Randomised controlled trial to compare surgical stabilisation of the l
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《英国医生杂志》
1 Nuffield Orthopaedic Centre, Oxford OX3 7LD, 2 University of Warwick, Division of Health in the Community, Coventry CV4 7AL, 3 Centre for Statistics in Medicine, Oxford OX3 7LF, 4 Clinical Trial Service Unit and Epidemiological Studies Unit, Radcliffe Infirmary, Oxford OX2 6HE
Correspondence to: J Fairbank jeremy.fairbank@ndos.ox.ac.uk
Objectives To assess the clinical effectiveness of surgical stabilisation (spinal fusion) compared with intensive rehabilitation for patients with chronic low back pain.
Design Multicentre randomised controlled trial.
Setting 15 secondary care orthopaedic and rehabilitation centres across the United Kingdom.
Participants 349 participants aged 18-55 with chronic low back pain of at least one year's duration who were considered candidates for spinal fusion.
Intervention Lumbar spine fusion or an intensive rehabilitation programme based on principles of cognitive behaviour therapy.
Main outcome measure The primary outcomes were the Oswestry disability index and the shuttle walking test measured at baseline and two years after randomisation. The SF-36 instrument was used as a secondary outcome measure.
Results 176 participants were assigned to surgery and 173 to rehabilitation. 284 (81%) provided follow-up data at 24 months. The mean Oswestry disability index changed favourably from 46.5 (SD 14.6) to 34.0 (SD 21.1) in the surgery group and from 44.8 (SD14.8) to 36.1 (SD 20.6) in the rehabilitation group. The estimated mean difference between the groups was –4.1 (95% confidence interval –8.1 to –0.1, P = 0.045) in favour of surgery. No significant differences between the treatment groups were observed in the shuttle walking test or any of the other outcome measures.
Conclusions Both groups reported reductions in disability during two years of follow-up, possibly unrelated to the interventions. The statistical difference between treatment groups in one of the two primary outcome measures was marginal and only just reached the predefined minimal clinical difference, and the potential risk and additional cost of surgery also need to be considered. No clear evidence emerged that primary spinal fusion surgery was any more beneficial than intensive rehabilitation.
Chronic low back pain is a common cause of distress and results in considerable personal and public financial consequences. Management is mostly non-operative, but spinal fusion has been used for nearly 90 years. Spinal fusion rates vary between and within countries.1 In England about 1000 lumbar fusions are performed per year.2 An almost direct relation exists between the numbers of operations performed each year and of orthopaedic and neurosurgeons per head of population.3 In the United States, spinal fusions for "degenerative changes" rose sharply from around 11 000 operations per year in 1996 to 37 000/year in 2001 (a 336% increase).4 Both the rationale and the techniques used to fuse the spine have been questioned.5 Multidisciplinary rehabilitation programmes that focus on physical, psychological, social, and occupational factors have been advocated for patients with chronic pain of the low back.6–8
This trial was conceived in response to the identification of weak evidence for surgery as a priority by the NHS standing group on health technology in 1994.9 10 The pragmatic trial was designed to compare two treatment strategies (spinal stabilisation surgery or intensive rehabilitation) for patients considered by surgeons to be candidates for surgical stabilisation of the lumbar spine.
Methods
This multicentre, randomised trial was set in 15 hospitals in the United Kingdom. Only consultant surgeons with training and expertise in performing spinal fusions participated. We approached an additional 39 centres where either the surgeon was unwilling to recruit patients or implementation of the intensive rehabilitation programme was impossible.
Eligibility criteria
We used the uncertainty of outcome principle to define our entry criteria and therefore depended on the current practice of many experienced spine surgeons and their patients.11 Patients who were candidates for surgical stabilisation of the spine were eligible if the clinician and patient were uncertain which of the study treatment strategies was best. Patients had to be aged between 18 and 55, with more than a 12 month history of chronic low back pain (with or without referred pain) and irrespective of whether they had had previous root decompression or discectomy.
Patients were ineligible if the surgeon considered that any medical or other reasons made one of the trial interventions unsuitable. These included infection or other comorbidities (inflammatory disease, tumours, fractures), psychiatric disease, inability or unwillingness to complete the trial questionnaires, or pregnancy. If patients had had previous surgical stabilisation surgery of the spine they were also excluded.
