Correlation of pain severity with thermography

Thermography can detect the discogenic pain in lumbar disc herniation and change the subjective pain into an objective color image. The sensitivity and specificity of thermography are as high as 89.5%, 79.1% and show high correlation with post-operative clinical results. Thus it has been used for diagnosis of disc herniation, the detection of the symptomatic level in multiple disc herniation and prediction of post-operative courses in lumbar disc herniations. The severity of pain in disc herniation is different according to the duration of symptoms, the types of disc herniation, the degree of protrusion and other numerous factors. The authors analyzed the thermographic findings of lumbar disc herniation, focused on the thermal difference and correlated the thermal difference with severity of pain in 147 patients with lumbar disc herniation. Patients having single level disc herniation with unilateral leg pain were grouped into acute (78 cases) and chronic (69 cases) groups according to the duration of symptoms. In the acute disc herniation group, significant thermal difference is noted according to subjective pain severity (P<0.05), degree of protrusion (P<0.01) and type of herniations (P<0.05). In the chronic disc herniation group, the thermal difference is not correlated with severity of pain and disc protrusion. In conclusion, thermal difference is well correlated with severity of pain in acute disc herniation. Thermography is useful for differentiation of acute and chronic disc herniation and it shows the severity of discogenic pain in lumbar disc herniations.