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affect the quality of life.5 CLBP accounts for about 15% of all cases of LBP; however, it has been reported to be the world-leading source of disability.6 In addition, CLBP is often associated with the socioeconomic burden and psychological distress.7 There is no published evidence of LBP cost in Saudi Arabia, the treatment cost for LBP in the USA is estimated to be more than $90 billion per year8 and $17 billion per year in the UK.9
LBP can be classified based on several criteria. It has been classified into acute and chronic based on how long the pain has persisted. It can also be classified into inflammatory and neuropathic based on the underlying mechanism.10 The main issue is how to differentiate the various subtypes clinically. In many occasions, differenti- ating the various phenotypes clinically is difficult. Smart et al11–13 proposed a mechanism-based classification to differentiate between different types of musculoskeletal LBP (central sensitisation, peripheral neuropathic and nociceptive).
Most of the mechanical LBP respond to rest and various physical modalities. Different conservative and surgical interventions have been used to manage CLBP; however, optimal therapy is still debatable.14 Many physical therapy interventions were tried in the management of CLBP such as soft tissue mobilisation and neurodynamic tech- niques,15 16 massage therapy,17 ultrasound, laser therapy, and shock wave therapy,18 exercises,19 Pilates practice,20 and acupuncture.21 While some of the rehabilitation interventions were effective in the short term, none of such interventions produce long-term effectiveness in the management of CLBP.2
Many pharmacological interventions have been used to manage CLBP. For example, non-steroid anti-inflamma- tory drugs and trammel were mild to moderately effec- tive in reducing pain without much effects on function.17 Similarly, opioids, benzodiazepines and duloxetine effects on reducing CLBP were small without inducing any improvement in function.22 Other drugs such as tricy- clic antidepressants and gabapentin were used; however, their efficacy was not established.23 Since CLBP persist for long term, pharmacological interventions are not a suit- able solution due to many reasons. Such reasons include toxicity due to long-term use, side and adverse effects in addition to problems with tolerance and addiction.24 Surgical procedures have been used in some cases of CLBP with a mixed outcome25; however, many patients are reluctant to go through surgery. Add to that the high cost of the surgery to the healthcare system. Further- more, the number of what is called ‘failed back surgery syndrome’ is in the rise.26
Since the conservative approaches currently used to manage CLBP do not seem to be effective on the long term, new approaches are needed to be developed. The new approaches should be safe, non-invasive and cost-effective.
Several lines of evidence indicate that pulsed low-fre- quency magnetic field (PLFMF) may be an attractive option for the management of CLBP. Magnetic field
blocked the sensory neuron action potential in cultured neurons27; however, it enhanced neuronal growth in the presence of growth factor.28 In rats, magnetic field suppressed the formation of oedema.29 Weintraub et al30 showed that magnetic field has a pronounced anti-no- ciceptive effect. Robertson et al31 showed that PLFMF affected pain and thermal signals in normal volunteers. Selvam et al32 reported that PLFMF restored the calcium ATPase activity of the plasma membrane and produced anti-inflammatory effects. PLFMF also inhibited pain processing in a dose-dependent manner.33 Clinically, PLFMF has been used for the treatment of different types of pain such as plantar fasciitis,34 lumber radicular pain,35 postoperative pain,36 peripheral neuropathy30 and osteo- arthritis.37 Recently, we concluded a study which showed that PLFMF was effective in reducing pain, improving sleep and quality of life in patients with carpal tunnel syndrome.38
In the case of CLBP, few studies were done and produced conflicting results. While Krammer et al,14 Oke and Umebese,39 and Harden et al40 reported that PLFMF was not superior to sham treatment in patients with CLBP, other studies reported that PLFMF signifi- cantly reduced pain intensity in patients with CLBP.41–43 Most of the studies which tested the effects of PLFMF on CLBP suffered from methodological problems and flaws. Such problems included failure to perform intention to treat as well as lack of proper blindness of patients and researchers. All these studies failed to classify the CLBP into different subgroups since CLBP is heterogeneous. Two of the studies reporting positive findings failed to compare PLFMF with other therapeutic modality.42 43 All the mentioned studies used small number sample sizes (16–40 patients).44 Some of these studies did not do any follow-up after the conclusion of the interventions or did a follow-up for a short period.45 Finally, the six studies used different machines producing different magnetic field intensity and frequency and different treatment protocols. Similarly, various studies reported controversial results regarding the effects of PLFMF on the level of disability and quality of life in patients with CLBP. Some studies reported that PLFMF improved the level of disability and/or quality of life41 42 46 while other studies reported no effects for PLFMF on disability and/ or quality of life.14 43 47 Two systematic reviews investi- gated the effects of PLFMF on CLBP. Andrade et al45 concluded that PLFMF treatment is superior to placebo treatment. However, Hug and Roosli48 concluded that available evidence is not sufficient to recommend the use of PLFMF clinically. Both reviews recommended better controlled randomised studies are needed to clarify the effects of PLFMF on CLBP.
PLFMF is known to be safe, non-invasive, low cost, easy to administer and has no known side effects in the manage- ment of patients with CLBP.48 Improving the condition of patients with CLBP will spare the patient going through several rounds of pharmacological and non-pharma- cological treatment as well as invasive procedures like
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Abdulla FA, et al. BMJ Open 2019;9:e024650. doi:10.1136/bmjopen-2018-024650
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