Jarzem 2005a.
| Methods | Randomized , placebo‐controlled, parallel design
Sample size : N = 350; after 26 withdrawals, 324 subjects remained (group 1: N = 84; group 2: N = 84; group 3: N = 78; group 4: N = 79)
Treatment duration: four weeks
Follow‐up: three months (outcomes not reported)
TENS administered by subjects at home; outcomes measured at home and in the clinic setting Subjects with prior TENS exposure were excluded |
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| Participants | Inclusion: Continuous low‐back pain without leg symptoms for at least three months; age between 18 and 70; able to make all required visits Exclusion: Maximal pain above T12; previous use of TENS; patient currently seeking to obtain disability compensation; history of cancer; corticosteroids or anticoagulant use; implanted pacemaker; sciatica; concomitant physiotherapy or chiropractic therapy; recent surgery in the previous three months; onset of major illness; pregnancy Age: total sample = 45.1 Pain duration in years: total sample = 10.1 (Group 1 = 10.1; group 2: 9.0; group 3 = 9.4; group 4 = 12.2) Baseline pain intensity not reported Gender breakdown: 50% female, 50% male Withdrawals and dropouts: 26 withdrawals (7.4% of sample) due to inability to return to clinic for all evaluation sessions; distribution of dropouts according to treatment group was not reported; note that only 70% returned questionnaires and diaries at the three‐months follow‐up (data contained in the questionnaires and diaries were not reported) |
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| Interventions | Group 1: Placebo TENS
Group 2: Conventional TENS
Group 3: Acupuncture‐like TENS
Group 4: NuWave TENS (not considered in this review) TENS device not reported Stimulation parameters not reported Electrode number and size not reported Electrode placement: adjusted to the patient's preference Treatment schedule: daily treatment for four weeks, average of 188 minutes of use per day Total treatment time: 5264 minutes or about 88 hours Concurrent treatment: exercise programs were assigned by physiotherapists to all subjects; medication use was monitored; subjects undergoing other physiotherapy or chiropractic therapy were excluded The placebo TENS devices had indicator lights to mimic operation; all subjects were told that some might or might not feel the stimulation |
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| Outcomes | Roland‐Morris Disability Questionnaire
McGill work scale
McGill activity scale
Zung depression scale
Physical measures (flexion, extension, straight leg raise, isometric dead‐lift score) Patient Diaries tracking pain intensity (VAS), frequency of pain medication usage, ancillary care, general medical concerns and usage of the TENS unit were not returned in 30% of cases and the data was not reported Outcomes not reported at three months follow‐up (30% loss to follow‐up) No reporting of adverse effects |
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| Notes | Quality 8/11 See Table 1 for questions | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | |
| Allocation concealment (selection bias) | Unclear risk | B ‐ Unclear |
| Blinding (performance bias and detection bias) All outcomes ‐ patients? | Low risk | |
| Blinding (performance bias and detection bias) All outcomes ‐ providers? | Unclear risk | Unclear from text |
| Blinding (performance bias and detection bias) All outcomes ‐ outcome assessors? | Low risk | |
| Incomplete outcome data (attrition bias) All outcomes ‐ drop‐outs? | High risk | 26 withdrawals (7.4% of sample) due to inability to return to clinic for all evaluation sessions; distribution of dropouts according to treatment group was not reported; note that only 70% returned questionnaires and diaries at the three‐months follow‐up (data contained in the questionnaires and diaries were not reported) |
| Incomplete outcome data (attrition bias) All outcomes ‐ ITT analysis? | High risk | |
| Similarity of baseline characteristics? | Low risk | |
| Co‐interventions avoided or similar? | Low risk | |
| Compliance acceptable? | Low risk | |
| Timing outcome assessments similar? | Low risk | |