Martin Underwood (Warwick Medical School, University of Warwick, Coventry, UK) has worked as a general practioner in Lusaka, Manchester, London and Coventry, UK. He has a track record of community based research into the improved diagnosis and management of musculoskeletal disorders, particularly back pain. He has completed large trials on exercise, manual therapy and cognitive behavioural approaches to treating low back pain. Other work has tested self-management approaches to management of chronic pain, as well as work on the role of intra-articular facet joint injections and qualitative work on the experience of living with back pain. On behalf of the UK National Institute for Health and Care Excellence (NICE), Underwood has chaired two guideline development groups and the Accreditation Advisory Committee. Current large projects include a trial of opioid reduction for people with chronic non-malignant pain. Here, he argues spinal surgery is an inappropriate intervention in the treatment of non-specific low back pain.
Low back pain, largely non-specific low back pain, is the leading global cause of disability. The specific causes of low back pain (malignancy, fracture, infection, inflammatory disorders such as ankylosing spondylitis) are not the subject of this article. A recent series of papers in the medical journal The Lancet has identified the massive increase in low back pain disability globally: 54% between 1990 and 2015. It advocates avoiding harmful and useless treatments for low back pain by “adopting a framework similar to that used in drug regulation”.1-3 There is a need to consider the role, if any, for surgery in the treatment of non-specific low back pain.
Clinical experience is unlikely to help us here since the natural history of chronic low back pain follows a fluctuating course. Inevitably, therefore, people seek a consultant when their back pain is at its worst, and regardless of the treatment we offer they are likely to be substantially improved a few weeks later. The phenomenon of substantial early improvement followed by little further change is well-documented in cohort studies, and in randomised controlled trials of conservative treatments for low back pain.4 There are fewer data from surgical studies. However, data from the British Spine Register show a slightly larger average improvement compared to non-surgical studies six weeks after surgery, but with a deterioration between six weeks and six months.5
There are some specific disorders associated with low back pain, for example cauda equina compression, for which surgery may clearly be indicated as a specific treatment for a specific lesion. Most spinal surgery is done for degenerative disease, although there is only a weak association between the presence of low back pain and degenerative change on MRI (magnetic resonance imaging).6,7 For many people who may be offered surgery for degenerative spinal disease, any radiological changes seen will not be making a contribution to their pain.
A further problem is that a recent systematic review of the accuracy of tests for patient selection found that it was not possible to identify a subset of patients for whom spinal fusion might be an effective treatment. This means that spinal fusion is a procedure for an abnormality only weakly related to the symptom it is trying to relieve with no way of identifying clinically the people who might benefit.8
The randomised controlled trial evidence for surgery as a treatment for low back pain is limited. Consequentially, NICE advises against disc replacement and further advises that spinal fusion should only be offered a part of a randomised controlled trial.9 The Medical Research Council spine stabilisation study did find a benefit, of borderline statistical significance, from spine stabilisation added to an intensive rehabilitation package. After two-years, participants gained an additional 4.1 (95% confidence interval [CI] 0.1–8.1) points on the Oswestry Disability Index.10 This equates to a small standardised mean difference (SMD, between groups difference/baseline standard deviation) of 0.28. The cost per Quality Adjusted Life Year (QALY), the key metric for deciding upon cost effectiveness, was £48,588, well over the threshold at which NICE would recommend funding.11
For perspective, it is worth considering the effect sizes seen in trials of acupuncture. A large meta-analysis of acupuncture, when compared to usual care for back and neck pain, found a moderate SMD of 0.55 (95% CI 0.51–0.58).12 Even when compared to sham acupuncture, one randomised controlled trial found a small SMD of 0.23 (95% CI 0.13 0.33) with a cost per QALY of £4,241.13 Whatever individuals’ views might be on the role of acupuncture in health care, few are likely to argue that these data indicate that surgery is likely to be superior to acupuncture.
A recent network meta-analysis of treatments for low back pain included studies of physical therapy, exercise plus cognitive behavioural therapy, spinal fusion, and disc replacement. This did not find a benefit from spinal fusion when compared to exercise plus cognitive behavioural treatment; 2.0 (95% CI -1.23–4.77) on the Oswestry Disability Index.14 It did find a statistically significant benefit for disc replacement when compared to exercise plus cognitive behaviour therapy; 6.4 points on Oswestry Disability Index (95% CI 3.16–9.31).14 This benefit is probably no larger than that seen in studies of acupuncture compared to usual care.
Surgery is inherently a very specific treatment. If there is an identifiable group of people for whom surgical treatment is indicated, then these people must have a pathognomonic (specific) cause for their low back pain. To justify surgery there needs to be evidence of a worthwhile benefit from multiple randomised trials. Further, if these conditions are satisfied, the benefit from surgical treatment needs to be large enough to justify the high financial and opportunity costs of performing surgery.
Some progress has been made in defining one possible sub-group that meets these criteria. Minimally invasive sacro-iliac joint fusion surgery for chronic sacro-iliac pain has been approved by NICE based on data from two small randomised controlled trials comparing it to usual care.15 In carefully selected patients with confirmed diagnosis of sacro-iliac problems, the short-term results of surgery are promising. In one trial, 81% of the people in the intervention group, and 26% in the control group, had successful outcomes at six months.15 However, we know little about the long-term outcomes and we do not know how this might compare to a sham procedure. Only a trial comparing sacro-iliac fusion with sham will tell us how much of the apparent benefit is due to the specific surgical procedure and how much is due to any non-specific effects. It is still too soon to declare sacro-iliac joint pain to be a specific back pain with a specific treatment. In practical terms, the limited applicability of the technique, and its high cost, mean it is unlikely to make a meaningful impact on the global tsunami of low back pain disability.
