Kaimen Rigor reviewed

Rigor-Reviewed Manuscript

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

Name: Kaimen Rigor review — Decompression alone or with fusion for degenerative lumbar spondylolisthesis (Nordsten-DS): five year follow-up of a randomised, multicentre, non-inferiority trial.
Item: Decompression alone or with fusion for degenerative lumbar spondylolisthesis (Nordsten-DS): five year follow-up of a randomised, multicentre, non-inferiority trial.
Rating: 96
Author: Alpha1

Kgomotso EL, Hellum C, Fagerland MW, Solberg T, Brox JI, Storheim K, Hermansen E, Franssen E, Weber C, Brisby H, Algaard KRH, Furunes H, Banitalebi H, Ljøstad I, Indrekvam K, Austevoll IM, Nordsten collaborators

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Kaimen Rigor review — 2.25★ (Weak), 0 critical, 3 high issues for “Decompression alone or with fusion for degenerative lumbar spondylolisthesis (Nordsten-DS): five year follow-up of a randomised, multicentre, non-inferiority trial.”

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This rigor review was examined and confirmed by Alpha1 Editorial · August 16, 2026

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

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DOI

10.1136/bmj-2024-079771

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Kaimen Rigor reviewed

Rigor-Reviewed Manuscript

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

Paper source

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

Read full text (PMC)

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Links back to this Kaimen Rigor review.

Alpha1 Editorial

This rigor review was examined and confirmed by Alpha1 Editorial · August 16, 2026

Kaimen Rigor review

Kaimen Rigor reviewed

2.25 / 5

Weak — serious problems found

Interventional Study

Critical

High-priority

How this rating was calculated▸

Started at 5★ — deductions

IntegrityIntegrity concern ×3−1.5★
ClaimsEfficacy rests on an unvalidated surrogate endpoint−0.5★
ClaimsTreatment effect not shown to be clinically meaningful−0.5★
ReportingData & code availability partially met−0.25★

Model-reported confidence: highReviewer agreement: highEngine: 7.39.0Source: full text

Not verified in this report

No data or code availability links were detected to verify.

Biggest issues

01Efficacy rests on an unvalidated surrogate endpoint
highOverreachreviewer-assessedFull detail
The primary outcome is a 30% or more reduction in the Oswestry Disability Index (ODI), a patient-reported functional disability scale. This is a surrogate for clinical benefit. The paper does not demonstrate target engagement at the tested dose (not applicable for surgical intervention) nor does it cite validated evidence linking a 30% ODI reduction to hard clinical outcomes. The ODI is a validated instrument, but the claim of non-inferiority is based on this surrogate without establishing a direct link to clinical outcomes such as mortality or major morbidity.
“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, defined as a clinically important outcome.”
Find in source
02Treatment effect not shown to be clinically meaningful
highOverreachreviewer-assessedFull detail
The primary outcome is a between-group difference of 0.4 percentage points (95% CI -11.2 to 11.9) in the proportion achieving a 30% ODI reduction. This difference is small and not anchored to a minimal clinically important difference for the between-group difference. The non-inferiority margin of -15 percentage points is predefined, but the observed difference is not explicitly shown to be clinically meaningful. The mean ODI change from baseline is -17.8 in both groups, but the clinical meaningfulness of this change is not discussed in terms of MCID.
“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).”
Find in source

Findings by category

101ArithmeticNumerical inconsistencies 302OverreachOverstated conclusions 03AuthenticityNone found 104DisclosureReporting gaps 05AvailabilityNone found · partly checked 06Copyedit4 minor suggestions

This Kaimen Rigor review uses Kaimen Rigor reviewers trained on a curated corpus of high-fidelity and retracted papers, with expert supervision and curation. It can still make mistakes; verify each finding against the source before relying on it.

This is a well-conducted and well-reported randomized non-inferiority trial with rigorous design, appropriate statistical methods, and transparent reporting. The main weakness is the vague data availability statement, which lacks a concrete access mechanism or timeframe.

