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 Laser Resurfacing Versus Dermabrasion for Scar Revision (NCT01176448), a randomized na study. The primary outcome is Safey Data Score Based on Ordinal Ratings of Erythema, Edema, Bleeding, Eschar After Resurfacing.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01176448 |
| Phase | NA |
| Condition | Cicatrix, Dermabrasion, Coagulation, Laser |
| Allocation | Randomized |
| Design model | Single Group |
| Masking | Single |
| Enrollment | 6 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Minnesota |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns scars undergoing resurfacing. The record says each scar was divided in half, with the halves randomized to fractionated laser treatment or dermabrasion. Enrollment was 6. Further participant characteristics, such as scar features or demographic details, are not reported in the registry record.
Intervention
The intervention was fractionated laser treatment, identified in the record as a device. The study description says it was applied to one half of a scar. The record does not report treatment settings, the number of treatment sessions, or other procedural details.
Comparator
The comparator was dermabrasion, also identified as a device. The record describes it as the control against which fractionated laser was compared. The halves of each scar were assigned to the two treatments through randomization.
Primary question
The primary question was how the treatments compared on a safety data score based on ordinal ratings of erythema, edema, bleeding, and eschar after resurfacing. Ratings were scheduled at Day 0, Week1, and Month 1. The registry record does not report the endpoint values or a treatment comparison, so it does not establish how the groups differed on this measure.
The record also lists a Visual Analog Scale for Assessing Scar Improvement as a secondary outcome. That outcome concerns scar improvement, whereas the stated primary endpoint focuses on signs used as indicators of safety. The registry record does not report results for either outcome. Consequently, the research question can be described, but the comparative result cannot be evaluated from the posted endpoint information.
3. Trial Design
The registry record describes a randomized study of fractionated laser therapy and dermabrasion for scar resurfacing. Each scar was divided in half, and the halves were randomized to the two treatments. This is a within-scar allocation as described in the record: the treatment comparison concerns halves of scars rather than separately described groups of whole scars. Enrollment was 6.
The record lists the study model as single-group while also identifying two interventions and describing randomized treatment assignment to scar halves. That combination of labels and description does not provide a fuller account of the analysis structure. The registry record does not report how the paired halves were handled statistically, or whether any participant-level or scar-level clustering was considered.
Masking is listed as single. The identity of the masked party and the procedures used to maintain masking are not reported in the registry record. The phase is listed as NA. The sponsor is the University of Minnesota. The study status is completed; the recorded start was 2010-04 and primary completion was 2010-08.
The record lists fractionated laser and dermabrasion as device interventions. Its summary presents dermabrasion as the historical standard and says the study intended to compare it with fractionated laser therapy for scar resurfacing. These statements describe the rationale and intended comparison, not evidence of comparative benefit or safety.
The registry record does not report a protocol-level description of randomization generation or concealment, eligibility criteria, planned sample-size justification, or a detailed statistical analysis plan. It also does not identify who was masked, how outcomes were collected, or how the analysis accounted for the halves of the same scar. Those details cannot be inferred from the randomized designation 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 | Patients With Scars |
|---|---|
| STARTED | 6 |
| COMPLETED | 6 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: Each scar was divided in half and the halves randomized to either Fractionated Laser treatment or Dermabrasion.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
Population: 12 long scars were recruited for individual study. Only 6 patients were needed as each patient had two separate scars to be studied. Each scar was divided in half, and the halves randomized to fractionated laser resurfacing or dermabrasion.
| Characteristic | Unit | Patients With Scars |
|---|---|---|
| Participants analysed | 6 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 6 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous | years | 54.6 (SD 6.5) |
| Sex: Female, Male: Female | Participants | 3 |
| Sex: Female, Male: Male | Participants | 3 |
| Region of Enrollment: United States | participants | 6 |
6. Primary Endpoint
The registry lists the primary outcome as Safey Data Score Based on Ordinal Ratings of Erythema, Edema, Bleeding, Eschar After Resurfacing, measured over Day 0, Week1, Month 1.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Error |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is described as a safety data score based on ordinal ratings of erythema, edema, bleeding, and eschar after resurfacing. The record identifies these signs as indicators of safety. Each sign was judged on a 4 point ordinal scale: 0=absent, 1=mild, 2=moderate, and 3=severe. The planned assessment times were Day 0, Week1, and Month 1.
