Low-back pain (LBP) represents a leading cause for work absenteeism and visits to health care professionals. Sixty to 90% of the adult population is at risk of developing LBP. While the majority of episodes appear to resolve within six weeks, recurrences are common. In addition, it is estimated that 10% to 20% of affected adults develop symptoms of chronic LBP (persistent pain lasting longer than three months). Chronic LBP has a significant impact on everyday life.
Transcutaneous electrical nerve stimulation (TENS) is widely used as a supplemental therapy in the management of LBP. It is a relatively safe, non-invasive and easy to use treatment option. TENS units deliver electrical stimulation to the underlying nerves via electrodes placed over the intact skin surface near the source of maximal pain.
Four high-quality randomized controlled trials (RCTs; 585 patients) comparing TENS with placebo for chronic low-back pain were included in this study. Due to conflicting evidence, it is unclear if TENS is beneficial in reducing back pain intensity. However, there was consistent evidence in two trials (410 patients) that TENS did not improve the level of disability due to back pain. There was moderate evidence that use of medical services and work status (e.g. loss of work, sick days) did not change during treatment. Finally, there did not seem to be a difference between conventional and acupuncture-like TENS.
Some adverse effects were reported, typically minor skin irritations observed equally in the treatment and placebo groups. However, there was one participant who developed a severe rash four days after the start of treatment.