ViBone in Cervical and Lumbar Spine Fusion: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for ViBone in Cervical and Lumbar Spine Fusion (NCT03425682), a registered phase not stated study. The primary outcome is Fusion Rates Per Level Using the Bridwell Interbody Grading Scale.

2. Clinical Question

3. Trial Design

This is a prospective, post-market, multi-center study of ViBone in cervical and lumbar spine fusion. The registry lists an enrollment of 118 and a status of COMPLETED. The study start date is 2018-05-14, and the primary completion date is 2021-01-15. Elutia Inc. is listed as the sponsor. Those details describe the record’s administrative and design context, not the observed primary-outcome results.

Two procedural groups are described. The cervical group includes patients undergoing anterior cervical discectomy and fusion (ACDF) using ViBone. The lumbar group includes patients undergoing lumbar interbody fusion using ViBone, with TLIF, PLIF, ALIF, and LLIF named in the study description. The brief summary describes the study population as undergoing one-to-three-level ACDF or lumbar interbody fusion.

The record does not describe a randomized treatment allocation, and allocation is not stated. Both named groups receive ViBone, while their procedures differ. They should therefore be read as procedural categories, not as a treatment group and a control group suitable for a direct causal comparison. Differences between their outcomes, if reported, could reflect differences in procedure or patient characteristics as well as other factors; the registry record does not provide a comparative analysis to separate such influences.

The primary outcome concerns fusion by level at 12 months among subjects with 12-month fusion-by-level data available. Secondary outcomes are percent change from baseline in the Oswestry Disability Index (ODI), Neck Disability Index (NDI), and Visual Analog Scale (VAS) at 12 months. The registry lists four outcome measures but no analysis records. Numerical results for the outcomes are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Subjects with 12 month fusion by level data available

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: 95 patients (48 cervical; 47 lumbar) were included in the data analyses because they met the inclusion criteria and had at least one follow-up (6- and/or 12-month).

6. Primary Endpoint

The registry lists the primary outcome as Fusion Rates Per Level Using the Bridwell Interbody Grading Scale, measured over 12 months.

The primary endpoint is fusion per level at 12 months, assessed using the Bridwell Interbody Grading Scale. The record defines successful fusion as a level graded I or II. Grade I is described as fused with remodeling and trabeculae present. Grade II is an intact graft that is not fully remodeled and incorporated, but has no lucency. Grades III and IV describe less favorable radiographic states: Grade III has a potential lucency at the top and bottom of the graft, while Grade IV is fusion absent with graft collapse or resorption.

Assessing fusion by level reflects the record’s focus on the result at each treated level, rather than treating a procedure as a single undivided observation. A grading scale also makes the radiographic criterion explicit: the endpoint distinguishes the grades counted as successful from grades that do not meet that definition. In general, a defined endpoint helps readers understand what an outcome represents and what observations are included in it.

The stated analysis population is subjects with 12-month fusion-by-level data available. The registry record does not report the number of levels assessed, the number meeting the Grade I or II definition, or the resulting fusion percentages for either procedural group. It therefore provides the endpoint definition and timeframe, but not a numerical estimate of fusion.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a prospective, post-market study with cervical and lumbar procedures using ViBone. The primary endpoint is a count-type outcome: fusion is evaluated per level, with Grade I or II on the Bridwell Interbody Grading Scale designated successful. The stated timeframe is 12 months, and the analysis population is subjects with 12-month fusion-by-level data available. The record does not report an analysis method for converting the observed grades into a result, or numerical outcome results.

What does an endpoint definition do?

In general, an endpoint definition sets out what is counted as an outcome and the time at which it is assessed. Here, the record names a grading scale and specifies which grades qualify as successful fusion. That makes the intended classification interpretable. It does not, by itself, show how many levels met the definition. Readers need the actual grade or success counts and a suitable denominator to understand the observed frequency; those figures are not reported in the registry record.

What can a confidence interval add?

In general, a confidence interval describes uncertainty around an estimate under the assumptions of the statistical method. A narrow interval indicates greater precision than a wide interval, while neither width nor location alone establishes clinical importance. For an outcome expressed as a proportion, the interval also helps show how much uncertainty remains around the estimated proportion. The registry record does not report a confidence interval for fusion or for the secondary outcomes, so their statistical precision cannot be evaluated from the record.

Why does the analysis population matter?

In general, an analysis population identifies which participants or observations contribute to a result. The stated primary population includes subjects for whom 12-month fusion-by-level data are available. This is not necessarily identical to everyone enrolled. Missing outcome data can affect interpretation if the availability of measurements is related to participant status, outcome, or other characteristics. The registry record does not report the number or characteristics of subjects without available 12-month fusion data, nor does it describe a method for handling missing data.