An ordinal scale records ordered categories: a higher category represents a more severe rating, but the spacing between categories is not necessarily equal. This is a general feature of ordinal measurement, not a claim about the observed data in this study. The record describes the endpoint as a mean, with standard error as the dispersion measure, but does not explain how the ratings across signs or time points were combined into a score. It also does not report the mean values or standard errors.
Assessing these signs can describe short-term tissue responses associated with resurfacing procedures. The registry record's endpoint definition therefore focuses on safety-related observations rather than scar appearance alone. The Visual Analog Scale for Assessing Scar Improvement is listed separately as a secondary outcome. No results for either outcome are reported in the registry record, so the endpoint definition should not be mistaken for evidence about the treatments' relative safety or scar improvement.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a randomized comparison and defines a primary safety endpoint, but it does not report the primary endpoint values or a treatment contrast. It is therefore not possible to determine from the posted results whether the safety ratings differed between fractionated laser and dermabrasion, in which direction any difference went, or how precisely a difference was estimated.
The endpoint was intended to summarize ordinal ratings of erythema, edema, bleeding, and eschar at Day 0, Week1, and Month 1. The record gives the scale categories and says the endpoint is expressed as a mean with standard error. However, it does not explain how separate signs or assessment times were incorporated into the score. Nor does it provide the score values, standard errors, confidence intervals, or a reported inferential comparison. Without those elements, the magnitude and uncertainty of the primary result cannot be assessed.
The record lists a Visual Analog Scale for Assessing Scar Improvement as a secondary outcome, but gives no result for it. The number of outcome measures is 2 and the number of analyses is 1, yet the registry record does not explain how that analysis relates to the listed outcomes or whether other analyses were conducted. No adjustment for multiple outcomes or assessment times is reported in the registry record.
The adverse-event information reports 0 serious adverse events among 6 at risk in the Fractionated Laser group and 0 among 6 at risk in the Dermabrasion group. It also reports 0 other adverse events among 6 at risk in each group. These are event counts as recorded, not a substitute for the unreported primary safety score. Deaths are listed as null, which does not provide a reported death count.
Even when no events are recorded in a group, the observation does not prove that the underlying risk is absent. General statistical interpretation requires attention to the limited amount of information, the event definitions and ascertainment, and the follow-up period. The record does not provide enough detail to assess those aspects fully. It also does not report confidence intervals or other uncertainty estimates for the adverse-event counts.
The posted information supports a description of the planned comparison and the recorded adverse-event counts, but not a conclusion about comparative safety or effectiveness. Any numerical planning illustrations based on an observed effect should be understood as planning exercises, not as observed power or confirmation of a treatment effect. The registry record does not give the primary effect estimate needed to evaluate such an illustration independently.
9. Statistical Methods Explained
Random allocation is intended to reduce systematic differences in treatment assignment. In this study, the registry record says each scar was split into halves and the halves randomized to fractionated laser or dermabrasion. This design description is important when interpreting the comparison: observations from two halves of the same scar may be related. As a general statistical principle, related observations are not necessarily independent, and an analysis that treats them as unrelated can misstate uncertainty. The registry record does not report how this relationship was addressed in the analysis.
What does an ordinal rating represent?
The primary endpoint uses an ordinal scale to rate erythema, edema, bleeding, and eschar. Its categories have an order from absent through mild and moderate to severe. General statistical interpretation distinguishes this ordering from a continuous measurement with equal intervals: the step from one category to the next need not represent the same change in severity throughout the scale. The record nevertheless identifies the endpoint parameter as a mean and the dispersion as a standard error. It does not explain the construction of the overall safety data score or whether the mean refers to a combined score, an individual sign, or a particular assessment time.
What does the standard error describe?
In general, a standard error describes the estimated uncertainty of a statistic such as a mean across repeated samples under an analysis model. It is not the same as the spread of individual observations. A confidence interval uses an estimate and its uncertainty to express a range of values compatible with the data and model. The registry record does not report standard errors or confidence intervals for the primary endpoint, so the precision of any treatment comparison cannot be judged.
Why does the analysis structure matter?
The record labels the model as single-group, but it also describes two randomized treatments applied to scar halves. These details do not establish which statistical model was used. General methods for paired or clustered observations account for dependence within a scar or participant; methods for independent groups make different assumptions. The registry record does not report the analysis model, unit of analysis, or treatment-effect estimate, so it is not possible to verify whether the analysis matched the allocation structure.
