Value of Multiple Modalities Using the Spectra WaveWriter Spinal Cord Stimulator System: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Value of Multiple Modalities Using the Spectra WaveWriter Spinal Cord Stimulator System (NCT03251937), a na na study. The primary outcome is Percentage of Subjects With 50% or Greater Reduction in Overall Pain From Baseline.

2. Clinical Question

In statistical terms, the study question is about the proportion of participants in the treated group who met a prespecified pain-reduction threshold at a stated follow-up time. That is a within-group outcome question. Without a comparison group, the record does not establish how that proportion differs from what would have happened under another treatment or without the device. The registry summary also refers to sustained relief, but the primary endpoint listed for this record concerns the assessment at 3 months post activation. Other details about the timing or definition of sustained relief are not reported in the registry record.

3. Trial Design

The record identifies VERITAS as a completed study of the Spectra WaveWriter SCS System for chronic pain. The trial is listed as a single-group model, with spinal cord stimulation as the only arm described. Enrollment was 97. Allocation is listed as NA, and masking is listed as none. The study is classified as phase NA. These labels do not describe a randomized controlled comparison.

The intervention is recorded as a device: the Spectra WaveWriter SCS System. The arm description names the same system. The registry summary gives the broad purpose as demonstrating the value of multiple modalities and sustained clinically significant pain relief among patients with chronic pain using the system. A detailed protocol for treatment delivery, device programming, or follow-up is not reported in the registry record.

The recorded study start was 2018-01-09, and primary completion was 2019-01-09. The status is completed. Those registry dates describe the study timeline, but do not establish how many of the 97 enrolled participants completed each follow-up assessment. Participant flow, withdrawals, and the number contributing to the primary endpoint are not reported in the registry record.

The stated primary endpoint is the percentage of participants with a 50% or greater reduction in overall pain from baseline, measured at 3 months post activation. The measure is a participant count expressed as a percentage in its title. No primary endpoint result is posted, and the record lists no analyses. The single-group structure permits a description of outcomes among participants who received the system, but it does not furnish a concurrent control-group contrast. The registry record does not report whether other endpoints were planned in a protocol or whether analyses beyond the posted record were conducted.

Boston Scientific Corporation is identified as the sponsor. Further details about investigator roles, data oversight, or the relationship between the sponsor and analysis decisions are not reported in the registry record. Those omissions matter when interpreting the transparency and scope of the registry entry, but they do not by themselves establish anything about the conduct or quality of the study.

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

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 Percentage of Subjects With 50% or Greater Reduction in Overall Pain From Baseline, measured over 3 months post activation.

The primary endpoint is titled “Percentage of Subjects With 50% or Greater Reduction in Overall Pain From Baseline.” It is assessed at 3 months post activation. In practical statistical terms, it classifies each assessed participant according to whether their overall pain reduction reached the specified threshold, then concerns the proportion who meet that criterion. The registry labels the measure as participants and the outcome type as a count of participants.

A threshold endpoint can make a study question easier to interpret: it focuses on how many participants reach a defined degree of change rather than only on an average change across everyone. It can also communicate a clinically framed outcome. That is a general explanation of threshold endpoints, not a claim about how well this particular endpoint captures every participant’s experience. A binary threshold necessarily groups people into categories, even though the underlying degree of pain change may vary within each category.

The threshold and assessment time are reported, but the record does not describe the pain instrument, how baseline pain was measured, how missing assessments were handled, or how the percentage was calculated in practice. Most importantly, the number and percentage meeting the endpoint are not reported in the registry record. The endpoint definition therefore identifies what was intended to be measured, but does not show the observed result or its precision.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry classifies the primary measure as a binary participant outcome: each participant either meets the threshold or does not, based on whether overall pain decreased by 50% or greater from baseline at 3 months post activation. This is a general description of a binary endpoint. The registry identifies the endpoint but does not post the count meeting the threshold, the number assessed, or an analysis result.

