Effects of Pulsed Low Frequency Magnetic Field Therapy on Pain Intensity in Patients with Musculoskeletal Chronic Low Back Pain: A Randomized Double Blind Placebo Controlled Trial

INTERVENTION: This is a two‐arm randomized, double blind, placebo controlled clinical trial. The trial will be conducted at the department of physical therapy of King Fahd Hospital of the University. King Fahd Hospital of the University is an 800 beds teaching hospital located at the Eastern Province of the Kingdom of Saudi Arabia. All researchers are clinicians at the departments of physical therapy and orthopedics. All participants will be recruited from the Hospital. All screening, interventions and evaluation will be done by qualified musculoskeletal physical therapists who have 5 or more years of clinical experience. Each participant will be assigned randomly to either the experimental group which will receive Pulsed Low Frequency Magnetic Field Therapy (PLFMF) and the conventional physical therapy program or the control group which will receive sham PLFMF and the conventional physical therapy program. Patients will be asked to lie down on the magnetic mattress for 20 minutes/session, three sessions a week for a total of 18 sessions (6 weeks). Each session (intervention or placebo) will last for 60 minutes as follows: 20 minutes for active PLFMF or placebo followed by 20 minutes for hot packs covering the lower back area and 20 minutes for exercises respectively. In the treatment group, the BEMER mattress will be activated whereas in the control group (placebo), no magnetic field will be generated. The conventional physical therapy program consists of: • Hot packs for 20 minutes; • Back, hamstring and calf muscles stretching (performed from long setting position) • Lumbar erector spinae muscles self‐stretching; • back muscles strengthening (back extension and bridging); • Abdominal muscles strengthening (posterior pelvic tilt and sit ups); Participants will be asked to hold the above positions for 5 seconds. Each exercise will be done 5 times per session with 1 minute rest between any two repetitions. The BEMER 3000 (BEMER Int. AG) will be used to deliver PLFMF (the machine will be pre‐programmed with an average intensity of 14 µT). The signal comprises of a series of half‐wave‐shaped sinusoidal intensity variations. The signal which starts with low values slowly increases and then decreases but it does not go back to the initial value (i.e. stay above zero). The intensity will gradually get denser with the repetition of the sequence leading to an increase in the ups and downs with repetition. Every second this procedure will be repeated 33.3 times with a reversal of polarity every 2 minutes. Trial staff will monitor adherence to the either treatment sessions through session attendance. CONDITION: Chronic low back pain PRIMARY OUTCOME: The percentage change in pain intensity by calculating the percentage change in numerical rating scale (NRS) of pain. ; The percentage change in pain will be calculated at each post‐baseline assessment as: ; 100 x ((difference between baseline and post‐pain NRS scores))/(baseline NRS score) SECONDARY OUTCOME: Change in condition assessed by Global perceived effect of condition change. Disability assessed by the Roland and Morris Disability Questionnaire. Fatigue assessed by Modified Fatigue impact scale. Function measurement assessed by Patient Specific Functional Scale. Quality of life assessed using Short Form 36 (SF‐36) quality of life questionnaire. Quality of sleep assessed by Pittsburgh Sleep Quality Index. The percentage change in pain intensity by calculating the percentage change in numerical rating scale (NRS) of pain. INCLUSION CRITERIA: • Clinical evidence of musculoskeletal chronic low back pain including subtype classification (nociceptive versus peripheral neuropathic versus central sanitization); • Age 18‐60 years old; • Primary complaint of pain (at least a score of 5 out of 10 on a 0‐ 10 numerical rating scale) in the area between the 12th rib and buttock crease, with or without leg pain for 3 months or more;