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Research

Decompression alone or with fusion for degenerative lumbar spondylolisthesis (Nordsten-DS): five year follow-up of a randomised, multicentre, non-inferiority trial

BMJ 2024; 386 doi: https://doi.org/10.1136/bmj-2024-079771 (Published 07 August 2024) Cite this as: BMJ 2024;386:e079771

Linked Editorial

Surgery for spinal stenosis with degenerative spondylolisthesis
  1. Eric Loratang Kgomotso, consultant orthopaedic surgeon1,
  2. Christian Hellum, consultant orthopaedic surgeon2,
  3. Morten Wang Fagerland, head of section3,
  4. Tore Solberg, professor4 5,
  5. Jens Ivar Brox, professor6 7,
  6. Kjersti Storheim, professor8 9,
  7. Erland Hermansen, clinical research scientist1 10 11,
  8. Eric Franssen, head of section12,
  9. Clemens Weber, consultant neurosurgeon, postdoctoral research fellow13 14,
  10. Helena Brisby, professor15 16,
  11. Knut Robert Hector Algaard, consultant radiologist17,
  12. Håvard Furunes, consultant orthopaedic surgeon, associate professor7 18,
  13. Hasan Banitalebi, consultant radiologist, doctoral student19 20,
  14. Inger Ljøstad, patient representative21,
  15. Kari Indrekvam, clinical director, associate professor1 22,
  16. Ivar Magne Austevoll, consultant orthopaedic surgeon, postdoctoral research fellow1 20
  17. on behalf of the Nordsten collaborators
    1. 1Kysthospitalet in Hagevik, Orthopaedic Department, Haukeland University Hospital, Bergen, Norway
    2. 2Division of Orthopaedic Surgery, Oslo University Hospital Ullevål, Oslo, Norway
    3. 3Oslo Centre for Biostatistics and Epidemiology, Research Support Services, Oslo, Norway
    4. 4Institute of clinical medicine, The Arctic University of Norway (UiT), Tromsø, Norway
    5. 5The Norwegian Registry for Spine Surgery (NORspine), University Hospital of North Norway, Tromsø, Norway
    6. 6Department of Physical Medicine and Rehabilitation, Oslo University Hospital, Oslo, Norway
    7. 7Medical Faculty, University of Oslo, Oslo, Norway
    8. 8Department of Physiotherapy, Oslo Metropolitan University, Oslo, Norway
    9. 9Research and Communication Unit for Musculoskeletal Health, Division of Clinical Neuroscience, Oslo University Hospital, Oslo, Norway
    10. 10Department of Research and Innovation, Møre and Romsdal Hospital Trust, Ålesund, Norway
    11. 11Institute of Health Sciences, Norwegian University of Technology and Science, Ålesund, Norway
    12. 12Orthopaedic Department, Stavanger University Hospital, Stavanger, Norway
    13. 13Department of Neurosurgery, Stavanger University Hospital, Stavanger, Norway
    14. 14Department of Quality and Health Technology, Faculty of Health Sciences, University of Stavanger, Stavanger, Norway
    15. 15Spine Surgery Team, Department of Orthopaedics, Sahlgrenska University Hospital, Gothenborg, Sweden
    16. 16Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sweden
    17. 17Radiology, Unilabs Radiology, Oslo, Norway
    18. 18Department of Orthopaedic Surgery, Innlandet Hospital Trust, Gjøvik, Norway
    19. 19Department of Diagnostic Imaging, Akershus University Hospital, Lorenskog, Norway
    20. 20Institute of Clinical Medicine, University of Oslo, Oslo, Norway
    21. 21Member of the Norwegian Back and Spine Patients Association
    22. 22Department of Clinical Medicine, University of Bergen, Bergen, Norway
    1. Correspondence to: I M Austevoll imau{at}helse-bergen.no (@AustevollIvar on X)
    • Accepted 12 April 2024

    Abstract

    Objective To assess whether decompression alone is non-inferior to decompression with instrumented fusion five years after primary surgery in patients with degenerative lumbar spondylolisthesis.

    Design Five year follow-up of a randomised, multicentre, non-inferiority trial (Nordsten-DS).

    Setting 16 public orthopaedic and neurosurgical clinics in Norway.

    Participants Patients aged 18-80 years with symptomatic lumbar spinal stenosis and a spondylolisthesis of 3 mm or more at the stenotic level.

    Interventions Decompression surgery alone and decompression with additional instrumented fusion (1:1).

    Main outcome measures The primary outcome was a 30% or more reduction in Oswestry disability index from baseline to five year follow-up. The predefined non-inferiority margin was a −15 percentage point difference in the proportion of patients who met the primary outcome. Secondary outcomes included the mean change in Oswestry disability index, Zurich claudication questionnaire, numeric rating scale for leg and back pain, and EuroQol Group 5-Dimension (EQ-5D-3L) questionnaire.

    Results From 12 February 2014 to 18 December 2017, 267 participants were randomly assigned to decompression alone (n=134) and decompression with instrumented fusion (n=133). Of these, 230 (88%) responded to the five year questionnaire: 121 in the decompression group and 109 in the fusion group. Mean age at baseline was 66.2 years (SD 7.6), and 69% were women. In the modified intention-to-treat analysis with multiple imputation of missing data, 84 (63%) of 133 people in the decompression alone group and 81 (63%) of 129 people in the fusion group had a at least a 30% reduction in Oswestry disability index, a difference of 0.4 percentage points. (95% confidence interval (CI) −11.2 to 11.9). The respective results of the per protocol analysis were 65 (65%) of 100 in the decompression alone group and 59 (66%) of 89 in the fusion group, a difference of −1.3 percentage points (95% CI −14.5 to 12.2). Both 95% CIs were higher than the predefined non-inferiority margin of −15%. The mean change in Oswestry disability index from baseline to five years was −17.8 in both groups (mean difference 0.02 (95% CI −3.8 to 3.9)). Results of the other secondary outcomes were in the same direction as the primary outcome. From two to five year follow-up, a new lumbar operation occurred in six (5%) of 123 people in the decompression group and 11 (10%) of 113 people in the fusion group, with a total from baseline to five years of 21 (16%) of 129 people and 23 (18%) of 125, respectively.

    Conclusions In participants with degenerative spondylolisthesis, decompression alone was non-inferior to decompression with instrumented fusion five years after primary surgery. Proportions of subsequent surgeries at the index level or an adjacent lumbar level were no different between the groups.