The record lists one analysis and two outcome measures. That count does not establish which outcome was analyzed, what hypothesis was tested, or how results were selected for reporting. The primary endpoint has multiple signs and multiple assessment times. A general analysis could treat these separately or combine them under a defined scoring rule, but no such rule or analysis detail is reported in the registry record. No statistical test, model specification, or adjustment procedure is reported.
What role do planning illustrations play?
Sample-size planning asks how many participants per arm may be needed under stated assumptions to detect a target effect with a chosen power and significance level. The planning description associated with this record specifies a two-sided significance level of 0.05, equal allocation, a normal approximation, and target effects expressed as fractions of an observed effect. These are planning assumptions, not features that demonstrate the study had a particular power. The record does not report a trial-specific sample-size justification. Because the primary outcome values and observed effect are not reported, any planning illustration based on that effect cannot be treated as an observed result or as evidence that the study could reliably detect a clinically relevant difference.
More generally, a planning calculation depends on the assumed outcome variability, target effect, analysis method, and design. If the planned analysis should account for paired scar halves, that structure could affect the assumptions used. The registry record does not report whether the planning calculation incorporated the within-scar allocation. A planning estimate should therefore be read as conditional on its stated assumptions, not as a retrospective measure of what the study could prove.
Statistical significance and practical importance are also distinct general concepts. A test result, if reported, would address compatibility with a null hypothesis under specified assumptions. The size and precision of an estimated difference, along with the clinical meaning of the measure, are needed to interpret its importance. Here, the registry record reports neither a primary treatment estimate nor its uncertainty, so neither significance nor magnitude can be evaluated.
10. Multiplicity, Missing Data and Analysis Populations
The primary endpoint includes ratings of erythema, edema, bleeding, and eschar, assessed at Day 0, Week1, and Month 1. The record also lists the Visual Analog Scale for Assessing Scar Improvement as a secondary outcome. Multiple outcomes, signs, or assessment times can create multiple opportunities to identify a result that appears notable. As a general statistical principle, an analysis plan should clarify which comparisons are primary and whether any adjustment or other strategy addresses multiplicity.
The registry record lists 2 outcome measures and 1 analysis, but does not explain how these relate to one another. It does not report whether the safety signs were combined, whether the time points were analyzed separately, which comparisons were prespecified, or whether a multiplicity adjustment was used. It is not possible to infer a correction—or the absence of one—from the counts alone.
Missing-data handling is not reported in the registry record. The record does not state whether endpoint observations were missing, how missing ratings would be handled, or whether any sensitivity analyses were planned. This absence of reporting should not be read as evidence that data were complete.
The analysis population is also not described. The registry record does not state whether the primary analysis included all randomized scar halves, only those with available observations, or another defined population. It does not report participant flow or the handling of any deviations from assigned treatment. These details matter because exclusions or incomplete follow-up can affect the interpretation of a randomized comparison. No particular missing-data or analysis-population approach can be attributed to this study from the registry record.
11. 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 |
|---|---|---|---|
| Fractionated Laser | 0 | 6 | 0.0% |
| Dermabrasion | 0 | 6 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Fractionated Laser | 0 of 6 |
| Dermabrasion | 0 of 6 |
The adverse-event record lists 0 serious adverse events among 6 at risk in the Fractionated Laser group and 0 among 6 at risk in the Dermabrasion group. For other adverse events, it likewise lists 0 among 6 at risk in each group. These are the posted counts and at-risk figures; they should not be combined into a newly calculated rate or treated as the primary endpoint results.
The primary endpoint is a safety data score based on ordinal ratings of erythema, edema, bleeding, and eschar. The adverse-event counts are a separate record of serious and other adverse events. The registry record does not explain how these event categories relate to the signs included in the primary score, and the counts do not supply the missing score values.
Zero recorded events does not establish that the true risk is zero. This is a general point about interpreting event data: the amount of information, observation period, event definitions, and completeness of reporting all affect what can be concluded. The registry record does not provide confidence intervals, detailed event definitions, or further ascertainment information. Deaths are listed as null; that entry is not a reported count of zero.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized comparison of fractionated laser and dermabrasion was intended for scar resurfacing, with treatment assigned to halves of scars. It also defines a primary safety endpoint using ordinal ratings and lists a secondary scar-improvement outcome. These details identify the clinical question and the kinds of outcomes the study planned to assess.
They do not establish the comparative result. The registry record does not report the primary score values, a between-treatment estimate, or an uncertainty interval. It also does not report results for the Visual Analog Scale for Assessing Scar Improvement. Without those results, the direction, magnitude, and precision of any difference cannot be assessed. The stated rationale for comparing the treatments is not a finding that either treatment performed better.