So far I have only considered the potential benefits from surgery as measured in randomised controlled trials. Such trials are not the most appropriate research method to identify potential harms. Spinal surgery has a high rate of complications; so high in fact that at least one UK provider of medical indemnity has stopped offering cover for spinal surgery performed in private hospitals.16 When assessing the risks of spinal fusion NICE noted a 17% complication rate and an 8% re-operation rate.17 A UK database study has examined what happens to people after spinal surgery. In the two years following surgery, one in five people (20.8%; 95% CI 19.7–21.9) needed further pain treatment (additional lumbar surgery, at least two pain related physician visits, or another surgical intervention such as neuromodulation or insertion of a drug infusion delivery system).9 These high complication rates put into perspective both the evidence of limited effectiveness for older surgical treatments such as spinal fusion, and the limited evidence for effectiveness of newer surgical treatments for low back pain such as disc replacement or sacro-iliac fusion.
In conclusion, it is clear that surgery for non-specific low back pain is an expensive procedure of limited clinical effectiveness with an unacceptable incidence of severe adverse events. It has no role in the treatment of non-specific low back pain outside of well-designed randomised controlled trials.
Martin Underwood is a general practioner in central Coventry for the Sky Blue Medical Group.
Declarations of interest: Underwood was Chair of the NICE accreditation advisory committee until March 2017, for which he received a fee. He is chief investigator or co investigator on multiple previous and current research grants from the UK National Institute for Health Research, Arthritis Research UK. Underwood received travel and accommodation expenses for speaking at conferences from the professional organisations hosting them. Underwood is a director and shareholder of Clinvivo Ltd that provides electronic data collection for health services research. He is part of an academic partnership with Serco Ltd related to return to work initiatives. Underwood is an editor of the NIHR journal series, for which he receives a fee. He has published multiple papers on back pain; some are referenced in this article.
1. Buchbinder, R., et al., Low back pain: a call for action. Lancet, 2018.
2. Foster, N.E., et al., Prevention and treatment of low back pain: evidence, challenges, and promising directions. Lancet, 2018.
3. Hartvigsen, J., et al., What low back pain is and why we need to pay attention. Lancet, 2018.
4. Artus, M., et al., The clinical course of low back pain: a meta-analysis
comparing outcomes in randomised clinical trials (RCTs)
and observational studies. BMC Musculoskelet Disord, 2014.15: p. 68.
5. Britsh Spine Registry End of year annual report 2016/17
6. Brinjikji, W., et al., MRI Findings of Disc Degeneration are More Prevalent in Adults with Low Back Pain than in Asymptomatic Controls: A Systematic Review and Meta-Analysis. AJNR Am J Neuroradiol, 2015. 36(12): p. 2394-9.
7. Steffens, D., et al., Does magnetic resonance imaging predict future low back pain? A systematic review. Eur J Pain, 2014. 18(6):p. 755-65.
8. Willems, P.C., et al., Spinal fusion for chronic low back pain: systematic review on the accuracy of tests for patient selection. Spine J, 2013. 13(2): p. 99-109.
9. Bernstein, I.A., et al., Low back pain and sciatica: summary of NICE guidance. BMJ, 2017. 356: p. i6748.
10. Fairbank, J., et al., Randomised controlled trial to compare surgical stabilisation of the lumbar spine with an intensive rehabilitation programme for patients with chronic low back pain: the MRC spine stabilisation trial. BMJ, 2005. 330(7502): p. 1233.
11. Rivero-Arias, O., et al., Surgical stabilisation of the spine compared with a programme of intensive rehabilitation for the management of patients with chronic low back pain: cost utility analysis based on a randomised controlled trial. BMJ, 2005. 330(7502): p. 1239.
12. MacPherson, H., et al., in Acupuncture for chronic pain and depression in primary care: a programme of research. 2017: Southampton (UK).
13. Thomas, K.J., et al., Longer term clinical and economic benefits of offering acupuncture care to patients with chronic low back pain. Health Technol Assess, 2005. 9(32): p. iii-iv, ix-x, 1-109.
14. Rihn, J.A., et al., Comparative Effectiveness of Treatments for Chronic Low Back Pain: A Multiple Treatment Comparison Analysis. Clin Spine Surg, 2017. 30(5): p. 204-225.
15. NICE. Minimally invasive sacroiliac joint fusion surgery for
chronic sacroiliac pain. 2017; Available from: https://www.nice.org.uk/guidance/ipg578/resources/minimally-invasivesacroiliac-joint-fusion-surgery-for-chronic-sacroiliac-painpdf-1899872114909893.
16. Hawkes, N., MDU ceases to cover private spinal surgery. BMJ. 2017 Jun 5;357:j2725. doi: 10.1136/bmj.j2725.
17. Weir, S., et al. The incidence and healthcare costs of persistent postoperative pain following lumbar spine surgery in the UK: a cohort study using the Clinical Practice Research Datalink (CPRD) and Hospital Episode Statistics (HES). BMJ Open. 2017 Sep 11;7(9):e017585. doi: 10.1136/bmjopen-2017-017585.