Spinery® A Novel Radio-Frequency Tumor Ablation Device for Spine Metastatic Tumors: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Spinery® A Novel Radio-Frequency Tumor Ablation Device for Spine Metastatic Tumors (NCT05467540), a na na study. The primary outcome is Change From Baseline in Worst Pain and Quality of Life Scores at 3 Months Using the Brief Pain Inventory (BPI) and EQ-5D-5L Questionnaires.

2. Clinical Question

3. Trial Design

SPARTA is described as a prospective, multicenter, single-arm clinical investigation of the Spinery radiofrequency ablation system for painful bone metastases. The registry lists the study as completed, with enrollment of 52 and five Italian centers. The recorded start date is 2022-07-11 and the primary completion date is 2024-02-15. The sponsor is Axon srl.

Participants received percutaneous radiofrequency ablation using the Spinery System. Assessments were planned at baseline, after the procedure and during follow-up visits at 1, 3 and 12 months. The stated purposes included evaluating safety, performance and efficacy, with outcome areas including pain, quality of life, usability and procedural safety. The primary outcome focuses on change from baseline to the 3-month visit in worst pain and quality-of-life scores.

The registry identifies the allocation as NA, masking as none and the model as single-group. There is no randomized comparator, and the record does not report a control arm. Consequently, the study is structured to describe outcomes over time in treated participants rather than to estimate a direct between-group treatment contrast. A before-and-after change may be clinically informative, but it is not equivalent to a controlled estimate of what would have happened without the procedure.

The phase is listed as NA. The registry record does not report the statistical analysis plan, a sample-size justification, interim analyses or a more detailed account of the procedure. The outcome analysis population is defined as participants who started treatment and completed the 3-month follow-up visit. The record does not state how many participants met that definition.

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: The Protocol Enrollment was 52 as planned. One participant withdrew consent after enrollment and prior to treatment allocation; therefore, 51 participants actually started the Spinery RF Ablation procedure. This explains the discrepancy between Protocol Enrollment and Started counts.

BaseLine

3-Month Follow-up

Reasons for not completing this period:

12-Month Follow-up

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All participants who started treatment and completed the 3-month follow-up visit are included in this analysis.

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: Baseline characteristics were assessed in all participants who started the Spinery RF Ablation procedure (N=51) prior to treatment. One participant withdrew consent after enrollment and before treatment allocation and was not included in the baseline analyses.

6. Primary Endpoint

The registry lists the primary outcome as Change From Baseline in Worst Pain and Quality of Life Scores at 3 Months Using the Brief Pain Inventory (BPI) and EQ-5D-5L Questionnaires, measured over Baseline and 3-month follow-up.

The primary endpoint concerns change from baseline to the 3-month follow-up in worst pain and quality-of-life scores, measured with the Brief Pain Inventory (BPI) and EQ-5D-5L. These questionnaires capture related but distinct experiences: the BPI assesses pain, while EQ-5D-5L describes health status and includes a visual analogue scale (VAS).

For the BPI, participants rated the worst pain in the last 24 hours for each treated lesion site on an 11-point numeric scale, from 0 (no pain) to 10 (pain as bad as you can imagine). Higher scores indicate worse pain. The registry describes the change as the average reduction from baseline to the 3-month visit. A reduction therefore has a favorable direction on this measure, although the numerical change estimate is not reported in the registry record.

EQ-5D-5L covers mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Responses are converted to a utility index from -0.594 (worst health state) to 1.000 (best health state), with higher scores indicating better quality of life. Its VAS ranges from 0 (worst imaginable health) to 100 (best imaginable health), also with higher scores indicating better health. The measures provide complementary perspectives, but their scores are not interchangeable. The registry record does not report numerical changes or their precision for these outcomes.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a continuous primary outcome summarized as a mean, with standard deviation as the dispersion measure. This is a common way to summarize questionnaire scores or changes in scores. The mean gives an average across the analyzed observations. The standard deviation describes how much individual observations vary around that average. These answer different questions: the mean concerns the average value, while the standard deviation concerns variability among observations.

