One-stage Breast Reconstruction Using Dermal Matrix/Implant Versus Two-stage Expander/Implant Procedure: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for One-stage Breast Reconstruction Using Dermal Matrix/Implant Versus Two-stage Expander/Implant Procedure (NCT00956384), a randomized na study. The primary outcome is BreastQ Quality of Life and Satisfaction Questionnaire.

2. Clinical Question

The clinical question is about patient-reported outcomes as well as surgical outcomes. The proposed practical distinction is that one-stage reconstruction uses dermal matrix and an implant, whereas the two-stage approach involves a tissue expander and implant. The registry background notes that the two-stage procedure involves separate procedures and office visits for expander inflation. Those descriptions explain the rationale for comparing approaches; they do not establish that either approach produces better outcomes.

The trial is listed as randomized, and two intervention groups are described. The registry’s model classification is also listed as single group, which does not neatly match those two randomized groups. The record does not explain this classification. Interpretation therefore rests on the listed interventions and posted group results, while recognizing that some aspects of the registry description do not align cleanly.

3. Trial Design

The registry identifies NCT00956384 as a completed randomized study comparing one-stage dermal matrix/implant reconstruction with two-stage tissue expander/implant reconstruction. Masking is listed as none. The registry lists the model as single group, despite also describing two interventions, two arms, and a randomized allocation. An explanation for the model classification is not reported in the registry record.

Enrollment is listed as 198. The posted primary outcome reports results for the two reconstruction groups, with outcome counts of 86.0 and 78.0. The record does not explain how these outcome-analysis counts relate to the enrollment figure, and the number of participants included in every analysis is not reported separately. The trial is marked completed. Its listed start date is 2009-09-01 and its primary completion date is 2017-12-31. Phase is listed as NA.

The primary outcome is the BREAST-Q Reconstruction Module, a patient-reported measure with domains for satisfaction with the breast and psychosocial, physical, and sexual wellbeing. The registry describes assessment at 2 weeks after mastectomy, 6 months, and 12 months following the final reconstruction procedure, with comparison of change from baseline. The posted primary result is described as mean final values at 12 months post-op. The record does not explain the relationship between that posted result and the described longitudinal change question.

Two secondary outcomes count participants with short-term and long-term surgical complications. The listed timeframes are 6- months post-op and 12 months post-op, respectively. The original sample-size rationale, allocation details beyond randomization, and detailed analysis-population definitions 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.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as BreastQ Quality of Life and Satisfaction Questionnaire, measured over 12 months post-op.

The primary endpoint is the BREAST-Q Reconstruction Module, a patient-reported questionnaire intended to assess quality of life and satisfaction after reconstruction. The registry describes four domains: satisfaction with the breast, psychosocial wellbeing, physical wellbeing, and sexual wellbeing. Each domain is scored from 1 to 100, with higher scores indicating better quality of life and greater satisfaction.

Patient-reported outcomes address experiences that may not be captured by clinical events alone. Satisfaction and wellbeing are directly relevant to how patients experience reconstruction, so a questionnaire can provide a structured way to compare these outcomes across treatment groups. The scores are not a direct measure of surgical complications, and they should be interpreted as questionnaire outcomes rather than as clinical-event counts.

The registry describes comparing change in scores over time, including baseline scores following reconstruction and later assessments. However, the posted primary result is a mean score on a scale at 12 months post-op, and the sponsor’s analysis is labeled as a mean difference in final values. The record does not report a posted change-from-baseline estimate for the primary outcome. That distinction matters: a comparison of final scores and a comparison of change scores are different statistical questions, and the registry does not explain how the posted final-value result addresses the described longitudinal objective.

The posted group means are 65.32 for one-stage reconstruction and 67.07 for two-stage reconstruction, with standard deviations of 13.63 and 16.05. These values describe group averages and variability; they do not show the range of individual experiences or establish how participants’ scores changed from their own baseline.

7. Results Posted in the Registry

• Two-stage Tissue Expander/Implant: mean 67.07 versus 65.32 on control; difference 1.75 (95% CI -2.83 to 6.33), standardized effect d = 0.12; z-test p = 0.454.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Number of Participants With Short Term Surgical Complications

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Two-stage Tissue Expander/Implant: 34.6% (27/78) versus 37.2% (32/86) on control; risk difference -2.6 percentage points (95% CI -17.3 to 12.1), risk ratio 0.93 (0.62–1.40); unadjusted two-proportion z-test p = 0.730.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Two-stage Tissue Expander/Implant and the control. The interval gives the range of effects that remain compatible with the data.

