Transcutaneous electrical nerve stimulation (TENS) for chronic low‐back pain
Abstract
Background
Chronic low‐back pain (LBP) affects a significant proportion of the population. Transcutaneous electrical nerve stimulation (TENS) was introduced more than 30 years ago as an adjunct to the pharmacological management of pain. However, despite its widespread use, the usefulness of TENS in chronic LBP is still controversial.
Objectives
The aim of this systematic review was to determine the effectiveness of TENS in the management of chronic LBP.
Search methods
We searched the Cochrane Central Register of Controlled Trials (Issue 2, 2005), MEDLINE, EMBASE and PEDro up to April 1, 2005.
Selection criteria
Only randomized controlled clinical trials (RCTs) evaluating the effect of TENS on chronic LBP were included. Abstracts were excluded unless further data could be obtained from the authors.
Data collection and analysis
Two reviewers independently selected trials and extracted data using predetermined forms. Heterogeneity was tested with Cochrane's Q test. A fixed effect model was used throughout for calculating continuous variables, except where heterogeneity existed, in which case, a random effects model was used. Results are presented as weighted mean differences (WMD) with 95% confidence intervals (95% CI), where the difference between the treated and control groups was weighted by the inverse of the variance. Standardized mean differences (SMD) were calculated by dividing the difference between the treated and control by the baseline variance. SMD were used when different scales were used to measure the same concept. Dichotomous outcomes were analyzed with odds ratios.
Main results
The only two RCTs (175 patients) meeting eligibility criteria differed in study design, methodological quality, inclusion and exclusion criteria, type and method of TENS application, treatment schedule, co‐interventions and final outcomes. In one RCT, TENS produced significantly greater pain relief than the placebo control. However, in the other RCT, no statistically significant differences between treatment and control groups were shown for multiple outcome measures. Pre‐planned subgroup analyses, intended to examine the impact of different stimulation parameters, sites of TENS application, treatment durations and baseline patient characteristics were not possible due to the small number of included trials.
Authors' conclusions
There is limited and inconsistent evidence to support the use of TENS as an isolated intervention in the management of chronic LBP. Larger, multi‐center, randomized controlled trials are needed to better resolve the true effectiveness of TENS. Increased attention should be given to the risks and benefits of long‐term use, which more appropriately addresses the realities of managing chronic low‐back pain.
PICOs
Plain language summary
A systematic review of randomized‐controlled trials (two trials, 175 patients) was conducted to examine the effectiveness of TENS in treating chronic low‐back pain. The available evidence supporting the use of TENS as an isolated treatment modality is limited and conflicting. The usefulness of TENS as part of a multi‐disciplinary rehabilitation approach was not investigated.