Objectives
The aim was to determine whether surgical stabilisation of the spine (by fusion or flexible stabilisation) was more or less effective at achieving worthwhile relief of symptoms over a two year period than an intensive rehabilitation programme based on principles of cognitive behaviour therapy.
Outcome measures
We assessed outcomes at baseline and 6, 12, and 24 months from randomisation by a trial research therapist in each centre. If the patient was unable to attend the follow-up appointments we mailed the questionnaire. We approached non-responders by phone, through their family doctor, and via national databases.
Primary outcome
The two primary measures at 24 months included a back pain specific questionnaire and a standardised walking test. The Oswestry low back pain disability index is scored from 0% (no disability) to 100% (totally disabled or bedridden) and designed to assess limitations of various activities of daily living.12 13 The shuttle walking test is a standardised, progressive, maximal test of walking speed and endurance.14–16
Secondary outcomes
The short form 36 general health questionnaire (SF-36) includes 35 items summarised in two measures related to physical and mental health. Each scale ranges from 0 (worst health state) to 100 (best health state). The summary measures are transformed to give a population mean of 50 (SD 10). The SF-36 is recommended as an outcome assessment for spinal disorders because it provides strong psychometric support and extensive normative data.
Psychological assessment—We used the distress and risk assessment method (DRAM), which includes the modified Zung depression index and somatic perception questionnaire, to assess anxiety and depression.17
Complications—We recorded the intraoperative use of anaesthetic agents, implants, and radiological investigations; complications of surgery and any adverse effects of rehabilitation; postoperative complications, implant failure and repeat surgery; and personal items and devices purchased by the patient because of lower back pain. Work status was monitored. We recorded "obvious pseudoarthrosis" only where it was clear to the treating surgeon that fusion had failed and that this was a problem to the patient.
Sample size
We used the Oswestry disability index to determine the sample size. The trial was designed to be able to detect a difference in mean score between the intervention groups of as little as 4 points.12 13 We estimated that 133 subjects would be required in each group to detect such a difference at the = 0.05 level with 80% power. We initially planned to recruit at least this number of patients in each of three separate clinical groups to allow reliable subgroup analysis, but most of the patients were recruited in one clinical category.
Interventions
Spinal stabilisation surgery—The particular technique used for spinal fusion was left to the discretion of the operating surgeon. This allowed choice of the most appropriate surgical approach, implant (if any), interbody cages, and bone graft material for that patient. A small number of surgeons used flexible stabilisation of the spine (the Graf or Global technique). This was recorded for each patient before randomisation.
Intensive rehabilitation programme—Each centre was modelled on a daily outpatient programme of education and exercise running on five days per week for three weeks continuously. Further details of the programme are reported elsewhere.15 Most centres offered 75 hours of intervention (range 60-110 hours), with one day of follow-up sessions at one, three, six, or 12 months after treatment. The rehabilitation programmes were led by physiotherapists but included clinical psychologists in all but one centre, as well as medical support. The daily exercises were individually tailored and paced to increase repetitions and duration, aiming to build on the participants' baseline ability. They included stretching of major muscle groups, spinal flexibility exercises, general muscle strengthening, spine stabilisation exercises, and cardiovascular endurance exercise using any mode of aerobic exercise (treadmill walking, step-ups, cycling, rowing). All but one centre included daily sessions of hydrotherapy. We used principles of cognitive behaviour therapy to identify and overcome fears and unhelpful beliefs that many patients develop when in pain.
Treatment allocation and recruitment
Surgeons approached patients who were candidates for spinal fusion. Each centre employed a trial research therapist to organise the trial locally, recruit patients, book treatment appointments, and carry out assessments. Patients were given verbal, written, and videotape (OMI, Oxford) explanations of the background and nature of the trial. The trial research therapists obtained written consent and carried out baseline assessments before randomisation.
Randomisation was generated centrally by computer program, with minimisation for various potential confounding factors: age, smoking, litigation, Oswestry score, clinical classification, and planned use of the Graf procedure.
Statistical methods
We carried out an intention to treat analysis. We used analysis of covariance (ANCOVA) to analyse quantitative outcomes at 24 months, with corresponding baseline values and treatment group as covariates.
