Postoperative Management for Degenerative Spinal Conditions: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Postoperative Management for Degenerative Spinal Conditions (NCT02184143), a randomized na study. The primary outcome is Oswestry Disability Index (ODI).

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group trial with triple masking, according to the registry. Its status is completed. The study enrolled 248 participants and compared two postoperative management approaches: a CBPT program and an education program. Both programs consisted of weekly phone calls. The registry identifies Vanderbilt University Medical Center as the sponsor.

The study was designed around recovery after lumbar spine surgery for degenerative conditions. Its stated objective was to compare patient-centered outcomes in older adults. The central hypothesis focused on whether a self-management-oriented CBPT program would influence pain and disability and improve general health, physical activity, and physical function, with fear of movement and pain self-efficacy described as possible pathways. These statements describe the study rationale; they do not establish that those changes occurred.

The registry lists the start as 2014-08 and primary completion as 2017-11. It does not report the method used to generate the random allocation sequence, how allocation was concealed, or which people were masked. The meaning of triple masking in operational terms is not reported in the registry record, so it is not possible to identify precisely which roles were kept unaware of treatment assignment. Details about treatment fidelity, crossover, adherence, and co-interventions are also not reported in the registry record.

The primary outcome was ODI, recorded as a mean with a 95% confidence interval and assessed over a timeframe of up to 12 months. Physical activity is listed as a secondary outcome, and the registry lists four outcome measures in total. The numbers analyzed at each primary-measure time point are defined as participants who completed that measure, but those counts are not reported in the registry record. The record lists 0 analyses. It does not provide a single summarized primary comparison that could support a numerical interpretation of the relative outcomes.

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.

Before assignment: 248 participants were consented, enrolled, and randomized.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Number analyzed indicate the number of participants who completed the measure at each time point.

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.

6. Primary Endpoint

The registry lists the primary outcome as Oswestry Disability Index (ODI), measured over Up to 12 months..

The primary endpoint was the Oswestry Disability Index (ODI), a measure of disability related to spinal conditions. The registry describes its scale as running from 0 to 100, with higher scores indicating worse disability. It reports the outcome as a mean and specifies a 95% confidence interval. The planned timeframe is up to 12 months.

Disability is relevant to this study because the interventions were intended to support recovery after lumbar spine surgery, and the study hypothesis explicitly included disability among its patient-centered outcomes. The ODI provides a way to quantify disease-specific limitations rather than relying only on a broad description of recovery. A mean can summarize the group’s average score, while a confidence interval communicates uncertainty around that estimate.

In general, an ODI comparison between groups would be interpreted by considering the estimated difference, its confidence interval, the time point, and the number of participants contributing data. The registry record does not report numerical ODI means, a between-group estimate, or confidence limits for a single comparison. It also indicates that the primary outcome includes multiple categories or time points and is not reduced to one comparison. Therefore, the endpoint definition is available, but the size, direction, and precision of an effect are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Random allocation is intended to make the comparison groups comparable, on average, at the start of a trial. In general, this supports interpreting differences in outcomes as comparisons of assigned strategies, provided that follow-up and analysis are handled appropriately. Randomization does not guarantee identical groups in every characteristic, and it does not remove uncertainty in an estimated treatment effect. The registry identifies the allocation as randomized, but the sequence-generation and concealment methods are not reported in the registry record.

What does a parallel-group design mean?

In general, a parallel-group trial assigns participants to one of the study approaches and follows each participant in that assigned group. The registry describes this trial as parallel, with CBPT and Education as the two approaches. It does not report enough operational detail to determine whether the primary analysis followed assignment regardless of treatment received, used another analysis population, or made adjustments for departures from assigned treatment. Those analysis choices are not reported in the registry record.

How should masking be understood?

The registry labels masking as triple. Masking is intended, in general, to limit the influence of knowledge of assignment on care, measurement, or interpretation. Its practical meaning depends on which roles are masked and whether masking can be maintained. The registry does not identify the masked roles or explain how masking was implemented. Those details are not reported in the registry record; the label alone does not establish which potential sources of bias were controlled.

What does the primary measure represent?

The ODI is a continuous measure, and the registry specifies a mean as the summary parameter. The stated scale ranges from 0 to 100, with higher scores indicating worse disability. In general, a group mean describes the average measured score, while a between-group contrast describes how the group averages compare. A mean difference is most useful when accompanied by a confidence interval and a clear definition of the groups, time point, and analysis population. Numerical means and a single between-group contrast are not reported in the registry record.

A 95% confidence interval is an uncertainty interval for an estimate under the statistical model and its assumptions. In general, it describes the range of values reasonably compatible with the observed data under that procedure; it is not a guarantee that the true effect lies within a particular interval. Its width reflects precision, and its position relative to a clinically meaningful benchmark may matter for interpretation. The registry specifies 95% confidence intervals as the dispersion measure, but numerical intervals for the primary comparison are not reported in the registry record.