What does a change score represent?

A change score compares a participant’s follow-up measurement with that participant’s baseline measurement. The registry defines the primary timepoint as baseline and 3-month follow-up. For BPI worst pain, the stated quantity is the average reduction from baseline. Since higher BPI values indicate worse pain, a reduction corresponds to a lower pain score. For EQ-5D-5L, higher utility and VAS values indicate better health, so the direction of a reported change should be read using those scoring rules. The record does not provide the numerical mean changes.

Change scores can be useful because they focus on within-participant movement rather than the follow-up score alone. They also have limitations. A change score reflects measurement at both timepoints, so measurement error at either time can affect it. Participants may start at different baseline levels, and their scores may differ in how much room there is to move on the scale. An average change can conceal variation in individual trajectories. The standard deviation can describe some of that variation, but it cannot show the full distribution or explain why participants changed.

What does a confidence interval add?

In general, a confidence interval expresses uncertainty around an estimated quantity. A narrower interval indicates greater precision under the assumptions of the analysis; a wider interval indicates less precision. It is not a range containing every participant’s score, and it does not resolve design limitations such as the lack of a control group. The registry record does not report confidence intervals for the primary outcome, so the precision of the mean change cannot be assessed from the record.

A p-value, in general, describes how compatible the observed data are with a specified statistical null model, given the assumptions of the test. It does not measure the size or clinical importance of an effect, and it does not establish causation. The registry record does not report a primary-outcome p-value or identify a test used to evaluate change. The inferential method, any adjustment for baseline factors, and the detailed statistical plan are not reported in the registry record.

Why does the single-arm structure matter?

With no concurrent comparator, the primary comparison is between baseline and follow-up among treated participants. That design can describe how scores changed in the observed analysis population. It cannot, on its own, determine how much of a change was caused by the procedure. A controlled comparison can help account for changes that might occur over time regardless of treatment, whereas a single-arm before-and-after analysis has no such direct reference. This is a design limitation, not a flaw in the arithmetic used to summarize change.

The analysis population is defined as participants who started treatment and completed the 3-month follow-up visit. In general, restricting an analysis to people with measurements at both timepoints can produce bias if the availability of follow-up is related to outcomes. For example, if people with different experiences are differentially likely to complete follow-up, the observed mean may not represent the outcomes of everyone enrolled. This is a general concern, not a claim about why any participant may have lacked a visit. Reasons for missing visits, the number with usable measurements and methods for handling missing data are not reported in the registry record.

How should the planning illustration be read?

The record states that its sample-size assumptions are a planning illustration computed from the observed effect, rather than the trial’s own design. The stated assumptions include a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation and an effect defined as a stated fraction of the observed effect. These assumptions describe a hypothetical planning exercise, not the actual single-arm study design. The registry record does not report a sample-size justification for SPARTA.

Such planning figures, when available, are conditional on their assumptions. They are not an estimate of what the completed trial was powered to detect, and they are not observed power. Because the study itself has a single group, the two-arm equal-allocation assumption does not describe its enrollment structure. The registry record does not report the numerical planning estimates or enough numerical outcome information in this record to assess them independently. Any planning illustration based on an observed effect should not be treated as confirmation that the effect is reliable or causal.

Over-dispersion is a general statistical issue that arises when observed variability exceeds what a chosen model assumes. If a model understates variability, it can make estimates appear more precise than they are. The registry record identifies standard deviation as the endpoint’s dispersion measure but does not report a model or an over-dispersion assessment. There is therefore no basis in the record to say whether over-dispersion was relevant to the primary analysis.

