Effects of Programming Parameters on Back Pain Relief in Subthreshold Spinal Cord Stimulation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of Programming Parameters on Back Pain Relief in Subthreshold Spinal Cord Stimulation (NCT01550562), a randomized na study. The primary outcome is Pain Relief.

2. Clinical Question

The study’s stated purpose was to investigate how varying programming parameters in subthreshold spinal cord stimulation relate to pain relief. The registry lists pain relief responder rate, leg pain reduction, disability, percent pain relief, and quality of life measured by EQ-5D-5L as secondary outcomes. These outcomes broaden the intended assessment beyond average back pain intensity, but the record does not report results for them.

The central clinical research question is therefore identifiable, while its answer is not. The record describes a comparison of sham stimulation and two subthreshold treatment conditions, but contains no observed endpoint values or analysis results. It cannot establish whether pain intensity differed across those conditions, how large any difference might have been, or how uncertain an estimate would be.

3. Trial Design

The registry describes a randomized, double-masked crossover study of Boston Scientific Precision Plus spinal cord stimulation therapy. The intervention was a device, with sham stimulation and two subthreshold treatment conditions listed. The stated aim was to investigate the effects of varying programming parameters. The record does not specify the actual programming settings, the allocation sequence, or how the crossover periods were arranged.

In a crossover design, participants receive more than one study condition, and comparisons can be made within the same participant. General statistical context: within-participant comparisons can account for stable differences between people, because each participant can contribute observations under multiple conditions. That advantage depends on having usable measurements for the relevant conditions and on an appropriate analysis of the repeated observations. Here, the primary outcome population is described as having no study data available, so those comparisons cannot be evaluated from the registry record.

The study began in 2012-02, had a primary completion date of 2013-04, and is listed as terminated. The enrolled number is 1. The reason for termination and any details about recruitment or follow-up are not reported in the registry record. The phase is listed as NA. No inference about the reason for termination or whether the study followed its intended schedule can be made from these entries.

The record lists six outcome measures and zero analyses. The primary outcome is titled Pain Relief and is described as the mean within-patient difference in average back pain intensity among treatment groups. Its timeframe is 4,8,and 12 days post temporary lead(s) implantation. The record does not provide the planned statistical model, the definition of an analysis set, or procedures for handling incomplete measurements. Those omissions matter for interpreting a crossover comparison, especially when the record contains no outcome results.

Randomization and masking are design features, not evidence that a comparison was successfully completed or that bias was eliminated. With only one participant enrolled and no primary-outcome data available, the record does not provide a basis for estimating a group-level treatment contrast or assessing how consistently the intervention was delivered.

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: 1 subject was enrolled in this study.

First Intervention, 4 - 5 Days

Second Intervention, 4 - 5 Days

Third Intervention, 4 - 5 Days

Analysis population for the primary outcome, as defined in the registry: No study data are available.

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 Pain Relief, measured over 4,8,and 12 days post temporary lead(s) implantation.

The primary endpoint is titled Pain Relief. It is described as the mean within-patient difference in average back pain intensity among treatment groups, with assessment at 4,8,and 12 days post temporary lead(s) implantation. The registry does not specify a unit, a dispersion measure, or further details about how the average pain intensity was constructed. It also does not report endpoint values.

General statistical context: a within-patient difference compares a participant’s measurements under different conditions. A mean difference summarizes the average direction and magnitude of such comparisons across the analyzed participants. This approach fits the general purpose of a crossover study, where the same participant may receive multiple conditions. It can distinguish changes between study conditions from stable differences between people, provided measurements are collected and analyzed appropriately.

Pain intensity is used as the primary outcome because the stated study purpose concerns pain relief and the primary measure directly addresses average back pain intensity. The choice of a primary endpoint also identifies the main outcome question in advance of considering secondary measures. The registry does not report the protocol rationale for selecting this specific endpoint, the scale used, or a threshold for interpreting a difference as clinically important.

No primary outcome data are available in the registry record. As a result, there is no reported mean difference, uncertainty interval, or test result to interpret. The endpoint definition describes what the study intended to compare; it does not establish what was observed or whether any conditions differed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

General statistical context: the study’s randomized, double-masked, crossover design combines several design features. Randomization refers to assigning the order or allocation of study conditions by chance, while masking is intended to limit the influence of knowledge about the assigned condition. A crossover design allows comparisons across conditions within a participant. The registry records these design labels, but it does not provide operational details about allocation, masking, or condition sequence. It is therefore not possible to assess how these procedures were implemented.

What does a within-patient difference represent?

The primary outcome is described as the mean within-patient difference in average back pain intensity among treatment groups. In general, a within-patient contrast compares measurements taken from the same person under different conditions. This can reduce the influence of characteristics that remain stable within that person over the comparison period. A mean summarizes the collection of individual contrasts, but its interpretation depends on having measurements for the relevant conditions and a defined approach to combining them.

The registry does not report the pain scale, the individual condition contrasts, or a summary estimate. It also gives no dispersion measure. Dispersion describes how variable individual observations or contrasts are around a summary; without it, the spread of measurements cannot be assessed. Because no outcome data are available, the record cannot support an estimate of the mean difference or its variability.

