Topuz 2004.
| Methods | Randomized, placebo‐controlled trial, parallel design
Sample size: N = 60; after five dropouts, 55 subjects remained (group 1: N = 12; group 2: N = 15; group 3: N = 15; group 4: N = 13)
Treatment duration: two weeks
No follow‐up
TENS administered by researcher in clinic Subjects with prior TENS exposure were excluded |
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| Participants | Inclusion: low‐back pain for at least three months and ambulatory Exclusion: history of cancer; use of corticosteroids or anticoagulants; use of cardiac pacemaker; prior lumbar spine surgery; known heart disease; severe co‐existing disease; vertebral fracture; spinal infection; spinal tumour; severe orthopedic abnormalities; nerve root findings; previous use of a therapeutic electrical stimulation modality Mean age (SD): group 1 = 41.92 (7.70); group 2 = 45.20 (11.19); group 3 = 50.13 (11.97) Pain severity (SD): group 1 = 5.75 (1.35); group 2 = 6.53 (1.18); group 3 = 6.86 (1.24) Pain duration in months (SD): group 1 = 16.81 (8.75); group 2 = 16.46 (9.78); group 3 = 20.53 (14.42) Gender (% female): group 1 = 91.7%; group 2 = 60%; group 3 = 73.3% No significant differences in the Beck Depression Inventory between treatment groups Withdrawals and Dropouts ‐ five dropouts (8.3% of sample) for personal reasons; three of the dropouts were in the Placebo TENS group and two were in the percutaneous neuromodulation therapy group |
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| Interventions | Group 1: Placebo TENS
Group 2: Conventional TENS
Group 3: Low‐frequency TENS
Group 4: Percutaneous neuromodulation therapy (not considered) TENS device: Trio 300 units generating symmetric, biphasic, rectangular pulses Stimulation modes: Conventional TENS and Low Frequency TENS Pulse Frequency: 80Hz for Conventional TENS group; 4Hz for Low‐frequency TENS group Pulse Width: 100 μsec Amplitude: For the conventional TENS group, the amplitude was increased up to the subjects' perception of paresthesia; for the low frequency TENS group, amplitude was increased to a maximum tolerated level without inducing muscle contraction Electrode Placement: four electrodes (2x2 cm) were placed in a standard dermatomal pattern over the most painful lumbar region Treatment duration: 20 minutes per session Treatment schedule: five sessions per week for two weeks Cumulative stimulation time: 200 minutes or just over three hours Concurrent treatment: No specific restrictions on the use of analgesic medications, except corticosteroids Subjects were told that they might or might not perceive the electrical stimulation and that it was sometimes below a patient's threshold of perception |
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| Outcomes | Pain intensity (10 cm visual analogue scale)
Activity Pain (10 cm visual analogue scale)
Oswestry Disability Index
Low Back Pain Outcome Scale
Health Status Survey Short Form (SF‐36) 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) | Low risk | A ‐ Adequate |
| Blinding (performance bias and detection bias) All outcomes ‐ patients? | Low risk | |
| Blinding (performance bias and detection bias) All outcomes ‐ providers? | High risk | |
| Blinding (performance bias and detection bias) All outcomes ‐ outcome assessors? | Unclear risk | Unclear from text |
| Incomplete outcome data (attrition bias) All outcomes ‐ drop‐outs? | Low risk | five dropouts (8.3% of sample) for personal reasons; three of the dropouts were in the Placebo TENS group and two were in the percutaneous neuromodulation therapy group |
| 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 | |