Study of PM Modulation Therapy in Trial Phase: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study of PM Modulation Therapy in Trial Phase (NCT03110601), a non-randomized na study. The primary outcome is Change in Pain Relative to Baseline and After a Trial Period.

2. Clinical Question

3. Trial Design

The registry describes a completed, non-randomized, single-group device study. Its title concerns trialing PM modulation therapy in patients with chronic intractable low back pain, with or without leg pain. The registered condition is chronic pain, and the reported enrollment is 25. The study is listed as phase NA. Its reported start date is 2017-05-05 and primary completion date is 2017-10-12.

The intervention descriptions identify conventional SCS parameters and Stimgenics SCS parameters, each used for 4 days plus or minus 1 day with an external SCS modulator. The record also describes a 1-day period without stimulation as a washout. These descriptions identify the study conditions, but the record does not report a randomized assignment process. The registry explicitly flags that the arms are not a like-for-like control comparison. Therefore, the conventional period should not be interpreted as a randomized control group for the Stimgenics period.

The primary outcome is a continuous pain score, described as a mean measured before and after intervention. The endpoint timeframe is baseline and 4 days plus or minus 1 days. Four subjects are reported to have experienced known adverse events, such as lead migration, that prevented them from testing Stimgenics SCS. The record does not describe a broader analysis population or explain how these subjects were handled in the primary outcome analysis.

The registry lists the study as completed, but completion status alone does not establish that an outcome analysis was reported. Although one primary outcome measure is listed, the record reports no analyses. The outcome’s numerical estimates and their uncertainty 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.

Before assignment: Non-randomized cross-over study in which all eligible participants received the same order of procedures (i.e. Conventional SCS parameters for 4 days, then a washout period of 1 day, then PM-SCS parameters for 4 days).

Conventional SCS Parameters

Washout Period

Stimgenics SCS Parameters

Analysis population for the primary outcome, as defined in the registry: Chronic Back Pain Patients with or without leg pain; 4 subjects experience known adverse events (such as lead migration) that prevented them from testing Stimgenics SCS.

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: Chronic Back Pain Patients

6. Primary Endpoint

The registry lists the primary outcome as Change in Pain Relative to Baseline and After a Trial Period, measured over Baseline and 4 days plus or minus 1 days.

The primary endpoint is change in pain relative to baseline and after a trial period. Pain was assessed with an 11-point Numeric Pain Rating Scale (NPRS). The scale runs from 0, meaning no pain at all, to 10, meaning the worst pain imaginable. Participants rated their average pain for the past 7 days. The registry also describes ranges of 1-3 as mild pain, 4-6 as moderate pain, and 7-9 as severe pain.

This is a continuous measure: its values represent degrees of reported pain rather than a simple event/no-event outcome. The registry specifies the mean as the summary parameter and the standard deviation as the measure of dispersion. In general, a mean describes the average score in a group, while a standard deviation describes how spread out individual scores are around that average. Neither summary, by itself, describes how precisely an estimated change is known.

Repeated pain ratings can be useful for describing how reported symptoms vary between baseline and a later assessment. Here, the stated timeframe is baseline and 4 days plus or minus 1 days, and the outcome description refers to measurements before and after intervention. However, the numerical pain scores, the mean change, and its standard deviation are not reported in the registry record. The recorded endpoint therefore defines what was intended to be measured, but does not establish the direction, size, or precision of any observed change.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean summarize?

The primary measure is continuous, and the registry specifies the mean as its summary. In general, a mean is the arithmetic average of the observed scores. It can describe a group’s average pain rating at a particular assessment or the average of individual changes, depending on the analysis being used. Those approaches are not interchangeable in every setting. The registry record does not report which calculation was used for a change estimate, or any numerical mean for this outcome.

The standard deviation is the registered measure of dispersion. In general, it describes the extent to which individual values vary around a mean. A standard deviation is not the same as a confidence interval: the former describes variation among observations, while a confidence interval describes uncertainty around an estimated quantity. The registry record does not report a confidence interval for the primary endpoint.

What would a confidence interval add?

In general, a confidence interval gives a range of values compatible with an estimate under the statistical method used. Its width reflects both variability and the amount of information available, among other factors. A narrow interval indicates more precision than a wide interval, but interpretation also depends on the outcome and the question being asked. No confidence interval for pain change is reported in the registry record, so the precision of the primary result cannot be assessed from the posted outcome information.

What would a hypothesis test tell readers?

