This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Clinical Outcomes Study Using a New Implantable Neurostimulation System for Chronic Intractable Pain (NCT01665040), a na na study. The primary outcome is Proportion of Subjects Satisfied With Treatment at 90 Days Post-IPG Implantation.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01665040 |
| Phase | NA |
| Condition | Chronic Pain |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 40 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Boston Scientific Corporation |
| Results posted | Yes |
2. Clinical Question
Population
Participants with chronic intractable pain of the trunk and/or limbs. The registry record lists chronic pain as the condition and records enrollment of 40 participants.
Intervention
Implantation of a neurostimulation device, described as spinal cord stimulation with or without peripheral nerve stimulation of the trunk.
Comparator
There is no comparison group described. The study is identified as single-group, and allocation is listed as not applicable.
Primary question
What proportion of participants were satisfied with treatment at 90 days after permanent implantation, as measured by a 7-point Patient Satisfaction with Treatment questionnaire?
The registry record frames the primary objective as investigating patient satisfaction with treatment using the neurostimulation system. This is a question about participants’ reported experience at a specified follow-up point, rather than a randomized comparison of the device with another treatment or with no treatment.
The endpoint title identifies satisfaction at 90 days post-IPG implantation. The record does not report the number or proportion classified as satisfied, the rule used to classify a questionnaire response as satisfied, or an analysis estimate. Consequently, the clinical question is clear at the level of the stated objective, but the posted record does not provide the primary result needed to answer it quantitatively.
3. Trial Design
This completed study evaluated a neurostimulation device in a single group. The registry lists enrollment of 40 participants and describes treatment as spinal cord stimulation, with or without peripheral nerve stimulation of the trunk, for chronic intractable pain of the trunk and/or limbs. The listed intervention is neurostimulation device implantation.
The study is not described as a randomized comparison: allocation is listed as not applicable, and the study model is single-group. Masking is listed as none. Accordingly, the design does not establish a like-for-like control comparison. The registry record lists no phase beyond “NA.” The sponsor is Boston Scientific Corporation.
The record gives a start date of 2012-08 and a primary completion date of 2014-05, and lists the study status as completed. It identifies two outcome measures, but reports zero analyses. These entries do not establish what analysis methods were planned or whether analyses were conducted outside the posted record.
The registry describes the primary objective as investigating satisfaction with treatment. It does not report a protocol-level explanation of participant selection, treatment delivery details, follow-up procedures beyond the primary endpoint timeframe, or a statistical analysis plan. Those omissions limit how fully the design and the intended interpretation can be reconstructed from the registry record alone.
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
| Stage | Neurostimulation for Chronic Pain |
|---|---|
| STARTED | 40 |
| COMPLETED | 36 |
| NOT COMPLETED | 4 |
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.
| Characteristic | Unit | Neurostimulation for Chronic Pain |
|---|---|---|
| Participants analysed | 40 | |
| Age, Continuous | years | 53.9 (SD 13.6) |
| Sex: Female, Male: Female | Participants | 25 |
| Sex: Female, Male: Male | Participants | 15 |
6. Primary Endpoint
The registry lists the primary outcome as Proportion of Subjects Satisfied With Treatment at 90 Days Post-IPG Implantation, measured over 90-days post permanent implantation.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the proportion of participants satisfied with treatment at 90 days after permanent IPG implantation. The registry describes its measurement as a 7-point Patient Satisfaction with Treatment questionnaire and gives the outcome unit as participants. It is therefore a binary summary in the posted outcome classification: participants are counted according to whether they meet the study’s satisfaction definition.
Patient-reported satisfaction can capture an aspect of treatment experience that is not conveyed by a clinical event count alone. As a general statistical point, a proportion is easy to interpret when its numerator, denominator, and classification rule are clear. The registry record gives the endpoint wording and questionnaire scale, but does not report the threshold or response rule used to define “satisfied,” the number meeting that definition, or an estimated proportion.
The endpoint is stated at one follow-up time. It does not, by itself, describe how satisfaction changed over time, distinguish satisfaction attributable to the device from other influences, or quantify pain relief. The registry record also does not report the primary endpoint result or an analysis estimate, so the stated measure cannot be evaluated quantitatively from this record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a study intended to assess satisfaction after neurostimulation, but it does not post a numerical result for the primary endpoint. No count of satisfied participants, proportion, uncertainty interval, or analysis of that endpoint is reported in the registry record. The central satisfaction question therefore remains unanswered by the posted results; this is not evidence that satisfaction was either high or low.