    Trial registration ClinicalTrials.gov NCT02051374

    Introduction

    Degenerative lumbar spondylolisthesis is a forward slippage of one vertebra relative to the next vertebra below, caused by degeneration of facet joints and discs, and vertical shear forces between the vertebrae.1 Degenerative lumbar spondylolisthesis commonly occurs in the population aged 50 years and older, and is more frequent in women.2 People with a narrowing of the spinal canal at the same lumbar level (spinal stenosis) often have leg and back pain, neurogenic claudication, and impaired physical function. In clinical practice, patients with degenerative spondylolisthesis have symptomatic spinal stenosis and a concomitant spondylolisthesis.34

    Surgery is recommended in selected patients who have had no improvement after non-surgical care.3 Decompression of the narrowed spinal canal has traditionally been the main objective of operative treatment.4 Following suggestions from studies from the early 1990s,567 adding instrumented fusion (the use of bone grafts, screws, rods, and other devices to fuse the slipped vertebrae) became the preferred surgical method.89 More recently, evidence from randomised controlled trials and meta-analyses have indicated that decompression alone is sufficient for up to two years of follow-up.1011121314

    By contrast, one randomised controlled trial found that additional instrumented fusion gave superior results to decompression alone.15

    Results from randomised controlled trials that include outcomes from more than two years after surgery are sparse and contradictory.111516 In this study, we present the five year results of the Norwegian degenerative spondylolisthesis and spinal stenosis (Nordsten-DS) trial to assess whether decompression alone is non-inferior to decompression with instrumented fusion.

    Methods

    Trial oversight

    Nordsten-DS is an investigator initiated, multicentre, randomised, open label trial designed to evaluate the non-inferiority of decompression alone compared with decompression with instrumented fusion at two, five, and 10 years after the initial surgery.17 The Regional Committee for Medical and Health Research Ethics of Central Norway (project identifier 2013/366) approved the trial. The trial reporting follows the consolidated standards of reporting trials (CONSORT) guidelines.18 We previously published the trial protocol and the statistical analysis plan.1719 Information regarding patient involvement is provided in section 2 of appendix.

    An interim analysis at two years was conducted during patient recruitment when 150 included participants had completed the one-year follow-up to ensure trial safety and efficacy, following the protocol.1017

    Enrolment and randomisation

    The complete inclusion and exclusion criteria have been reported previously,1017 and are provided in table S2 in appendix. In brief, eligible patients were 18-80 years of age, with clinical symptoms of lumbar spinal stenosis (neurogenic claudication or radiating leg pain) verified by magnetic resonance imaging, and an at least 3 mm spondylolisthesis solely at the stenotic level on standing radiographs. We included patients regardless of whether they presented with signs of instability, such as predominant back pain, higher grade of spondylolisthesis, slippage or angulation of vertebral bodies on flexion-extension radiographs, and facet joints with increased fluid or high sagittal angle.152021 Patients were excluded if they had a thoracolumbar scoliosis of more than 20 degrees, excessive foraminal stenosis (ie, a deformed nerve root in the intervertebral foramen), were previously operated at the level of spondylolisthesis, or had a former fracture or fusion surgery in the thoracolumbar region. We included patients referred to public orthopaedic and neurosurgical departments by the primary care givers for surgical evaluation. The surgeons who conducted the trial surgeries were involved in screening for patient eligibility. The decision to undergo surgery or further non-surgical care was based on shared decision making. The shared decision making process was not explicitly outlined in the study protocol but is well anchored in the Norwegian clinics’ best practices and patient rights laws.22 Participating surgeons were well versed in balancing patient's expectation and potential gain from surgery with the risks of complications or an undesirable outcome. Patients who opted for surgery after shared decision making were invited to participate in the trial. They received the best available information for and against fusion surgery and on the scarcity of evidence for one treatment being superior, both in oral and written form. All patients who accepted trial participation gave written consent before randomisation. Section 2 in the appendix provides information about the surgical departments’ contribution to the enrolment of participants.

    The Medinsight database hosted by the clinical trial unit at Oslo University Hospital allowed for the computer generated random assignment of the eligible participants in a 1:1 ratio to undergo either decompression alone or decompression with instrumented fusion. The sequence was concealed from the investigators and stratified according to site using random block sizes of four and six participants. The trial coordinating centre at the research and communication unit for musculoskeletal health at Oslo University Hospital forwarded the treatment assignments by email to local trial coordinators who documented this information in patients’ records and informed the surgeons. Individual participants and their surgeons were not masked to the treatment assignment.

    The routines for the collection and storage of data have been previously described.10 All data, stored at the clinical trial unit at Oslo University Hospital, were inaccessible to the research group until 23 March 2023; confirmation is provided in section 4.1 in appendix.

    Interventions

    The participants assigned to decompression alone were operated with a decompression preserving the posterior midline (without removal of the spinous process or the supraspinous-interspinous ligament complex). The approach could be bilateral, ipsilateral, or ipsilateral with a crossover to the contralateral side. For the participants assigned to decompression with instrumented fusion, a posterior decompression (with or without preserving midline structures, at the surgeon’s discretion) was followed by implantation of pedicle screws with rods and bone grafting across the level of spondylolisthesis, and optional use of an intervertebral fusion device. Implants were selected according to established practices at the trial centres. All participating surgeons routinely performed the procedures used in the trial. A microscope or magnifying glass was recommended for the decompression procedure in both treatment groups.

    Outcome measures

    The primary outcome was a reduction in the Oswestry disability index (version 2.0) of 30% or more from baseline to five year follow-up,23 defined as a clinically important outcome. 24 The disability index comprises 10 items that assess functional impairment with a total score from 0 to 100, with higher scores indicating more disability.

    Secondary outcomes were the mean score changes in the Oswestry disability index, the Zurich claudication questionnaire,25 which assesses symptom severity (range 1-5, higher scores indicating more severity), functional impairment (1-4, higher scores indicating more impairment), and satisfaction with treatment (1-4, higher scores indicating lower satisfaction); the numeric rating scale26 for leg pain and for back pain, which assesses pain experienced during the past week (range 0-10, with higher scores indicating more pain), and the score on the three level version of the EuroQol Group 5-Dimension (EQ-5D-3L) questionnaire (ranging from −0.59 to 1.0, with higher scores indicating better health related quality of life).27 A seven point global perceived effect scale measuring the self-perceived benefit of the surgery was used, and participants’ responses of “much worse” or “worse than ever” were also used to assess adverse outcomes. All questionnaires were translated into Norwegian and validated for psychometric properties (section 4.2.1 in appendix). To evaluate adverse events and treatment during follow-up, we assessed the frequency of complications, patient reported neurological symptoms (sensory, motor, or both) in the lower limbs, subsequent surgeries on the index level or adjacent lumbar levels, use of pain medication, and use of other health services related to the participants’ spine health (ie, physiotherapy chiropractor, acupuncture, and visits to hospitals and general practitioners).

