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 Impact of Prisma on Donor Site Pain (NCT04050124), a randomized na study. The primary outcome is Pain Score on Visual Analogue Scale (VAS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04050124 |
| Phase | NA |
| Condition | Skin Graft Disorder, Donor Site Complication |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 17 |
| Arms in the primary outcome | 2 |
| Lead sponsor | NYU Langone Health |
| Results posted | Yes |
2. Clinical Question
Population
Patients undergoing split-thickness skin grafting. The registry record describes the study population in those terms but does not report further eligibility details or a more specific population definition.
Intervention
Promogran Prisma, described as the primary contact dressing at the donor grafting site after standard-of-care split-thickness skin grafting.
Comparator
Standard-of-care dressings. The registry record names this comparator but does not provide a detailed description of the dressing regimen.
Primary question
How did donor-site pain on postoperative day 1, measured using a visual analogue scale, compare between participants assigned to Promogran Prisma and participants assigned to standard-of-care dressings?
The study was intended to assess the feasibility of evaluating a composite collagen, silver-oxidized regenerated cellulose matrix against standard-of-care dressing for donor-site pain, in preparation for a larger study. Its primary outcome was a pain score on a visual analogue scale, where lower scores indicate lower pain. The posted group summaries give a median score of 2 in each arm, with a full range from 0 to 8 in each arm.
This question is limited to the recorded pain outcome at the specified time point. The results do not describe pain at other time points, nor do they report a broader assessment of recovery or dressing performance. The record does not report an inferential comparison between the groups, so the group summaries alone do not establish whether any difference in pain is statistically distinguishable from chance variation.
3. Trial Design
The registry describes a randomized, parallel-group study with no masking. Participants were assigned to Promogran Prisma or standard-of-care dressings. The study is listed as completed, with an enrollment of 17. The posted primary outcome results include 7 participants in the Promogran Prisma arm and 9 in the standard-of-care arm; the registry does not explain the difference between the enrollment figure and the outcome counts.
In the Promogran Prisma group, the dressing was described as the primary contact dressing at the donor grafting site following standard-of-care split-thickness skin grafting. The registry record does not give a corresponding detailed description of the standard-of-care dressing regimen. It also does not report how the random sequence was generated, whether assignment was concealed, or how the dressing was applied and maintained.
The study focused on feasibility for a potential larger study, rather than reporting a set of multiple clinical outcomes. One primary outcome measure is posted: pain score on postoperative day 1. No secondary outcome measures are posted, and the registry lists no statistical analyses. The record does not report a protocol-based sample-size justification or explain how the enrollment target was chosen. Random assignment can help make groups comparable on average, but the small posted outcome counts and lack of masking mean that the results should be read as preliminary descriptive evidence, not as a definitive comparison.
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 | Promogran Prisma | Standard of Care (SOC) Dressings |
|---|---|---|
| STARTED | 8 | 9 |
| COMPLETED | 7 | 9 |
| NOT COMPLETED | 1 | 0 |
Reasons for not completing this period:
| Reason | Promogran Prisma | Standard of Care (SOC) Dressings |
|---|---|---|
| Death | 1 | 0 |
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 | Promogran Prisma | Standard of Care (SOC) Dressings | Total |
|---|---|---|---|---|
| Participants analysed | 7 | 9 | 16 | |
| Age, Continuous | years | 70.5 (38 to 92) | 69.55 (53 to 84) | 69.88 (38 to 92) |
| Sex: Female, Male: Female | Participants | 2 | 5 | 7 |
| Sex: Female, Male: Male | Participants | 5 | 4 | 9 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 7 | 9 | 16 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 1 | 0 | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 6 | 6 |
| Race (NIH/OMB): White | Participants | 6 | 3 | 9 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | participants | 7 | 9 | 16 |
6. Primary Endpoint
The registry lists the primary outcome as Pain Score on Visual Analogue Scale (VAS), measured over Postoperative Day 1.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | score on a scale |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the pain score on postoperative day 1, measured with a visual analogue scale. Participants select the number that best reflects their current pain. The scale ranges from 0 to 10, with 0 meaning no pain and 10 meaning unbearable pain. The registry defines lower scores as indicating lower pain.
Pain is relevant to the study question because the intervention is a dressing applied at a skin graft donor site and the study aims to assess pain at that site. A numeric rating provides a direct report of participants’ perceived pain at the specified time. It can capture variation between participants rather than reducing the experience to a simple yes-or-no outcome.
