Pathogenesis of lumbo-sacral nerve root lesion: from the view point of thermographic findings of the lower limbs

Pathogenesis of the lumbo-sacral nerve roots lesion is discussed especially on the role of the sympathetic nerve using thermographic investigation of the lower limbs. 50 persons without any lumbar symptom were selected as control, and 97 patients with lumbo-sacral nerve roots lesion, including 64 with lumbar disc herniation (LDH) and 33 with lumbar canal stenosis (LCS), were the subjects of this study. In 33 patients group thermography was taken before and after selective nerve root block. The thermograms of the control group showed almost symmetrical thermatome. 49 (76.6%) of LDH group had hypothermal area on the affected limb, however, particularity of the hypothermal area did not define between L5 and S1 nerve root lesion. The patients with hypothermal area of the lower limb were characterised as having apparent neurological deficits and longer duration of the history from the onset, compared with the group without hypothermal area. 25 (75.8%) of LCS group showed not only hypothermal but also complicated thermographic findings. The patients with the complicated findings tended to have severer neurological deficits. Through thermographic findings after nerve root block, it is suggested that skin distribution of the particular nerve root, for example L5 or S1 nerve root distribution, exists in the lower limbs probably related to sympathetic nerve. This study concludes that thermograms of the lower limbs reflect pathogenesis of lumbo-sacral nerve root lesion in some extent, and probably indicate the prognosis of the lesion.