Why does crossover structure matter?

General statistical context: observations from the same participant are usually related rather than independent. An analysis that treats related measurements as if they came from separate participants may misrepresent uncertainty. A crossover analysis generally needs to account for the participant-level pairing and may also need to consider sequence, period, or carryover effects, depending on the study design and data. These are general considerations, not methods confirmed for this study. The registry does not report the planned model or whether those issues were addressed.

The record does not specify how many treatment periods each participant was to complete, the order of the conditions, or any washout arrangement. No assumptions about these protocol details can therefore be made. The design label alone is insufficient to reconstruct the analysis or determine whether measurements from all conditions were available.

How should the planning illustration be understood?

The registry’s sample-size assumptions describe a planning illustration based on the observed effect. They state a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and a target effect defined as a stated fraction of the observed effect. The accompanying convention distinguishes participants per arm for non-time-to-event calculations from a total number of events for time-to-event calculations.

General statistical context: sample-size planning asks how many observations might be needed to detect a specified effect under stated assumptions. It is not a measurement of evidence from the trial. A planning illustration based on an observed effect depends on an effect estimate being available, and the registry does not report one for the primary outcome. Accordingly, such a calculation cannot be interpreted as the trial’s observed power or as evidence that a treatment difference was or was not detected. The record does not report the trial’s own sample-size justification.

What does the absence of analysis results mean?

The record lists zero analyses, and the primary outcome population is described as having no study data available. No test statistic, p-value, confidence interval, or adjusted estimate is reported. General statistical context: a p-value, when reported, assesses how compatible data are with a specified statistical model and null hypothesis; it does not give the probability that a treatment works. A confidence interval expresses uncertainty around an estimate under the method used. Neither quantity can be reconstructed without the outcome data and analysis details.

There is no reported statistical analysis plan, including any model for repeated measurements, adjustment for baseline values, or approach to outliers. These methods must not be inferred from the design label or outcome description. The registry record also does not report whether the analysis was intended to follow an intention-to-treat principle or another analysis population.

Why is precision not assessable?

Precision refers to how narrowly the data identify an effect estimate. It is commonly conveyed by a confidence interval, which is wider when estimates are more uncertain and narrower when estimates are more precise. Here, neither the estimate nor its interval is reported. Enrollment of 1 is recorded, but the record does not say whether that participant contributed complete observations for every condition and timepoint. Thus, neither the intended within-person contrast nor its precision can be evaluated.

The central statistical conclusion is limited: there is no posted estimate to interpret. General methods explain what the intended comparison could measure, but they cannot fill in missing results or identify methods that the registry does not report.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists six outcome measures, including the primary Pain Relief outcome and secondary measures of pain relief responder rate, leg pain reduction, disability, percent pain relief, and quality of life measured by EQ-5D-5L. It reports zero analyses. A multiplicity strategy for evaluating several outcomes or comparisons is not reported in the registry record.

General statistical context: when many outcomes or contrasts are tested, the chance of at least one apparently unusual result can increase. Statistical plans may address that issue by identifying a primary comparison, adjusting significance thresholds, or interpreting secondary results as exploratory. The registry identifies a primary outcome but does not report whether any multiplicity adjustment was planned or used. Since there are no posted results, it is not possible to assess the impact of multiple testing.

Missing-data procedures are also not reported in the registry record. The primary outcome population is described as having no study data available. That statement does not explain whether measurements were never collected, were incomplete, or were not entered into the registry. It also does not describe any imputation, exclusion, or sensitivity analysis. No missing-data mechanism or handling method should be inferred.

The analysis population is not described beyond the registry’s statement that no study data are available for the primary outcome. The record does not say whether all randomized participants, participants with complete measurements, or another group were intended for analysis. With enrollment of 1, the distinction cannot be evaluated from the posted results. There is no reported statistical plan for handling the crossover structure, repeated measurements, or incomplete observations.

These omissions limit both reproducibility and interpretation. Without an analysis plan and outcome results, the record cannot show how endpoints were selected for analysis, how multiplicity was handled, or whether missing measurements affected estimates.

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’s adverse-event entry lists the randomized group with 1 participant at risk for serious adverse events and 0 affected. It also lists 1 participant at risk for other adverse events and 0 affected, with 0 deaths. These are the posted counts for the recorded group.

General statistical context: event counts describe what is recorded in the registry; they do not by themselves establish the safety profile of an intervention. With only 1 participant listed at risk, the counts provide very limited information about how frequently events might occur in a broader population. A zero count is not proof that an event cannot occur or that all possible harms were assessed.

The record does not list any top serious adverse-event terms. It does not provide further details about event definitions, timing, severity grading, attribution to the device or stimulation condition, or the completeness of adverse-event collection. The adverse-event figures should therefore be read as a small set of registry counts, not as a comprehensive safety comparison across the sham and treatment conditions.

The record reports the study as terminated, but it does not state that safety events caused termination. No explanation for termination is reported in the registry record.