    Statistical analysis

    All primary and secondary outcomes were analysed in a full analysis set, that is, the modified intention-to-treat set consisting of all the participants who received the trial treatment assigned at randomisation and had available data at one or more time point after randomisation.28 The null hypothesis (H0) was that the proportion of participants who met the primary outcome (a reduction of 30% or more in the Oswestry disability index) should be 15 percentage points lower in the decompression group than in the fusion group. The predefined non-inferiority margin was based on established knowledge that decompression alone is less extensive, less invasive, cheaper, and possibly safer,2930 which would justify an acceptable loss of effectiveness. A difference of 15 percentage points corresponds to a number needed to benefit from additional fusion of seven (number needed to treat was 100/15=6.67).31 This means that at least seven patients need instrumented fusion in addition to decompression to meet one additional patient with a successful outcome. To reject H0, 116 participants were required in each group to be 80% certain (power) that the lower limit of a 95% confidence interval (CI) of the difference (decompression alone minus decompression with instrumented fusion) in the percentage of participants with a successful outcome on Oswestry disability index was above −15 percentage points.32 Considering a possible dropout of 10%, 128 participants were required in each group.

    To declare non-inferiority for decompression alone, the null hypothesis had to be rejected in the analyses of both the modified intention-to-treat set with multiple imputation of missing data (information provided in section 4.3.1 in appendix) and in a per protocol set. The per protocol set consisted of all the participants in the modified intention-to-treat set who did not undergo a subsequent surgery at the index level or an adjacent lumbar level during the follow-up period and had available data for the primary outcome. Two sensitivity analyses were performed: one in the modified intention-to-treat set with complete cases (without imputation for missing data) and one in which missing values at five years were replaced by values recorded at two years, when available.

    The primary outcome and all categorical secondary outcomes were analysed with Newcombe hybrid score confidence intervals.33 This included the proportion of participants with a clinically meaningful improvement as assessed by the Zurich claudication questionnaire and numeric rating scale for leg and back pain. All repeated continuous outcomes (scores on the Oswestry disability index, Zurich claudication questionnaire, numeric rating scale for leg pain, numeric rating scale for back pain, and EQ-5D-3L) were analysed with linear mixed models. The linear mixed models contained fixed effects for treatment, time, the interaction between treatment and time, the trial centre, and a random intercept at the patient level. Time was modelled as piecewise linear with knots at three months and two years. Based on the fitted models, mean values were estimated with 95% CIs at baseline (inclusion), three months, one year, two years, and five years after surgery, the change from baseline to five years within each treatment group, and the between group difference (with 95% CIs) in change from baseline to five years.

    The assumption of normally distributed data was assessed with visual inspection of histograms and descriptive statistics, and no major deviations were observed. We did not predefine any method for adjustment of confidence intervals for multiple comparisons of secondary outcomes. These results are presented as point estimates with unadjusted confidence intervals from which no definite conclusions can be made. The analyses were done using Stata/SE software, version 17.0.

    Patient and public involvement

    Patient involvement is an important factor in the Nordsten trials. This paper's patient representative and co-author (IL) is a member of the Nordsten scientific board and working group. She regularly participates in discussions to ensure that the patients' perspectives and involvement are adequately integrated into the research process. She bridges the gap between researchers and the Norwegian Back and Spine Patients Association, facilitating communication and collaboration. In furtherance of this, she has created the first draft of a popular science piece covering the present five year results, which will be distributed by letter to the study participants and the funders.

    Results

    From 12 February 2014 to 18 December 2017, we screened 738 patients who were referred to 16 Norwegian public orthopaedic and neurosurgical clinics for degenerative spondylolisthesis, of whom 267 were enrolled in the Nordsten-DS trial (fig 1). The randomisation assigned 134 participants to the decompression group and 133 to the fusion group. At five year follow-up, seven participants (3%; three from the decompression group and four from the fusion group) had died and 25 (10%; nine to the decompression group and 16 to the fusion group) were lost to follow-up, resulting in available data for patient reported outcome measurements from 121 participants in the decompression group and 109 in the fusion group. The modified intention-to-treat set consisted of 133 participants assigned to the decompression group and 129 participants in the fusion group (one patient withdrew consent before surgery, and four did not receive the assigned treatment). The per protocol set consisted of 189 participants: 100 in the decompression group and 89 in the fusion group (44 were reoperated), of which seven had missing data for primary outcome (two at baseline and five at five years). Primary outcomes were missing in 29 people (three at baseline and 26 at five years) (fig 1).

    Fig 1
    Fig 1

    Screening, randomisation, and follow-up of the trial participants. Patients who were referred with the diagnosis of lumbar spinal stenosis were screened for the presence of spondylolisthesis. 738 patients who were assessed for eligibility in the trial could have been excluded for more than one reason. The diagnosis of foraminal stenosis of grade 3 was made according to the classification of Lee et al.34 From 15 April 2014 (the start of inclusion) to 29 August 2015, a score of less than 25 on the Oswestry disability index (ODI) was an exclusion criterion. MRI=magnetic resonance imaging

    Table 1 shows that the treatment groups had similar patient characteristics, outcome measurements, and radiological parameters at baseline.

    Table 1

    Patient characteristics at baseline (modified intention-to-treat set). Values are numbers (percentage) unless stated otherwise

    View this table:

    Primary outcome

    In the analysis of participants in the modified intention-to-treat set with multiple imputation, 84/133 (63%) in the decompression group and 81/129 (63%) in the fusion group met the primary outcome (an Oswestry disability index reduction of at least a 30% from baseline to five year follow-up). The difference between the groups was 0.4 percentage points (95% CI −11.2 to 11.9). In the per protocol set, the results were 65/100 (65%) in the decompression group and 59/89 (66%) in the fusion group, a difference of −1.3 percentage points (−14.5 to 12.2). The 95% CIs were within the predefined non-inferiority margin of −15 percentage points in both analysis sets. The lower bounds of the 95% CIs corresponded to numbers needed to treat of 8.9 (100/11.2) in the in the modified intention-to-treat set with multiple imputation and 6.9 (100/14.5) in the per protocol set, which means that at least seven to nine patients needed to be fused to have one additional patient meet at least a 30% improvement in functional status. The results of the sensitivity analyses were in the same direction as the primary analysis and did not cross the non-inferiority margin (fig 2).