Both independent reviewers agreed on all dimension statuses and study type (interventional). The statistics verification component checked 3 tests (all consistent); coverage is limited to tests with a test statistic and df or an effect estimate with CI. No retracted or non-existent references were found. The copyedit pass flagged 4 minor issues (typos, consistency).

Numerical inconsistencies

1 finding · worst low

Values that contradict each other or are impossible for the stated sample: recomputed p-values and test statistics, GRIM/GRIMMER checks on summary numbers, percentages against their own counts, totals against their parts, and estimates against their own confidence intervals.

Internal contradictions in the reported numbersAssessed

Recomputed 3 tests: 3 consistent, 0 inconsistent; 3 via agent-written checks.

Overstated conclusions

3 findings · worst high

Conclusions that reach past what the paper's own results support — including a significance claim that no longer holds when the statistic is recomputed, and efficacy resting on an unvalidated surrogate endpoint.

Efficacy rests on an unvalidated surrogate endpointAssessed
Treatment effect not shown to be clinically meaningfulAssessed
Conclusions only partially backed by the presented evidenceAssessed

3 major claims checked against the paper's own evidence: 1 only partially supported (evidence backs part of the claim; gaps or caveats remain); the rest adequately supported.

Premise concern: surrogate not validated for clinical benefit; effect size not shown to be clinically meaningful.

Data authenticity concerns

None found

An adversarial read for patterns associated with data that may not be genuine: results that look too clean, implausibly large effects, duplicated data or images, and methods that do not match the results reported.

Checked — nothing surfaced.

Reporting gaps

1 finding · worst medium

Required detail the manuscript never states — study design, biological variables, ethics approval and consent, key resources, statistical reporting, data and code availability, and overall transparency.

Data/code availability incompleteAssessed

Eight Dimensions7 pass · 1 warn

The introduction cites prior randomized trials and meta-analyses indicating decompression alone is sufficient up to two years, but notes contradictory longer-term results. The rationale for the trial is to assess non-inferiority at five years, addressing the gap in longer-term evidence. Limitations of prior research (sparse and contradictory outcomes beyond two years) are explicitly acknowledged.

Sub-criteria

prior work citedADEQUATE

premise rationaleADEQUATE

limitations addressedADEQUATE

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 90% conf

The paper establishes a clear scientific premise by citing prior RCTs and meta-analyses, and justifies the need for longer-term follow-up data.

Evidence

“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. By contrast, one randomised controlled trial found that additional instrumented fusion gave superior results to decompression alone. Results from randomised controlled trials that include outcomes from more than two years after surgery are sparse and contradictory.”

Introduction ¶3Find in source

“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.”

Introduction ¶4Find in source

PASSReviewer 2· 90% conf

The paper establishes a clear scientific premise by citing prior RCTs and meta-analyses, and justifies the need for longer-term follow-up data.

Evidence

“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.”

Introduction ¶3Find in source

“Results from randomised controlled trials that include outcomes from more than two years after surgery are sparse and contradictory.”

Introduction ¶4Find in source

Randomization method (computer-generated, 1:1, random block sizes) and unit (individual participant) are clearly described. Blinding is open-label with a stated rationale (surgical nature), and the data analyst was masked. Power analysis is reported with effect size, alpha, and power. Inclusion/exclusion criteria are pre-specified and referenced. Outlier handling is addressed through the pre-specified analysis populations (mITT, per-protocol) and multiple imputation for missing data. Controls are inherent in the comparator arm. Independent replication is not applicable for a single pivotal trial.

Sub-criteria

controlsN/A

power analysisADEQUATE

blinding levelsADEQUATE

outlier handlingADEQUATE

randomization unitADEQUATE

inclusion exclusionADEQUATE

randomization methodADEQUATE

replicate distinctionN/A

independent replicationN/A

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 95% conf

The trial design is rigorous: computer-generated randomization with concealment, stratification by site, pre-specified inclusion/exclusion criteria, a priori power analysis, and a pre-specified analysis plan.

Evidence

“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.”

MethodsFind in source

“To reject H 0 , 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.”

Statistical analysisFind in source

“Individual participants and their surgeons were not masked to the treatment assignment.”