The posted summary uses the median and full range. The median describes the middle of the observed scores, while the range indicates the lowest and highest scores reported. In both groups, the median is 2 and the range is 0 to 8. These summaries show the central reported score and the spread of the observed values, but they do not show how individual scores were distributed within the range. The registry does not report a mean, standard deviation, confidence interval, or other uncertainty estimate for this endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary outcome summaries are the same for both groups: the median postoperative day 1 visual analogue scale pain score is 2, and the full range is 0 to 8. The outcome summary includes 7 participants assigned to Promogran Prisma and 9 assigned to standard-of-care dressings. These are descriptive summaries; the registry reports no statistical analysis comparing the groups.
Equal medians do not mean that every participant reported the same score, or that the groups had identical score distributions. The full ranges show that scores varied within both groups, but a range does not reveal how many participants had scores near either end or how values were distributed between the minimum and maximum. The registry does not post individual participant scores or additional distributional summaries, so the amount and pattern of within-group variation cannot be assessed more fully from the record.
No p-value, confidence interval, adjusted estimate, or other inferential result is reported. Consequently, the record does not quantify the uncertainty around a between-group effect or establish whether the observed summaries reflect a reproducible difference. Since the medians are equal, a comparison based only on the posted medians has no difference in those central values; that descriptive observation is not a formal estimate of the treatment effect. A formal conclusion would require an analysis appropriate to the design and outcome, along with its uncertainty.
The purpose described in the registry is feasibility assessment in preparation for a larger study. That context matters: the study is small, with outcome counts of 7 and 9, and the posted record does not include a statistical comparison. The results therefore provide a limited account of the recorded pain outcome, rather than a precise estimate of how the two dressing approaches differ. No claim about benefit, lack of benefit, or equivalence follows from the equality of these summary statistics.
The record also reports adverse-event information separately from the pain outcome. It lists no serious adverse events in either group, no other adverse events in either group, and one death in the Promogran Prisma group compared with none in the standard-of-care group. The registry does not report a causal assessment of the death. These counts should not be used to infer that the dressing caused or prevented an event.
9. Statistical Methods Explained
The registry identifies the design as randomized and parallel-group, with no masking. In a randomized study, assignment is intended to reduce systematic differences between groups at the outset. A parallel-group design means participants are assigned to one group and assessed in that group. The record does not report the method used to generate the random sequence, whether allocation was concealed, or any procedures used to support adherence to assignment.
What does the median describe?
The median is a measure of the center of a set of observations. It is the point that divides ordered values into lower and upper portions. Unlike the mean, it is not directly pulled toward very high or very low observations. For an outcome reported as a median, however, the median alone does not describe the full distribution. The registry reports a median score of 2 in each arm, along with a full range of 0 to 8. The range gives the minimum and maximum but does not show the frequency of scores between them.
What does the range add?
A full range conveys the observed spread from the lowest to the highest reported score. It can make clear that observations were not all concentrated at the median, but it is sensitive to the most extreme observations and does not indicate how common those extremes were. In this study, both groups have the same posted range. That does not establish that the score distributions were otherwise alike. Additional distributional information, such as participant-level scores or suitable quantiles, is not reported in the registry record.
Why is a confidence interval useful?
General statistical explanation: a confidence interval expresses uncertainty around an estimated quantity, such as a difference between groups. It provides a range of values compatible with the data under the analysis assumptions. A narrow interval indicates greater precision than a wide interval, while an interval that includes values representing little or no difference may leave the direction or size of an effect uncertain. The registry record does not report a confidence interval for the pain outcome or a between-group estimate, so the precision of a comparative effect cannot be judged from the posted results.
Why can the outcome type affect analysis?
General statistical explanation: scores on a bounded scale can be summarized or analyzed in different ways. A mean-based analysis focuses on average scores and commonly relies on assumptions about the outcome distribution and variability. A rank-based or other distribution-sensitive approach may be useful when those assumptions are not suitable, but it answers a different statistical question. The registry gives a median and range, but does not report the analysis method, its assumptions, or a formal comparison. It is therefore not possible to identify which inferential method, if any, was planned or used.
What do the planning assumptions mean?
The registry describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. These are planning assumptions, not a report of the original trial design or a measure of observed power. The registry does not report the trial's own sample-size justification, and no numerical planning estimates are reported in the registry record. Any such planning exercise should be treated as an illustration for future research, not as evidence that the current study had a particular probability of detecting an effect.
The record lists zero statistical analyses. It does not report a model, hypothesis test, covariate adjustment, confidence interval, or multiplicity procedure. No analysis can therefore be attributed to the sponsor from the registry information. The posted medians and ranges remain descriptive summaries rather than estimates accompanied by an inferential assessment.
