THERMOGRAPHY AS A DIAGNOSTIC-AID IN SCIATICA

Thermography has been proposed as a diagnostic aid in patients with sc iatica. Supporters of thermography state that: (a) normal patients hav e normal thermograms of their lower extremities, and (b) abnormal pati ents (with disk ruptures causing sciatica) have abnormal thermograms. To test these two hypotheses, 56 patients with clinically documented a cute sciatica, with a supporting diagnostic study [computed tomography (CT), CT/myelography, and/or magnetic resonance imaging] showing a ru ptured disk, had presurgical thermograms. One year after surgical inte rvention, they had to have had a documented success to surgical treatm ent intervention to stay in the study. These 56 patients were then mat ched with 56 control (normal) patients who had electronic thermograms. The 112 thermograms were then interpreted blindly by two thermographe rs. The sensitivity and specificity of thermography as a diagnostic ai d in sciatica were statistically analyzed. The sensitivity of thermogr aphy (its ability to be positive when sciatica was clinically obvious) was 60% and 50% for the two thermographic readers. The specificity of thermography (its ability to be negative in asymptomatic patients) wa s 45% and 48% for the two thermographers. Our conclusions are no diffe rent than those published in 1985: thermography is not useful as a dia gnostic aid in sciatica. Key Words: Thermography-Sciatica-Diagnostic a id.