Vibratory stimulation for the alleviation of chronic pain.

The pain relieving effect of vibratory stimulation was studied in 731 patients suffering from acute pain (135 patients) or chronic pain (596 patients). Most of the patients had previously undergone treatments of various kinds without sufficient pain relief. The effect of vibratory stimulation was assessed before, during and after stimulation using different rating scales. About 70% of the patients reported reduction of pain during vibratory stimulation. In many patients there was a clear relation between the degree of reduction of pain and the intensity of pain before the beginning of stimulation. In general, relief of pain by more than 50% during stimulation was obtained in the patients who reported light, light to moderate, or moderate pain. The patients with moderate to severe, or severe pain before stimulation generally reported a reduction of pain of 50% or less. The best pain reducing site was found to be either the area of pain or close to it, the antagonistic muscle or a trigger point near the painful area. In most patients suffering from musculoskeletal pain the best pain reducing effect was obtained when the vibratory stimulation was applied with moderate pressure (at which contact was achieved with underlying bone) at a frequency of 50-150 Hz. To obtain a maximal duration of pain relief the stimulation had to be applied for 30-45 minutes. Many of the patients experienced pain relief lasting for more than 3 hours. It may be noticed that in many patients the pain relief lasted for 12 hours or more. There was a good correlation between the degree of pain relief and its duration. In the patients who experienced a pain reduction of 50% or less the pain relief generally lasted for less than 6 hours while in the patients who experienced pain relief of more than 50% it lasted for more than 6 hours. In comparison with high or low frequency TENS, vibratory stimulation was found to be as effective and in some patients even more effective in reducing chronic musculoskeletal or orofacial pain. The effect of 20 Hz, 100 Hz and 200 Hz vibratory stimulation, high frequency TENS, low frequency TENS and "placebo" vibratory stimulation was examined in various chronic musculoskeletal pain syndromes. 82% of the patients experienced a relief of pain with any of the above mentioned methods; 47% of the patients experienced a reduction of pain with vibratory stimulation or TENS stimulation.(ABSTRACT TRUNCATED AT 400 WORDS)