MethodsFind in source

PASSReviewer 2· 95% conf

The trial design is rigorous with adequate randomization, blinding (open-label with rationale), power analysis, and pre-specified analysis populations.

Evidence

MethodsFind in source

“Individual participants and their surgeons were not masked to the treatment assignment.”

MethodsFind in source

Statistical analysisFind in source

Sex is reported (69% women overall) and both sexes are included, so sex_justified is not applicable. Age, weight (BMI), and health status (comorbidities, ASA scores) are reported. Demographics include age, sex, education, marital status, and smoking. Species/strain and housing conditions are not applicable for a human trial.

Sub-criteria

demographicsADEQUATE

sex reportedADEQUATE

sex justifiedN/A

age weight healthADEQUATE

housing conditionsN/A

species strain sourceN/A

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 90% conf

Key demographic and clinical characteristics are reported, including age, sex, BMI, comorbidities, and baseline outcome scores.

Evidence

“Mean age at baseline was 66.2 years (SD 7.6), and 69% were women.”

AbstractFind in source

“Female sex | 92/133 (69) | 88/129 (68)”

Table 1Find in source

PASSReviewer 2· 90% conf

Demographic and baseline clinical characteristics are well reported, including age, sex, and comorbidities.

Evidence

“Female sex | 92/133 (69) | 88/129 (68)”

Table 1Find in source

“Age, years (SD) | 66.0 (7.4) | 66.5 (7.9)”

Table 1Find in source

“Hypertension | 46/133 (35) | 44/129 (34)”

Table 1Find in source

The Regional Committee for Medical and Health Research Ethics of Central Norway (project identifier 2013/366) approved the trial, and written informed consent was obtained from all participants. Regulatory compliance is implied through adherence to CONSORT and Norwegian regulations.

Sub-criteria

iacuc statementN/A

informed consentADEQUATE

irb ethics statementADEQUATE

regulatory complianceADEQUATE

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 95% conf

Ethical approval from a named committee and informed consent are documented.

Evidence

“The Regional Committee for Medical and Health Research Ethics of Central Norway (project identifier 2013/366) approved the trial.”

MethodsFind in source

“All patients who accepted trial participation gave written consent before randomisation.”

MethodsFind in source

PASSReviewer 2· 95% conf

Ethical approval from a named committee and informed consent are reported.

Evidence

“The Regional Committee for Medical and Health Research Ethics of Central Norway (project identifier 2013/366) approved the trial.”

MethodsFind in source

“All patients who accepted trial participation gave written consent before randomisation.”

MethodsFind in source

“The trial reporting follows the consolidated standards of reporting trials (CONSORT) guidelines.”

MethodsFind in source

The surgical interventions are described in detail (decompression technique, fusion with pedicle screws and rods). No specific drug, biologic, or device is named, but the surgical procedures are the investigational product. Statistical software (Stata/SE version 17.0) is identified. Other bench resources are not applicable.

Sub-criteria

mycoplasma testingN/A

reagents identifiedADEQUATE

organisms identifiedN/A

antibodies identifiedN/A

cell line authenticationN/A

software tools identifiedADEQUATE

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 85% conf

The investigational product (surgical procedures) is described in detail, and statistical software is identified.

Evidence

“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.”

MethodsFind in source

“The analyses were done using Stata/SE software, version 17.0.”

Statistical analysisFind in source

PASSReviewer 2· 85% conf

The investigational product (surgical procedures) is described in detail, and statistical software is identified.

Evidence

MethodsFind in source

“The analyses were done using Stata/SE software, version 17.0.”

Statistical analysisFind in source

Tests are named (Newcombe hybrid score CIs, linear mixed models). Assumptions are checked (visual inspection of histograms). Exact p-values are not reported; instead, effect estimates with 95% CIs are provided, which is appropriate for a non-inferiority trial. Software is identified. Data presentation includes per-group n and CIs. Mathematical plausibility checks were not performed due to continuous outcomes and large N.

