Introduction: Prior research has reported that individuals with non-specific chronic low back pain (NSCLBP) display impaired balance control and functional disability. Theoretically, if pain is a cause of suboptimal balance control, remission from pain may improve the balance control of these individuals. However, no systematic review has summarized evidence regarding whether reduced pain intensity in individuals with NSCLBP following conservative interventions is related to corresponding improvements in balance control. The current systematic review and meta-analysis address this gap by synthesizing the evidence regarding the temporal association between these two variables.
Methods: Relevant studies were searched from the Medline, Cochrane Library, Embase, Web of Science, and PsycINFO databases. Four reviewers independently screened the eligibility of randomized controlled trials investigating the effects of conservative treatments (nonsurgical and nonpharmacological) for NSCLBP on pain intensity and balance control. Pain intensity was measured with the Visual Analog Scale, or the Numeric Pain Rating Scale. Balance-control parameters included the concern about falls (Falls Efficacy Scale-International), postural sway, one-leg stance, star-excursion balance test, timed up-and-go test, five times sit-to-stand test, and gait parameters. A series of meta-regressions were performed to establish the associations between post-treatment changes in pain intensity and corresponding changes in balance control. The evidence level was assessed based on van Tulder’s criteria.
Results: Of 7,311 identified records, 42 studies involving 1,913 participants with NSCLBP were included. Strong to moderate evidence revealed that reduced pain was related to reduced sway (smaller center of pressure area and slower velocity). Limited evidence suggested an association between pain relief and improved one-leg stance with eyes open, and that reduced pain was associated with improvements in posteromedial and composite scores of the star-excursion balance test. Furthermore, moderate to limited evidence indicated that pain relief was associated with improved functional activities as measured by the five times sit-to-stand test, timed up-and-go test, Falls Efficacy Scale-International, and walking speed.
Discussion: Pain relief following conservative interventions may enhance balance control in individuals with NSCLBP. However, pain relief alone may only account for part of such improvements. Temporal changes in cognitive function or psychological factors may also play potential roles in the recovery of balance control. Future studies should adjust for potential confounders in the analysis to clarify the influence of pain reduction in improved balance control.