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

The record establishes the intended research question and a few basic design details. It describes a randomized, double-masked crossover study of subthreshold spinal cord stimulation, with sham stimulation and two treatment conditions. The primary outcome was defined as the mean within-patient difference in average back pain intensity among treatment groups at 4,8,and 12 days post temporary lead(s) implantation.

It does not establish the result of that comparison. The registry reports enrollment of 1, no study data available for the primary outcome, and zero analyses. There is no reported estimate of pain intensity difference, no uncertainty interval, and no statistical test result. Consequently, the posted record cannot show the direction or size of any difference among the conditions.

The absence of results is not evidence that the conditions were the same, nor is it evidence that one condition was better. It means the registry record does not supply an analyzable primary result. General statistical context: a meaningful comparison requires observed outcomes and an analysis that accounts for the design and the uncertainty in the data. A design description alone cannot demonstrate an effect.

The secondary outcomes identify other intended areas of assessment, including responder rate, leg pain, disability, and quality of life. No results for these measures are reported. The adverse-event record lists zero serious events and zero other events among 1 participant at risk, along with zero deaths; these counts do not provide a broad assessment of safety.

The registry lists the study as terminated and gives a primary completion date of 2013-04, but the reason for termination is not reported in the registry record. It is not possible to infer whether termination was related to recruitment, logistics, safety, or any other cause. The most defensible reading is therefore descriptive: the record documents a planned comparison and limited enrollment, but does not provide results that answer the clinical question.

13. Why This Trial Matters Statistically

This study is statistically notable because its crossover design and primary outcome imply a within-participant comparison, while the registry contains no outcome data with which to evaluate that comparison. The contrast between a clearly stated estimand—a mean within-patient difference in average back pain intensity—and the absence of a reported estimate highlights an important distinction: defining a research question is not the same as producing evidence that answers it.

General statistical context: crossover designs can be efficient when each participant contributes observations under multiple conditions, because stable individual differences can be separated from condition-related changes. But that potential depends on complete, interpretable measurements and an analysis suited to the repeated observations. The registry does not report details of the crossover schedule or analysis, and the primary outcome population is recorded as having no study data available. The design’s statistical advantages therefore cannot be assessed in this record.

The record also illustrates why enrollment and results must be interpreted together. Enrollment is 1, the study is terminated, and zero analyses are listed. A randomized and double-masked label does not make an unreported effect estimate available, and the posted adverse-event counts cannot substitute for outcomes. The absence of a primary estimate means that precision, uncertainty, and the magnitude of any difference are unknown.

Finally, the record distinguishes intended outcomes from reported findings. It lists multiple secondary outcomes and a planning illustration, yet neither provides observed evidence about the primary comparison. This is a useful reminder that sample-size illustrations and endpoint definitions are not trial results. For statistical interpretation, the decisive limitation is not a particular p-value or confidence interval, but that no such primary analysis is reported.

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 most direct limitation is that the registry reports no study data for the primary outcome. Enrollment was 1, and no analyses are listed. There is therefore no reported estimate, uncertainty measure, or test result for the comparison of average back pain intensity among treatment groups.

The study is listed as terminated, but the reason is not reported in the registry record. The record does not explain whether termination affected data collection, whether the enrolled participant completed the planned conditions, or whether results were available outside the registry. None of these possibilities can be resolved from the posted information.

Important operational details of the crossover design are absent. The condition sequence, period structure, duration of each condition, washout arrangements, and programming parameters are not reported in the registry record. The statistical model and handling of repeated measurements are also not reported. These gaps prevent evaluation of whether the intended within-patient contrast could be estimated appropriately.

The primary endpoint lacks a reported unit and dispersion measure, and the record does not specify the pain scale or a threshold for clinical importance. The statistical analysis plan, multiplicity approach, missing-data procedures, and analysis population are not reported. Although secondary outcomes are listed, no results are available for them. These limitations are specific to the information recorded for this study and prevent conclusions about the magnitude, precision, or clinical interpretation of any treatment difference.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effects of Programming Parameters on Back Pain Relief in Subthreshold Spinal Cord Stimulation — NCT01550562.
• Registry record last updated 2021-04-29; status last verified 2021-03.
• Results first posted 2021-04-29.
• 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 NCT01550562, a randomized, double-masked crossover study titled “Effects of Programming Parameters on Back Pain Relief in Subthreshold Spinal Cord Stimulation.” The official title is “Precision™ High-Rate Sub-perception Spinal Cord Stimulation for the Treatment of Chronic Intractable Pain.” Boston Scientific Corporation is listed as sponsor.

The study concerned low back pain and Boston Scientific Precision Plus spinal cord stimulation therapy. Sham stimulation and two subthreshold treatment conditions are listed. The primary outcome was the mean within-patient difference in average back pain intensity among treatment groups at 4,8,and 12 days post temporary lead(s) implantation.

The record lists enrollment of 1, a start date of 2012-02, a primary completion date of 2013-04, and status as terminated. It lists six outcome measures and zero analyses. No primary-outcome data are available, and the reason for termination and statistical analysis plan are not reported in the registry record. The adverse-event entry lists zero serious events, zero other events, and zero deaths among 1 participant at risk.