Sub-criteria

tests namedADEQUATE

exact p valuesN/A

effect sizes ciADEQUATE

data presentationADEQUATE

software identifiedADEQUATE

assumptions verifiedADEQUATE

mathematical plausibilityN/A

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 90% conf

Statistical methods are appropriate and well-described, with effect sizes and confidence intervals reported; p-values are not the primary focus.

Evidence

“The primary outcome and all categorical secondary outcomes were analysed with Newcombe hybrid score confidence intervals.”

Statistical analysisFind in source

“The difference between the groups was 0.4 percentage points (95% CI −11.2 to 11.9).”

ResultsFind in source

PASSReviewer 2· 90% conf

Statistical methods are appropriate and well-described, with effect sizes and confidence intervals reported; p-values are not the primary focus.

Evidence

“The primary outcome and all categorical secondary outcomes were analysed with Newcombe hybrid score confidence intervals.”

Statistical analysisFind in source

“The difference between the groups was 0.4 percentage points (95% CI −11.2 to 11.9).”

ResultsFind in source

“The assumption of normally distributed data was assessed with visual inspection of histograms and descriptive statistics, and no major deviations were observed.”

Statistical analysisFind in source

The data availability statement says requests should be submitted to an email for consideration, with the scientific board possibly granting access. This is a managed-access route but lacks details on conditions or timeframe, making it 'reported_but_inadequate'. No repository deposit or accession numbers are provided, and no custom code is mentioned.

Sub-criteria

code sharingN/A

accession numbersN/A

repository depositNOT REPORTED

data availability statementINADEQUATE

Per reviewer (2) — the votes behind the verdict

WARNReviewer 1· 80% conf

A data availability statement exists but is vague, lacking a concrete access mechanism or timeframe.

Evidence

“All data requests should be submitted to ivar.magne.austevoll@helse-bergen.no for consideration. The NORDSTEN scientific board may grant access to anonymised data following a research protocol”

Data availabilityFind in source

WARNReviewer 2· 80% conf

A data availability statement exists but is vague, lacking a clear mechanism or timeframe for access.

Evidence

“All data requests should be submitted to ivar.magne.austevoll@helse-bergen.no for consideration. The NORDSTEN scientific board may grant access to anonymised data following a research protocol”

Data availabilityFind in source

Trial registration number is provided (NCT02051374). CONSORT guidelines are followed. All pre-specified outcomes are reported, including secondary and adverse events. Limitations are discussed (open-label, per-protocol sample size). Conclusions are proportional to the evidence. Funding sources and competing interests are declared.

Sub-criteria

funding coiADEQUATE

trial registrationADEQUATE

reporting guidelineADEQUATE

methods completenessADEQUATE

all outcomes reportedADEQUATE

limitations discussedADEQUATE

conclusions proportionalADEQUATE

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 90% conf

The trial is registered, follows CONSORT, reports all outcomes, discusses limitations, and provides funding/COI statements.

Evidence

“Trial registration ClinicalTrials.gov NCT02051374”

AbstractFind in source

“Another limitation was the absence of double blinding; only the data analyst was masked to treatment assignments.”

LimitationsFind in source

PASSReviewer 2· 90% conf

The trial is registered, follows CONSORT, reports all outcomes, discusses limitations, and provides funding and COI statements.

Evidence

“Trial registration ClinicalTrials.gov NCT02051374”

AbstractFind in source

“The trial reporting follows the consolidated standards of reporting trials (CONSORT) guidelines.”

MethodsFind in source

“Another limitation was the absence of double blinding; only the data analyst was masked to treatment assignments.”

LimitationsFind in source

Registered (1 ID: ClinicalTrials.gov). Reporting guideline cited: CONSORT.

Broken references and links

None found · partly checked

References checked against Crossref, OpenAlex and Retraction Watch for retractions and resolvability, plus declared data and code links probed for whether they resolve to content matching the paper.

Nothing surfaced — but not everything feeding this category ran (missing: data/code link verification), so read this as a partial clean bill.

Checked 50 references by DOI: 45 verified — 5 no DOI (shown, not verified).

Copyediting

4 minor

Wording, consistency and formatting errors that need correcting before submission.

No major wording or formatting errors. 4 minor suggestions below.