    Fig 2
    Fig 2

    Primary outcome. No of patients/total no (%) refers to the proportion of patients with 30% or more reduction in Oswestry disability index in each specified analysis. The between group differences in percentage points and its 95% confidence intervals (CIs) were calculated as decompression alone minus decompression with fusion. For patients in the modified intention-to-treat set with imputation of missing data at five year, the missing values were replaced by multiple imputation

    Secondary outcomes

    The mean change in Oswestry disability index from baseline to five years was −17.8 in the decompression group and −17.8 in the fusion group (mean difference −0.02 (95% CI −3.9 to 3.8)). The mean change in leg pain measured by the numeric rating scale showed values of −3.5 in the decompression group and −2.9 in the fusion group (mean difference −0.59 (95% CI −1.36 to 0.18)). For back pain the results were −2.8 and −2.6 (−0.22 (−0.95 to 0.52)), respectively. Mean change in Zurich claudication questionnaire and the EQ-5D also had similar small differences (table 2). Figures in the appendix show the results of complete cases analyses of patient reported continuous outcomes from baseline to five year follow-up. The between-group differences in percentages of participants meeting a clinically meaningful improvement according to the Zurich claudication questionnaire and numeric rating scale pain scales from baseline to five years after surgery were in line with the results of the primary outcome (table 2).

    Table 2

    Secondary patient reported outcome measurements (modified intention-to-treat set). Data are mean (95% confidence interval)

    View this table:

    Table 3 shows the recorded adverse events from two to five year follow-up, 16 (13%) of 119 in the decompression group and 21 (19%) of 109 in the fusion group reported new neurological sensory and/or motor symptoms of the lower limbs. About 5% in each group perceived themselves to be substantially deteriorated (“much worse” or “worse than ever”) according to the GPE score (table S4 in appendix).

    Table 3

    Additional secondary outcomes (modified intention-to-treat set) Values are number (percentage), unless stated otherwise

    View this table:

    Except for higher blood loss during surgery and incidence of dural tears in the fusion group, no significant between group differences were observed regarding adverse events. Neither the consumption of pain medication nor the use of health services was different during follow-up (table 3 and tables S4 and S6 in appendix). A subsequent lumbar surgery was done in 21 (16%) of 129 participants in the decompression group and in 23 (18%) of 125 participants in the fusion group. Of these, comparing people in the decompression group and fusion group, 11 and 15 had subsequent surgery from index surgery to two year follow-up, and 6 and 11 had surgery from two to five years. Some participants had more than one reoperation, giving a total number of 28 subsequent surgeries in each group.

    Discussion

    The Nordsten-DS randomised controlled trial involving 267 participants with lumbar spinal stenosis and degenerative spondylolisthesis showed that surgery with decompression alone was non-inferior to surgery with decompression and instrumented fusion at five year follow-up. Results of secondary outcomes concerning pain, symptom severity, functional status, and reoperation rates were in accordance with the primary outcome.

    Strengths and limitations

    Some major strengths of this trial were its large sample size, the external data monitoring, the use of validated outcomes, the high follow-up rate, and the strong involvement of a patient representative (IL).40 The pragmatic design, wherein patients were recruited from 16 public institutions and surgery was performed by both orthopaedic and neurosurgical spine surgeons, improved the generalisability of the results.

    Due to the eligibility criteria, one cannot generalise the trial results to patients with degenerative scoliosis, severe foraminal stenosis, and previous surgery at the index level or with spondylolisthesis at multiple levels. Another limitation was the absence of double blinding; only the data analyst was masked to treatment assignments.

    An evidence based margin of non-inferiority for this research question does not exist, which is why the predefined −15 percentage points limit was chosen empirically. The 95% CI of the between group difference in percentages reaching the primary outcome did not cross the non-inferiority margin in this analysis. However, the sample size for the per protocol analysis was below the a priori required sample size.

    Comparison with other studies

    Two randomised controlled trials from 2016 of patients with degenerative spondylolisthesis included longer term follow-ups, similar to the current trial.1115 One included participants from seven Swedish hospitals.11 The trial had a superiority design, did not present information about radiological instability, and had available data for 80 (59%) of 135 participants at five year follow-up. The Swedish trial found no between group differences in Oswestry disability index and pain scores, corresponding to our findings. The reoperation rate over the course of five years from index surgery was 22% in the decompression group and 21% in the fusion group, quite similar to our findings.

    The other trial recruited 66 patients from five US spine centres, 51 of whom were from one site.15 Each centre had one surgeon who performed all the surgeries in the trial. At four year follow-up, 45 participants (68%) had data for analysis. Compared with our trial, the US trial had a less pragmatic design. They only included grade 1 lumbar spondylolisthesis (slip of 3-14 mm). Furthermore, they did not include patients who had a dynamically unstable condition, defined as motion of the spondylolisthesis of more than 3 mm measured on dynamic radiographs, or those with mechanical low back pain in the upright posture. Their results at a four year follow-up favoured fusion, as assessed by the generic physical component summary score of the 36-item short-form health survey. The reoperation rate of that study at four years was 34% in the decompression alone group, and all patients were deemed to have clinical instability. In the fusion group, 14% had a subsequent surgery, and all had adjacent level degeneration. In our trial, there were slightly more reoperations in the decompression group during the first two years, mainly operated with a subsequent fusion at the index level, while more participants in the fusion group had a subsequent operation between two and five year follow-up, mainly at a new lumbar level.

    The reasons for the noticeable difference in reoperation rates between the US trial compared with the present trial and the Swedish trial are unknown. Diverging reoperation rates could partially be explained by differences in treatment traditions and radiological assessment. If a patient operated on without additional fusion complains of persisting back pain, the threshold for offering reoperation with fusion could be low. A surgical alternative is less apparent when the patient is primarily operated with fusion. The rationale might be that the back pain is caused by spondylolisthesis so-called instability.152021

    In this trial, non-inferiority for decompression alone was maintained over five years and the reduction in back pain was similar between the groups, even though a high number of participants had radiological and clinical signs of instability. A secondary exploratory Nordsten-DS study on treatment effect modifiers did not find that participants with more typical preoperative signs of instability and back pain benefited from an additional fusion.41 The high prevalence of non-specific low back pain in the general population and the scarcity of evidence for a causal relationship between back pain and degenerative spondylolisthesis are valid arguments for not routinely offering subsequent fusion surgery for persistent back pain.4243

    Decompression without fusion is a faster,101115 less invasive,44 safer,13 and more cost-effective treatment for patients with degenerative spondylolisthesis.44 Despite the two year results from randomised controlled trials and meta-analyses recommending decompression alone as primary treatment for these patients,1011121314153445 only a few countries have reported a change in surgical practice.4647 In the US, the fusion rate for degenerative spondylolisthesis continued to increase from 67% in 2016 to 90.4% in 2019.48 To ensure implementation of evidence from follow-ups longer than two years, the results from the present trial need to be acknowledged by patients and healthcare providers as well as by decision and policy makers. Selective use of information supporting fusion surgery will lead to patients receiving more extensive and risky surgery than is necessary.