What does a binary endpoint represent?

For a binary outcome, the central descriptive quantity is often the proportion of assessed participants with the event or outcome of interest. In this study, the outcome of interest is meeting the stated reduction threshold. A useful report would identify both the number meeting the threshold and the number assessed, so that readers can see the numerator and denominator underlying the proportion. Neither is reported for the primary endpoint in the registry record. Enrollment of 97 is not a substitute for the number assessed at follow-up.

Converting a continuous measure of pain change into a threshold can make an outcome easier to communicate, but it also discards detail about how far individual changes lie above or below the cutoff. General statistical explanation: two participants can fall on opposite sides of a threshold despite having similar changes, while two participants on the same side can have quite different changes. This feature does not invalidate a threshold endpoint; it means interpretation depends on the endpoint definition and should not be confused with an average change in pain. The registry does not report a continuous pain-change result alongside the threshold endpoint.

What can a single-group analysis estimate?

A single-group study can estimate the frequency of an outcome among participants with measured follow-up, if the result and denominator are reported. It does not by itself estimate the difference between outcomes under two assigned treatments. In general, a control group can help provide a reference for changes that might occur without the intervention or under another intervention. Here, the registry lists one group and no randomized comparator. A comparative effect is therefore not reported in the registry record.

General statistical explanation: a confidence interval around a proportion would express uncertainty associated with estimating that proportion from a sample, under the selected method and assumptions. Its width depends in part on the amount of information and the observed proportion. No interval is reported, and the endpoint data needed to assess it are absent. A p-value would answer a specified testing question under a statistical model; it is not a measure of clinical importance and does not replace the estimated outcome or its uncertainty. No primary endpoint p-value or test is reported in the registry record.

What do the planning assumptions mean?

The registry describes a sample-size planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It states that the effect to detect is a stated fraction of the observed effect. The planning description says that time-to-event calculations use total events, while other calculations give participants per arm. These are planning assumptions, not a description of the actual study design: the trial is recorded as single-group, not as a two-arm randomized comparison.

General explanation: a planning calculation asks how much information a hypothetical study might need to detect a chosen effect under specified assumptions. It does not show that the study actually enrolled that number per arm, nor does it show the probability that the completed study found a result. The record does not provide the calculated planning values in the registry record reported for this trial, and the observed primary effect is also not reported. Thus, no numerical sample-size planning conclusion can be drawn from the planning description alone. Such calculations are not observed power.

The normal approximation is a general method for approximating the distribution of a statistic. Whether it is adequate depends on the outcome and data structure. General explanation: with binary outcomes, the quality of an approximation can be affected by the number of events and non-events. The registry does not give primary endpoint counts, so there is no basis in this record to assess approximation adequacy for an efficacy calculation. The assumptions about equal allocation between two arms also do not align with the recorded single-group design, making clear that the planning illustration is not a report of the trial’s implemented analysis.

What analysis details are unavailable?

The record lists zero analyses. It does not report a statistical model, a method for calculating uncertainty, covariate adjustment, a prespecified analysis population, or a primary endpoint result. It also does not report whether the endpoint was analyzed for all enrolled participants, only those with follow-up, or another group. These details should not be inferred from the endpoint title or study summary.

General statistical explanation: analysis choices can affect how estimates are constructed and which participants contribute information. For example, an analysis that excludes participants without an assessment may answer a different descriptive question from one that handles missing outcomes under explicit assumptions. The record does not state which approach was used. This absence prevents a detailed appraisal of the analysis, but it does not establish that no analysis occurred outside the registry entry.

Finally, the safety counts are descriptive counts in this registry record. They are not an efficacy analysis, and the record does not provide comparative safety estimates. Without a control group and further event definitions or follow-up details, the counts should be read as the reported observations rather than as a causal comparison.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Spinal Cord Stimulation")
n      <- c(40)
events <- c(31)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Spinal Cord Stimulation  40  31  77.5  61.5  89.2  62.5  87.7  62.4  87.6

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists one outcome measure and zero analyses. The primary endpoint is identified, but no primary result is posted. Additional information about planned secondary outcomes, outcome hierarchies, or the number of statistical tests conducted is not reported in the registry record.

