Magnetic Mini-Mover Procedure to Treat Pectus Excavatum: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Magnetic Mini-Mover Procedure to Treat Pectus Excavatum (NCT00466206), a na phase 1, phase 2 study. The primary outcome is Affect on Cardiac Activity.

2. Clinical Question

The registry describes a pilot study of a magnetic device-based procedure for pectus excavatum, a sunken chest deformity. The investigators’ stated purpose was to examine the effects, including potential harms, of using an internal and external magnetic device to correct the deformity in children. The primary outcome concerned whether cardiac activity, assessed with an electrocardiogram (EKG), showed an adverse change near the magnetic field.

This question is about a safety-related measurement as well as the procedure’s intended effect on the deformity. The registry record does not report the primary endpoint result, so it does not establish how many participants experienced an adverse EKG change.

3. Trial Design

The registry identifies the study as Phase I and Phase II and labels it completed. The recorded start is 2007-04, and primary completion is recorded as 2010-05. Enrollment is listed as 10. The study model is single group, allocation is listed as not applicable, and masking is listed as none. These features describe a small, unmasked pilot without a separate control group.

The treatment arm is named “3MP - Treatment Arm” and is described as the Magnetic Mini-Mover Procedure using the Magnimplant and Magnatract. The intervention list includes the Magnetic Mini-Mover Procedure, Magnatract, and the 3MP procedure. The registry describes Magnatract as an external magnet in a removable external brace. It does not provide additional operational detail about how the procedure was delivered or how long participants used the devices.

The intended candidate group is described as children and adolescents with congenital pectus excavatum who were otherwise healthy and seeking corrective surgery. The brief summary gives an age range of 8 to 14 years for potential candidates. That description concerns eligibility or candidacy; the record does not provide participant-level ages or a fuller account of who enrolled.

The primary outcome population is described as a per-protocol single-arm pilot of ten subjects. The record lists five outcome measures and one secondary outcome, patient compliance. It does not report the criteria used to define the per-protocol population or how compliance was measured.

Because the design has no recorded comparator arm, changes over time cannot be separated from other influences using a concurrent control comparison. The record does not report randomization, and its allocation entry is not applicable. The study is useful as a description of a pilot investigation, but its design does not support a controlled estimate of the treatment’s comparative effect.

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

Analysis population for the primary outcome, as defined in the registry: Per protocol, this is a single-arm, pilot study of ten subjects.

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 Affect on Cardiac Activity, measured over One month post-explantation.

The primary endpoint is titled “Affect on Cardiac Activity” and is measured as a number of participants. Its description specifies the number of patients who experienced an adverse change in EKG findings. EKGs were to be performed before implantation, one month after implantation, and after explantation. The registry gives the timeframe as one month post-explantation, while the description also identifies measurements at other procedure-related time points.

EKG monitoring is relevant to the question posed by the investigators because the study concerns a magnetic field near the heart. In general, an endpoint based on a clinical measurement can help turn a safety concern into an observable outcome. Comparing measurements made at different scheduled times may identify changes that warrant attention, although an observed change alone does not show that the device caused it.

The endpoint is a participant count, not a continuous measure of the size of an EKG change. The record does not specify the criteria used to classify an EKG as an adverse change, the threshold for a clinically important change, or how ambiguous findings would be assessed. It also does not report the observed primary endpoint count. The outcome’s planned measurement schedule and definition are recorded, but the result needed to describe what was observed is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation begins with the type of outcome. The primary endpoint is a count of participants who experienced an adverse EKG change. This is a binary participant-level outcome: each participant is classified as having or not having the specified event, and the endpoint reports the number with the event. The registry does not report the observed count or the detailed rule used to classify a change.

What does a participant count convey?

A count conveys how many participants in the recorded group met an outcome definition. It is not the same as a measure of how large a change was, how long it lasted, or how clinically important it was. For the EKG endpoint, the intended count would summarize whether an adverse change occurred, not the magnitude of an EKG difference. Because the endpoint result is not reported in the registry record, no estimate of the frequency of that primary outcome can be described from the record.

In general, a proportion combines an event count with the number of participants assessed. It can be useful for describing the observed frequency, but it does not by itself establish causation or tell how uncertain the estimate is. Here, the primary outcome’s numerator is unavailable. The adverse-event record does include counts and numbers at risk for serious and other adverse events, so those can be described as recorded group counts; they should not be mistaken for the missing EKG result.

Why does the single-group design matter?

In general, a comparison group helps distinguish changes associated with an intervention from changes that could arise for other reasons, including the natural course of a condition, measurement variation, or events occurring over time. This study is recorded as single group, with allocation not applicable and no separate comparator. The observations can describe what was recorded among treated participants, but they cannot provide a randomized or concurrent-control estimate of the intervention’s comparative effect.

A pre- and post-procedure measurement schedule can show whether measurements differ across time points for participants with available measurements. However, a within-participant change is not equivalent to a controlled treatment effect. The record does not report the EKG values, the number of participants with measurements at each time, or the primary endpoint result. It also does not report a statistical method for comparing the scheduled measurements.