Number of Participants With Long Term Surgical Complications

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Two-stage Tissue Expander/Implant: 15.4% (12/78) versus 26.7% (23/86) on control; risk difference -11.4 percentage points (95% CI -23.7 to 1.0), risk ratio 0.58 (0.31–1.08); unadjusted two-proportion z-test p = 0.076.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Two-stage Tissue Expander/Implant and the control. The interval gives the range of effects that remain compatible with the data.

Across the secondary endpoints, the registry presents a mixed and incomplete statistical picture rather than a consistent pattern that clearly corroborates the primary result. The short-term complication outcome has a reported logistic-regression p-value below the stated threshold, but the registry does not post the model’s effect estimate or confidence interval. The unadjusted calculation and the sponsor’s reported analysis therefore cannot be directly compared on a common effect scale.

The long-term complication outcome has no sponsor analysis posted. Its unadjusted estimate is uncertain, with an interval that includes no difference. Taken together, the secondary results do not resolve the uncertainty in the primary patient-reported outcome. They concern surgical complications, which are distinct outcomes from satisfaction and quality of life, so agreement between them would not be expected to be automatic.

Secondary outcomes commonly add context, but individual findings are less persuasive when many outcomes or analyses are considered without a reported plan for controlling multiplicity. Testing multiple outcomes increases the chance of at least one result appearing notable by chance. The registry record does not report whether multiplicity was addressed, whether these analyses were prespecified, or how missing data were handled. The short-term reported p-value should therefore be considered alongside its absent effect estimate, the unadjusted result, and the broader uncertainty rather than treated as conclusive on its own.

The record also does not report the clinical importance threshold for either complication outcome or the full definitions and ascertainment procedures for complications. The secondary outcomes can describe observed events, but their statistical presentation does not establish a definitive between-group difference or explain how any difference should be weighed against patient-reported outcomes.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Number of Participants With Short Term Surgical Complications
• Number of Participants With Long Term Surgical Complications

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: each BREAST-Q domain is scored on a numerical scale, and the posted group summaries are means with standard deviations. A mean is an average across the participants whose scores contribute to that result. A standard deviation describes how spread out individual scores are around the group mean. It is not the same as a confidence interval, which describes uncertainty in an estimated quantity such as a group mean or difference between group means.

What does the mean difference describe?

The unadjusted re-calculation compares the two group means. It uses the two-stage group as the first value in the contrast and the one-stage group as the reference, so the reported mean difference is 1.75. Under that definition, a positive estimate means the posted two-stage mean is higher. This is a straightforward summary of the posted final values, not an adjustment for other participant characteristics or for repeated assessments. The registry’s reported analysis gives a different mean difference, -2.69, and labels its measure as a mean difference in final values. The record does not provide enough analysis detail to establish why the estimates differ in direction and magnitude.

What does a t-test assess?

The registry identifies a two-sided t-test for its primary comparison. In general, a t-test assesses whether the observed difference between group means is large relative to the variability and uncertainty expected under a null hypothesis of no difference. A two-sided test allows evidence in either direction. The p-value describes how unusual the data, or more extreme data, would be under the test’s null hypothesis and assumptions. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of a difference.

The unadjusted re-calculation also uses the posted group means, standard deviations, and outcome group counts to estimate a mean difference and its uncertainty. It should be read as a simple comparison of the posted summaries. It does not reproduce an undocumented or more elaborate sponsor model. The record does not report whether the sponsor’s primary analysis adjusted for baseline scores, repeated measurements, or other covariates.

Why do the analysis descriptions matter?

The outcome description concerns change over time, with assessments at multiple timepoints, but the posted result and reported analysis are described as final values. Change scores account for the difference between a participant’s later score and their baseline score; a final-value comparison instead compares scores at a stated endpoint. These methods can answer related but nonidentical questions. The registry does not report the analysis details needed to determine whether or how the repeated measurements were incorporated into the reported primary result.

For the binary secondary outcomes, each result counts participants with a complication. The re-calculation reports a risk difference, which is the difference between the group proportions. In general, a risk difference gives an absolute comparison on the probability scale. It can be positive or negative depending on the order used for the groups. The registry also lists a logistic regression analysis for the short-term outcome. Logistic regression is generally used to model a binary outcome, but the specific model specification, adjustment variables, and reported estimate are not included in the record.