The safety entries report 40 participants at risk for serious adverse events and 11 affected, alongside 40 at risk for other adverse events and 4 affected. Deaths are listed as 0. These are descriptive counts from a single study group. With no control group, the counts do not provide a comparative estimate of safety or establish how the events relate causally to the intervention. The registry record does not provide event-level timing, severity detail beyond the serious/other classification, or an account of whether individuals could contribute to both categories.
The listed serious-event terms include Infection at 12.5%, Musculoskeletal and Connective Tissue Disorders at 7.5%, and Nervous System Disorders at 7.5%. These category percentages are not accompanied by further details about event definitions, the denominator used for each term, or overlap among categories. They should not be added or interpreted as mutually exclusive shares without that information.
As a general statistical point, estimates from a single group describe what was recorded among participants in that group. They cannot isolate the contribution of treatment from other possible influences, and their precision depends on the amount and completeness of observed data. Because the primary endpoint estimate and its uncertainty are not posted, its precision cannot be assessed. The enrollment count alone does not substitute for a reported endpoint result.
The absence of analyses in the registry record is important when reading the outcome entries. It does not establish that no analyses were performed; it means that the record does not report them. No adjustment strategy, confidence interval, hypothesis test, or handling of missing endpoint data can be attributed to the study on the basis of the posted record.
9. Statistical Methods Explained
The registry record identifies a participant-count outcome for the primary endpoint and describes the study as single-group. It does not report an inferential analysis, an estimate of the satisfaction proportion, or an uncertainty interval. The concepts below are general explanations of how such data can be analyzed; they are not claims about methods used in this study.
What does a proportion describe?
For a binary endpoint, each participant is classified into one of two outcome categories under a defined rule. A proportion is the count in the category of interest divided by the number of participants with usable endpoint information. To interpret it, readers need to know both the classification rule and the denominator. For this endpoint, the registry names a 7-point questionnaire but does not report how responses were converted into the category “satisfied,” how many participants had usable responses, or the resulting count.
A proportion is a descriptive estimate for the participants included in its denominator. It is not automatically an estimate of what would occur in a different population. General statistical inference uses uncertainty intervals to indicate the range of values compatible with the data and analysis assumptions. Such intervals would not correct a missing comparison group or settle questions about selection, measurement, or missing responses.
What would a confidence interval add?
In general, a confidence interval accompanies an estimate to show its statistical precision under a specified method and assumptions. A wider interval indicates less precision than a narrower interval. It does not show the probability that a particular treatment effect is true, and it does not remove sources of bias. No confidence interval for the primary endpoint is reported in the registry record, so readers cannot assess the estimate’s precision from the posted results.
What can a single-group design estimate?
In general, a single-group study can describe outcomes observed after an intervention. Without a concurrent comparison group, it cannot separate the intervention’s contribution from other explanations for the observed outcomes. Changes or reports may also be influenced by participants’ circumstances, expectations, natural variation, or other care; these are general possibilities, not findings reported for this study. A single-group satisfaction proportion would therefore describe responses under the study conditions, rather than provide a randomized estimate of comparative benefit.
Why does the endpoint definition matter?
A questionnaire scale contains response options, but a binary proportion requires a rule that maps responses to categories. Different rules can produce different classifications. A complete endpoint description would make the target response category explicit and explain how incomplete questionnaires were handled. The registry gives the scale and endpoint wording but does not report those operational details. It is therefore not possible to reconstruct the primary endpoint classification from the registry record alone.
How should the safety counts be understood?
As a general matter, counts of participants with events describe how many people were recorded as affected, while event counts describe how many events occurred. Those quantities are not interchangeable: one participant can experience more than one event. The registry lists participants at risk and affected for serious and other adverse events, but does not provide a detailed event-level breakdown in the record summarized by these entries. The serious-event term percentages are category summaries; definitions and overlap are not reported. They should be read as descriptive safety information, not as a comparative risk estimate.
What analysis details are unavailable?