We used multiple imputation to handle missing data. To impute the missing data we constructed multiple regression models including variables potentially related to the fact that the data were missing and also variables correlated with that outcome. We used Stata (StataCorp, College Station, Texas, USA)18 and PROC MI in SAS (SAS Institute, Cary, NC, USA) to obtain similar answers, and only the former are presented.
Results
A total of 349 patients were randomised between June 1996 and February 2002 from 15 centres in the UK (176 allocated to surgery and 173 to rehabilitation). The figure shows the progression through the trial. Table 1 shows the baseline characteristics of patients who entered the trial.
Table 1 Baseline characteristics of patients and clinical details at trial entry. Values are numbers of patients unless otherwise indicated
Compliance with treatment and follow-up
Table 2 shows data on participants' compliance with their treatment and follow-up. Forty eight (28%) patients randomised to rehabilitation had surgery by two years. Seven (4%) patients randomised to surgery had rehabilitation instead of surgery.
Table 2 Compliance with allocated intervention and further treatment
Complications
Intraoperative complications occurred in 19 surgical cases (table 3). Eleven patients required further operations on their lumbar spine during the two year follow-up. We did not identify any specific complications of the rehabilitation programmes.
Table 3 Complication due to surgery (each subject could have more than one complication)
Clinical outcomes
Oswestry scores improved slightly more in favour of surgery (–4.1, 95% confidence interval –8.1 to –0.1, P = 0.045). After imputation for missing follow-up data the mean difference was –4.5 (–8.2 to –0.8, P = 0.02) (tables 4 and 5). No significant heterogeneity in the effect on the Oswestry score was observed between the predefined groups of patient (table 6). No other difference between groups in any of the other outcomes at 24 months reached significance, even when we used imputed values (tables 4 and 5).
Table 4 Mean (SD) outcome values at 24 months, and differences in changes from baseline to 24 months
Table 5 Summary of results from available cases and from multiple imputation analyses
Table 6 Mean Oswestry disability score (with standard deviations) at baseline and 24 months by different subgroups
Discussion
Katz J. Lumbar spinal fusion: surgical rates, costs, and complications. Spine 1995;20: 78S-83S.
Department of Health (England). Hospital episode statistics, 1998-2003. London: DoH, 1998-2003.
Cherkin D, Deyo R, Loeser J, Bush T, Waddell G. An international comparison of back surgery rates. Spine 1994;19: 1201-6.
Deyo RA, Gray DT, Kreuter W, Mirza S, Martin, BI. United States trends in lumbar fusion surgery for degenerative conditions. Spine 2005 (in press).
Gibson J, Grant I, Waddell G. The Cochrane review of surgery for lumbar disc prolapse and degenerative lumbar spondylosis. Spine 1999;24: 1820-32.
Mayer T, Gatchel R, Kishino N. Objective assessment of spine function following industrial injury. A prospective study with comparison group and one year follow up. Spine 1985;10: 482-93.
Lindstrom I, Ohlund C, Eek C. The effect of graded activity on patients with sub acute low back pain: A randomised prospective clinical study with an operant conditioning behavioural approach. Phys Ther 1992;72: 279-93.
Guzman J, Esmail R, Karjalainen K, Malmivaara A, Irvin E, Bombardier C. Multidisciplinary rehabilitation for chronic low back pain: systematic review. BMJ 2001;322: 1511-6.
NHS Standing Group. Health technology (SGHT) report. London: Department of Health, 1994.
Turner J, Ersek M, Herron L, Heselkorn J, Kent D, Ciol M, et al. Patient outcomes after lumbar spinal fusions. JAMA 1992;268: 907-11.
Weijer C, Shapiro S, Cranley Glass K. For and against: clinical equipoise and not the uncertainty principle is the moral underpinning of the randomised controlled trial. BMJ 2000;321: 756-8.
Fairbank J, Pynsent P. The Oswestry Disability Index. Spine 2000;25: 2940-53.
Roland M, Fairbank J. The Roland-Morris disability questionnaire and the Oswestry disability questionnaire. Spine 2000;25: 3115-24.
Taylor S, Frost H, Taylor A, Barker K. Reliability and responsiveness of the shuttle walking test in patients with chronic low back pain. Physiother Res Int 2001;6: 170-8.