In general, statistical interpretation depends on the estimand, analysis population, handling of missing data, model and uncertainty measure, not just the average. Here, the outcome definition and completed-visit population are described, but the numerical estimates and several analysis details are absent. Those omissions limit independent assessment of both the results and the methods used to obtain them.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome title includes both BPI worst-pain and EQ-5D-5L quality-of-life scores. These are distinct measures and may yield separate estimates. When multiple outcomes or tests are considered, multiplicity can arise: the chance of at least one apparently notable result can increase as more comparisons are examined. Statistical methods sometimes address this by defining a hierarchy of outcomes or adjusting the interpretation of multiple tests. The registry record does not report a multiplicity strategy, a hierarchy between the measures or the inferential tests used.

The registry record lists two outcome measures and no analysis records. Numerical primary outcome estimates, p-values and confidence intervals are not reported in the registry record. It is therefore not possible to determine how multiple outcomes were analyzed, whether any adjustment was applied, or whether the reported primary outcome title reflects a single combined analysis or separate measures. The detailed statistical analysis plan is not reported in the registry record.

The primary analysis population is defined as all participants who started treatment and completed the 3-month follow-up visit. That is a complete-visit definition for this endpoint; it does not describe how missing measurements were handled. The number who completed the visit, the number with usable questionnaire data, reasons for missing data, and any imputation or sensitivity analyses are not reported in the registry record. In general, complete-visit analyses can be difficult to interpret if follow-up availability is related to participants’ health or outcomes. That is a methodological concern, not evidence that such a pattern occurred in this study.

The record also does not report whether analyses included all enrolled participants for other outcomes or how safety populations were defined beyond the reported at-risk counts. Without those details, the analysis populations and missing-data assumptions cannot be fully evaluated.

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 2% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: death (25.5%).

The safety record lists 51 participants at risk for serious adverse events and 13 affected by serious adverse events. It separately lists 51 at risk for other adverse events and 1 affected by other adverse events. Deaths are recorded as 13. Death is also listed as the leading serious-event term, with 25.5%. These entries describe what the registry record reports; they do not establish a causal relationship between an event and the device or procedure.

The at-risk counts are the denominators shown for the respective safety categories. The record does not explain the difference between the enrollment figure and the safety at-risk figures, nor does it describe event timing, duration of exposure, event severity beyond the serious classification, or the attribution process. It also does not establish from these summary fields whether the death count and serious-event affected count refer to the same participants or events. They should not be combined or treated as independent counts without further detail.

The 25.5% figure is attached to the serious-event term Death in the registry listing. The record does not give the underlying term-level count or clarify the calculation details for that percentage. The event figures should therefore be read as registry summaries, not as a comparative risk estimate. With no control group, they cannot show whether event occurrence differed from what would have happened under another treatment or without the procedure.

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

The registry record establishes that SPARTA was a prospective, multicenter, single-arm study of percutaneous radiofrequency ablation for painful bone metastases. It defines a primary assessment of change from baseline to the 3-month follow-up in BPI worst pain and EQ-5D-5L quality-of-life scores. It also describes the scoring directions and reports safety summaries. These details clarify what the study set out to assess.

The record does not report numerical estimates for the primary outcome. As a result, it cannot quantify the average change, show how variable participant changes were, or indicate how precisely any average was estimated. Without those results, it is not possible to determine from this registry record whether scores improved, worsened or remained similar. The stated outcome and the fact that assessments were planned do not substitute for reported outcome values.

Even if a before-and-after change were available, the design would not establish that the procedure caused it. There is no concurrent control group to provide a comparison for changes over time unrelated to treatment. A single-arm study can describe outcomes among participants who received the intervention, but causal attribution requires caution. Other care, disease course, measurement variability and follow-up patterns may contribute to observed changes; the registry record does not separate their effects.

The safety summaries likewise do not establish causation. They report serious adverse events, other adverse events and deaths, but the record does not give details of event timing or attribution. The absence of a comparative group also means these counts cannot be interpreted as a comparative safety estimate.

The sample-size assumptions describe a planning illustration based on an observed effect, not the design of the completed single-arm study. Such planning figures are not observed power and do not demonstrate that an effect is reliable. Overall, the registry record is informative about the study’s structure, endpoint definitions and reported safety counts, but it does not provide the numerical primary outcome results needed to characterize the observed change.