Multiplicity is a general statistical concern when several outcomes, time points, or tests are examined. The more questions addressed, the more important it can be to specify which result is primary and how interpretation accounts for multiple testing. The record identifies a primary outcome but does not describe a multiplicity strategy. This does not establish that multiple analyses were performed; it means the approach is not reported in the registry record.

Missing-data handling is also not described. The record gives enrollment of 97, but does not report the number with a primary endpoint assessment at 3 months post activation, the extent of missing outcome data, reasons for missingness, or any method used to address it. Enrollment alone cannot determine the denominator for the endpoint.

The analysis population is not reported in the registry record. There is no statement indicating whether the primary endpoint was assessed among everyone enrolled, those who received the device, those with observed follow-up, or another defined group. The record also does not describe exclusions or participant flow. These gaps limit assessment of how representative the reported outcome would be, if a result were posted, and how it relates to all enrolled participants.

General statistical explanation: missing outcomes can affect an estimate when the participants without measurements differ in relevant ways from those with measurements. The direction and magnitude of any such effect cannot be determined without information about missingness and the analysis. No assumptions or sensitivity analyses for missing data are reported in the registry record.

12. 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 5% reporting threshold.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: angina (1.0%), myocardial infarction (1.0%), sinus node dysfunction (1.0%), back pain (1.0%), pulmonary embolism (1.0%).

The registry lists 97 participants at risk for serious adverse events and 7 affected. For other adverse events, it lists 97 at risk and 0 affected. It also records 1 death. These are the counts shown in the registry record; the record does not provide further context about timing, duration of follow-up, or how event categories were defined.

The listed serious-event terms are Angina, Myocardial Infarction, Sinus Node Dysfunction, Back Pain, Pulmonary Embolism, and Spondylolisthesis. Each term is accompanied by a reported value of 1.0%. The record does not explain the relationship between those terms and the count of 7 affected participants, including whether a participant could appear under more than one term. The categories therefore should not be added together or treated as a complete accounting of the 7 affected participants.

The death count is reported separately, and whether it overlaps with a serious adverse event or any listed term is not reported in the registry record. These counts describe reported events in the study group; they do not establish that the device caused an event. A comparative assessment of event frequency is not available because the study is recorded as single-group and no control group is listed. The safety counts should be interpreted as registry-reported observations, not as a risk comparison or a causal conclusion.

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

The record establishes that a completed, single-group study enrolled 97 participants and specified a primary endpoint based on a 50% or greater reduction in overall pain from baseline at 3 months post activation. It also identifies the Spectra WaveWriter SCS System as the intervention and provides some adverse-event counts. These registry entries describe the registry entry, but they do not provide a numerical result for the primary endpoint.

Without the number meeting the threshold, the number assessed, or an uncertainty interval, the primary outcome cannot be quantified or evaluated for precision. The stated aim of demonstrating pain relief is a description of the study purpose, not evidence that the endpoint was reached. A completed status likewise indicates registry status, not that a particular outcome occurred.

The single-group design also sets a limit on what an observed proportion could establish. General statistical interpretation: a proportion in one treated group describes outcomes among the participants assessed, while a comparison between groups is needed to estimate a difference associated with treatment assignment under the study design. This record lists no comparator, so it cannot provide a controlled treatment contrast. Other explanations for observed change cannot be separated using the registry information alone.

The adverse-event entries show 7 affected among 97 at risk for serious adverse events, 0 affected among 97 at risk for other adverse events, and 1 death. The record does not report enough detail to establish overlap between the death, serious events, and individual terms, or to attribute events to the device. Counts in a single group do not provide comparative safety estimates.

