Paraspinal musculature and adjacent segment disease after lumbar fusion: a systematic review and meta-analysis of fusion with and without posterior instrumentation.

In 30 seconds

This systematic review and Bayesian meta-analysis compared standalone anterior, oblique, or lateral lumbar fusion with fusion involving posterior dissection and pedicle screw instrumentation in adults treated for degenerative lumbar conditions. Across 27 comparative studies involving 4,388 patients, standalone fusion was associated with lower odds of radiographic adjacent segment disease (OR 0.51, 95% CI: 0.28-0.96) and ASD-related reoperation (OR 0.58, 95% CI: 0.33; 0.86). All included studies were rated at serious risk of bias, so the findings do not establish that avoiding posterior muscle dissection causes the reduction.

Key findings

• Standalone fusion was associated with lower odds of radiographic ASD (OR 0.51, 95% CI: 0.28-0.96).
• Odds of reoperation for ASD were lower with standalone fusion (OR 0.58, 95% CI: 0.33; 0.86), but all-cause reoperation did not differ significantly.
• Cage subsidence was more likely after standalone fusion (OR 1.99, 95% CI: 1.22; 3.12).
• Fusion success and perioperative complications did not differ significantly; ODI scores were lower with standalone fusion (MD: -1.37, 95% CI: -2.76; -0.03).

Why it matters

The results highlight a potential trade-off in lumbar fusion: approaches avoiding posterior dissection were associated with less ASD and ASD-related reoperation, but more cage subsidence. This may inform consideration of surgical approach and the possible role of paraspinal muscle preservation, while the serious risk of bias across studies means the observed associations require cautious interpretation.

What to keep in mind

All 27 included studies were rated at serious risk of bias. The comparative evidence is observational, so it cannot establish that avoiding posterior dissection reduces ASD; the authors call for prospective randomized trials.