Frost H, Lamb S, Shackleton C. A functional restoration programme for chronic low back pain: a prospective outcome study. Physiotherapy 2000;86: 285-93.
Pratt R, Fairbank J, Virr A. The reliability of the shuttle walking test, the Swiss spinal stenosis questionnaire, the Oxford spinal stenosis Score, and the Oswestry disability index in the assessment of patients with lumbar spinal stenosis. Spine 2002;27: 84-91.
Main CJ, Wood PLR, Hollis S, Spanswick CC, Waddell G. The distress and risk assessment method: A simple patient classification to identify distress and evaluate the risk of poor outcome. Spine 1992;17: 42-52.
Royston P. Multiple imputation of missing values. Stata J 2004;4: 227-41.
M?ller H, Hedlund R. Surgery versus conservative treatment in adult isthmic spondylolisthesis. A prospective randomized study part 1. Spine 2000;25: 1171-5.
Fritzell P, Hagg O, Wessburg P, Nordwall A, Group SLSS. Chronic back pain and fusion: a comparison of three surgical techniques: a prospective multicentre randomized study from the Swedish Lumbar Spine Study Group. Spine 2002;27: 1131-41.
Brox J, S?rensen R, Friis A, Nygaard ?, Indahl A, Keller A, et al. Randomized clinical trial of lumbar instrumented fusion and cognitive intervention and exercises in patients with chronic low back pain and disc degeneration. Spine 2003;28: 1913-21.
Schonstein E, Kenny D, Keating J, Koes B, Herbert R. Physical conditioning programs for workers with back and neck pain: a Cochrane systematic review. Spine 2003;28(19): E391-5.
Liddle S, Baxter G, Gracey J. Exercise and chronic low back pain: what works? Pain 2004;107: 176-90.
European Commission Rersearch Directorate General. COST B13 Management Committee. European guidelines for the management of low back pain. www.backpaineurope.org, 2005 (accessed 17 May 2005).
H?gg O, Fritzell P, Elkselius L, Nordwall A. Predictors of outcome in fusion surgery for chronic low back pain. A report from the Swedish lumbar spine study. Eur Spine J 2003;12: 22-33.
Taylor S, Taylor A, Foy M, Fogg A. Responsiveness of common outcome measures for patients with low back pain. Spine 1999;24: 1805-12.(Jeremy Fairbank, consultant orthopaedic )
Correspondence to: J Fairbank jeremy.fairbank@ndos.ox.ac.uk
Objectives To assess the clinical effectiveness of surgical stabilisation (spinal fusion) compared with intensive rehabilitation for patients with chronic low back pain.
Design Multicentre randomised controlled trial.
Setting 15 secondary care orthopaedic and rehabilitation centres across the United Kingdom.
Participants 349 participants aged 18-55 with chronic low back pain of at least one year's duration who were considered candidates for spinal fusion.
Intervention Lumbar spine fusion or an intensive rehabilitation programme based on principles of cognitive behaviour therapy.
Main outcome measure The primary outcomes were the Oswestry disability index and the shuttle walking test measured at baseline and two years after randomisation. The SF-36 instrument was used as a secondary outcome measure.
Results 176 participants were assigned to surgery and 173 to rehabilitation. 284 (81%) provided follow-up data at 24 months. The mean Oswestry disability index changed favourably from 46.5 (SD 14.6) to 34.0 (SD 21.1) in the surgery group and from 44.8 (SD14.8) to 36.1 (SD 20.6) in the rehabilitation group. The estimated mean difference between the groups was –4.1 (95% confidence interval –8.1 to –0.1, P = 0.045) in favour of surgery. No significant differences between the treatment groups were observed in the shuttle walking test or any of the other outcome measures.
Conclusions Both groups reported reductions in disability during two years of follow-up, possibly unrelated to the interventions. The statistical difference between treatment groups in one of the two primary outcome measures was marginal and only just reached the predefined minimal clinical difference, and the potential risk and additional cost of surgery also need to be considered. No clear evidence emerged that primary spinal fusion surgery was any more beneficial than intensive rehabilitation.