    For successful shared decision making, clinicians should thoroughly inform patients about the pros and cons of alternative surgical and non-surgical treatments and communicate corresponding realistic prognoses for reaching pain and functional goals. Unfortunately, very little is known about patients’ goals regarding spine surgery. A recent study49 showed that patients’ preoperative expectations may be higher than the commonly reported outcomes of spinal surgery.10111550 Future investigations should assess patients’ functional and pain goals before surgery relative to their perceived benefits after surgery.

    The results of this five year analysis cannot exclude the possibility that subgroups of patients may benefit from an additional fusion (eg, age, gender, socioeconomic status, and different radiological variables). At the two year follow-up, we did not identify any subgroups that would favour one of the two treatments.41 Following the Nordsten-DS trial protocol, we will also investigate potential treatment effect modifiers in a separate study related to the five year follow-up, as well as alongside the 10 year follow-up.17

    Conclusion

    In this multicentre, randomised trial of patients with degenerative lumbar spondylolisthesis, the five year results of decompression alone were non-inferior to those of decompression with instrumented fusion. A subsequent reoperation occurred in about one in five participants in both groups. The results expand on the current evidence that, for most of these patients, fusion surgery is superfluous.

    What is already known on this topic

    • Two year follow-up data indicate that additional instrumented fusion is a superfluous adjunct to decompression surgery for patients operated on for lumbar stenosis and degenerative spondylolisthesis

    • Still, in most countries, additional fusion surgery prevails as the first treatment option despite disadvantages such as increased risk and costs

    • The little of change in surgical practice may be due to concerns about inferior outcomes and higher reoperation rates for people operated with decompression only

    What this study adds

    • Nordsten-DS is the first trial with a sufficient sample size and follow-up rate to investigate outcomes in the longer term

    • At five year follow-up, surgery with decompression alone gave non-inferior clinical results and similar reoperation rates compared with additional fusion surgery

    • This new evidence supports surgeons, patients, and administrators to choose the simpler, cheaper, and safer type of surgery

    Ethics statements

    Ethical approval

    The Regional Committee for Medical and Health Research Ethics of Central Norway (project identifier 2013/366) was approved on 8 May 2013.

    Data availability statement

    All data requests should be submitted to ivar.magne.austevoll{at}helse-bergen.no for consideration. The NORDSTEN scientific board may grant access to anonymised data following a research protocol review. The statistical analysis plan can be found on the clinicaltrials.gov website: https://storage.googleapis.com/ctgov2-large-docs/74/NCT02051374/SAP_001.pdf.

    Acknowledgments

    The NORDSTEN collaborators: Haukeland University Hospital, Kysthospitalet i Hagevik, Orthopaedic department: Turid Rognsvåg, Janne Haugland, Eva Saltskår Jentoft, Magnus Valland, Ørjan Stensletten, Andreas Seip, Frode Rekeland, Rune Birketvedt; Haukeland University Hospital, Neurosurgical department: Samer Habiba, Kristine Helland, Linda Sæterdal; Haukeland University Hospital: Orthopaedic department Maria Rieber-Mohn, Andreas Seip, Truls Hanestad, Sylvi Ann Sagstad, Per Torgeir Nilsen; Innlandet Hospital Trust, Division Elverum, Orthopaedic department: Arnfinn Pedersen, Hege Westgård, Anders Tønsager; Innlandet Hospital Trust, Division Gjøvik, Orthopaedic department: Espen Mørk, Inger Opheim, Hege Bergum Nilsen, Øyvind Sletten, Aina Strøm, Eirik Østvold Melandsø, Maria Van My Nguyen Giebers; Innlandet Hospital Trust, Division Lillehammer, Orthopaedic department: Vinjar Hansen, Greger Lønne, Roar Rønning, Gisle Szacinski, Marthe Stine Rustad; Møre and Romsdal Hospital Trust, Ålesund Hospital, Orthopaedic department: Jørn Aaen, Vidar Punsvik, Anita Karin Vassbakk, Alf Hellevik; Oslo University Hospital, Ullevål, Orthopaedic Division and Division of Clinical Neuroscience: Espen Sjåberg, Ellen Aksnes, Roger Trana, Ole Rasmus Robak, Morten Karlsen, Jon Magne Hoseth, Ali Al-Ashtari, Geir Jomaas, Marte Magnusson, Maren Hjelle Guddal, Ingrid Fjellheim Bånerud, Eira Ebbs, Marie Skovli Pettersen, Ørjan Nesse Vigdal, Mads Rolfsen, Trine Strøm, Hege C Thrygg, Fiona Aanesen; Stavanger University Hospital, Orthopaedic department and Neurosurgical department: Knut Harboe, Elisabeth Rettedal, Kirstine Hansen, Gabriel Lande, Hilde Olsen; St. Olav’s Hospital, Neurosurgical department: Øyvind Sletten, Tomm Müller, Camilla Brattbakk, Hege Andresen, Øystein Nygaard; Sørlandet Hospital Trust, Arendal Hospital, Orthopaedic department: Pål Amesen, Yngve Sporstøl, Ted P Lundgren, Anne-Charlotte Fosse Haug, Elisabeth Lilleholdt Muller; Sørlandet Hospital Trust, Kristiansand Hospital, Orthopaedic department: Odd Arild Ågedal, Kjartan Krogedal, Kamaran Raza, Bettina Døsvik; Telemark Hospital Trust, Skien Hospital, Orthopaedic department: Knut Jørgen Haug, Yngve Sporstøl, Ingrid Edbo; University Hospital of Northern Norway, Neurosurgical department: Rune Hennig, Andreas Sørlie, Jørgen Isaksen, Jens Munch-Ellingsen, Kristine Evanger, Caroline W. Thórisdóttir, Vibeke Grønaas, Marilyn Botn, Silje M. Nilssen, Lasse Andreassen, Sunniva Andreassen, Sara Kristin Sørend; Vestre Viken Hospital Trust, Bærum Hospital, Orthopaedic department: Vidar Opland, Merete Finjarn, Ellen Langslet, Wender Figved, Lars Forberg, Morten Karlsen, Erik Øygarden, Lauritz Dahl.

    We thank all the participants and the research support at each site that made Nordsten-DS successful. We thank Katarina Mølsæter (data and safety monitoring board, Møre and Romsdal Health Trust) for her meticulous monitoring and review of the data; Anniken Remseth and Bodil Røyset for handling the trial finances; Jørn Aaen, Frode Rekeland, Oliver Grundnes and Masoud Anwar for their involvement in the NORDSTEN study group; all the local trial coordinators and surgeons who contributed to the trial; the staff at the Research and Communication Unit for Musculoskeletal Health (FORMI) at Oslo University Hospital (Ingrid Fjellheim Bånerud, Maren Hjelle Guddal, Eira K Ebbs, Marie Skovli Pettersen, and Ørjan Nesse Vigdal) for meticulous work with data collection; Veronika Dybvik, Sondre Hagerup, Hannah Standal, and Benedickte Aasen for uploading of radiology images; Tordis Bøker for participating in radiological assessments, and Eira K Ebbs (FORMI) for providing linguistic assistance in writing the manuscript and the English translation of the patient information letter.

