Transcutaneous Electrical Nerve Stimulation (TENS) is commonly used as an electroanalgesic and has been shown to be efficacious in the treatment of chronic musculoskeletal pain (Johnson et al. 2007). TENS is believed to preferentially stimulate large alpha sensory nerves and reduce pain at the presynaptic level in the dorsal horn of the spinal cord through nociceptive inhibition (Cheing et al. 1999).
| Author Year Country PEDro Score Research Design Total Sample Size | Methods | Outcome |
| Bi et al. 2015 China RCT PEDro=7 Nstart=52 Nend=48 | Population: TENS group: Mean age=35.5±9.0 yr; Gender: males=17, females=7; Time since injury=7.0±4.1 mo; Level of injury: tetraplegia=10, paraplegia=16; Severity of injury: complete=15, incomplete=11; Type of pain=neuropathic. Control group: Mean age=33.6±8.5 yr; Gender: males=15, females=9; Time since injury=6.8±3.1 mo; Level of injury: tetraplegia=7, paraplegia=19; Severity of injury: complete=18, incomplete=8; Type of pain=neuropathic. Intervention: Participants were randomized to either a TENS group and treated with TENS or a control group and treated with sham TENS for 20 min, 3 times/wk for 12 wks. Outcome Measures: Pain (visual analog scale (VAS) and the McGill Pain Questionnaire (MPQ)). Transcutaneous electrical nerve stimulation (TENS) | 1. Significant difference between the TENS and control group in VAS pain severity scores (p<0.05). 2. Significant difference between the TENS and control group in MPQ pain severity scores (p<0.05). |
| Ozkul et al. 2015 Turkey RCT Crossover PEDro=5 N=24 | Population: Mean age=32.33; Gender: males=18, females=6; Level of injury: paraplegia=6, quadriplegia=18; Severity of injury: incomplete=7, complete=17; Mean time post injury=12.46mo; Type of pain=neuropathic. Treatment: Participants received transcutaneous electrical nerve stimulation (TENS) and visual illusion (VI) in a randomized sequence. Each treatment was delivered for 2wk with a 1wk washout period in between. Outcomes were assessed pre and post each treatment period. Outcome Measures: Visual Analogue Scale – Pain Intensity (VAS-PI), Neuropathic Pain Scale (NPS), Brief Pain Inventory (BPI). | 1. There was a reduction in VAS-PI immediately after VI (p=0.07) and TENS (p=0.08), but there was no statistically significant group effect. 2. There was a significant reduction in pain 2wk post TENS (p=0.04) but not 2wk post VI (p>0.05). 3. On NPS, VI significantly decreased the following pain types: hot (p=0.047), sharp (p=0.02), unpleasant (p=0.03), and deep (p=0.047); TENS did not show any significant effects. 4. On BPI, VI significantly decreased the negative effect of pain on moving ability (p=0.04) and TENS significantly decreased the negative effect of pain on mood (p=0.03), relationships (p=0.04), and sleep (p=0.04). |
| Norrbrink 2009 Sweden PCT N=24 | Population: Age=47.2yr; Gender: males=20, females=4; Level of injury: C=13, T=8, L=3. Type of pain=neuropathic and musculoskeletal Intervention: Patients were provided with either low frequency (2Hz) or high frequency (80Hz) transcutaneous electrical nerve stimulation (TENS) stimulation for 30-40 min 3x/day for 2 wk followed by a 2 wk washout period and switched stimulation frequency. Outcome Measures: Numeric Rating Scale (NRS) | 1. No significant difference was found between the two modes of stimulation. 2. 21% reported reduction of greater than or equal to 2 units of general pain intensity (more than 1.8 considered significant clinical reduction), 29% in worst pain intensity and 33% in pain unpleasantness. 3. 29% reported a favorable effect on the global pain relief scale from HF and 38% from LF stimulation. |
| Zeb et al. 2018 Pakistan Pre-Post N=60 | Population: Mean age=52.6±0.5; Gender: males=45, females=15; Severity of injury: all incomplete; Type of pain=neuropathic. Intervention: Participants engaged in high frequency (80 Hz) transcutaneous electrical nerve stimulation (TENS) for 45 min/day, 4 days/wk for 8wks with assessments at baseline and post-intervention. Outcome Measures: Pain intensity (visual analog score (VAS)). | 1. Mean pain intensity decreased in a linear fashion and showed a significant difference from pre- to post-intervention (p<0.05). |
| Davis & Lentini 1975 USA Case Series N=31 | Population: Type of pain=neuropathic Treatment: Patients were tested with transcutaneous nerve stimulation. Outcome Measures: Subjective patient report. | 1. Those with a cervical injury (n=4) were not successfully treated with TENS. About 1/3 of patients (n=11) felt that the treatment was a success, with those experiencing at-injury site pain most effectively treated. |
Discussion
In an RCT, TENS was found to significantly reduce pain severity compared to a sham group over a 12 week intervention (Bi et al. 2015). Ozkul and colleagues (2015) found TENS was effective in reducing pain intensity, mood, and sleep interference compared to VI overall. However, VI resulted in significant reduction in hot, sharp, unpleasant, and deep pain types while TENS was not. In terms of low vs. high frequency TENS, Norrbring (2009) found no significant difference between the two frequencies in reducing pain post SCI.
Conclusion
There is level 1b evidence (Bi et al. 2-15) that transcutaneous electrical nerve stimulation reduced pain post SCI.