Chronic low back pain is a common cause of distress and results in considerable personal and public financial consequences. Management is mostly non-operative, but spinal fusion has been used for nearly 90 years. Spinal fusion rates vary between and within countries.1 In England about 1000 lumbar fusions are performed per year.2 An almost direct relation exists between the numbers of operations performed each year and of orthopaedic and neurosurgeons per head of population.3 In the United States, spinal fusions for "degenerative changes" rose sharply from around 11 000 operations per year in 1996 to 37 000/year in 2001 (a 336% increase).4 Both the rationale and the techniques used to fuse the spine have been questioned.5 Multidisciplinary rehabilitation programmes that focus on physical, psychological, social, and occupational factors have been advocated for patients with chronic pain of the low back.6–8
This trial was conceived in response to the identification of weak evidence for surgery as a priority by the NHS standing group on health technology in 1994.9 10 The pragmatic trial was designed to compare two treatment strategies (spinal stabilisation surgery or intensive rehabilitation) for patients considered by surgeons to be candidates for surgical stabilisation of the lumbar spine.
Methods
This multicentre, randomised trial was set in 15 hospitals in the United Kingdom. Only consultant surgeons with training and expertise in performing spinal fusions participated. We approached an additional 39 centres where either the surgeon was unwilling to recruit patients or implementation of the intensive rehabilitation programme was impossible.
Eligibility criteria
We used the uncertainty of outcome principle to define our entry criteria and therefore depended on the current practice of many experienced spine surgeons and their patients.11 Patients who were candidates for surgical stabilisation of the spine were eligible if the clinician and patient were uncertain which of the study treatment strategies was best. Patients had to be aged between 18 and 55, with more than a 12 month history of chronic low back pain (with or without referred pain) and irrespective of whether they had had previous root decompression or discectomy.
Patients were ineligible if the surgeon considered that any medical or other reasons made one of the trial interventions unsuitable. These included infection or other comorbidities (inflammatory disease, tumours, fractures), psychiatric disease, inability or unwillingness to complete the trial questionnaires, or pregnancy. If patients had had previous surgical stabilisation surgery of the spine they were also excluded.
Objectives
The aim was to determine whether surgical stabilisation of the spine (by fusion or flexible stabilisation) was more or less effective at achieving worthwhile relief of symptoms over a two year period than an intensive rehabilitation programme based on principles of cognitive behaviour therapy.
Outcome measures
We assessed outcomes at baseline and 6, 12, and 24 months from randomisation by a trial research therapist in each centre. If the patient was unable to attend the follow-up appointments we mailed the questionnaire. We approached non-responders by phone, through their family doctor, and via national databases.
Primary outcome
The two primary measures at 24 months included a back pain specific questionnaire and a standardised walking test. The Oswestry low back pain disability index is scored from 0% (no disability) to 100% (totally disabled or bedridden) and designed to assess limitations of various activities of daily living.12 13 The shuttle walking test is a standardised, progressive, maximal test of walking speed and endurance.14–16
Secondary outcomes
The short form 36 general health questionnaire (SF-36) includes 35 items summarised in two measures related to physical and mental health. Each scale ranges from 0 (worst health state) to 100 (best health state). The summary measures are transformed to give a population mean of 50 (SD 10). The SF-36 is recommended as an outcome assessment for spinal disorders because it provides strong psychometric support and extensive normative data.
Psychological assessment—We used the distress and risk assessment method (DRAM), which includes the modified Zung depression index and somatic perception questionnaire, to assess anxiety and depression.17
Complications—We recorded the intraoperative use of anaesthetic agents, implants, and radiological investigations; complications of surgery and any adverse effects of rehabilitation; postoperative complications, implant failure and repeat surgery; and personal items and devices purchased by the patient because of lower back pain. Work status was monitored. We recorded "obvious pseudoarthrosis" only where it was clear to the treating surgeon that fusion had failed and that this was a problem to the patient.
Sample size
We used the Oswestry disability index to determine the sample size. The trial was designed to be able to detect a difference in mean score between the intervention groups of as little as 4 points.12 13 We estimated that 133 subjects would be required in each group to detect such a difference at the = 0.05 level with 80% power. We initially planned to recruit at least this number of patients in each of three separate clinical groups to allow reliable subgroup analysis, but most of the patients were recruited in one clinical category.
