RESUMO
OBJECTIVE: To evaluate the effects of high-energy pulsed electromagnetic fields on unspecific back pain. METHODS: A prospective, randomized, sham-controlled clinical trial with repeated measurements was performed. The study included 5 visits (V0 to V4) with 3 interventions during V1, V2 and V3. Sixty-one patients aged between 18 and 80 years with unspecific back pain (acute inflammatory diseases and specific causes were reasons for exclusion) were included. The treatment group (n = 31) received 1-2 pulses/s, with an intensity of 50 mT, and an electric field strength of at least 20 V/m on 3 consecutive weekdays for 10 min each time. The control group (n = 30) received a comparable sham therapy. Pain intensity (visual analogue scale), local oxyhaemoglobin saturation, heart rate, blood pressure, and perfusion index were evaluated before (b) and after (a) V1 and V3 interventions. Change in visual analogue scale for V1 (ChangeV1a-b) and V3 (ChangeV3a-b), and ChangeData between V3a and V1b (ChangeV3a-V1b) for the remaining data were calculated (results were mean (standard deviation) (95% confidence interval; 95% CI)). RESULTS: Concerning the visual analogue scale: (i) compared with the control group, the treatment group had higher ChangeV1a-b (-1.25 (1.76) (95% CI -1.91 to -0.59) vs -2.69 (1.74) (95% CI -3.33 to -2.06), respectively), and comparable Change V3a-b (-0.86 (1.34) (95% CI -1.36 to -0.36) vs -1.37 (1.03) (95% CI -1.75 to 0.99), respectively); and (ii) there was a significant marked decrease in Change V3a-1b in the treatment group compared with the control group (-5.15 (1.56) (95% CI -5.72 to -4.57) vs -2.58 (1.68) (95% CI -3.21 to -1.96), p = 0.001, respectively). There was no significant ChangeV3a-V1b in local oxyhaemoglobin saturation, heart rate, blood pressure or perfusion index between the 2 groups and for the same group (before vs after). CONCLUSION: Non-thermal, non-invasive electromagnetic induction therapy had a significant and rapid influence on unspecific back pain in the treatment group.
