The effect of additional transcutaneous auricular vagus nerve stimulation on back muscle endurance of chronic low back pain

Background: This study aims to investigate the effects of adding transcutaneous auricular vagus nerve stimulation (tVNS) to exercise therapy on back extensor muscle endurance of patients with mechanical chronic low back pain (CLBP). Methods: A randomized controlled group study was conducted on 22 patients with mechanical CLBP aged 16-55. Participants were randomized into an exercise group (control) and an exercise with a tVNS group (experimental). The outcome was back extensor muscle endurance measured by the Biering Sorensen Test (BST), evaluated before and after 2 weeks of intervention. Results: There was a significant improvement in pre-post evaluation in the intervention group (before: 40.30± 31.20 and after: 66.49±45.87, p<0.05), with a large effect size (Cohen’s d=0.918). No difference in pre-post evaluation in the control group (before: 58.18±50.75; after: 66.82±38.56; p>0.05) with a small effect size (Cohen’s d=0.414). There was no significant difference between the delta BST of the two groups (p=0.418). Conclusion: Our results suggest that no difference was found between the two groups. However, tVNS addition to exercise therapy showed beneficial effects potency on back muscle endurance of the experimental group in CLBP patients during a relatively short period in two weeks of intervention. Further research is needed to confirm the potential of tVNS therapy in CLBP.