4 copyedit issues flagged: mostly consistency, typo.

Kaimen Rigor Action ItemsFinal pass before journal submission

The published paper is methodologically robust and transparent; an informed reader should weigh the vague data availability statement as a minor limitation. No erratum or correction is warranted based on the rigor checks, though the copyedit issues (typos, missing leading zero) could be corrected in a minor revision.

1.
HIGHdata code
In the Data availability statement, specify the mechanism for data access (e.g., a data access committee, review process, and expected timeframe) to meet the 'reported_and_adequate' standard.
The current vague statement may deter researchers from requesting data and does not meet journal requirements for data availability.
2.
HIGHdata code
Add a statement about code sharing if any custom analysis code was used; otherwise, explicitly state that no custom code was used.
Transparency about code availability is essential for reproducibility.
3.
HIGHreporting
In the Data availability section, consider providing a link to the full trial protocol and statistical analysis plan.
This would enhance transparency and allow readers to verify that the analysis followed the pre-specified plan.
4.
MEDIUMcopyedit
In the Abstract, Results, change 'had a at least a 30% reduction' to 'had at least a 30% reduction'.
Duplicate article 'a' is a typo.
5.
MEDIUMcopyedit
In the Results, Primary outcome, change 'in the in the modified intention-to-treat set' to 'in the modified intention-to-treat set'.
Duplicate phrase 'in the' is a consistency error.
6.
MEDIUMcopyedit
In Table 2, EQ-5D-3L row, change '0.68 (0.63 to 073)' to '0.68 (0.63 to 0.73)'.
Missing leading zero in '073' is a typo.
7.
MEDIUMcopyedit
In Methods, Statistical analysis, change 'number needed to treat was 100/15=6.67' to 'number needed to treat was 100/15 = 6.67' for consistent spacing around the equals sign.
Consistency in formatting improves readability.
8.
MEDIUMreporting
In the Discussion, expand on the per-protocol sample size shortfall and its potential impact on the non-inferiority conclusion.
The per-protocol sample size was below the a priori required sample size, which could affect the robustness of the non-inferiority claim.
9.
MEDIUMreporting
Clarify the role of the data monitoring committee and any interim analysis results in the Methods to enhance transparency.
This information is often expected in trial reports and would improve completeness.
10.
LOWreporting
Consider reporting exact p-values for secondary outcomes where feasible, or explicitly state that CIs are used for inference.
While CIs are appropriate for a non-inferiority trial, some readers may expect p-values for secondary outcomes.
11.
LOWreporting
Include a CONSORT flow diagram in the main text (currently referenced as Fig 1) to improve reporting completeness.
A flow diagram is a standard element of CONSORT reporting and is already referenced, but should be included in the main text.

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

Read full text (PMC)

DOI

10.1136/bmj-2024-079771

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Record fingerprint

046b3899793a5b863495482f2e09db8c9b574670feda55270a8f8eb790e33f5f

Verify via API

Issued Aug 16, 2026Engine 7.39.0

Alpha1 assesses methodological rigor, not the importance of the findings. See how we calibrate →

Kaimen Rigor review

Kaimen Rigor reviewed

2.25 / 5

Weak — serious problems found

Interventional Study

Critical

High-priority

How this rating was calculated▸

Started at 5★ — deductions

IntegrityIntegrity concern ×3−1.5★
ClaimsEfficacy rests on an unvalidated surrogate endpoint−0.5★
ClaimsTreatment effect not shown to be clinically meaningful−0.5★
ReportingData & code availability partially met−0.25★

Model-reported confidence: highReviewer agreement: highEngine: 7.39.0Source: full text

Not verified in this report

No data or code availability links were detected to verify.