    Footnotes

    • Contributors: CH, MVF, TS, JIB, KS, EH, KI, and IMA were responsible for study conception and trial design. MVF was responsible for the statistical analysis. ELK and IMA were responsible for the first draft of the manuscript. All authors were responsible for the interpretation of the data and for drafting and approving the final submitted manuscript. EK, CH, and IMA are the guarantors. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted. The corresponding author had full access to all the data in the study and was responsible for deciding to submit it for publication.

    • Funding: Grants from the public Western Norway Regional Health Authority, the Central Norway Regional Health Authority, and the non-profit foundation Sophies Minde supported the trial. The funding authorities were not involved in the trial design, data collection or analysis, interpretation of the results, or manuscript drafting.

    • Competing interests: All authors have completed the ICMJE uniform disclosure form www.icmje.org/disclosure-of-interest/ and declared that they have had no financial relationships with any organisation that may have a financial interest in the submitted work in the previous three years and no relationships or activities that could have influenced the submitted work.

    • Transparency: ELK and IMA affirm that the manuscript is an honest, accurate, and transparent account of the Nordsten-DS five year trial being reported, that no important aspects of the study have been omitted, and that any discrepancies from the study as explained in the original statistical analysis plan (27 December 2022). The database lock approval form provided in appendix confirms that data were inaccessible to the research group until 13 March 2023.

    • Dissemination to participants and related patient and public communities: The patient representative (IL), along with ELK, KS, and IMA are responsible for a lay summary of the results of the study that will be made available on the trial website, in the annual letter to the research participants and the Norwegian Back and Spine Patients Association’s magazine. An English translation of the information letter is available in section 2 of the appendix. As with the two year results, the five year results will be disseminated through public media channels.

    • Provenance and peer review: Not commissioned; externally peer reviewed.