Interventions
Spinal stabilisation surgery—The particular technique used for spinal fusion was left to the discretion of the operating surgeon. This allowed choice of the most appropriate surgical approach, implant (if any), interbody cages, and bone graft material for that patient. A small number of surgeons used flexible stabilisation of the spine (the Graf or Global technique). This was recorded for each patient before randomisation.
Intensive rehabilitation programme—Each centre was modelled on a daily outpatient programme of education and exercise running on five days per week for three weeks continuously. Further details of the programme are reported elsewhere.15 Most centres offered 75 hours of intervention (range 60-110 hours), with one day of follow-up sessions at one, three, six, or 12 months after treatment. The rehabilitation programmes were led by physiotherapists but included clinical psychologists in all but one centre, as well as medical support. The daily exercises were individually tailored and paced to increase repetitions and duration, aiming to build on the participants' baseline ability. They included stretching of major muscle groups, spinal flexibility exercises, general muscle strengthening, spine stabilisation exercises, and cardiovascular endurance exercise using any mode of aerobic exercise (treadmill walking, step-ups, cycling, rowing). All but one centre included daily sessions of hydrotherapy. We used principles of cognitive behaviour therapy to identify and overcome fears and unhelpful beliefs that many patients develop when in pain.
Treatment allocation and recruitment
Surgeons approached patients who were candidates for spinal fusion. Each centre employed a trial research therapist to organise the trial locally, recruit patients, book treatment appointments, and carry out assessments. Patients were given verbal, written, and videotape (OMI, Oxford) explanations of the background and nature of the trial. The trial research therapists obtained written consent and carried out baseline assessments before randomisation.
Randomisation was generated centrally by computer program, with minimisation for various potential confounding factors: age, smoking, litigation, Oswestry score, clinical classification, and planned use of the Graf procedure.
Statistical methods
We carried out an intention to treat analysis. We used analysis of covariance (ANCOVA) to analyse quantitative outcomes at 24 months, with corresponding baseline values and treatment group as covariates.
We used multiple imputation to handle missing data. To impute the missing data we constructed multiple regression models including variables potentially related to the fact that the data were missing and also variables correlated with that outcome. We used Stata (StataCorp, College Station, Texas, USA)18 and PROC MI in SAS (SAS Institute, Cary, NC, USA) to obtain similar answers, and only the former are presented.
Results
A total of 349 patients were randomised between June 1996 and February 2002 from 15 centres in the UK (176 allocated to surgery and 173 to rehabilitation). The figure shows the progression through the trial. Table 1 shows the baseline characteristics of patients who entered the trial.
Table 1 Baseline characteristics of patients and clinical details at trial entry. Values are numbers of patients unless otherwise indicated
Compliance with treatment and follow-up
Table 2 shows data on participants' compliance with their treatment and follow-up. Forty eight (28%) patients randomised to rehabilitation had surgery by two years. Seven (4%) patients randomised to surgery had rehabilitation instead of surgery.
Table 2 Compliance with allocated intervention and further treatment
Complications
Intraoperative complications occurred in 19 surgical cases (table 3). Eleven patients required further operations on their lumbar spine during the two year follow-up. We did not identify any specific complications of the rehabilitation programmes.
Table 3 Complication due to surgery (each subject could have more than one complication)
Clinical outcomes
Oswestry scores improved slightly more in favour of surgery (–4.1, 95% confidence interval –8.1 to –0.1, P = 0.045). After imputation for missing follow-up data the mean difference was –4.5 (–8.2 to –0.8, P = 0.02) (tables 4 and 5). No significant heterogeneity in the effect on the Oswestry score was observed between the predefined groups of patient (table 6). No other difference between groups in any of the other outcomes at 24 months reached significance, even when we used imputed values (tables 4 and 5).
Table 4 Mean (SD) outcome values at 24 months, and differences in changes from baseline to 24 months
Table 5 Summary of results from available cases and from multiple imputation analyses
Table 6 Mean Oswestry disability score (with standard deviations) at baseline and 24 months by different subgroups
Discussion
Katz J. Lumbar spinal fusion: surgical rates, costs, and complications. Spine 1995;20: 78S-83S.
Department of Health (England). Hospital episode statistics, 1998-2003. London: DoH, 1998-2003.
Cherkin D, Deyo R, Loeser J, Bush T, Waddell G. An international comparison of back surgery rates. Spine 1994;19: 1201-6.