What does the lack of a control group mean?

In general, random assignment to comparable treatment groups can help distinguish treatment effects from differences in patient characteristics and other influences. This record does not describe randomized allocation or a separate control treatment. Both listed procedural groups use ViBone, and the groups are defined by cervical versus lumbar surgery. They are not like-for-like arms for estimating a treatment contrast. Any difference between their outcomes would be difficult to attribute to the graft material alone, particularly without a reported comparative analysis.

How should planning calculations be read?

In general, sample-size calculations describe a planned study under specified assumptions; they are not observed evidence about what happened in a completed study. The record describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It also states that the effect to detect is a stated fraction of the observed effect. For non-time-to-event outcomes, such illustrations are expressed as participants per arm for 80% power or another stated power level; time-to-event calculations use a total event count. No numerical planning results are reported in the registry record. Such calculations should not be read as observed power or as proof that the study could detect a clinically important effect.

The record lists zero analysis records. It does not report statistical tests, model specifications, adjustments, confidence intervals, interim analyses, or a statistical analysis plan. Those methods cannot be inferred from the prospective or multi-center description, and none should be assumed to have been used. The record also does not report how measurements from multiple levels within a subject were handled. In general, observations from the same subject may be related, so an analysis of levels may need to account for that dependence. Whether such an approach was used is not reported in the registry record.

There are three named secondary outcomes, each assessed as percent change from baseline at 12 months. In general, a change-from-baseline outcome compares a follow-up measurement with an initial measurement, while its interpretation depends on the measurement scale and analysis definition. The record does not give the exact analysis method, baseline values, follow-up values, or results for these measures. The outcome titles alone are not enough to reconstruct an effect estimate or its uncertainty.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists the primary fusion outcome and three secondary outcomes: percent change from baseline in ODI, NDI, and VAS at 12 months. The record does not report a statistical analysis plan, a testing hierarchy, or a method for accounting for multiple outcome comparisons. It is therefore not possible to tell whether the secondary outcomes were intended as confirmatory or exploratory, or whether any adjustment for multiplicity was planned or used.

In general, evaluating multiple outcomes can increase the chance of finding at least one apparently notable result by chance if each is tested separately. A prespecified hierarchy or multiplicity adjustment can help control that risk, but the registry record does not state whether either approach was used. No outcome-specific tests or results are reported, so the implications cannot be assessed from the posted record.

The primary-outcome population is described as subjects with 12-month fusion-by-level data available. The number without available outcome data, reasons for missingness, and any missing-data handling method are not reported in the registry record. Baseline and follow-up data availability for the secondary outcomes are also not reported. In general, complete-case results can be affected if missingness is related to outcomes or participant characteristics; assessing that possibility requires information absent from this record.

The record does not describe other analysis populations, such as an intention-to-treat population, or state whether all enrolled subjects were included in each outcome analysis. It also does not report exclusions or sensitivity analyses. These omissions limit assessment of the analysis population and robustness of any result. With no numerical analyses posted, the registry record cannot establish how multiplicity or missing data affected the study’s findings.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The adverse-event figures are reported separately for the Cervical Fusion - ACDF and Lumbar Interbody Fusion groups. For serious adverse events, the listed numbers at risk are 48 for the cervical group and 47 for the lumbar group; the corresponding numbers affected are 0 and 0. The other adverse-event figures likewise list 48 and 47 at risk, with 0 affected in each group. Deaths are listed as 0 in both groups.

These are the posted counts in the adverse-event record. They should not be interpreted as a complete account of safety without information about event definitions, collection procedures, follow-up duration, or whether all participants were observed for the same period. Those details are not reported in the registry record. The at-risk figures are presented for these adverse-event listings; they should not be substituted for the denominator of the primary fusion analysis, whose population is defined by available 12-month fusion-by-level data.

A zero count in a registry listing means no events are recorded in that field; it does not establish that the risk of an event is absent. In general, safety estimates depend on the amount and duration of observation and on how events are collected and classified. The record does not provide uncertainty intervals or further safety analyses, so the counts alone do not quantify the precision of a safety estimate.

12. What the Result Does, and Does Not, Mean

The record identifies a prospective, post-market evaluation of ViBone in cervical and lumbar fusion and defines a radiographic primary endpoint at 12 months. It specifies which Bridwell grades count as successful fusion and identifies an available-data population for the primary outcome. These details explain what the study intended to assess.

They do not establish a numerical fusion result. The number of levels assessed, the number meeting the Grade I or II definition, and the percentages by procedure are not reported in the registry record. The three secondary outcomes are named, but their numerical results are also not reported. No analysis records are listed. It is therefore not possible to describe the size, direction, or precision of the study’s outcome estimates from this registry record.