What does a confidence interval do?

In general, a confidence interval expresses the precision of an estimate under a specified statistical model and sampling framework. A narrower interval indicates greater precision than a wider interval, while an interval that spans a broad range indicates substantial uncertainty. An interval does not correct for selection, measurement, or design limitations, and it does not prove that a treatment caused an observed result. No confidence interval for the primary endpoint is reported in the registry record, and none can be described without the underlying result and analysis information.

For binary outcomes, statistical methods may use different assumptions about how event counts arise. In general, a binomial model treats each participant’s outcome as an event or non-event with a common event probability under the model. With limited observations, estimates can be imprecise, and the choice of method for intervals or tests can matter. The registry record does not report a model, test, or interval method for the primary outcome.

What can the adverse-event counts establish?

The recorded serious adverse-event count is 0 affected among 10 at risk, and the recorded other-adverse-event count is 5 affected among 10 at risk. These are descriptive counts in the treatment group. In general, a zero count in a small study still leaves uncertainty about the frequency of an event outside the observed participants. Similarly, an observed event count does not reveal whether events were related to treatment unless attribution is recorded and reported. Event terms, timing, severity details, and attribution are not reported in the registry record details used.

The adverse-event count does not answer the primary EKG question. An EKG change may be specified as an endpoint independently of the adverse-event categories, and the registry does not state that the endpoint and adverse-event classifications are interchangeable. Each should be interpreted according to its own definition and result.

How should planning illustrations be understood?

In general, a sample-size calculation describes how many participants an imagined study might require under chosen assumptions about the effect, variability, allocation, significance level, and statistical method. Such a calculation is prospective planning, not a finding from participants already studied. The stated illustration framework uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; it describes the effect to detect as a stated fraction of an observed effect. These are planning assumptions, and they do not describe the design actually recorded for this single-group study.

Planning figures based on an observed effect are especially dependent on that effect estimate: an unstable estimate from a small pilot can make a planning result unstable as well. In general, planning illustrations should not be read as observed power, proof that the pilot was adequately powered, or evidence of treatment benefit. No numerical planning estimates are reported in the registry record details, and the record does not report the trial’s sample-size justification.

The registry lists no analysis entries. The statistical plan, any prespecified model, handling of repeated EKG measurements, missing-data procedures, and multiplicity approach are not reported in the registry record. Without those details and the primary result, the endpoint’s statistical precision and the robustness of any analysis cannot be evaluated from the registry information.

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("Magnetic Mini-Mover Group")
n      <- c(10)
events <- c(0)
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  Magnetic Mini-Mover Group  10  0  0.0  0.0  30.8  0.0  27.8  0.2  28.5

11. Multiplicity, Missing Data and Analysis Populations

The registry lists five outcome measures and identifies patient compliance as a secondary outcome. It does not report how many outcomes were treated as confirmatory, whether one outcome had priority for formal testing, or whether any adjustment for multiple comparisons was planned. The approach to multiplicity is not reported in the registry record. In general, when several outcomes or repeated comparisons are examined, the chance of at least one apparently unusual result can increase; an analysis plan helps clarify how such results should be interpreted.

The primary EKG endpoint involves assessments at multiple scheduled times: before implantation, one month after implantation, and after explantation. The record does not explain whether the primary assessment was a comparison between particular time points, whether all measurements contributed to a single classification, or how multiple readings were handled. The stated endpoint timeframe is one month post-explantation. The relationship between that timeframe and the full schedule is not further clarified in the registry record.

The primary outcome population is described as per protocol, but the record does not define the criteria for inclusion in that population. It does not state how many participants had complete EKG measurements, how missing measurements were handled, or whether analyses were planned for all enrolled participants as well as the per-protocol population. Missing-data methods are not reported in the registry record.

The registry lists no analysis entries. The statistical analysis plan, outcome-specific analysis populations, and any methods for handling repeated measurements are not reported. These omissions limit assessment of whether the reported outcomes, if results were available, would reflect the intended analyses and how sensitive they might be to missing observations or analytic choices.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 1% reporting threshold.

Most frequent non-serious adverse event terms

For the Magnetic Mini-Mover Treatment group, the registry records 0 serious adverse events among 10 at risk and 5 other adverse events among 10 at risk. These are separate categories and should be read as counts of affected participants in the group, not as a comparison with an untreated group. The registry does not list serious adverse-event terms.

A zero serious-event count means that no serious events are recorded as affecting participants in this group; it does not establish that the risk is absent. In general, uncommon events may not appear in a small pilot, and a single-group record cannot show how the event frequency compares with another treatment or with no treatment. The record does not provide detailed timing, severity, attribution, or descriptions for the other adverse events.

The other-adverse-event count is a safety observation, but it cannot by itself identify a cause or indicate whether the events were related to the procedure. It also does not answer the primary EKG endpoint, whose result is not reported in the registry record. Safety counts should therefore be interpreted as descriptive registry entries rather than as a complete account of the procedure’s safety profile.