Biggest issues

01Efficacy rests on an unvalidated surrogate endpoint
highOverreachreviewer-assessedFull detail
The primary outcome is a 30% or more reduction in the Oswestry Disability Index (ODI), a patient-reported functional disability scale. This is a surrogate for clinical benefit. The paper does not demonstrate target engagement at the tested dose (not applicable for surgical intervention) nor does it cite validated evidence linking a 30% ODI reduction to hard clinical outcomes. The ODI is a validated instrument, but the claim of non-inferiority is based on this surrogate without establishing a direct link to clinical outcomes such as mortality or major morbidity.
“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, defined as a clinically important outcome.”
Find in source
02Treatment effect not shown to be clinically meaningful
highOverreachreviewer-assessedFull detail
The primary outcome is a between-group difference of 0.4 percentage points (95% CI -11.2 to 11.9) in the proportion achieving a 30% ODI reduction. This difference is small and not anchored to a minimal clinically important difference for the between-group difference. The non-inferiority margin of -15 percentage points is predefined, but the observed difference is not explicitly shown to be clinically meaningful. The mean ODI change from baseline is -17.8 in both groups, but the clinical meaningfulness of this change is not discussed in terms of MCID.
“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).”
Find in source

Findings by category

101ArithmeticNumerical inconsistencies 302OverreachOverstated conclusions 03AuthenticityNone found 104DisclosureReporting gaps 05AvailabilityNone found · partly checked 06Copyedit4 minor suggestions

Numerical inconsistencies

1 finding · worst low

Internal contradictions in the reported numbersAssessed

Recomputed 3 tests: 3 consistent, 0 inconsistent; 3 via agent-written checks.

Overstated conclusions

3 findings · worst high

Efficacy rests on an unvalidated surrogate endpointAssessed
Treatment effect not shown to be clinically meaningfulAssessed
Conclusions only partially backed by the presented evidenceAssessed

3 major claims checked against the paper's own evidence: 1 only partially supported (evidence backs part of the claim; gaps or caveats remain); the rest adequately supported.

Premise concern: surrogate not validated for clinical benefit; effect size not shown to be clinically meaningful.

Data authenticity concerns

None found

Checked — nothing surfaced.

Reporting gaps

1 finding · worst medium

Data/code availability incompleteAssessed

Eight Dimensions7 pass · 1 warn

Sub-criteria

prior work citedADEQUATE

premise rationaleADEQUATE

limitations addressedADEQUATE

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 90% conf

The paper establishes a clear scientific premise by citing prior RCTs and meta-analyses, and justifies the need for longer-term follow-up data.

Evidence

Introduction ¶3Find in source

Introduction ¶4Find in source

PASSReviewer 2· 90% conf

The paper establishes a clear scientific premise by citing prior RCTs and meta-analyses, and justifies the need for longer-term follow-up data.

Evidence

“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.”

Introduction ¶3Find in source

“Results from randomised controlled trials that include outcomes from more than two years after surgery are sparse and contradictory.”

Introduction ¶4Find in source

Sub-criteria

controlsN/A

power analysisADEQUATE

blinding levelsADEQUATE

outlier handlingADEQUATE

randomization unitADEQUATE

inclusion exclusionADEQUATE

randomization methodADEQUATE

replicate distinctionN/A

independent replicationN/A

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 95% conf

Evidence

MethodsFind in source

Statistical analysisFind in source

“Individual participants and their surgeons were not masked to the treatment assignment.”

MethodsFind in source

PASSReviewer 2· 95% conf

The trial design is rigorous with adequate randomization, blinding (open-label with rationale), power analysis, and pre-specified analysis populations.

Evidence

MethodsFind in source

“Individual participants and their surgeons were not masked to the treatment assignment.”

MethodsFind in source

Statistical analysisFind in source

Sub-criteria

demographicsADEQUATE

sex reportedADEQUATE

sex justifiedN/A

age weight healthADEQUATE

housing conditionsN/A

species strain sourceN/A

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 90% conf

Key demographic and clinical characteristics are reported, including age, sex, BMI, comorbidities, and baseline outcome scores.

Evidence

“Mean age at baseline was 66.2 years (SD 7.6), and 69% were women.”

AbstractFind in source

“Female sex | 92/133 (69) | 88/129 (68)”

Table 1Find in source

PASSReviewer 2· 90% conf

Demographic and baseline clinical characteristics are well reported, including age, sex, and comorbidities.