The registry record does not report a statistical analysis plan, a hypothesis test, a model, or an approach to uncertainty estimation for the primary endpoint. It also does not state whether any analysis adjusted for other variables. No such choices should be inferred from the endpoint description. The record lists two outcome measures and zero analyses, which signals that the posted registry results do not include an analysis set from which those methods could be evaluated.
General statistical methods can only be interpreted in context: the analysis population, endpoint definition, missing-data handling, and prespecified plan all affect what an estimate means. Since these details and the primary result are not reported, a methods-based assessment of the primary endpoint is not possible from the registry record. The appropriate conclusion is limited to what is documented: a satisfaction outcome was specified for follow-up, but its numerical result and analysis are absent.
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.
| Arm | Participants | Events | Observed % | Clopper-Pearson 95% CI | Wilson 95% CI | Bayesian 95% credible interval |
|---|---|---|---|---|---|---|
| Neurostimulation for Chronic Pain | 40 | 32 | 80.0% | 64.4% to 90.9% | 65.2% to 89.5% | 65.1% to 89.4% |
R code and output
arm <- c("Neurostimulation for Chronic Pain")
n <- c(40)
events <- c(32)
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 Neurostimulation for Chronic Pain 40 32 80.0 64.4 90.9 65.2 89.5 65.1 89.411. Multiplicity, Missing Data and Analysis Populations
The registry record lists two outcome measures and identifies satisfaction at 90 days post-IPG implantation as the primary endpoint. It reports zero analyses. The record does not describe a multiplicity strategy, such as how testing or interpretation would account for multiple outcomes or multiple statistical comparisons. It is not possible to determine whether multiplicity was relevant to an analysis conducted outside the posted record.
Missing-data handling for the primary endpoint is not reported in the registry record. In particular, the record does not state how many participants completed the questionnaire, how many had usable responses, how incomplete responses were handled, or which participants were included in an analysis. The enrollment count should not be assumed to equal the endpoint denominator.
The record also does not define analysis populations, such as a population based on all enrolled participants or one limited to participants with evaluable follow-up. Nor does it report sensitivity analyses assessing the impact of missing responses or alternative endpoint definitions. These details matter because the estimated proportion and its interpretation depend on who is counted and how responses are classified.
As a general statistical principle, missing outcomes can affect both the estimate and its precision, especially if the availability of responses is related to participants’ outcomes. That is a general concern, not evidence that missing data occurred in this study. Without a reported denominator and analysis population, the extent and consequences of missingness cannot be assessed from the registry record.
12. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Neurostimulation for Chronic Pain | 11 | 40 | 27.5% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Neurostimulation for Chronic Pain | 0 of 40 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Neurostimulation for Chronic Pain | 4 of 40 |
Most frequent serious adverse event terms
| Event term | Organ system | Neurostimulation for Chronic Pain |
|---|---|---|
| Infection | Infections and infestations | 5 of 40 |
| Musculoskeletal and Connective Tissue Disorders | Musculoskeletal and connective tissue disorders | 3 of 40 |
| Nervous System Disorders | Nervous system disorders | 3 of 40 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Neurostimulation for Chronic Pain |
|---|---|---|
| Falls | Injury, poisoning and procedural complications | 4 of 40 |
Serious events with the highest arm-level rate: infection (12.5%), musculoskeletal and connective tissue disorders (7.5%), nervous system disorders (7.5%).
The registry lists 40 participants at risk for serious adverse events, with 11 affected. For other adverse events, it lists 40 at risk and 4 affected. Deaths are listed as 0. These are counts for the single neurostimulation group, not comparisons against an untreated or alternative-treatment group.
The record also lists Infection at 12.5%, Musculoskeletal and Connective Tissue Disorders at 7.5%, and Nervous System Disorders at 7.5% among the top serious-event terms. These percentages are presented as category summaries. The registry record does not report enough detail to determine whether categories overlap, how terms were grouped, or what denominator was used for each percentage. They should not be combined into a total.
As a general point, a count of participants affected is different from a count of events: one participant may experience more than one event. The posted entries do not establish whether the serious and other adverse-event groups are mutually exclusive at the participant level. They also do not establish that an event was caused by the device. In a single-group study, the figures are descriptive safety observations, not comparative risk estimates.
13. What the Result Does, and Does Not, Mean
The record establishes that the study was completed, enrolled 40 participants, and specified treatment satisfaction at 90 days after permanent implantation as its primary outcome. It also records adverse-event counts and selected serious-event terms. These details describe the study’s objective, design, and some safety reporting.