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

The record establishes that a completed, single-group pilot study of the Magnetic Mini-Mover Procedure was registered for pectus excavatum, with enrollment listed as 10. It describes a treatment arm using the Magnimplant and Magnatract and gives a primary question focused on adverse EKG changes. It also records the number of participants affected by serious and other adverse events in the treatment group.

What the record does not establish is the result of the primary endpoint. The registry describes how EKG assessment was planned and defines the outcome as a number of participants with an adverse change, but does not report that number. Thus, the record cannot show from the primary endpoint how many participants experienced an adverse EKG change, how precise an estimate might be, or whether results differed across the planned measurement times.

The design also does not establish a comparative treatment effect. There is no separate control group, allocation is not applicable, and masking is listed as none. In general, observations from treated participants alone cannot determine what would have happened to comparable participants without the intervention. The adverse-event counts are useful as descriptions of events recorded in this group, but they do not resolve that comparison or demonstrate causation.

The serious adverse-event count of 0 affected among 10 at risk should not be interpreted as proof that serious harms cannot occur. The other-adverse-event count of 5 affected among 10 at risk should not be interpreted as proof that the procedure caused those events. The record lacks the event details and attribution needed for those conclusions.

Overall, the registry supports a description of the study’s design, intended EKG endpoint, and recorded adverse-event counts. The primary result, detailed analyses, missing-data approach, and statistical plan are not reported in the registry record. The statistical meaning of the study is therefore constrained by both its single-group pilot design and the limited outcome reporting available.

14. Why This Trial Matters Statistically

This trial matters statistically because it illustrates the difference between a clearly stated research question and a result that can be interpreted quantitatively. The registry defines a safety-focused primary endpoint, identifies the assessment method, and describes when EKGs were intended to be obtained. Those details make the target of measurement understandable. However, without the reported primary endpoint count, readers cannot assess the observed result or its precision.

It also illustrates why study design affects what an estimate can mean. A single-group pilot can record outcomes among participants who receive the procedure, but it does not supply a concurrent comparison for separating the intervention’s association from other influences. The absence of a comparator is not repaired by having measurements at more than one time point; repeated measurements may describe change, but they do not create a control group.

The recorded safety counts highlight a further distinction between absence of an observed serious event and certainty that risk is absent. In general, small pilots are limited in their ability to characterize uncommon events. Conversely, a count of other adverse events requires context about event definitions, timing, severity, and attribution before it can be interpreted beyond description. Such detail is not reported in the registry record.

Finally, this record demonstrates why planning calculations must be kept separate from observed evidence. A planning illustration based on assumed effects and methods is not an outcome, and it is not observed power. The stated planning framework assumes a two-arm equal-allocation design, whereas the registered study is single group. Recognizing that difference prevents hypothetical planning assumptions from being mistaken for the trial’s actual design or results.

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 main trial-specific limitation is the absence of the primary endpoint result in the registry record. Although the EKG outcome is described and its timing is specified, the number of participants with an adverse change is not reported. The registry therefore does not permit a direct statistical interpretation of the study’s main endpoint.

The study is recorded as single group, with no comparator arm, allocation not applicable, and no masking. This design limits causal and comparative conclusions. The enrollment is listed as 10, and the primary outcome population is described as a per-protocol pilot of ten subjects. The record does not give participant-level characteristics, explain the per-protocol criteria, or report the number with complete endpoint measurements.

Outcome definitions and analysis details are limited. The record does not specify the threshold for an adverse EKG change, how repeated measurements were combined, or the method used to analyze them. It lists five outcome measures but does not report a multiplicity strategy. The statistical plan, missing-data methods, and outcome-specific analysis populations are not reported in the registry record.

Safety reporting is also incomplete for detailed interpretation. The serious-event and other-event counts are recorded, but serious-event terms are not listed, and event descriptions, timing, severity, and attribution are not reported in the registry record details. The counts therefore cannot establish causation or provide a complete safety profile.

The study is marked completed, but completion status does not address these reporting gaps. The registry record does not report a sample-size justification or analysis entries. These limitations should be kept in view when interpreting the descriptive counts and the intended primary question.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Magnetic Mini-Mover Procedure to Treat Pectus Excavatum — NCT00466206.
• Registry record last updated 2016-01-01; status last verified 2015-12.
• Results first posted 2012-09-03.
• 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.

19. Record Summary

The registry record describes a completed Phase I and Phase II single-group pilot study of the Magnetic Mini-Mover Procedure for pectus excavatum. It lists enrollment of 10, no masking, and no comparator arm. The treatment is described as using the Magnimplant and Magnatract, including an external magnet in a removable brace.

The primary endpoint concerns the number of participants who experienced an adverse change in EKG findings. The record describes assessments before implantation, one month after implantation, and after explantation, and gives the outcome timeframe as one month post-explantation. The primary endpoint result is not reported in the registry record.

For the treatment group, serious adverse events are recorded as 0 affected among 10 at risk, and other adverse events as 5 affected among 10 at risk. The registry lists five outcome measures and patient compliance as a secondary outcome, but the analysis entries, statistical plan, and missing-data approach are not reported in the registry record.