Over-dispersion is a general concern when count or binary data vary more than a model assumes. For the binary outcomes here, the record does not report a dispersion assessment or enough modeling detail to evaluate that issue. No conclusion about the presence or absence of over-dispersion can be drawn from the posted summaries alone.

The posted p-values and confidence intervals should be interpreted alongside their analysis definitions. A p-value gives evidence relative to a specified null model; a confidence interval communicates the uncertainty and plausible range for an estimate under the method used. Neither alone establishes clinical importance. The registry does not report a clinically important difference threshold for the BREAST-Q scores, nor the full statistical analysis plan, missing-data handling, or analysis-population rules.

The re-calculated estimates are explicitly unadjusted comparisons based on posted summary statistics. They are useful for understanding the observed data in a common metric, but they do not override the analysis reported by the study sponsor. In general, randomized allocation supports comparison between assigned groups, but interpretation also depends on how participants were followed, what data were available, and how the analysis handled deviations or missing scores. Those details are not reported in the registry record.

11. Confidence Intervals and Precision

A confidence interval describes the uncertainty around an estimated effect under a statistical method. It is not a range containing a known fixed proportion of individual participant scores. A wide interval indicates that the data are compatible with a broader range of group differences; an interval that spans zero leaves the direction of the difference uncertain under that analysis.

For the unadjusted primary comparison, the mean difference is 1.75 points, with a 95% confidence interval from -2.831 to 6.331. The interval includes zero and extends to both a negative and a positive difference. Thus the posted summaries do not estimate the direction of the group contrast precisely enough to rule out either direction under this calculation. The p-value is 0.454. The interval and p-value describe statistical uncertainty, not whether a difference would be important to patients.

The sponsor-reported primary interval is -10.57 to 5.19 around a mean difference of -2.69. It also includes zero and permits values in either direction. The sponsor’s estimate and the unadjusted re-calculation differ, so they should not be blended into a single estimate. The registry does not report enough detail to reconcile their analysis methods.

For short-term complications, the unadjusted risk-difference interval is -0.173 to 0.121. For long-term complications, it is -0.237 to 0.009. Both intervals include zero. The long-term interval is close to zero at its positive end but still spans values on either side of no difference. These are unadjusted estimates, and the posted registry analysis for short-term complications does not include its own estimate or interval.

Precision is influenced by the amount of outcome information and the variability of the data. The registry does not provide an original precision target or a clinically important difference threshold for the primary score. Consequently, the intervals can describe statistical uncertainty, but the record alone cannot establish whether the precision is sufficient for a particular clinical decision.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are illustrative, not a description of the trial’s original design. For these non-time-to-event outcomes, the figures are participants per arm, rather than a combined total. The planning assumptions listed are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each scenario uses the stated fraction of the observed effect as the effect to detect. The original trial’s own sample-size assumptions are not reported in the registry record.

The 80% power column indicates the number of participants per arm that the planning calculation estimates would be needed to have an 80% chance of detecting the specified effect under the listed assumptions, if that effect were the true effect and the assumptions held. The 90% power column gives the corresponding planning quantity for a higher chance of detection. Power is a design property under specified assumptions; it does not tell whether a particular result is true or important.

The scenarios consider planning for 100%, 75%, or 50% of the observed effect. The smaller the effect a future study aims to detect, the more participants it generally needs, because smaller differences are harder to distinguish from random variation. The effect observed in a completed study is uncertain, so using it as the basis for planning is only an illustration and may not represent the effect a future study should target.

These figures are not observed power. They do not determine whether the completed trial was adequately powered, and they do not change the uncertainty in the posted estimates. The planning figures should be read as conditional examples based on the stated assumptions, not as a retrospective verdict on the trial’s design.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 1.750; pooled standard deviation σ = 14.830.
2. n = 2 × (1.96 + 0.842)² × 14.830² / 1.750² = 1,127.2, rounded up to 1,128 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 1.75                      # observed difference in means
sigma <- 14.8295727650887                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(956384)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 1,128 (80% power), 1,510 (90% power)
 75% of observed effect: n per arm = 2,004 (80% power), 2,683 (90% power)
 50% of observed effect: n per arm = 4,509 (80% power), 6,037 (90% power)
power.t.test: 1128.2 
Simulated power at n = 1,128 per arm: 0.799 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The registry reports a sponsor primary analysis using a two-sided t-test. It gives a mean difference in final values of -2.69, a 95% confidence interval from -10.57 to 5.19, and a p-value of 0.05. This is the study’s reported analysis and should be distinguished from the unadjusted re-calculation, which uses the posted group means and standard deviations and estimates a mean difference of 1.75, with a 95% confidence interval from -2.831 to 6.331 and an unadjusted p-value of 0.454.

