Percutaneous electrical nerve stimulation for low back pain - A randomizedcrossover study

Context Low back pain (LBP) contributes to considerable disability and lost wages in the United States. Commonly used opioid and nonopioid analgesic d rugs produce adverse effects and are of limited long-term benefit in the ma nagement of this patient population. Objective To compare the effectiveness of a novel nonpharmacologic pain the rapy, percutaneous electrical nerve stimulation (PENS), with transcutaneous electrical nerve stimulation (TENS) and flexion-extension exercise therapi es in patients with long-term LBP. Design A randomized, single-blinded, sham-controlled, crossover study from March 1997 to December 1997. Setting An ambulatory pain management center at a university medical center . Patients Twenty-nine men and 31 women with LBP secondary to degenerative di sk disease. Interventions Four therapeutic modalities (sham-PENS, PENS, TENS, and exerc ise therapies) were each administered for a period of 30 minutes 3 times a week for 3 weeks. Main Outcome Measures Pretreatment and posttreatment visual analog scale (V AS) scores for pain, physical activity, and quality of sleep; daily analges ic medication usage; a global patient assessment questionnaire; and Health Status Survey Short Form (SF-36). Results PENS was significantly more effective in decreasing VAS pain scores after each treatment than sham-PENS, TENS, and exercise therapies (after-t reatment mean +/- SD VAS for pain, 3.4 +/- 1.4 cm, 5.5 +/- 1.9 cm, 5.6 +/- 1.9 cm, and 6.4 +/- 1.9 cm, respectively). The average +/- SD daily oral in take of nonopioid analgesics (2.6 +/- 1.4 pills per day) was decreased to 1 .3 +/- 1.0 pills per day with PENS (P < .008) compared with 2.5 +/- 1.1, 2. 2 +/- 1.0, and 2.6 +/- 1.2 pills per day with sham-PENS, TENS, and exercise , respectively. Compared with the other 3 modalities, 91 % of the patients reported that PENS was the most effective in decreasing their LBP. The PENS therapy was also significantly more effective in improving physical activi ty, quality oi sleep, and sense of well-being (P < .05 for each). The SF-36 survey confirmed that PENS improved posttreatment function more than sham- PENS, TENS, and exercise. Conclusions In this sham-controlled study, PENS was more effective than TEN S or exercise therapy in providing short-term pain relief and improved phys ical function in patients with long-term LBP.