Effectiveness of transcutaneous electrical nerve stimulation on postoperative pain with movement.

This study tested the effectiveness of episodic transcutaneous electrical nerve stimulation (TENS) as a supplement to pharmacologic analgesia on pain with movement and at rest after abdominal surgery and evaluated whether its use during walking and vital capacity maneuvers enhances performance of these activities. TENS, with a modulated frequency, intensity as high as the subject could tolerate, and electrodes placed on either side and parallel to the incision, was compared to placebo TENS and pharmacologic analgesia alone (control) by using a crossover design. Self-report of pain intensity, walking function, and vital capacity were assessed on 33 subjects. TENS resulted in significantly less pain than the control during both walking (P <.5) and vital capacity activities (P <.1) and significantly less pain than placebo TENS during vital capacity (P <.01). TENS also produced significantly better gait speeds than the control (P <.05) and greater gait distances (P <.01) than the control and placebo TENS. Vital capacity and pain intensity at rest were not significantly different among the 3 treatments. These results suggest TENS reduces pain intensity during walking and deep breathing and increases walking function postoperatively when used as a supplement to pharmacologic analgesia. The lack of effect on pain at rest supports the hypothesis that TENS works through reducing hyperalgesia.