Transcutaneous Nerve Stimulation Relieves Pain in Office-Based Hysteroscopy

Results from a randomized trial published in Obstetrics & Gynecology show that patients who received transcutaneous electrical nerve stimulation (TENS) during office-based hysteroscopy without sedation had less pain and higher patient satisfaction compared with a placebo group.¹

Although in-office hysteroscopy is associated with increased safety and reduced complication rates, it may not be performed as frequently as possible because of pain management issues.^2,3 Previous findings show that a significant number of women are not able to benefit from office-based hysteroscopy because of pain.⁴

Researchers at CEU Cardinal Herrera University, Valencia, Spain assigned 46 women to each of 3 groups: a control group; an active  TENS group, in which participants were connected to a TENS unit via electrodes that were placed on either side of the spinal cord at the T10-L1 and S2-S4 levels and delivered electrical current; and a placebo group, in which electrodes were placed in the same locations, but did not deliver electrical stimulation from the TENS unit. The active TENS group received self-adjusted, high-frequency TENS that varied randomly between 80 and 100 Hz, with a pulse duration of 400 microseconds.

The main study outcome was pain levels, which were self-reported using visual analog scale (VAS) scores (0 to 100 mm) assessed at 5 different points: baseline, on entry of the hysteroscope into the cervical channel, on contact with the endometrium, immediately postbiopsy (performed if the exam revealed abnormal findings), and 5 minutes after the end of the procedure.

The analysis of participants’ VAS scores showed a clinically relevant reduction in pain (defined as a minimum 10-mm difference) in the active TENS group vs placebo at 3 of the stages examined:

• entry: −11 mm (95% confidence interval [CI], −17 to −5 mm; P <.001);
• contact: −21.9 mm (95% CI, −30 to −13.9 mm; P <.001); and
• biopsy: −30.5 mm (95% CI, −47.1 to −13.8 mm;  P <.001).

In addition, the active TENS group reported higher patient satisfaction vs placebo on a 0 to 10 rating scale (1.3; 95% CI, 0.5-2.2; P =.001). There were no between-group differences in terms of vital signs, vasovagal symptoms such as dizziness and nausea, or adverse events such as skin allergy.

“The advantages of TENS include it being inexpensive, quick, easy to use, noninvasive, safe, free from any side effects, and it does not require the injection of any drugs that may cause undesirable reactions,” the authors wrote. The higher patient satisfaction ratings for TENS further suggest that the use of the procedure could increase acceptance and use of office-based hysteroscopy.