Do manual therapies help low back pain? A comparative effectiveness meta-analysis.

Area of Science:

• Integrative medicine and evidence-based practice.
• Clinical epidemiology and meta-analysis.

Background:

• Previous research on spinal manipulation therapies (SMTs) for non-surgical low back pain has yielded equivocal results.
• Nearly 40 years of studies on SMTs have not provided conclusive evidence regarding their effectiveness.

Purpose of the Study:

• To determine the relative effectiveness of spinal manipulation therapies (SMTs), medical management, physical therapies, and exercise for acute and chronic non-surgical low back pain.
• To extend meta-analysis methodology to derive comparative effectiveness information from existing literature.

Main Methods:

• A meta-analysis was conducted using studies previously included in evidence syntheses.
• Effect sizes were standardized, and probabilities of recovery were calculated.
• Nested model comparisons differentiated nonspecific effects from treatment effects, with aggregate data compared against sham controls.

Main Results:

• For acute low back pain, 81% of variance was due to nonspecific factors, with treatments showing no significant superiority over sham interventions.
• For chronic low back pain, 66% of variance was nonspecific, but treatments influenced 32% of outcomes, with SMTs showing some response.
• Both acute and chronic pain outcomes largely fell within the confidence bands predicted by natural history alone.

Conclusions:

• Meta-analyses can effectively extract comparative effectiveness data, but small treatment effect sizes explain inconsistent research findings.
• The probability of treatment superiority aligns with random chance, suggesting treatments' primary role may be in patient motivation and expectation management.
• Exercise, when provided with authoritative support, emerges as an effective strategy for both acute and chronic low back pain.