    http://creativecommons.org/licenses/by-nc/4.0/

    This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

    References

    1. ↵
      1. Newman PH
      . Degenerative spondylolisthesis. Orthop Clin North Am1975;6:197-8. doi:10.1016/S0030-5898(20)31211-6 pmid:1089933
      OpenUrlCrossRefPubMed
    2. ↵
      1. Jensen RK,
      2. Harhangi BS,
      3. Huygen F,
      4. Koes B
      . Lumbar spinal stenosis. BMJ2021;373:n1581. doi:10.1136/bmj.n1581. pmid:34187838
      OpenUrlFREE Full Text
    3. ↵
      1. Lurie J,
      2. Tomkins-Lane C
      . Management of lumbar spinal stenosis. BMJ2016;352:h6234. doi:10.1136/bmj.h6234. pmid:26727925
      OpenUrlCrossRefPubMed
    4. ↵
      1. Rosenberg NJ
      . Degenerative spondylolisthesis: surgical treatment. Clin Orthop Relat Res1976;(117):112-20.pmid:132322
    5. ↵
      1. Fischgrund JS,
      2. Mackay M,
      3. Herkowitz HN,
      4. Brower R,
      5. Montgomery DM,
      6. Kurz LT
      . 1997 Volvo Award winner in clinical studies. Degenerative lumbar spondylolisthesis with spinal stenosis: a prospective, randomized study comparing decompressive laminectomy and arthrodesis with and without spinal instrumentation. Spine (Phila Pa 1976)1997;22:2807-12. doi:10.1097/00007632-199712150-00003 pmid:9431616
      OpenUrlCrossRefPubMed
    6. ↵
      1. Herkowitz HN,
      2. Kurz LT
      . Degenerative lumbar spondylolisthesis with spinal stenosis. A prospective study comparing decompression with decompression and intertransverse process arthrodesis. J Bone Joint Surg Am1991;73:802-8. doi:10.2106/00004623-199173060-00002 pmid:2071615
      OpenUrlAbstract/FREE Full Text
    7. ↵
      1. Kornblum MB,
      2. Fischgrund JS,
      3. Herkowitz HN,
      4. Abraham DA,
      5. Berkower DL,
      6. Ditkoff JS
      . Degenerative lumbar spondylolisthesis with spinal stenosis: a prospective long-term study comparing fusion and pseudarthrosis. Spine (Phila Pa 1976)2004;29:726-33, discussion 733-4. doi:10.1097/01.BRS.0000119398.22620.92 pmid:15087793
      OpenUrlCrossRefPubMed
    8. ↵
      1. Kepler CK,
      2. Vaccaro AR,
      3. Hilibrand AS,
      4. et al
      . National trends in the use of fusion techniques to treat degenerative spondylolisthesis. Spine (Phila Pa 1976)2014;39:1584-9. doi:10.1097/BRS.0000000000000486. pmid:24979276
      OpenUrlCrossRefPubMed
    9. ↵
      1. Martin BI,
      2. Mirza SK,
      3. Spina N,
      4. Spiker WR,
      5. Lawrence B,
      6. Brodke DS
      . Trends in lumbar fusion procedure rates and associated hospital costs for degenerative spinal diseases in the United States, 2004 to 2015. Spine (Phila Pa 1976)2019;44:369-76. doi:10.1097/BRS.0000000000002822. pmid:30074971
      OpenUrlCrossRefPubMed
    10. ↵
      1. Austevoll IM,
      2. Hermansen E,
      3. Fagerland MW,
      4. et al.,
      5. NORDSTEN-DS Investigators
      . Decompression with or without fusion in degenerative lumbar spondylolisthesis. N Engl J Med2021;385:526-38. doi:10.1056/NEJMoa2100990. pmid:34347953
      OpenUrlCrossRefPubMed
    11. ↵
      1. Försth P,
      2. Ólafsson G,
      3. Carlsson T,
      4. et al
      . A randomized, controlled trial of fusion surgery for lumbar spinal stenosis. N Engl J Med2016;374:1413-23. doi:10.1056/NEJMoa1513721. pmid:27074066
      OpenUrlCrossRefPubMed
    12. ↵
      1. Inose H,
      2. Kato T,
      3. Yuasa M,
      4. et al
      . Comparison of decompression, decompression plus fusion, and decompression plus stabilization for degenerative spondylolisthesis: a prospective, randomized study. Clin Spine Surg2018;31:E347-52. doi:10.1097/BSD.0000000000000659. pmid:29877872
      OpenUrlCrossRefPubMed
    13. ↵
      1. Kaiser R,
      2. Kantorová L,
      3. Langaufová A,
      4. et al
      . Decompression alone versus decompression with instrumented fusion in the treatment of lumbar degenerative spondylolisthesis: a systematic review and meta-analysis of randomised trials. J Neurol Neurosurg Psychiatry2023;94:657-66. doi:10.1136/jnnp-2022-330158. pmid:36849239
      OpenUrlAbstract/FREE Full Text
    14. ↵
      1. Wei F-L,
      2. Zhou C-P,
      3. Gao Q-Y,
      4. et al
      . Decompression alone or decompression and fusion in degenerative lumbar spondylolisthesis. EClinicalMedicine2022;51:101559. doi:10.1016/j.eclinm.2022.101559. pmid:35865739
      OpenUrlCrossRefPubMed
    15. ↵
      1. Ghogawala Z,
      2. Dziura J,
      3. Butler WE,
      4. et al
      . Laminectomy plus Fusion versus Laminectomy Alone for Lumbar Spondylolisthesis. N Engl J Med2016;374:1424-34. doi:10.1056/NEJMoa1508788. pmid:27074067
      OpenUrlCrossRefPubMed
    16. ↵
      1. Inose H,
      2. Kato T,
      3. Sasaki M,
      4. et al
      . Comparison of decompression, decompression plus fusion, and decompression plus stabilization: a long-term follow-up of a prospective, randomized study. Spine J2022;22:747-55. doi:10.1016/j.spinee.2021.12.014. pmid:34963630
      OpenUrlCrossRefPubMed
    17. ↵
      1. Austevoll IM,
      2. Hermansen E,
      3. Fagerland M,
      4. et al
      . Decompression alone versus decompression with instrumental fusion the NORDSTEN degenerative spondylolisthesis trial (NORDSTEN-DS); study protocol for a randomized controlled trial. BMC Musculoskelet Disord2019;20:7. doi:10.1186/s12891-018-2384-0. pmid:30611229
      OpenUrlCrossRefPubMed
    18. ↵
      1. Schulz KF,
      2. Altman DG,
      3. Moher D,
      4. CONSORT Group
      . CONSORT 2010 Statement: updated guidelines for reporting parallel group randomised trials. Trials2010;11:32. doi:10.1186/1745-6215-11-32. pmid:20334632
      OpenUrlCrossRefPubMed
    19. ↵
      ClinicalTrials.gov. The NORDSTEN study—degenerative spondylolisthesis (NORDSTEN/DS). https://clinicaltrialsgov/study/NCT02051374 2023.
    20. ↵
      1. Simmonds AM,
      2. Rampersaud YR,
      3. Dvorak MF,
      4. Dea N,
      5. Melnyk AD,
      6. Fisher CG
      . Defining the inherent stability of degenerative spondylolisthesis: a systematic review. J Neurosurg Spine2015;23:178-89. doi:10.3171/2014.11.SPINE1426. pmid:25978079
      OpenUrlCrossRefPubMed
    21. ↵
      1. Pisano AJ,
      2. Butler JS,
      3. Sebastian A,
      4. et al
      . Does surgically managed grade i degenerative lumbar spondylolisthesis require fusion?Clin Spine Surg2019;32:133-6. doi:10.1097/01933606-900000000-99504. pmid:29975202
      OpenUrlCrossRefPubMed
    22. ↵
      1. Kasper J,
      2. Lager AR,
      3. Rumpsfeld M,
      4. et al
      . Status report from Norway: Implementation of patient involvement in Norwegian health care. Z Evid Fortbild Qual Gesundhwes2017;123-124:75-80. doi:10.1016/j.zefq.2017.05.015. pmid:28546052
      OpenUrlCrossRefPubMed
    23. ↵
      1. Fairbank JC,
      2. Couper J,
      3. Davies JB,
      4. O’Brien JP
      . The Oswestry low back pain disability questionnaire. Physiotherapy1980;66:271-3.pmid:6450426
      OpenUrlPubMedWeb of Science
    24. ↵
      1. Austevoll IM,
      2. Gjestad R,
      3. Grotle M,
      4. et al
      . Follow-up score, change score or percentage change score for determining clinical important outcome following surgery? An observational study from the Norwegian registry for Spine surgery evaluating patient reported outcome measures in lumbar spinal stenosis and lumbar degenerative spondylolisthesis. BMC Musculoskelet Disord2019;20:31. doi:10.1186/s12891-018-2386-y. pmid:30658613
      OpenUrlCrossRefPubMed
    25. ↵
