The effect of transcutaneous electrical nerve stimulation and low-level continuous heat on non-specific low back pain: a randomized controlled trial

Abstract

BACKGROUND: In the present investigation, there were two objectives 1) to determine if Transcutaneous electrical nerve stimulation (TENS) needs to be continuous or can be intermittent and still achieve pain relief and 2) to see how long pain relief lasts after 4 hours of application of tens, heat or both. METHODS: Individuals with non-specific chronic lower back painwere divided into 6 groups randomly and either received TENS, Low level continuous Heat (LLCH) or a combination of the 2. TENS (threshold intensity, frequency 20 Hz) was either ramped continuously or for the last 15 minutes of each hour. Pain was assessed by a visual analog scale (VAS) and pain from pressure on the back. Range of motion (ROM) in the trunk where pain was felt was measured. RESULTS: TENS with LLCH and even TENS applied for 15 minutes an hour with LLCH reduced pain in the lower back as assessed by the algometry and VAS for pain. The greatest reduction in VAS and pain from pressure was for TENS continuously and LLCH applied together. Pain relief for the LLCH and TENS groups or LLCH alone was largely maintained at 10 hours while TENS alone only showed pain relief only while applied. LLCH caused the majority of pain relief but TENS added significantly. For ROM at the trunk, flexion showed the greatest increase after the 3 heat modalities. CONCLUSIONS: LLCH and TENS offer the best pain relief when used continuously for 4 hours but using TENS for 15 minutes an hour provided very acceptable results.