquid crystal thermography was used to determine low back skin temperature patterns in 62 patients hospitalized for low back pain and 22 college volunteers with no previous history of back pain. The patients were separated into four groups according to their diagnoses at discharge: patients with 1) degenerative discogenic lesions, 2) acquired lesions, 3) congenital and developmental lesions, 4) back pain resulting from unknown causes. No significant differences were found between the average equilibrated thermogram temperatures of the control subjects (32.4 +/- 0.5 degrees C) and patient groups. However, the temperature gradients found on the thermograms of patients with discogenic lesions (3.1 +/- 0.6 degrees C) and acquired lesions (3.1 +/- 1.0 degrees C) were significantly greater (p less than .05) than those of the pain-free subjects (2.5 +/- 0.5 degrees C). Tenderness to palpation was associated with elevated skin temperatures in 80 percent of the patients studied. This study suggests that liquid crystal thermography may be a potentially useful tool for localizing soft tissue trauma in patients with low back pain.