In general, a p-value summarizes how incompatible observed data are with a specified statistical null model, given the model’s assumptions. It is not the probability that a treatment is effective, and it does not measure the size or clinical importance of an effect. The registry record lists no analysis and reports no p-value for the primary outcome. The statistical analysis plan, including any specified hypothesis test, is not reported in the registry record.

Why does allocation matter?

This study is registered as non-randomized and single group. In general, randomized allocation can reduce systematic differences between groups by using chance to assign participants. With non-randomized periods or conditions, differences in timing or other factors may contribute to observed differences. The record flags that its arms are not a like-for-like control comparison. It does not report a model, adjustment procedure, or other method for separating intervention-period differences from other influences.

The washout description states that no stimulation was provided for 1 day. In general, a washout period may be used to separate treatment periods, but its presence alone does not demonstrate that prior effects have ended or that order effects were eliminated. Whether and how such issues were assessed is not reported in the registry record. The record also does not report the order of the conditions for individual participants.

How should the planning assumptions be understood?

The record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes planning for a stated fraction of the observed effect. Such assumptions concern hypothetical planning, not evidence that the trial had a particular probability of detecting an effect. Sample-size calculations are planning illustrations, never observed power. Numerical planning results are not reported in the registry record.

In general, normal approximations rely on the suitability of an approximate normal model for the quantity being analyzed. Equal allocation is a planning condition for the illustration, not evidence that this non-randomized, single-group trial assigned participants equally to independent arms. The record’s stated allocation and model should take priority when interpreting the design.

Finally, no numerical primary outcome estimates or analyses are reported. General explanations of means, variation, intervals, and tests clarify what those methods would mean if reported; they cannot fill in the absent results. The statistical analysis plan, including the handling of repeated measurements and the specific analysis population, is not reported in the registry record.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Conventional SCS", "Stimgenics SCS")
n   <- c(24, 20)
m   <- c(4.2, 2.4)
sp  <- c(2, 1.8)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Conventional SCS  24  4.200  2.000  3.355  5.045
CARM  Stimgenics SCS  20  2.400  1.800  1.558  3.242

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and no analyses. It does not report a statistical analysis plan, so it is not possible to determine whether multiple hypotheses, outcomes, time points, or comparisons were considered, or whether any multiplicity adjustment was planned. The single listed primary outcome does not by itself establish that only one analysis was performed.

Missing-data procedures are not reported in the registry record. The record identifies 4 subjects whose known adverse events, such as lead migration, prevented them from testing Stimgenics SCS, but it does not explain how their pain scores were handled, whether any other measurements were missing, or what assumptions were used for missing observations. The count of subjects unable to test the intervention should not be treated as a description of the complete primary-outcome analysis population.

The analysis populations are also not reported. The registry does not specify whether the primary result was intended to include all enrolled subjects, only subjects who completed particular trial periods, or another defined group. It does not give a method for handling non-completion or deviations from the intervention periods.

These omissions matter because choices about outcome selection, missing observations, and analysis populations can affect the meaning of an estimate. With no reported numerical outcome analysis, readers cannot assess whether those decisions changed the result or its precision. These details are not 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

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: epidural abscess (4.0%).

The registry reports adverse-event counts separately for conventional SCS, the washout period, and Stimgenics SCS. For serious adverse events, it lists 1 affected among 25 at risk for conventional SCS, none among 20 at risk during washout, and none among 20 at risk for Stimgenics SCS. It reports no deaths in any of the listed groups.

For other adverse events, the record lists 3 affected among 25 at risk during conventional SCS, and none among 20 at risk during washout or Stimgenics SCS. The registry’s listed top serious-event term is epidural abscess, reported as 4.0%. The record does not provide further event-level details in the registry record reported for these results.

These figures are descriptive counts tied to the group-specific numbers at risk. They are not a randomized comparison: allocation is non-randomized, and the record identifies a single-group model. The counts also should not be read as proof that an event can or cannot occur under a given condition. The registry reports that 4 subjects had known adverse events, such as lead migration, that prevented them from testing Stimgenics SCS; the relationship between that statement and the event counts is not further explained. Safety findings do not supply the missing numerical results for the pain endpoint.

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

The registry record establishes that this completed study assessed pain using an 11-point Numeric Pain Rating Scale and describes conventional SCS, a no-stimulation washout period, and Stimgenics SCS trial periods. It also reports adverse-event counts for those periods. These registry entries describe the registered study and the outcomes recorded in the registry.

