Thermal Therapy in Patients Suffering from Non-Specific Chronic Low Back Pain—A Systematic Review

Thermal therapy is frequently used as an adjunct to treatment in patients suffering from chronic low back pain. It is also an inherent part of patients’ self-administered pain treatment. This review aims to update the evidence for thermal therapy treatments in non-specific chronic low back pain patients and to rate the methodological quality of the corresponding clinical trials. Previous studies have reported contradictory evidence for the effectiveness of thermal therapy. An electronic search on MEDLINE (PubMed), PEDro, CENTRAL and CINHAL databases was conducted between May 2016 and February 2018. Clinical trials comparing local thermal therapy to conservative or no treatment were assessed for eligibility. Pain, physical function and global health were defined as outcome parameters. A total of n = 9 studies met the inclusion criteria. All of them applied an electrophysical agent as the thermal treatment: continuous ultrasound (n = 6), short-wave diathermy (n = 2), microwave diathermy (n = 1). Out of the n = 6 studies on ultrasound treatment, n = 2 reported significant within and between-group results for pain reduction after 4 to 6 weeks of treatment. Both short-wave diathermy studies demonstrated significant between-group results for pain reduction after 3 weeks of treatment. Contradictory results for all other observed outcome parameters were reported regardless of the intervention. Moreover, significant within-group results for the control groups questioned the effectiveness of the intervention treatments. Therefore, the effect of thermal therapy, (electrophysical agents), is not superior to any control treatment except for ultrasound treatment on short-term pain reduction.