The two estimates differ in direction, and their reported analysis descriptions do not fully explain how they relate. The registry does not provide enough detail about the sponsor’s analysis to reproduce or reconcile its estimate. The sponsor’s reported result is therefore not replaced by the re-calculation; the re-calculation is a separate, simple comparison of posted summary statistics.

The sponsor’s confidence interval spans zero, as does the interval from the unadjusted re-calculation. The sponsor reports p = 0.05, while the interval and the different estimate require careful reading. The registry does not report enough information to resolve the relationship among the estimate, interval, and p-value. Neither result alone establishes clinical importance, and the record does not provide a threshold for interpreting the score difference as meaningful to patients.

15. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary patient-reported outcome and two secondary surgical-complication outcomes. Considering multiple endpoints creates a multiplicity issue: if many statistical tests are conducted, the chance of at least one apparently notable result can increase even when there is no true effect. Statistical plans may address this in different ways, for example by specifying a primary endpoint, ordering tests, or adjusting thresholds. Whether the trial used any such approach is not reported in the registry record.

The registry does identify the primary outcome, but it does not provide a complete statistical analysis plan. It is therefore not possible to determine whether the posted primary analysis was prespecified in its reported final-value form, how the several BREAST-Q domains were handled, or whether the analyses across timepoints and domains were part of a planned testing strategy. The record describes four questionnaire domains and multiple assessment times, while the posted primary result is a mean final value at 12 months post-op. The relationship between these descriptions is not explained.

Missing-data methods are also not reported. The registry does not state how missing questionnaire scores or incomplete follow-up were handled, whether analyses included all randomized participants or only participants with available outcome data, or whether any sensitivity analyses were conducted. The posted arm outcome counts do not by themselves explain why these counts differ from the enrollment figure or establish the analysis population.

Further details not reported in the registry record include the original sample-size justification, interim analyses, adjustment for baseline measures or other covariates, and the exact model specification for the reported logistic regression. These omissions limit assessment of whether the analyses followed a prespecified plan and how robust the results are to alternative analytic choices. They do not prove that particular procedures were absent; they mean that the record does not document them.

16. 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 non-serious adverse event terms

The registry reports no serious adverse events in either reconstruction group. The at-risk counts are 86 and 78, and the serious-event counts are zero in both groups. No deaths are reported in either group. These figures describe the posted safety record for the listed groups; they do not establish that no serious events occurred outside the registry’s reporting or observation procedures.

The registry separately lists other adverse events affecting 7 participants in the one-stage group and 6 participants in the two-stage group. The record does not provide event terms or describe their severity, timing, attribution, or overlap with surgical complications. These counts should not be interpreted as counts of all complications or as evidence that the events were caused by a procedure.

Safety counts need to be read with their observation period and reporting definitions in mind. The registry does not provide detailed adverse-event collection methods, event-level descriptions, or a fuller account of follow-up for these figures. Zero reported serious events is a statement about the recorded data, not proof that a procedure has no serious risks.

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

The posted results show group averages and complication counts for two breast reconstruction approaches, with uncertainty around the estimated comparisons. For the primary BREAST-Q final-value comparison, the unadjusted estimate is small relative to the uncertainty expressed by its confidence interval, which includes zero. The sponsor-reported estimate also has an interval that includes zero, though the reported estimate differs from the unadjusted calculation. The record does not provide enough detail to reconcile those analyses.

These results do not establish that the procedures are equivalent. A failure to demonstrate a clear difference is not the same as evidence that the approaches produce identical outcomes. Establishing equivalence or non-inferiority would require a prespecified margin and an analysis designed for that purpose; such details are not reported in the registry record. Nor do the results establish superiority of either approach.

The registry’s background describes potential practical differences between the procedures, but the results summarized in the record do not quantify the full experience of reconstruction, all possible benefits and harms, or patient preferences. The primary endpoint measures patient-reported quality of life and satisfaction, whereas the secondary outcomes count surgical complications. Each addresses a different aspect of the comparison.

