The evaluation of pain intensity is long lasting problem of many medical disciplines. The subjective evaluation is most frequently used for the determination of the intensity of pain. Most common used method is visual analogue scale – VAS. Several other scales were also elaborated, but they are more complicated. They are based on the subjective description of quantitative and qualitative components of pain. Very frequently used are the Melzack’s scale and McGill University scale. Recording of the neural unit activity represents another objective method which can be used experimentally in animals and exceptionally in man during neurosurgical operations. Also the imaging methods (fMRI and PET) serve for the objective evaluation of pain but for routine use they are expensive and complicated. Therefore we try to implement the biochemical characteristics for the objective evaluation of pain. In our previous experiments on rats we found that after the nociceptive stimulation the final products of free radicals – malondialdehyde (MDA) and thiobarbituric acid reactive substances (TBARS) – are increased. Also the antioxidative enzymes – superoxiddismutase (SOD) and glutathionperoxidase (GSHPx) are increased. In present study, 17 men with chronic low back pain (dorsalgia and discopathia) were tested. It was found out that in patients with low back pain TBARS were increased in blood plasma. The patients with dorsalgia had higher levels of SOD if compared with the control group. The levels of MDA and GSHPx did not differ significantly from the control group. Our first results in patients with the low back pain confirmed some changes of the biochemical characteristics, which have been observed in animal’s model of pain. From this study it can be concluded that these biochemical diagnostics represent one of the possible ways of the objective evaluation of the pain intensity.

        Key words: low-back pain, free radicals, biochemical evaluation of pain