The effectiveness of acupuncture/TENS for phantom limb syndrome. I: A systematic review of controlled clinical trials

Phantom limb pain (PLP) is a complex condition that affects up to 85% of amputees, causing significant pain at the site where the limb was removed. This systematic review investigated the efficacy of acupuncture and transcutaneous electrical nerve stimulation (TENS) in the treatment of PLP and phantom limb sensation. The investigators conducted a comprehensive search in 18 databases in English, Chinese, and Korean, identifying five controlled trials with 237 total participants, published between 1988 and 2010. Two studies evaluated acupuncture compared with usual care, two evaluated TENS compared with sham TENS, and one compared different sites of TENS application.

The acupuncture studies showed promising results when combined with rehabilitation. Yang et al. demonstrated significant improvement in pain after earthquake-related treatment, with a reduction on the visual analog scale from 1.82±1.919 to 0.17±0.804 (p < 0.05), maintained for three months. Liaw et al.

showed that contralateral acupuncture was more effective when applied early, especially in the first week after PLP onset. The TENS studies also showed positive results. Katz and Melzack demonstrated that high-intensity auricular TENS significantly reduced both phantom limb sensation and pain compared with sham TENS. Finsen et al.

found that low-frequency (2 Hz) segmental TENS reduced postoperative analgesic requirements. Liao et al. showed that contralateral-side stimulation was more effective than stimulation on the stump (2.23±2.24 vs. 5.77±2.46 on VAS).

The methodological quality of the studies was limited, with only two non-randomized studies of good quality and one randomized controlled trial of very low quality. Common problems included lack of adequate randomization, insufficient description of methods, absence of sample-size calculation, and lack of reporting of adverse events. Heterogeneity of outcomes and interventions precluded meta-analysis. Proposed mechanisms of efficacy include modulation of pain perception through the central nervous system, sensory cortical reorganization, and the gate control theory of pain.

In traditional Chinese medicine, PLP is viewed as resulting from disturbance of qi 氣 and blood stasis in the meridians. The clinical implications suggest that both acupuncture and TENS may be valuable therapeutic options for patients with PLP, especially considering that fewer than 10% of patients obtain lasting relief with conventional medical treatments. Early application appears more beneficial, and contralateral placement may be more effective than local stimulation of the stump. Despite methodological limitations, all studies reported positive effects regardless of time elapsed since amputation, suggesting potential benefit at different stages of the condition.

The absence of reported adverse events in all studies suggests these interventions are safe, although this may reflect underreporting rather than true absence of side effects.