Accordingly, the registry supports a description of the intended outcome, study structure, enrollment, study status, and reported safety counts. It does not support a conclusion about the observed rate of threshold pain reduction, its statistical precision, a causal effect of the intervention, or comparative safety. Those questions require results and analysis details that are not reported in the registry record.

14. Why This Trial Matters Statistically

This study is statistically notable for the gap between a clearly named clinical endpoint and the absence of a posted endpoint result. The registry identifies a threshold-based pain outcome at a specific follow-up time, but does not report the number meeting the threshold, the number assessed, or an analysis. Readers can understand the intended question, yet cannot judge the observed answer or its precision from the registry record.

The single-group design also highlights the difference between describing outcomes and estimating comparative effects. A one-group proportion can be informative as a description when the result and denominator are available. However, it does not provide a concurrent benchmark for interpreting what might have occurred under another treatment or without the intervention. The registry records no randomized allocation or control group, so a causal comparison is not available from this entry.

The record also illustrates why enrollment should not be mistaken for the number analyzed. It lists enrollment of 97, but does not say how many participants contributed to the primary endpoint at 3 months post activation. Without follow-up and missing-data information, the denominator and representativeness of a potential endpoint estimate remain unknown.

Finally, the planning description refers to two-arm assumptions despite the recorded single-group model. That distinction is important when interpreting any sample-size planning illustration: planning assumptions are not the trial’s observed outcomes or design characteristics. In general, transparent reporting connects the question, design, analysis population, result, and uncertainty. Several of those elements are not reported in the registry record, limiting statistical interpretation without changing what the record does establish.

15. 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 primary limitation for interpreting efficacy is that no primary endpoint result is reported. Although the record specifies a threshold and assessment time, it gives neither the number meeting the threshold nor the number assessed. There is no reported uncertainty interval, test result, or analysis estimate.

The single-group design provides no concurrent control comparison. As a result, the registry record cannot separate changes associated with receiving the device from other influences on outcomes over time. This is a design limitation for comparative interpretation, not a claim that any specific alternative explanation occurred.

Participant characteristics and eligibility criteria are not reported in the registry record beyond the broad chronic pain and back pain condition labels. Participant flow, follow-up completion, withdrawals, and the number contributing data at the primary time point are also not reported. The analysis population and missing-data approach are not reported, so the extent to which endpoint findings might represent all enrolled participants cannot be assessed.

The registry does not describe the pain assessment instrument, the detailed endpoint calculation, or device use and programming procedures. It also does not report a detailed statistical analysis plan, any multiplicity approach, or further information about outcome analyses. The record lists zero analyses, but this registry entry alone does not establish whether analyses were conducted elsewhere.

Safety interpretation is limited by the absence of additional event definitions, timing, follow-up context, and details about overlap among serious events, listed terms, and the death. Because no comparator is listed, these safety counts cannot be used as a comparative risk estimate. These limitations reflect what is not reported in the registry record and should not be taken as evidence about information that may exist outside it.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Value of Multiple Modalities Using the Spectra WaveWriter Spinal Cord Stimulator System — NCT03251937.
• Registry record last updated 2021-04-01; status last verified 2021-03.
• Results first posted 2020-03-16.
• 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.

19. Record Summary

The registry identifies VERITAS as a completed, single-group study of the Spectra WaveWriter SCS System in chronic pain. Enrollment was 97. Allocation is listed as NA, masking as none, and phase as NA. The recorded start date was 2018-01-09, and primary completion was 2019-01-09. Boston Scientific Corporation is named as sponsor.

The primary endpoint was the percentage of participants with a 50% or greater reduction in overall pain from baseline at 3 months post activation. The primary result and any analysis are not reported in the registry record. The entry lists 7 affected among 97 at risk for serious adverse events, 0 affected among 97 at risk for other adverse events, and 1 death. No control group is listed, so the record does not report a comparative efficacy or safety estimate.