13. Why This Trial Matters Statistically

This trial is statistically relevant because it illustrates the difference between describing change and estimating a comparative treatment effect. Its primary outcome is based on scores measured before treatment and at follow-up in a single group. That can characterize outcomes among participants with the required visits, but without a comparator it cannot distinguish treatment-related change from other changes occurring over time.

The outcome measures also require careful interpretation. BPI worst pain and EQ-5D-5L assess different aspects of participants’ experience and use different scales and directions. A mean change in one measure cannot be substituted for a change in the other. Reporting both can offer complementary information, but interpretation depends on clear estimates, variability and uncertainty for each measure. Those numerical primary outcome results are not reported in the registry record.

The analysis population highlights another central issue: follow-up completion. The stated primary population includes participants who started treatment and completed the 3-month visit. That makes the availability of outcome data part of the interpretation. Knowing how many participants contributed, why others may not have contributed and how missing data were handled would help readers judge the scope of any estimate. Those details are not reported in the registry record.

The record also shows why planning assumptions must be separated from observed trial design. The sample-size assumptions describe a hypothetical two-arm planning illustration, whereas SPARTA is recorded as single-group. Planning estimates based on an observed effect are conditional illustrations, not proof of efficacy, precision or adequate design. The study’s own sample-size justification is not reported in the registry record.

These features make the record useful for understanding what was measured and how the study was organized, while also marking the limits of what can be concluded statistically. Transparent outcome estimates, uncertainty measures and analysis details are needed to move from an endpoint definition to an assessment of the evidence.

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 central limitation for interpreting the primary endpoint is that numerical BPI and EQ-5D-5L change estimates are not reported in the registry record. The record therefore does not permit assessment of the magnitude, direction or precision of change. It also does not report confidence intervals, p-values or the statistical tests used for the primary outcome.

The single-arm design has no concurrent control group. Baseline-to-follow-up change cannot by itself distinguish a procedure-related effect from other influences over time. The study is described as prospective and multicenter, but the registry record does not report randomization, and allocation is listed as NA. Masking is listed as none. The phase is also listed as NA.

The primary outcome population is limited to participants who started treatment and completed the 3-month visit. The registry record does not report how many met this definition, the number with usable questionnaire data, reasons for non-completion or missing-data methods. Without these details, the potential impact of incomplete follow-up cannot be assessed.

Enrollment was 52 across five Italian centers, while the safety at-risk figures are 51. The record does not explain the difference. It provides safety counts but does not report event timing, attribution details or a comparator for interpreting those counts. The record also does not report a detailed statistical analysis plan, multiplicity handling, interim analyses or a sample-size justification.

These limitations concern what can be learned from the registry record; they do not show that an unreported method was or was not used. The record provides the endpoint definitions and study structure, but leaves important result and analysis details unavailable for independent statistical assessment.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Spinery® A Novel Radio-Frequency Tumor Ablation Device for Spine Metastatic Tumors — NCT05467540.
• Registry record last updated 2025-11-28; status last verified 2025-11.
• Results first posted 2025-11-28.
• 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

SPARTA is registered as a completed, prospective, multicenter, single-arm study of the Spinery System for painful bone metastases. The record reports enrollment of 52 across five Italian centers, with baseline, post-procedure and follow-up assessments at 1, 3 and 12 months. The primary outcome is change from baseline to 3 months in BPI worst-pain and EQ-5D-5L quality-of-life scores. The primary analysis population is defined as participants who started treatment and completed the 3-month visit.

The registry describes the questionnaire scales but does not report numerical estimates for the primary outcome or their precision. Safety summaries list 13 participants with serious adverse events, 1 with other adverse events and 13 deaths, with 25.5% for the serious-event term Death. The record does not establish causation for these events. Its sample-size assumptions describe a planning illustration, not the trial’s own design. The single-arm structure and unreported outcome estimates limit causal and quantitative interpretation.