Multicenter Prospective Trial of Office-based Carpal Tunnel Release With Ultrasound Guidance (ROBUST): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Multicenter Prospective Trial of Office-based Carpal Tunnel Release With Ultrasound Guidance (ROBUST) (NCT05675046), a na na study. The primary outcome is Boston Carpal Tunnel Questionnaire - Symptom Severity Scale (BCTQ-SSS).

2. Clinical Question

This is a question about change over time within a treated group. It is not a randomized comparison of CTR-US with another procedure, usual care, or no treatment. Without a concurrent control group, a measured change cannot by itself separate the effects of the procedure from other explanations for changes over time. The registry record also does not report the primary outcome estimate, so the direction, size, and precision of the observed change cannot be described from this record.

3. Trial Design

ROBUST is described as a multicenter prospective single-group trial of people with symptomatic CTS treated with ultrasound-guided carpal tunnel release in an office-based setting. The registry lists enrollment of 149 and records the study as completed. The recorded start date is 2023-02-16 and the primary completion date is 2023-09-24. The intervention is CTR-US using the UltraGuideCTR device.

The design has no concurrent control arm. The registry lists allocation as NA, masking as NONE, and the model as SINGLE GROUP. Consequently, the primary endpoint is framed as change from baseline to follow-up in the treated group, not as a difference between independently assigned groups. The registry does not report random assignment, and it would be inappropriate to interpret the study as a randomized comparison.

The primary outcome timeframe is baseline and 3 Months. The registry also names secondary outcomes covering return to normal daily activities, return to work among employed subjects, functional status, hand function, pain, quality of life, adverse events, and satisfaction. These outcomes describe additional aspects of recovery and experience, but their numerical results are not reported in the registry record.

The registry record does not report a sample-size justification, a detailed statistical analysis plan, the analysis population, or how missing observations were handled. It also does not describe interim analyses. These omissions limit assessment of how the planned analyses related to the design and how completely the outcome data represent enrolled participants.

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: Subjects could choose between having both hands treated (bilateral) at the same time if both hands met study criteria, or having one hand treated (unilateral) in the study. Bilateral patients with both hands treated are reported based on their averaged score, where applicable.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Boston Carpal Tunnel Questionnaire Symptom Severity Scale (BCTQ-SSS) change at 3 months

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 Boston Carpal Tunnel Questionnaire - Symptom Severity Scale (BCTQ-SSS), measured over Baseline and 3 Months.

The primary endpoint is mean change in the Boston Carpal Tunnel Questionnaire Symptom Severity Scale (BCTQ-SSS) from baseline to 3 months. The BCTQ-SSS is specific to CTS and consists of 11 symptom-severity questions. The registry describes the instrument as reproducible, internally consistent, valid, and responsive to clinical change in CTS and after carpal tunnel release.

Each response contributes to a score ranging from 1 to 5, calculated as the mean of the responses. Higher scores indicate more severe symptoms. The change score expresses the follow-up score relative to baseline: a negative value indicates decreased symptom severity, while a positive value indicates increased symptom severity. For participants with both hands treated, the record says scores are reported on the basis of the averaged score.

A mean change summarizes the average direction and magnitude of change in the measured scale, while the reported 95% confidence interval is intended to describe uncertainty around that estimate. A confidence interval is not a range containing most individual participants’ changes. It concerns uncertainty in the estimated mean under the analysis used. The registry names the mean and 95% confidence interval as the summary, but neither the numerical mean change nor its interval is reported in the registry record. The endpoint’s definition therefore supports interpretation of a result if one is available, but it does not establish the result itself.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the primary summary measure?

The primary outcome is continuous: the BCTQ-SSS is scored on a scale, and the planned summary is a mean change from baseline to 3 months. A mean is a measure of the center of a set of values. For a change outcome, the values represent within-participant change as defined by the registry. The sign of the mean has a specific interpretation: negative means decreased symptom severity, and positive means increased symptom severity.

The mean is useful for summarizing average change, but it does not describe every participant’s response. Participants may have changes that differ in direction and size. A mean can conceal that variation, so interpretation is usually strengthened by information about dispersion, the distribution of changes, and the number of observations analyzed. The registry specifies a 95% confidence interval for the mean, but the numerical interval and other distributional details are not reported in the registry record.

How should a confidence interval be read?

General statistical explanation: a confidence interval expresses uncertainty about an estimated quantity using a method with stated long-run coverage properties when its assumptions hold. It is not an interval that contains a specified proportion of individual outcomes, and it does not mean that there is a particular probability that the fixed mean lies inside the interval after the interval has been calculated. The width indicates how precisely the mean is estimated under the chosen method and assumptions. Since the registry record does not give the primary estimate or interval limits, precision cannot be evaluated for this endpoint.

