Study Design. Systematic literature review.
Objective. To categorize published evidence systematically for lumbar fusion for chronic low back pain (LBP) in order to provide an updated and comprehensive analysis of the clinical outcomes.
Summary of Background Data. Despite a large number of publications of outcomes of spinal fusion surgery for chronic LBP, there is little consensus on efficacy.
Methods. A MEDLINE and Cochrane database search was performed to identify published articles reporting on validated patient-reported clinical outcomes measures (2 or more of visual analogue scale, Oswestry Disability Index, Short Form  Health Survey [SF-36] PCS, and patient satisfaction) with minimum 12 months of follow-up after lumbar fusion surgery in adult patients with LBP due to degenerative disc disease. Twenty-six total articles were identified and stratified by level of evidence: 18 level 1 (6 studies of surgery vs. nonoperative treatment, 12 studies of alternative surgical procedures), 2 level 2, 2 level 3, and 4 level 4 (2 prospective, 2 retrospective). Weighted averages of each outcomes measure were computed and compared with established minimal clinically important difference values.
Results. Fusion cohorts included a total of 3060 patients. The weighted average improvement in visual analogue scale back pain was 36.8/100 (standard deviation [SD], 14.8); in Oswestry Disability Index 22.2 (SD, 14.1); in SF-36 Physical Component Scale 12.5 (SD, 4.3). Patient satisfaction averaged 71.1% (SD, 5.2%) across studies. Radiographical fusion rates averaged 89.1% (SD, 13.5%), and reoperation rates 12.5% (SD, 12.4%) overall, 9.2% (SD, 7.5%) at the index level. The results of the collective studies did not differ statistically in any of the outcome measures based on level of evidence (analysis of variance, P > 0.05).
Conclusion. The body of literature supports fusion surgery as a viable treatment option for reducing pain and improving function in patients with chronic LBP refractory to nonsurgical care when a diagnosis of disc degeneration can be made.