Interpretation is further limited by uncertainty about the primary analysis: the registered outcome description concerns change across time, while the posted primary result concerns final values. The record does not report a clinically important score difference, detailed missing-data handling, or full analysis populations. The statistical estimates can therefore be understood as comparisons of the posted outcomes, but they cannot by themselves answer every clinical or practical question about choosing between approaches.

These findings are not medical advice. They describe what the registry reports and the precision of those estimates. A complete assessment would require additional details about trial conduct, outcome collection, and the analysis plan that are not reported in the registry record.

18. Why This Trial Matters Statistically

This trial is statistically interesting because its primary question concerns patient-reported outcomes, while its posted result and registry description do not align perfectly. The described objective is to compare change in satisfaction and quality-of-life scores across multiple assessments, but the posted primary result is a mean final score at 12 months post-op. Those analyses target related but distinct quantities. A reader needs to know which quantity was planned and analyzed to interpret the estimate precisely.

The comparison also illustrates why the estimate, confidence interval, and p-value should be read together. A group mean difference is not enough to determine how precisely the data distinguish between treatment approaches. Here, the unadjusted primary interval spans zero, while the sponsor’s reported estimate and interval differ from the re-calculation. The registry does not provide the analytic detail needed to reconcile the two results, making transparent reporting especially important.

The trial also highlights the distinction between statistical evidence and clinical importance. BREAST-Q scores range from 1 to 100, but no threshold for a clinically important difference is reported. Without such a threshold, the precision of the score comparison can be described statistically, but the patient relevance of a particular difference cannot be judged from the registry record alone.

Finally, the secondary outcomes show why a single reported p-value should not carry the whole interpretation. The short-term outcome has a reported regression p-value without its estimate or interval, while the long-term result has no sponsor analysis posted. Multiple outcomes, incomplete analysis details, and unclear missing-data procedures all affect how much weight individual findings can bear. The case underscores the value of prespecified, clearly reported estimands and analysis methods.

19. 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.

Several limitations are specific to the registry record for this trial. The primary outcome description concerns changes in BREAST-Q scores over time, but the posted primary result and sponsor analysis are described as final values. The record does not explain how the final-value analysis relates to the stated longitudinal objective or whether baseline scores were incorporated.

The sponsor-reported mean difference and the unadjusted re-calculation differ in direction and magnitude. The registry does not provide model details, adjustment variables, or an analysis plan sufficient to reconcile them. The sponsor’s primary p-value is reported as 0.05, while its confidence interval spans zero. The record does not clarify the relationship between this p-value and interval.

The registry lists randomized allocation and two intervention groups but classifies the model as single group. It does not explain this classification. Enrollment is reported as 198, while the posted primary arm outcome counts are 86.0 and 78.0; the record does not explain how those outcome counts relate to enrollment or specify the analysis population for each outcome.

Details of eligibility criteria, participant characteristics, allocation procedures, follow-up completeness, and missing-data handling are not reported in the registry record. The registry also does not report the original sample-size justification, interim analyses, a clinically important BREAST-Q difference, or a multiplicity plan. The short-term complication analysis lacks a posted effect estimate and confidence interval, and no sponsor analysis is posted for the long-term complication endpoint. These limitations restrict independent assessment of the analysis and the practical meaning of the results.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: One-stage Breast Reconstruction Using Dermal Matrix/Implant Versus Two-stage Expander/Implant Procedure — NCT00956384.
• Registry record last updated 2024-12-05; status last verified 2024-10.
• Results first posted 2024-12-05.
• 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.

23. Record Summary

NCT00956384 is a completed randomized comparison of one-stage dermal matrix/implant and two-stage tissue expander/implant breast reconstruction. The registry reports a primary BREAST-Q quality-of-life and satisfaction outcome and two secondary surgical-complication outcomes. Masking is listed as none, enrollment as 198, and the model classification as single group, although two randomized groups are described.

The posted primary outcome is a mean final BREAST-Q score at 12 months post-op. The registry’s outcome description instead refers to change over multiple timepoints. The sponsor reports a mean difference of -2.69, with a 95% confidence interval from -10.57 to 5.19 and p = 0.05. An unadjusted re-calculation gives a mean difference of 1.75, with a 95% confidence interval from -2.831 to 6.331 and p = 0.454.

The secondary findings have incomplete reporting, and the registry does not report full analysis details, missing-data methods, or the original sample-size rationale. The results describe the posted data but do not establish equivalence or superiority.