Effects of thermotherapy and transcutaneous electrical nerve stimulation on patients with primary dysmenorrhea: A randomized, placebo-controlled, double-blind clinical trial

Abstract

Objectives: To evaluate the effects of thermotherapy and transcutaneous electrical nerve stimulation (TENS) on pain intensity, pressure pain threshold (PPT) and conditioned pain modulation (CPM) in patients with primary dysmenorrhea (PD).

Design: A randomized, placebo-controlled, double-blind clinical trial.

Setting: Physiotherapy Department of the Universidade Cidade de São Paulo, São Paulo (Brazil).

Interventions: Eighty-eight dysmenorrheic women were randomly allocated into four groups: Thermotherapy + TENS(n = 22), Thermotherapy(n = 22), TENS(n = 22) and Placebo(n = 22). Thermotherapy was applied by microwave diathermy (20 min), and TENS (200 μs, 100 Hz, 30 min), into the lower abdomen both.

Main outcome measures: Pain intensity was measured using the numeric rating scale (NRS) and the McGill Pain Questionnaire (Br-MPQ). PPT and CPM were recorded from women's abdominal and lumbar. The evaluation was done in 5 times: baseline, after 20, 50, 110 min and 24 h from intervention.

Results: There was a significant decrease in the NRS for Thermotherapy + TENS vs. TENS, for Thermotherapy vs. TENS and for Placebo, after 20 min; for Thermotherapy vs. TENS and for Placebo, after 110 min and 24 h. Abdome PPT increased in the Thermotherapy + TENS vs. TENS and Placebo, after 50 min; for Thermotherapy + TENS vs. Placebo and for Thermotherapy vs. Placebo, after 110 min. No changes in lumbar PPT and CPM were observed.

Conclusions: The use of thermotherapy reduced NRS compared to the TENS and Placebo after 20, 110 min and 24 h. Thermotherapy demonstrated an increase in the PPT in the abdomen after 50 and 110 min and decreased the Br-MPQ scores after 110 min in patients with PD.

Keywords: Dysmenorrhea; Pelvic pain; Termotherapy; Transcutaneous electrical nerve stimulation.