Background: Individuals with chronic low back pain (CLBP) present with deficits in the paraspinal musculature, including smaller cross-sectional areas (CSA) and decreased activation during loading tasks, compared with healthy controls. Neuromuscular electrical stimulation (NMES) is used during rehabilitation to improve muscle activation and strength, but research into the efficacy of NMES on individuals with CLBP is limited. Although evidence suggests that deficits in the paraspinal musculature are associated with subjective reports of pain and disability in CLBP patients, it is unknown if treatment with NMES can help reverse these deficits. The aim of this preliminary study was to compare the effects of a novel medium-frequency electrotherapy device (the StimaWELL 120MTRS system) on subjective reports of pain intensity, pain interference, disability, and catastrophizing in CLBP patients.

Methods: A pilot study was designed to assess the effect of a progressive NMES treatment using the StimaWELL 120MTRS system (Figure 1). This study is part of a larger project investigating the effect of NMES on paraspinal muscle morphology and function for CLBP. Four patients with CLBP received 20 supervised electrotherapy treatments, 2x/week, over a 10-week period. Treatments began at 20 minutes, and were increased by 5 minutes every 6 sessions, up to a maximum of 30 minutes. Outcomes measures were obtained at 3 time points (baseline, 6-week and 11-week) and included pain intensity (Numerical Pain Rating Scale), pain interference (Brief Pain Inventory), disability (Oswestry Disability Index), and catastrophizing (Pain Catastrophizing Scale). The change in each outcome over time was assessed for each participant.

Results: Four participants (3 women, 1 man – 34±12.6 yrs old) with CLBP completed the intervention. Average time since onset of pain was 8.9 ± 14.1 years. By week 11, mean LBP improved from 4.25±0.96 to 2.25±1.5, a change of 2±1.42. Disability improved from 21%± 6.61% to 8%±5.74%, a change of 13%±4.16%. Pain interference improved from 3.54±2.94 to 0.75±0.64, a change of 2.79±3.17. Pain catastrophizing improved from 21.25±17.23 to 8.75±7.5, a change of 12.5±15.72. No long-term adverse effects were reported. One participant reported transient numbness at the application site twice post-treatment.

Discussion: This study provides preliminary evidence that a NMES intervention using the StimaWELL 120MTRS system is safe and feasible for clinical use. Of note was participants’ improved pain and disability, along with other pain and psychosocial variables, following the intervention. We aim to conduct a larger scale investigation to expand our findings and evaluate whether this intervention can lead to improvements in paraspinal muscle morphology and function.

Figure 1. StimaWELL 120MTRS system