      1. Tuli SK,
      2. Yerby SA,
      3. Katz JN
      . Methodological approaches to developing criteria for improvement in lumbar spinal stenosis surgery. Spine (Phila Pa 1976)2006;31:1276-80. doi:10.1097/01.brs.0000217615.20018.6c. pmid:16688044
      OpenUrlCrossRefPubMed
    26. ↵
      1. Hjermstad MJ,
      2. Fayers PM,
      3. Haugen DF,
      4. et al.,
      5. European Palliative Care Research Collaborative (EPCRC)
      . Studies comparing numerical rating scales, verbal rating scales, and visual analogue scales for assessment of pain intensity in adults: a systematic literature review. J Pain Symptom Manage2011;41:1073-93. doi:10.1016/j.jpainsymman.2010.08.016. pmid:21621130
      OpenUrlCrossRefPubMedWeb of Science
    27. ↵
      1. EuroQol Group
      . EuroQol–a new facility for the measurement of health-related quality of life. Health Policy1990;16:199-208. doi:10.1016/0168-8510(90)90421-9 pmid:10109801
      OpenUrlCrossRefPubMedWeb of Science
    28. ↵
      1. Abraha I,
      2. Montedori A
      . Modified intention to treat reporting in randomised controlled trials: systematic review. BMJ2010;340:c2697. doi:10.1136/bmj.c2697. pmid:20547685
      OpenUrlAbstract/FREE Full Text
    29. ↵
      1. Deyo RA,
      2. Mirza SK,
      3. Martin BI,
      4. Kreuter W,
      5. Goodman DC,
      6. Jarvik JG
      . Trends, major medical complications, and charges associated with surgery for lumbar spinal stenosis in older adults. JAMA2010;303:1259-65. doi:10.1001/jama.2010.338. pmid:20371784
      OpenUrlCrossRefPubMedWeb of Science
    30. ↵
      1. Kim CH,
      2. Chung CK,
      3. Choi Y,
      4. et al
      . Increased proportion of fusion surgery for degenerative lumbar spondylolisthesis and changes in reoperation rate: a nationwide cohort study with a minimum 5-year follow-up. Spine (Phila Pa 1976)2019;44:346-54. doi:10.1097/BRS.0000000000002805. pmid:30028778
      OpenUrlCrossRefPubMed
    31. ↵
      1. Katz N,
      2. Paillard FC,
      3. Van Inwegen R
      . A review of the use of the number needed to treat to evaluate the efficacy of analgesics. J Pain2015;16:116-23. doi:10.1016/j.jpain.2014.08.005. pmid:25419989
      OpenUrlCrossRefPubMed
    32. ↵
      1. Sedgwick P
      . What is a non-inferiority trial?BMJ2013;347:f6853. doi:10.1136/bmj.f6853.
      OpenUrlFREE Full Text
    33. ↵
      1. Fagerland MW,
      2. Lydersen S,
      3. Laake P
      . Chapter 4. Statistical Analysis of Contingency Tables.Chapman & Hall/CRC, 2017doi:10.1201/9781315374116.
      OpenUrlCrossRef
    34. ↵
      1. Shen Z,
      2. Guan X,
      3. Wang R,
      4. et al
      . Effectiveness and safety of decompression alone versus decompression plus fusion for lumbar spinal stenosis with degenerative spondylolisthesis: a systematic review and meta-analysis. Ann Transl Med2022;10:664. doi:10.21037/atm-22-2208. pmid:35845482
      OpenUrlCrossRefPubMed
      1. Dupuis PR,
      2. Yong-Hing K,
      3. Cassidy JD,
      4. Kirkaldy-Willis WH
      . Radiologic diagnosis of degenerative lumbar spinal instability. Spine (Phila Pa 1976)1985;10:262-76. doi:10.1097/00007632-198504000-00015 pmid:3992347
      OpenUrlCrossRefPubMed
      1. Cho IY,
      2. Park SY,
      3. Park JH,
      4. Suh SW,
      5. Lee SH
      . MRI findings of lumbar spine instability in degenerative spondylolisthesis. J Orthop Surg (Hong Kong)2017;25:2309499017718907. doi:10.1177/2309499017718907. pmid:28685666
      OpenUrlCrossRefPubMed
      1. Modic MT,
      2. Steinberg PM,
      3. Ross JS,
      4. Masaryk TJ,
      5. Carter JR
      . Degenerative disk disease: assessment of changes in vertebral body marrow with MR imaging. Radiology1988;166:193-9. doi:10.1148/radiology.166.1.3336678. pmid:3336678
      OpenUrlCrossRefPubMedWeb of Science
      1. Pfirrmann CW,
      2. Metzdorf A,
      3. Zanetti M,
      4. Hodler J,
      5. Boos N
      . Magnetic resonance classification of lumbar intervertebral disc degeneration. Spine (Phila Pa 1976)2001;26:1873-8. doi:10.1097/00007632-200109010-00011 pmid:11568697
      OpenUrlCrossRefPubMed
      1. Lee S,
      2. Lee JW,
      3. Yeom JS,
      4. et al
      . A practical MRI grading system for lumbar foraminal stenosis. AJR Am J Roentgenol2010;194:1095-8. doi:10.2214/AJR.09.2772. pmid:20308517
      OpenUrlCrossRefPubMed
    40. ↵
      1. Mojadeddi ZM,
      2. Öberg S,
      3. Rosenberg J
      . Low degree of patient involvement in contemporary surgical research: A scoping review. J Postgrad Med2023;69:153-8. doi:10.4103/jpgm.jpgm_83_23. pmid:37357485
      OpenUrlCrossRefPubMed
    41. ↵
      1. Hellum C,
      2. Rekeland F,
      3. Småstuen MC,
      4. et al
      . Surgery in degenerative spondylolisthesis: does fusion improve outcome in subgroups? A secondary analysis from a randomized trial (NORDSTEN trial). Spine J2023;23:1613-22. doi:10.1016/j.spinee.2023.06.386. pmid:37355044
      OpenUrlCrossRefPubMed
    42. ↵
      1. Speed C
      . Low back pain. BMJ2004;328:1119-21. doi:10.1136/bmj.328.7448.1119. pmid:15130982
      OpenUrlFREE Full Text
    43. ↵
      1. Jacobsen S,
      2. Sonne-Holm S,
      3. Rovsing H,
      4. Monrad H,
      5. Gebuhr P
      . Degenerative lumbar spondylolisthesis: an epidemiological perspective: the Copenhagen Osteoarthritis Study. Spine (Phila Pa 1976)2007;32:120-5. doi:10.1097/01.brs.0000250979.12398.96. pmid:17202902
      OpenUrlCrossRefPubMedWeb of Science
    44. ↵
      1. Alvin MD,
      2. Lubelski D,
      3. Abdullah KG,
      4. Whitmore RG,
      5. Benzel EC,
      6. Mroz TE
      . Cost-utility analysis of instrumented fusion versus decompression alone for grade i l4-l5 spondylolisthesis at 1-year follow-up: a pilot study. Clin Spine Surg2016;29:E80-6. doi:10.1097/BSD.0000000000000103. pmid:26889996
      OpenUrlCrossRefPubMed
    45. ↵
      1. Huang P,
      2. Liu Z,
      3. Liu H,
      4. et al
      . Decompression versus decompression plus fusion for treating degenerative lumbar spinal stenosis: a systematic review and meta-analysis. Pain Pract2023;4:390-398. doi:10.1111/papr.13193. pmid:36504445
      OpenUrlCrossRefPubMed
    46. ↵
      1. Fritzell P,
      2. Hägg O,
      3. Gerdhem P,
      4. et al.
      Swespine Annual Report 2022. 2022.
    47. ↵
      1. Solberg T,
      2. Olsen LR,
      3. Berglund MB
      . The Norwegian Registry for Spinal Surgery. Annual Report. 2022.
    48. ↵
      1. Sastry RA,
      2. Chen JS,
      3. Shao B,
      4. et al
      . Patterns in decompression and fusion procedures for patients with lumbar stenosis after major clinical trial results, 2016 to 2019. JAMA Netw Open2023;6:e2326357. doi:10.1001/jamanetworkopen.2023.26357. pmid:37523184
      OpenUrlCrossRefPubMed
    49. ↵
      1. Taso M,
      2. Sommernes JH,
      3. Bjorland S,
      4. et al
      . What is success of treatment? Expected outcome scores in cervical radiculopathy patients were much higher than the previously reported cut-off values for success. Eur Spine J2022;31:2761-8. doi:10.1007/s00586-022-07234-7. pmid:35551484
      OpenUrlCrossRefPubMed
    50. ↵
      1. Nerland US,
      2. Jakola AS,
      3. Solheim O,
      4. et al
      . Minimally invasive decompression versus open laminectomy for central stenosis of the lumbar spine: pragmatic comparative effectiveness study. BMJ2015;350:h1603. doi:10.1136/bmj.h1603. pmid:25833966
      OpenUrlAbstract/FREE Full Text
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