The record does not report the primary satisfaction result. It therefore does not show how many participants met the satisfaction definition, what proportion they represented, or how precise that estimate might be. The absence of a result in the registry record cannot be interpreted as a positive or negative finding.
The study’s single-group design also limits what any descriptive outcome could establish. Even if a satisfaction proportion were reported, it would describe participant responses in this group; without a comparator, it would not quantify a difference attributable to neurostimulation. The registry does not report a comparative treatment effect or an analysis designed to estimate one.
The safety counts document events recorded in the group, but they do not establish causation or relative safety. The record gives no control-group figures and does not provide enough information to assess event overlap or the detailed basis for the listed category percentages.
In short, the registry record supports a description of the intended satisfaction assessment and the posted safety counts, but not a quantitative conclusion about the primary endpoint or a comparative conclusion about treatment. Additional results and analysis details are not reported in the registry record.
14. Why This Trial Matters Statistically
This study illustrates an important distinction between specifying an outcome and reporting its result. The registry names a patient-reported satisfaction endpoint, its questionnaire, and its follow-up timeframe. Yet the numerical outcome and its analysis are not reported. Without the numerator, denominator, and endpoint classification rule, readers cannot evaluate the primary result or its precision.
It also highlights how design determines the scope of statistical interpretation. A single-group study can provide descriptive information about participants in the study, but it does not supply a like-for-like control comparison. This matters when readers encounter outcome or safety counts: descriptive observations should not be mistaken for estimates of comparative effect or causal attribution.
The safety entries show why denominators and definitions matter. Counts of affected participants, event categories, and category percentages answer different questions. The record does not provide the detail needed to resolve overlap among terms or establish the denominator for each listed percentage. Careful interpretation avoids combining categories or treating them as independent measures.
More broadly, the record demonstrates the value of complete reporting. A clear endpoint definition, analysis population, missing-data approach, and uncertainty estimate help readers understand what an outcome represents. Their absence does not determine what the study found, but it limits what can be concluded from its registry record. Statistical literacy includes recognizing those limits rather than filling gaps with assumptions.
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 most immediate limitation for interpretation is that the primary endpoint result is not reported in the registry record. The endpoint description does not include the number classified as satisfied, the analyzed denominator, or an estimate of the proportion. The rule defining satisfaction on the 7-point questionnaire is also not reported. This prevents quantitative interpretation of the study’s stated primary question.
The study is single-group, with allocation listed as not applicable and masking listed as none. It therefore has no like-for-like control comparison in the registry description. The posted safety counts are descriptive and cannot establish relative risk or attribute events to the intervention.
Although the record lists enrollment of 40, it does not report how many participants contributed usable primary-endpoint data. The analysis population, losses to follow-up, missing-data handling, and sensitivity analyses are not reported. It is not possible to determine whether the endpoint denominator matched enrollment.
The adverse-event entries provide participant counts and selected serious-event terms, but the registry record does not report event-level details, category definitions, overlap, or the denominator underlying each term percentage. The entries therefore support only a limited descriptive reading.
The registry lists two outcome measures but zero analyses. A statistical analysis plan, multiplicity approach, inferential methods, and uncertainty estimates are not reported in the registry record. These limitations constrain assessment of both the primary endpoint and the broader statistical evidence available.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Clinical Outcomes Study Using a New Implantable Neurostimulation System for Chronic Intractable Pain — NCT01665040.
- Registry record last updated 2020-11-19; status last verified 2020-11.
- Results first posted 2019-01-03.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
19. Record Summary
The registry record describes a completed, single-group study of an implantable neurostimulation system for chronic intractable pain of the trunk and/or limbs. Enrollment was 40, allocation was listed as not applicable, and masking was listed as none. The primary objective concerned treatment satisfaction at 90 days after permanent implantation, measured with a 7-point Patient Satisfaction with Treatment questionnaire.
The record does not report a numerical result or analysis for that primary endpoint. It lists 40 participants at risk and 11 affected for serious adverse events, 40 at risk and 4 affected for other adverse events, and 0 deaths. Selected serious-event terms and percentages are also listed, without details sufficient to assess category overlap. The study’s design and reporting support only descriptive interpretation of the posted safety counts, not a controlled comparison.