The adverse-event entries show no serious or other adverse events recorded in either listed group, with the at-risk counts stated in the record. These counts are limited information about recorded events and do not demonstrate the absence of risk. They also do not replace the primary endpoint, which included graded observations of specific signs after resurfacing.
General interpretation of a clinical comparison depends on more than a treatment label or event count. It requires the outcome estimate, its uncertainty, a clear description of the analysis, and an understanding of the population and follow-up. The registry record does not report several of these elements, including the primary analysis details and handling of missing data. The size of the enrolled study is recorded as 6, but the record does not provide a trial-specific sample-size justification.
The appropriate conclusion is therefore limited: the registry record documents the intended randomized comparison and some adverse-event counts, but does not provide enough primary outcome information to judge comparative safety or scar improvement. No claim that one treatment works better, works equally well, or is safer than the other follows from the posted information.
13. Why This Trial Matters Statistically
This study is statistically notable for its allocation structure. The registry record says that each scar was divided in half and the halves randomized to different treatments. Such a design can make within-scar comparisons relevant, but it also means that the relationship between paired observations matters for uncertainty estimation. The record's single-group model label does not clarify how this structure was analyzed. This illustrates why a clear account of the unit of randomization and unit of analysis is essential.
The endpoint also raises a measurement question. It is constructed from ordinal ratings of erythema, edema, bleeding, and eschar, while the record describes the parameter as a mean. Means can be used for ordinal data in some analyses, but interpretation depends on how the score was defined and what assumptions are reasonable. The registry record does not explain how the signs or assessment times were combined. Without that information or the actual endpoint values, readers cannot assess the meaning or precision of the intended comparison.
The distinction between an outcome definition and an outcome result is central. A detailed description of signs and rating categories tells readers what was intended to be measured; it does not show the observed treatment contrast. Likewise, adverse-event counts of zero in both listed groups do not establish equivalence or absence of risk, especially without uncertainty estimates and additional reporting context.
Finally, the record lists a secondary improvement outcome and multiple safety assessment times, but does not explain how multiplicity was handled. Together, these features show why transparent reporting of the analysis plan, outcome construction, missing data, and estimates with uncertainty is important for interpreting a small randomized comparison.
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 registry record does not report the primary endpoint results. It gives the safety score definition, scale, and assessment times, but no values, treatment contrast, standard errors, or confidence intervals. The listed secondary scar-improvement outcome also has no reported result. This prevents assessment of the magnitude, direction, or precision of the treatment comparison.
The endpoint construction is not fully described. Although four signs are named and the record identifies the measure as a mean, it does not explain whether signs were combined, how ratings across Day 0, Week1, and Month 1 were handled, or what score was used in the analysis. The analysis method and the treatment of paired scar halves are also not reported.
Enrollment was 6. The registry record does not report a trial-specific sample-size justification or enough outcome information to evaluate the precision achieved. Its design description says scar halves were randomized, but the record's single-group model label does not resolve the statistical structure.
Further limitations in reporting include the absence of participant characteristics, detailed masking procedures, missing-data methods, analysis-population definitions, and multiplicity procedures. The adverse-event counts are reported, but the record does not provide confidence intervals or detailed ascertainment information. Deaths are listed as null, not as a reported zero count. These gaps constrain interpretation; they should not be filled by assuming unreported methods or results.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Laser Resurfacing Versus Dermabrasion for Scar Revision — NCT01176448.
- Registry record last updated 2019-11-01; status last verified 2019-10.
- Results first posted 2013-06-27.
- 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.
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18. Record Summary
NCT01176448 is a completed randomized study sponsored by the University of Minnesota, with a recorded start of 2010-04 and primary completion of 2010-08. It compared fractionated laser treatment with dermabrasion for scar resurfacing. The record says each scar was divided in half and the halves randomized to treatment. Enrollment was 6, and masking is listed as single.
The primary endpoint was a safety data score based on ordinal ratings of erythema, edema, bleeding, and eschar, assessed at Day 0, Week1, and Month 1. A Visual Analog Scale for Assessing Scar Improvement was listed as a secondary outcome. The primary endpoint values and secondary outcome results are not reported in the registry record.
The adverse-event record lists 0 serious and 0 other adverse events among 6 at risk in each group. Deaths are listed as null. Analysis details, missing-data handling, and a trial-specific sample-size justification are not reported in the registry record.