The record does not report numerical pain results or any analysis. It therefore does not show the average pain scores, the amount of change from baseline, or the uncertainty around an estimated change. Without those results, readers cannot determine from the registry record whether pain ratings were higher, lower, or similar after a trial period, or how precisely any change was estimated.

The design also does not support treating the intervention periods as randomized, like-for-like groups. It is listed as non-randomized and single group, and the registry explicitly cautions that the arms are not a like-for-like control comparison. A difference between periods, if one were reported, could not automatically be attributed to the stimulation parameters without considering the design and potential sources of bias.

The reported safety counts are descriptive and do not establish comparative safety. The record’s statement that 4 subjects could not test Stimgenics SCS because of known adverse events is relevant to understanding exposure to that condition, but the handling of those subjects in an outcome analysis is not reported.

Accordingly, the posted record documents the trial’s question, measurement scale, intervention periods, and selected safety information. It does not provide enough primary-outcome information to characterize the observed pain result or its precision. No conclusion about treatment benefit or lack of benefit follows from the missing outcome analysis.

14. Why This Trial Matters Statistically

This trial illustrates why a registered endpoint and a reported result are different things. The registry describes a clear type of primary measurement: change in reported pain on an 11-point scale between baseline and a short trial period. It also specifies a mean and standard deviation as the intended summary. But without numerical outcome estimates or an analysis, the endpoint definition alone cannot answer the study’s primary question.

The design description is statistically important as well. Non-randomized allocation and a single-group model make it essential to distinguish intervention periods from independent randomized comparison groups. The registry itself warns that the arms are not a like-for-like control comparison. This affects how readers should interpret any comparison and highlights why design details and analysis methods matter alongside outcome numbers.

The record also identifies subjects who could not test Stimgenics SCS following known adverse events. That information matters when considering which participants may have contributed measurements under each condition, but the analysis population and missing-data handling are not described. A count of enrolled participants is not a substitute for knowing which observations contributed to a specific estimate.

Finally, the registry shows how adverse-event counts can be reported even when the primary efficacy analysis is absent. Those counts can describe what was recorded in the listed periods, but do not resolve the missing pain outcome or establish a comparative safety effect. The statistical lesson is to assess the design, endpoint, analysis population, uncertainty, and reporting together rather than treating registration status or completion as evidence of a result.

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.

A central limitation of interpretation is that numerical primary-outcome results are not reported in the registry record. There is no reported mean pain change, standard deviation for the result, confidence interval, or statistical test. The registry lists one outcome measure and no analyses, leaving the size, direction, and precision of the primary result unknown.

The design is non-randomized and single group. The record itself states that the arms are not a like-for-like control comparison. Any comparison across the described periods would therefore require caution, and the registry does not report an analytic approach for addressing potential differences across periods or other influences. The order of conditions for individual participants is not reported.

The primary outcome description refers to ratings of average pain over the past 7 days, while the trial period is described as 4 days plus or minus 1 day. The registry does not explain how this rating window was handled in relation to the trial periods. Further details about measurement timing and the analysis of repeated measurements are not reported.

The record reports that 4 subjects experienced known adverse events, such as lead migration, that prevented testing Stimgenics SCS. It does not explain how their outcome data were handled, which subjects entered each primary analysis, or how missing observations were addressed. Thus, the analysis population and possible effects of incomplete testing cannot be evaluated.

Further limitations include the absence of a reported statistical analysis plan and multiplicity procedures. The registry’s completion status and safety counts do not resolve these gaps. They provide context about the trial, but not the missing outcome analysis.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Study of PM Modulation Therapy in Trial Phase — NCT03110601.
• Registry record last updated 2019-04-16; status last verified 2019-04.
• Results first posted 2019-04-16.
• 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 describes a completed, non-randomized, single-group device trial for chronic intractable low back pain, with or without leg pain. Enrollment was 25. The trial conditions were conventional SCS, a 1-day washout without stimulation, and Stimgenics SCS; each stimulation period was described as 4 days plus or minus 1 day.

The primary outcome was change in pain relative to baseline, assessed with an 11-point Numeric Pain Rating Scale. The registry reports no numerical primary-outcome results and lists no analyses. Four subjects are reported to have experienced known adverse events that prevented them from testing Stimgenics SCS.

Safety counts are reported by period, including 1 serious adverse event in the conventional SCS group and none in the other listed groups. The registry cautions that the intervention arms are not a like-for-like control comparison. The analysis plan, analysis populations, and missing-data procedures are not reported in the registry record.