Evidence

“Female sex | 92/133 (69) | 88/129 (68)”

Table 1Find in source

“Age, years (SD) | 66.0 (7.4) | 66.5 (7.9)”

Table 1Find in source

“Hypertension | 46/133 (35) | 44/129 (34)”

Table 1Find in source

Sub-criteria

iacuc statementN/A

informed consentADEQUATE

irb ethics statementADEQUATE

regulatory complianceADEQUATE

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 95% conf

Ethical approval from a named committee and informed consent are documented.

Evidence

“The Regional Committee for Medical and Health Research Ethics of Central Norway (project identifier 2013/366) approved the trial.”

MethodsFind in source

“All patients who accepted trial participation gave written consent before randomisation.”

MethodsFind in source

PASSReviewer 2· 95% conf

Ethical approval from a named committee and informed consent are reported.

Evidence

“The Regional Committee for Medical and Health Research Ethics of Central Norway (project identifier 2013/366) approved the trial.”

MethodsFind in source

“All patients who accepted trial participation gave written consent before randomisation.”

MethodsFind in source

“The trial reporting follows the consolidated standards of reporting trials (CONSORT) guidelines.”

MethodsFind in source

Sub-criteria

mycoplasma testingN/A

reagents identifiedADEQUATE

organisms identifiedN/A

antibodies identifiedN/A

cell line authenticationN/A

software tools identifiedADEQUATE

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 85% conf

The investigational product (surgical procedures) is described in detail, and statistical software is identified.

Evidence

MethodsFind in source

“The analyses were done using Stata/SE software, version 17.0.”

Statistical analysisFind in source

PASSReviewer 2· 85% conf

The investigational product (surgical procedures) is described in detail, and statistical software is identified.

Evidence

MethodsFind in source

“The analyses were done using Stata/SE software, version 17.0.”

Statistical analysisFind in source

Sub-criteria

tests namedADEQUATE

exact p valuesN/A

effect sizes ciADEQUATE

data presentationADEQUATE

software identifiedADEQUATE

assumptions verifiedADEQUATE

mathematical plausibilityN/A

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 90% conf

Statistical methods are appropriate and well-described, with effect sizes and confidence intervals reported; p-values are not the primary focus.

Evidence

“The primary outcome and all categorical secondary outcomes were analysed with Newcombe hybrid score confidence intervals.”

Statistical analysisFind in source

“The difference between the groups was 0.4 percentage points (95% CI −11.2 to 11.9).”

ResultsFind in source

PASSReviewer 2· 90% conf

Statistical methods are appropriate and well-described, with effect sizes and confidence intervals reported; p-values are not the primary focus.

Evidence

“The primary outcome and all categorical secondary outcomes were analysed with Newcombe hybrid score confidence intervals.”

Statistical analysisFind in source

“The difference between the groups was 0.4 percentage points (95% CI −11.2 to 11.9).”

ResultsFind in source

“The assumption of normally distributed data was assessed with visual inspection of histograms and descriptive statistics, and no major deviations were observed.”

Statistical analysisFind in source

Sub-criteria

code sharingN/A

accession numbersN/A

repository depositNOT REPORTED

data availability statementINADEQUATE

Per reviewer (2) — the votes behind the verdict

WARNReviewer 1· 80% conf

A data availability statement exists but is vague, lacking a concrete access mechanism or timeframe.

Evidence

“All data requests should be submitted to ivar.magne.austevoll@helse-bergen.no for consideration. The NORDSTEN scientific board may grant access to anonymised data following a research protocol”

Data availabilityFind in source

WARNReviewer 2· 80% conf

A data availability statement exists but is vague, lacking a clear mechanism or timeframe for access.

Evidence

“All data requests should be submitted to ivar.magne.austevoll@helse-bergen.no for consideration. The NORDSTEN scientific board may grant access to anonymised data following a research protocol”

Data availabilityFind in source

Sub-criteria

funding coiADEQUATE

trial registrationADEQUATE

reporting guidelineADEQUATE

methods completenessADEQUATE

all outcomes reportedADEQUATE

limitations discussedADEQUATE

conclusions proportionalADEQUATE

Per reviewer (2) — the votes behind the verdict

PASSReviewer 1· 90% conf

The trial is registered, follows CONSORT, reports all outcomes, discusses limitations, and provides funding/COI statements.

