Lumbar spinal fusion (LSF) is a surgical procedure which aims to decompress and stabilize the lumbar spine in various degenerative disorders such as spinal stenosis, spondylolisthesis, disc herniation, and discogenic low back pain [
1‐
3]. Data provided by the US Department of Health and Human Services shows a substantial increase in hospitalizations for spinal fusion in the USA from 61,000 in 1993 to 296,211 in 2002 and over 451,000 in 2012 [
4]. Similarly, the contribution of spinal fusion to the national bill in the USA increased from $4.3 billion to $33.9 billion between 1998 and 2008 [
5]. Ageing and surgical advancement are likely to contribute to a further raise in use of LSF [
6].
The increasing use of LSF is remarkable, since definite proof of treatment efficacy of LSF for symptomatic degenerative lumbar spine conditions is still lacking [
7]. For example, there is insufficient evidence from randomized controlled trials supporting positive outcomes after surgery compared to nonsurgical treatment in patients with degenerative lumbar spondylolysis [
8]. Furthermore, Atlas et al. [
9] report in their prospective cohort study that long-term low back pain and patient satisfaction are similar regardless of surgical or nonsurgical treatment in patients with lumbar spinal stenosis. Pekkanen et al. [
10] show in their prospective cohort study a decrease in disability after LSF for degenerative conditions, although the patients did not reach similar disability outcomes compared to a general population at 1-year follow-up. In addition, several studies analysing cost-effectiveness report questionable outcomes of LSF in patients with degenerative spondylolisthesis [
11‐
13]. Moreover, LSF is not without any risks given the incidence of graft-specific complications (5.4–10.0 % [
14‐
16]) and revisions (2.0–6.9 % [
17‐
21]). Phillips et al. [
22] report in their systematic review that LSF compared to nonsurgical treatment significantly decreases pain and disability in patients with refractory chronic low back pain. However, the methodology of this study is criticized because of non-reporting of methodological quality of included studies, an unclear selection of studies, and inadequate pooling of results [
23]. Finally, the positive effect of LSF on patients with chronic low back pain seems to decrease at longer follow-up [
24]. Therefore, LSF might not be effective for the entire heterogeneous group of patients [
25].
In summary, LSF is increasingly used as treatment of degenerative disorders of the lumbar spine while evidence seems to show inconclusive outcomes and questionable cost-effectiveness. In particular, there is lack of understanding of long-term outcomes after LSF [
8]. An overview of the natural course of pain and disability in current LSF management is needed to improve understanding of recovery after LSF and to gain insight into optimal timing of rehabilitation or physiotherapy in the period after LSF. To the knowledge of the authors, no overview of the natural course after LSF exists. Therefore, the main objective is to systematically review and meta-analyse the natural course of pain and disability in patients with degenerative disorders of the lumbar spine such as spinal stenosis, spondylolisthesis, disc herniation, or discogenic low back pain after first-time LSF surgery.