Why do time points matter?

The primary outcome timeframe is up to 12 months, and the registry indicates that the outcome includes multiple categories or time points. Repeated measurements can describe how outcomes change during follow-up, but a reader needs to know which time point is primary and how repeated observations were handled. In general, a method that accounts for within-person correlation may be appropriate when analyzing repeated outcomes; separate comparisons at each time point raise different interpretive and multiplicity considerations. The model, time-point hierarchy, and method used for repeated observations are not reported in the registry record.

What is multiplicity, in general?

Multiplicity arises when a study evaluates several outcomes, time points, or contrasts. Conducting many statistical tests can increase the chance of at least one apparently noteworthy finding under a null scenario. Approaches to address this can include defining a primary contrast in advance, adjusting inference, or interpreting findings as exploratory. The record lists four outcome measures and multiple categories or time points for the primary outcome, but an adjustment strategy or prespecified hierarchy is not reported in the registry record. The record also lists 0 analyses, so it supplies no analysis results from which to assess how multiplicity was handled.

How should planning calculations be read?

In general, a sample-size calculation estimates the amount of information needed to detect a specified effect under chosen assumptions. It is a planning tool, not a result about the effect found in a completed study. The registry describes planning illustrations based on the observed effect, using a two-sided significance level of 0.05, equal allocation, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. Such illustrations are not the trial’s own sample-size justification, which is not reported in the registry record, and they are not evidence of achieved power. The record does not report the actual illustration values in the information summarized for this analysis.

The registry reports a mean and confidence interval for the primary outcome but does not report the test, model, covariates, missing-data method, or analysis population used for a treatment comparison. General statistical guidance cannot fill those gaps: different reasonable models can yield different estimates and uncertainty, especially when follow-up is incomplete or repeated outcomes are correlated. Accordingly, the design labels and endpoint definition describe important features of the trial, but they are insufficient to reconstruct its statistical analysis or its comparative result.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome is described as having multiple categories or time points, and it is not reduced to one comparison in the registry record. This matters because an outcome measured repeatedly can yield several possible contrasts, each answering a somewhat different question. The record does not identify one time point as the sole primary contrast, state a hierarchy among time points, or describe a multiplicity adjustment. Those details are not reported in the registry record. The record lists four outcome measures, with physical activity named as a secondary outcome, but a complete analysis plan is not reported.

The registry defines the number analyzed at each time point as the participants who completed the measure at that time point. It does not report those counts, reasons for non-completion, or the amount and pattern of missing data. The approach to missing outcomes, including whether imputation or another method was used, is not reported in the registry record. Without follow-up counts and a stated method, it is not possible to assess how incomplete data may affect the estimates.

The analysis population is also not specified. The record does not say whether participants were analyzed according to randomized assignment, only if they received the assigned program, or under another rule. It does not report how withdrawals, non-adherence, or deviations from the intervention were handled. These details are not reported in the registry record.

These omissions do not establish that multiplicity or missing data were mishandled. They mean that a reader cannot evaluate the analysis choices or their implications using the registry entry alone. The listing of 0 analyses and the lack of a single summarized primary comparison further limit statistical interpretation.

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 registry lists 0 serious adverse events, 0 other adverse events, and 0 deaths in each group. It lists 124 participants at risk in the CBPT Intervention group and 124 in the Education Intervention group for both event categories. These are the figures recorded for the trial’s adverse-event entries.

In general, an event count of zero means that the registry entry records no events in that category for the stated group and risk count. It does not, by itself, explain how events were defined, collected, verified, or attributed, or whether all participants were observed for the same duration. Those details are not reported in the registry record. A zero count also does not establish that the underlying risk is zero; the amount of information depends on the number followed, event ascertainment, and follow-up.

The adverse-event figures should therefore be read as registry-reported counts, not as a complete assessment of comparative safety. The record does not provide event narratives, event severity beyond the serious-event classification, timing, withdrawals related to events, or a statistical comparison of event rates. Those details are not reported in the registry record.

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

The record establishes that a randomized, parallel-group study compared weekly telephone CBPT with weekly telephone education after lumbar spine surgery for degenerative conditions. It identifies ODI as the primary outcome and describes the scale, direction, and broad follow-up timeframe. It also records 248 participants enrolled and lists zero serious adverse events, zero other adverse events, and zero deaths in each group among the stated at-risk counts.

What the record does not establish is whether ODI differed between the groups, how large any difference was, or how precisely it was estimated. Numerical group means, a between-group estimate, confidence limits, and a p-value for a single primary comparison are not reported in the registry record. The primary outcome has multiple categories or time points and is not reduced to one comparison. Thus, no conclusion about the direction, magnitude, or statistical uncertainty of the comparative disability outcome can be drawn from this entry.

