The Effects of Transcutaneous Auricular Vagus Nerve Stimulation and Exercise on Functional Capacity of Chronic Low Back Pain

Background: Mechanical chronic low back pain (CLBP) known as a complex problem with low resolution rate and increased disabilities. Several studies showed vagus nerve stimulation benefit to chronic pain, but no study has evaluated functional outcome of CLBP yet. This study aims to investigate the effects of adding transcutaneous auricular vagus nerve stimulation (tVNS) to exercise therapy on functional capacity (lower extremity strength and functional mobility) of CLBP patients.Methods: A randomized controlled group study was conducted in ۲۲ patients mechanical CLBP aged ۱۶-۵۵. Participants were randomized into an exercise group (control) and an exercise with tVNS group (experimental). Outcome were lower extremity muscle strength measured by Five Times Sit to Sand test (FTSST), and functional mobility using Timed up and Go test (TUG) were evaluated before and after ۲ weeks intervention.Results: The mean FTSST of control group pre-test was ۱۲.۱۷± ۳.۰۱ and of post-test was ۱۲.۱۲± ۴.۰۵ with no significant difference (p=۰,۹۴۵). The mean FTSST of experimental group pre-test was ۱۸.۰۶ ± ۹.۲۰ and of post-test was ۱۲.۳۳ ± ۲.۴۲, indicating a significant difference (p=۰.۰۳۹), but there was no significant difference on Δ FTSTS between groups (p=۰.۱۱۹). The mean TUG of control group pre-test was ۹.۲۳ ± ۲.۰۰ and of post-test was ۸.۷۱ ± ۳.۱۳ indicating no significant difference (p=۰.۵۵۳). The mean TUG of experimental group pre-test was ۱۰.۱۳ ± ۲.۶۸ and of post-test was ۷.۷۶ ± ۱.۴۶ indicating a significant difference (p=۰.۰۱۱), while there was no significant difference on ΔTUG between groups (p=۰.۱۱۷).Conclusion: Our results suggest that tVNS addition to exercise therapy has beneficial effects on lower extremity muscle strength and functional mobility in CLBP patients during relatively short period in two weeks of intervention. Further research is needed to investigate the potential of tVNS therapy in CLBP.

Keywords:

Chronic low back pain , transcutaneous auricular vagus nerve stimulation (tVNS) , Exercise Therapy , functional capacity , Five Times Sit to Stand test (FTSST) , timed up and go test (TUG)