The registry does not state how the confidence interval was calculated. It does not report whether the analysis used a particular distributional assumption, a model, a transformation, or an adjustment. Those choices can affect an interval, especially when data are skewed, incomplete, or clustered. No such method should be inferred from the stated mean and confidence interval alone.

Why does the single-group design matter?

The primary comparison is baseline versus follow-up within a treated group. This can describe observed change over time, but it does not provide a counterfactual comparison: the change that would have occurred in a comparable group without the procedure. A randomized or otherwise well-constructed comparator can help address that question, whereas a single-group design cannot isolate the intervention’s contribution from other changes over time. This is a general design consideration, not a conclusion about the direction or size of the ROBUST outcome.

Baseline and follow-up measurements are related because they come from the same participants, when both measurements are available. A suitable analysis of change should account for that pairing. The registry record identifies a mean change but does not describe the analysis procedure, so it is not possible to determine how the relationship between measurements was handled. Nor does the record report whether any model adjusted for other variables.

What can the planning illustrations tell readers?

Any sample-size figures associated with these results are planning illustrations based on the observed effect, not the trial’s original design and not observed power. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a stated fraction of the observed effect. For time-to-event outcomes, the illustration reports total events; for other outcomes, it reports participants per arm.

These assumptions describe hypothetical planning calculations. They do not change the ROBUST study into a two-arm trial, and they do not show that the original study was designed with those assumptions. The registry record does not report its sample-size justification. It also does not report numerical primary results from which readers could assess an observed effect or its uncertainty. Such planning figures, when available, should not be described as observed power or as proof that the study was adequately powered.

What remains unknown about the analysis?

The registry record does not report a detailed statistical plan, a named analysis population, the number of participants with paired BCTQ-SSS observations, or the handling of missing data. It does not report whether analyses accounted for the multicenter setting or for participants whose both hands were treated beyond the stated averaging approach. It does not report whether the primary analysis was adjusted or unadjusted. These gaps prevent a detailed assessment of reproducibility and of the assumptions underlying any estimate.

General statistical explanation: over-dispersion occurs when observed variability exceeds what a model assumes. If a model ignores extra variability, its standard errors may be too small and its intervals too narrow. The relevance of over-dispersion depends on the type of outcome and analysis; it should not be presumed for this continuous endpoint. The registry record does not describe an analysis that would permit assessment of this issue.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists secondary outcomes in addition to the primary BCTQ-SSS endpoint. When a study assesses multiple outcomes or multiple time points, the chance of at least one apparently notable result can increase if many tests are interpreted without a plan for multiplicity. General statistical practice may address this through prespecified outcome hierarchies, adjusted testing procedures, or careful emphasis on estimation and uncertainty. The registry record does not report a multiplicity strategy, testing hierarchy, or detailed statistical plan. Numerical secondary outcome results are not reported in the registry record, so their interpretation is not possible.

Missing data are also important for a baseline-to-follow-up endpoint. The number enrolled does not establish how many participants posted both measurements, and the registry record does not report the primary analysis population or follow-up completeness. It does not state why observations may have been missing, whether missingness differed across participants, or what method was used to handle missing values. Without that information, readers cannot assess whether the reported mean—if available—would represent all enrolled participants or only those with suitable measurements.

General statistical explanation: complete-case analysis, imputation, and model-based methods rely on different assumptions. Their suitability depends on the pattern and reasons for missingness, as well as the analysis objective. No particular method can be attributed to this study from the registry record. The record also does not report sensitivity analyses examining whether conclusions would change under alternative assumptions about missing outcomes.

The same caution applies to analysis populations. The registry record does not specify whether the primary analysis included all enrolled participants, only those treated, or a subset with evaluable follow-up. The number contributing to the primary endpoint is not reported in the registry record. These omissions limit assessment of both missing-data bias and the degree to which the analysis corresponds to the enrolled study population.

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.

Most frequent non-serious adverse event terms

The registry reports serious adverse events for the CTR-US group with 149 at risk and 0 affected; deaths are reported as 0. It also reports other adverse events with 149 at risk and 1 affected. The record does not list serious adverse-event terms. These are registry counts, not a detailed account of event type, timing, severity beyond the serious classification, or clinical course.

The categories should be read as reported rather than combined or converted into rates. The registry record does not provide additional detail about the single other adverse event, so its nature and relationship to the device or procedure cannot be characterized from this entry. It also does not provide enough detail to assess the duration or completeness of safety follow-up, or whether every participant was observed for the same period.

General statistical explanation: a count of zero reported serious events does not establish that the underlying risk is zero. Rare events may not appear in a study of this size, and safety estimates depend on how events were defined, collected, and followed. Here, the registry’s figures support reporting the recorded counts and denominators only; they do not establish a comparative safety profile because there is no control group.

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

The registry record describes a prospective, multicenter, single-group study of office-based CTR-US and defines a primary symptom-severity outcome measured from baseline to 3 months. It also reports adverse-event counts for the treated group. These details can explain what the study set out to measure and what safety counts are recorded.