The two procedural groups do not provide a treatment-versus-control comparison. Both use ViBone, and one group undergoes cervical ACDF while the other undergoes lumbar interbody fusion. Allocation is not stated, and the record does not describe randomization. Even if outcome values were available for both groups, differences could not be attributed to ViBone alone on the basis of this design description.

The listed adverse-event entries show 0 serious events and 0 other events affected in each group, with 0 deaths listed. These entries are counts, not a complete assessment of safety or a guarantee of no risk. Information about event ascertainment, follow-up completeness, and uncertainty is not reported in the registry record.

In general, a study result is most informative when the estimate, its uncertainty, the analysis population, and the methods are all clear. Here, the endpoint and broad design are described, but numerical outcome analyses and key methodological details are absent. The record supports understanding of the study question and its registered structure; it does not support a quantitative conclusion about fusion outcomes, patient-reported outcomes, or comparative treatment effects.

13. Why This Trial Matters Statistically

This study is statistically notable for the distinction between a well-defined endpoint and a reported result. The registry specifies fusion per level, a 12-month timeframe, and a grading threshold of Grade I or II. Those details make the intended outcome concrete. Yet the numerical counts and percentages needed to estimate the result are not reported in the registry record. A precise definition cannot replace observed data.

The endpoint is assessed per level, while the study population is described in terms of subjects with available 12-month data. In general, when several levels may be observed within one subject, those observations may be related rather than independent. The registry record does not report how such within-subject dependence was handled. This is important when interpreting the precision of a level-based outcome, because the analysis method can affect uncertainty estimates.

The study also illustrates why groups defined by different procedures are not automatically valid comparison arms. The cervical and lumbar groups both receive ViBone, and their procedures differ. Without randomization, a control treatment, or a reported comparative analysis, a contrast between them would not isolate an effect attributable to the graft material.

Finally, the record lists three secondary patient-reported measures but gives no analysis results or multiplicity plan. In general, multiple outcomes require careful interpretation, especially when the analysis plan is unavailable. Here, the absence of numerical results and analysis records means that readers cannot evaluate effect sizes, uncertainty, or the relationship between primary and secondary findings. Statistically, the most useful conclusion is about what can and cannot be evaluated from the registry record: the study question and endpoint are described, but estimates and their inferential context are not.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The principal limitation for interpreting outcomes is that numerical results are not reported in the registry record. The primary endpoint’s definition is available, but the fusion counts, percentages, and denominators are not. Numerical findings for ODI, NDI, and VAS are also absent, and the record lists no analysis records. Effect magnitude, direction, and precision therefore cannot be evaluated.

The primary analysis population is limited to subjects with 12-month fusion-by-level data available. The record does not state how many subjects or levels contributed, how many lacked measurements, or why data were unavailable. It does not describe any missing-data method or sensitivity analysis. This makes it impossible to assess the completeness or representativeness of the primary-outcome analysis population.

The design description does not include a separate control treatment or randomized allocation. The cervical and lumbar groups undergo different procedures while both use ViBone, so they do not form a like-for-like comparison. The record does not report a comparative model or adjustment for differences between groups. It also does not report how multiple levels within a subject were handled in the analysis.

Further details about the statistical plan, interim analyses, outcome assessment procedures, and multiplicity handling are not reported in the registry record. The adverse-event counts are listed, but details about collection, event definitions, and follow-up completeness are not. These gaps constrain interpretation of both the clinical outcomes and the safety entries. The completed status and enrollment listing do not fill in the absent outcome or methods information.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: ViBone in Cervical and Lumbar Spine Fusion — NCT03425682.
• Registry record last updated 2025-03-04; status last verified 2025-02.
• Results first posted 2025-03-04.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT03425682 is a prospective, post-market, multi-center study of ViBone in cervical and lumbar spine fusion, sponsored by Elutia Inc. The listed enrollment is 118, and the record status is COMPLETED. The start date is 2018-05-14, and the primary completion date is 2021-01-15.

The primary endpoint is fusion per level at 12 months, with Grade I or II on the Bridwell Interbody Grading Scale defined as successful fusion. The primary population is subjects with 12-month fusion-by-level data available. Secondary outcomes are percent change from baseline in ODI, NDI, and VAS at 12 months.

The registry describes cervical ACDF and lumbar interbody fusion groups, both using ViBone. It does not describe randomized allocation or a like-for-like control group. Numerical outcome results and analysis records are not reported in the registry record. Adverse-event entries list 0 serious events, 0 other events, and 0 deaths in each group.