Evidence

“Trial registration ClinicalTrials.gov NCT02051374”

AbstractFind in source

“Another limitation was the absence of double blinding; only the data analyst was masked to treatment assignments.”

LimitationsFind in source

PASSReviewer 2· 90% conf

The trial is registered, follows CONSORT, reports all outcomes, discusses limitations, and provides funding and COI statements.

Evidence

“Trial registration ClinicalTrials.gov NCT02051374”

AbstractFind in source

“The trial reporting follows the consolidated standards of reporting trials (CONSORT) guidelines.”

MethodsFind in source

“Another limitation was the absence of double blinding; only the data analyst was masked to treatment assignments.”

LimitationsFind in source

Registered (1 ID: ClinicalTrials.gov). Reporting guideline cited: CONSORT.

Broken references and links

None found · partly checked

References checked against Crossref, OpenAlex and Retraction Watch for retractions and resolvability, plus declared data and code links probed for whether they resolve to content matching the paper.

Nothing surfaced — but not everything feeding this category ran (missing: data/code link verification), so read this as a partial clean bill.

Checked 50 references by DOI: 45 verified — 5 no DOI (shown, not verified).

Copyediting

4 minor

Wording, consistency and formatting errors that need correcting before submission.

No major wording or formatting errors. 4 minor suggestions below.

4 copyedit issues flagged: mostly consistency, typo.

Kaimen Rigor Action ItemsFinal pass before journal submission

1.
HIGHdata code
In the Data availability statement, specify the mechanism for data access (e.g., a data access committee, review process, and expected timeframe) to meet the 'reported_and_adequate' standard.
The current vague statement may deter researchers from requesting data and does not meet journal requirements for data availability.
2.
HIGHdata code
Add a statement about code sharing if any custom analysis code was used; otherwise, explicitly state that no custom code was used.
Transparency about code availability is essential for reproducibility.
3.
HIGHreporting
In the Data availability section, consider providing a link to the full trial protocol and statistical analysis plan.
This would enhance transparency and allow readers to verify that the analysis followed the pre-specified plan.
4.
MEDIUMcopyedit
In the Abstract, Results, change 'had a at least a 30% reduction' to 'had at least a 30% reduction'.
Duplicate article 'a' is a typo.
5.
MEDIUMcopyedit
In the Results, Primary outcome, change 'in the in the modified intention-to-treat set' to 'in the modified intention-to-treat set'.
Duplicate phrase 'in the' is a consistency error.
6.
MEDIUMcopyedit
In Table 2, EQ-5D-3L row, change '0.68 (0.63 to 073)' to '0.68 (0.63 to 0.73)'.
Missing leading zero in '073' is a typo.
7.
MEDIUMcopyedit
In Methods, Statistical analysis, change 'number needed to treat was 100/15=6.67' to 'number needed to treat was 100/15 = 6.67' for consistent spacing around the equals sign.
Consistency in formatting improves readability.
8.
MEDIUMreporting
In the Discussion, expand on the per-protocol sample size shortfall and its potential impact on the non-inferiority conclusion.
The per-protocol sample size was below the a priori required sample size, which could affect the robustness of the non-inferiority claim.
9.
MEDIUMreporting
Clarify the role of the data monitoring committee and any interim analysis results in the Methods to enhance transparency.
This information is often expected in trial reports and would improve completeness.
10.
LOWreporting
Consider reporting exact p-values for secondary outcomes where feasible, or explicitly state that CIs are used for inference.
While CIs are appropriate for a non-inferiority trial, some readers may expect p-values for secondary outcomes.
11.
LOWreporting
Include a CONSORT flow diagram in the main text (currently referenced as Fig 1) to improve reporting completeness.
A flow diagram is a standard element of CONSORT reporting and is already referenced, but should be included in the main text.

Full text (53,709 chars)Analyzed: Aug 16, 2026