The primary numerical result is not reported in the registry record. Therefore, the mean change in BCTQ-SSS, the 95% confidence interval, and the number of participants contributing to that outcome cannot be stated. The direction and magnitude of average symptom change, and the precision of that estimate, remain unknown from this record. The listed secondary outcomes likewise have no numerical results reported in the registry record.

Even if a within-group change estimate were available, a single-group before-and-after design would describe change among participants over time, not the difference between CTR-US and an alternative. It would not by itself show how participants would have changed without the procedure. The registry record does not report randomization or a concurrent comparator, so causal and comparative conclusions are not supported by the design described.

The safety counts indicate that the registry reports 0 serious adverse events among 149 at risk, 1 other adverse event among 149 at risk, and 0 deaths. They do not provide event-level detail for the other adverse event or establish that no unrecorded or later events occurred. The figures should be interpreted as registry reporting, not as proof of absence of risk.

Overall, the record supports a description of study conduct, endpoint definition, and recorded safety counts. It does not report the primary efficacy estimate or enough analysis detail to assess missing data, multiplicity, or the statistical model. Readers should distinguish those documented features from conclusions about treatment effect, comparative performance, or safety beyond the recorded counts.

13. Why This Trial Matters Statistically

ROBUST is statistically informative as an example of a prospective, multicenter, single-group study using a condition-specific patient-reported symptom measure. The registry specifies the scale, the direction of score interpretation, the baseline-to-follow-up change, and a confidence-interval summary. Those details matter because an estimate is only interpretable when readers know what was measured, when it was measured, and which direction indicates greater severity.

The design also makes a central interpretive issue clear: change within a treated group is not the same quantity as a comparative treatment effect. This distinction applies broadly to clinical research. Before-and-after results can describe the course of measured outcomes, while a comparator is needed to estimate how outcomes differ under alternative treatment conditions. The design description therefore sets limits on the claims that could be supported, regardless of the eventual size of a within-group change.

The record also illustrates why registration details and posted results need to be read together. Defining an endpoint does not reveal its observed value. In this case, the primary mean change and its confidence interval are not reported in the registry record, so readers cannot assess magnitude or precision. Likewise, a listed secondary outcome is not itself a result.

Finally, the safety counts demonstrate the importance of separating event categories and retaining their context. The recorded counts can be reported, but the limited event detail and lack of a comparator constrain what can be concluded. These distinctions—measurement versus result, change versus comparison, and event count versus comprehensive risk assessment—are broadly useful when interpreting clinical trial records.

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 limitation for interpreting the primary outcome is that its numerical result is not reported in the registry record. The mean BCTQ-SSS change, 95% confidence interval, and number analyzed are unavailable, preventing assessment of the observed direction, magnitude, and precision. Numerical results for the listed secondary outcomes are also not reported in the registry record.

The single-group design has no concurrent control arm. A change from baseline can describe the measured trajectory in participants who received CTR-US, but it cannot distinguish the intervention’s contribution from other influences on change over time. The record lists allocation as NA and masking as NONE; it does not describe random assignment or a blinded comparison.

The registry record does not report the primary analysis population, completeness of follow-up, missing-data methods, or sensitivity analyses. It does not report a detailed statistical plan, multiplicity approach, sample-size justification, or interim analyses. These omissions limit assessment of the analysis choices and of possible bias from incomplete observations or multiple outcomes.

The primary endpoint is measured at 3 months, so the record does not establish longer-term symptom outcomes. The bilateral scoring rule is described as averaging scores for participants with both hands treated, but further analysis details are not reported. Safety information is limited to the reported counts and does not include a listed serious-event term or details about the single other adverse event. The record therefore supports only a bounded description of the study and recorded events, not broad comparative or long-term conclusions.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Multicenter Prospective Trial of Office-based Carpal Tunnel Release With Ultrasound Guidance (ROBUST) — NCT05675046.
• Registry record last updated 2026-01-06; status last verified 2025-12.
• Results first posted 2025-06-03.
• 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 record identifies ROBUST as a completed, multicenter, prospective, single-group study of office-based ultrasound-guided carpal tunnel release using the UltraGuideCTR device for symptomatic CTS. Enrollment is listed as 149. The primary outcome is mean change in BCTQ-SSS from baseline to 3 months; negative values indicate decreased symptom severity and positive values indicate increased symptom severity. For participants with both hands treated, the record describes reporting based on averaged scores.

The primary mean change and 95% confidence interval are not reported in the registry record. The record lists 149 at risk and 0 affected for serious adverse events, 149 at risk and 1 affected for other adverse events, and 0 deaths. It does not list serious-event terms. The single-group design does not provide a concurrent treatment comparison, and analysis details concerning missing data, analysis populations, and multiplicity are not reported in the registry record.