The research hypothesis is not a finding. Its expectations about pain, disability, general health, physical activity, physical function, fear of movement, and pain self-efficacy describe the questions motivating the trial. They do not demonstrate that any of these outcomes changed or that one intervention was superior. Outcome estimates for those questions are not reported in the registry record.

Likewise, the adverse-event counts describe what the registry records, not every possible safety dimension or the complete experience of each participant. Details about event ascertainment and follow-up are not reported. The absence of a reported comparison must not be read as evidence of equivalence, and the absence of a numerical estimate must not be mistaken for a null effect. The appropriate statistical conclusion is limited: the registry describes the trial and its endpoints but does not report a single numerical primary-outcome result that can be interpreted.

13. Why This Trial Matters Statistically

This trial addresses a statistical question that is broader than whether two programs can be compared: it concerns how outcomes during postoperative recovery should be measured and interpreted across time. A continuous disability measure such as the ODI can provide a quantitative summary, but its meaning depends on the time point, the group contrast, and the precision of the estimate. A defined outcome and randomized design are useful foundations; they do not substitute for reported results.

The registry’s reference to multiple primary-outcome categories or time points highlights a common design issue. Repeated measurements may help describe the course of recovery, while also creating choices about which comparison is primary and how uncertainty is handled across several analyses. In general, a prespecified primary contrast and transparent reporting of the analysis plan help readers distinguish confirmatory evidence from secondary or exploratory findings. The relevant hierarchy and multiplicity approach are not reported in the registry record.

The study also illustrates why outcome completion matters. The registry defines analyzed participants as those who completed the measure at each time point, but does not report those counts. In general, follow-up completion affects the amount of information available and can affect interpretation if missingness is related to outcome or treatment. Without counts, reasons, and a missing-data method, readers cannot judge that aspect of the evidence.

Finally, a planning illustration based on an observed effect answers a different question from a trial’s original sample-size justification or its actual treatment-effect analysis. Keeping those purposes distinct prevents planning calculations from being mistaken for evidence that an effect was demonstrated. In this record, the design and measurement question are identifiable, while the numerical comparative result and key analysis details remain unavailable.

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 main trial-specific limitation for interpretation is that the registry does not present a single summarized comparison for the primary outcome. It notes multiple outcome categories or time points, but does not identify a primary time-point contrast or provide numerical ODI estimates. The direction, magnitude, and precision of the disability comparison therefore cannot be assessed from this record.

The registry states that participants analyzed at each time point are those who completed the measure, but it does not list the number completing ODI at each time point. Reasons for missing measurements, follow-up completeness, and missing-data methods are not reported in the registry record. This prevents assessment of how much outcome information was available and whether incomplete follow-up could influence interpretation.

Although the study is labeled randomized and triple masked, the registry does not report sequence generation, allocation concealment, or which roles were masked. It also does not describe intervention adherence, crossover, treatment fidelity, or how deviations from assigned groups were handled. These details are not reported in the registry record and limit assessment of how the intended comparison was implemented.

The record lists four outcome measures and physical activity as a secondary outcome, but does not supply a statistical analysis plan, a multiplicity strategy, or a defined analysis population. It lists 0 analyses. The original sample-size justification is not reported in the registry record. Consequently, the registry information is insufficient to reconstruct the analysis or determine whether the reported design features were followed as planned.

These are limitations of what can be concluded from the registry record, not proof that the trial was conducted poorly or that its findings are invalid. A full assessment would require the outcome results and analysis details, which are not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Postoperative Management for Degenerative Spinal Conditions — NCT02184143.
• Registry record last updated 2019-08-02; status last verified 2019-06.
• Results first posted 2019-08-02.
• 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

The registry describes NCT02184143, a completed, randomized, triple-masked, parallel-group trial sponsored by Vanderbilt University Medical Center. It enrolled 248 participants and compared weekly telephone CBPT focused on self-management with weekly telephone education about postoperative recovery for older adults after lumbar spine surgery for degenerative conditions. The recorded start was 2014-08, and primary completion was 2017-11.

The primary outcome was the mean ODI, measured on a scale from 0 to 100, with higher scores indicating worse disability. Its timeframe was up to 12 months. Physical activity was listed as a secondary outcome, and four outcome measures were recorded. The number analyzed was defined as those completing the measure at each time point, but those counts are not reported in the registry record.

The registry lists 0 analyses and does not reduce the primary outcome’s multiple categories or time points to one comparison. Numerical primary-outcome estimates and analysis details are not reported in the registry record. The adverse-event entries list zero serious events, zero other events, and zero deaths in each group, with 124 at risk per group.