Deyo RA, Gray DT, Kreuter W, Mirza S, Martin, BI. United States trends in lumbar fusion surgery for degenerative conditions. Spine 2005 (in press).
Gibson J, Grant I, Waddell G. The Cochrane review of surgery for lumbar disc prolapse and degenerative lumbar spondylosis. Spine 1999;24: 1820-32.
Mayer T, Gatchel R, Kishino N. Objective assessment of spine function following industrial injury. A prospective study with comparison group and one year follow up. Spine 1985;10: 482-93.
Lindstrom I, Ohlund C, Eek C. The effect of graded activity on patients with sub acute low back pain: A randomised prospective clinical study with an operant conditioning behavioural approach. Phys Ther 1992;72: 279-93.
Guzman J, Esmail R, Karjalainen K, Malmivaara A, Irvin E, Bombardier C. Multidisciplinary rehabilitation for chronic low back pain: systematic review. BMJ 2001;322: 1511-6.
NHS Standing Group. Health technology (SGHT) report. London: Department of Health, 1994.
Turner J, Ersek M, Herron L, Heselkorn J, Kent D, Ciol M, et al. Patient outcomes after lumbar spinal fusions. JAMA 1992;268: 907-11.
Weijer C, Shapiro S, Cranley Glass K. For and against: clinical equipoise and not the uncertainty principle is the moral underpinning of the randomised controlled trial. BMJ 2000;321: 756-8.
Fairbank J, Pynsent P. The Oswestry Disability Index. Spine 2000;25: 2940-53.
Roland M, Fairbank J. The Roland-Morris disability questionnaire and the Oswestry disability questionnaire. Spine 2000;25: 3115-24.
Taylor S, Frost H, Taylor A, Barker K. Reliability and responsiveness of the shuttle walking test in patients with chronic low back pain. Physiother Res Int 2001;6: 170-8.
Frost H, Lamb S, Shackleton C. A functional restoration programme for chronic low back pain: a prospective outcome study. Physiotherapy 2000;86: 285-93.
Pratt R, Fairbank J, Virr A. The reliability of the shuttle walking test, the Swiss spinal stenosis questionnaire, the Oxford spinal stenosis Score, and the Oswestry disability index in the assessment of patients with lumbar spinal stenosis. Spine 2002;27: 84-91.
Main CJ, Wood PLR, Hollis S, Spanswick CC, Waddell G. The distress and risk assessment method: A simple patient classification to identify distress and evaluate the risk of poor outcome. Spine 1992;17: 42-52.
Royston P. Multiple imputation of missing values. Stata J 2004;4: 227-41.
M?ller H, Hedlund R. Surgery versus conservative treatment in adult isthmic spondylolisthesis. A prospective randomized study part 1. Spine 2000;25: 1171-5.
Fritzell P, Hagg O, Wessburg P, Nordwall A, Group SLSS. Chronic back pain and fusion: a comparison of three surgical techniques: a prospective multicentre randomized study from the Swedish Lumbar Spine Study Group. Spine 2002;27: 1131-41.
Brox J, S?rensen R, Friis A, Nygaard ?, Indahl A, Keller A, et al. Randomized clinical trial of lumbar instrumented fusion and cognitive intervention and exercises in patients with chronic low back pain and disc degeneration. Spine 2003;28: 1913-21.
Schonstein E, Kenny D, Keating J, Koes B, Herbert R. Physical conditioning programs for workers with back and neck pain: a Cochrane systematic review. Spine 2003;28(19): E391-5.
Liddle S, Baxter G, Gracey J. Exercise and chronic low back pain: what works? Pain 2004;107: 176-90.
European Commission Rersearch Directorate General. COST B13 Management Committee. European guidelines for the management of low back pain. www.backpaineurope.org, 2005 (accessed 17 May 2005).
H?gg O, Fritzell P, Elkselius L, Nordwall A. Predictors of outcome in fusion surgery for chronic low back pain. A report from the Swedish lumbar spine study. Eur Spine J 2003;12: 22-33.
Taylor S, Taylor A, Foy M, Fogg A. Responsiveness of common outcome measures for patients with low back pain. Spine 1999;24: 1805-12.(Jeremy Fairbank, consultant orthopaedic )