10. Multiplicity, Missing Data and Analysis Populations
The registry posts one primary outcome measure and no secondary outcome measures. It lists no statistical analyses. There is therefore no reported set of multiple outcome tests from which to assess how multiplicity was handled. Whether any analyses beyond those registered were conducted is not reported in the registry record, and no adjustment procedure is described.
The record does not report a missing-data method, the number of participants with missing primary outcome scores, or how missing observations would be treated in an analysis. The posted outcome counts are 7 in the Promogran Prisma arm and 9 in the standard-of-care arm, while total enrollment is 17. The registry does not explain the difference between these counts. It would not be appropriate to assume that the difference represents missing outcome data, withdrawal, or any particular reason without an explanation in the record.
The analysis population is also not defined. The record does not state whether results were intended to include all randomized participants, only participants who received the assigned dressing, or another population. It does not report protocol deviations, treatment adherence, or exclusions from analysis. Those details matter because different analysis populations can lead to different interpretations of a randomized comparison.
As a result, the available record does not establish how missingness, multiplicity, or analysis-set decisions may have affected the findings. The descriptive endpoint summaries can be read as posted, but they do not resolve these methodological questions.
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 |
|---|---|---|---|
| Promogran Prisma | 0 | 8 | 0.0% |
| Standard of Care (SOC) Dressings | 0 | 9 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Promogran Prisma | 1 of 8 |
| Standard of Care (SOC) Dressings | 0 of 9 |
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 |
|---|---|
| Promogran Prisma | 0 of 8 |
| Standard of Care (SOC) Dressings | 0 of 9 |
The registry reports zero participants with serious adverse events in each group. It also reports zero participants with other adverse events in each group. The adverse-event groups list 8 participants at risk in the Promogran Prisma group and 9 in the standard-of-care group for both categories. These are reported counts, not evidence that the risk of an event is absent beyond the observation captured in this study.
The death count is reported separately: one death in the Promogran Prisma group and none in the standard-of-care group. The registry does not state that the death was caused by the dressing or provide a causal assessment. The death count should therefore be described as an event recorded in the group, not attributed to the intervention.
Small group counts limit what can be learned from zero event counts: uncommon events may not appear in a study of this size. The registry does not report further details about event definitions, event timing, severity grading beyond the serious-event category, or follow-up for safety. The adverse-event figures are descriptive and should be interpreted in that context.
12. What the Result Does, and Does Not, Mean
The posted findings describe a small randomized comparison focused on feasibility and postoperative day 1 donor-site pain. The median pain score was 2 in each group, and the full range was 0 to 8 in each. These summaries indicate that the reported central value and observed endpoints of the score range were the same across the groups. They do not establish that the distributions, individual experiences, or comparative effects were identical.
No inferential comparison or uncertainty estimate is reported. The findings therefore cannot determine whether a difference between dressing approaches exists, how large it might be, or how precisely it could be estimated. A lack of a reported difference is not evidence of equivalence. Equivalence would require a suitable design and a prespecified margin, with an analysis addressing whether the uncertainty falls within that margin; these elements are not reported in the registry record.
The study's stated purpose was to assess feasibility in preparation for a larger study. The posted outcome summaries may inform understanding of what was recorded in this study, but they do not by themselves show that the study met a particular feasibility criterion. Such criteria and corresponding feasibility results are not reported in the registry record. The enrollment and outcome counts are small, and the record does not explain why the endpoint counts differ from total enrollment.
The safety counts also need a restrained reading. No serious or other adverse events are reported in either group, while one death is recorded in the Promogran Prisma group. No causal relationship is reported. These data do not support attributing the death to the dressing, and the zero adverse-event counts do not rule out events that were not observed or reported.
Overall, the record supports a descriptive account of pain scores and reported adverse events in this study. It does not establish a treatment effect, the absence of an effect, or a safety difference between groups.
13. Why This Trial Matters Statistically
This study illustrates the distinction between a feasibility-oriented clinical trial and a definitive comparative evaluation. Its stated purpose was to assess the feasibility of evaluating a donor-site dressing for pain in preparation for a larger study. The registry reports a randomized design, one primary pain outcome, and descriptive summaries, but no statistical analyses. That combination makes clear how much can and cannot be learned from posted summary statistics alone.
The pain outcome is reported using a median and full range. Those statistics offer an accessible description of the observed scores, but they do not quantify uncertainty in a between-group contrast. The same medians and ranges in both arms are not enough to show that all aspects of the distributions match or that the treatments are equivalent. Participant-level data or additional distributional summaries and a prespecified comparative analysis would be needed to answer different, more detailed statistical questions.
The record also illustrates why a randomized label does not by itself answer every design question. The randomization method, allocation concealment, analysis population, missing-data handling, and statistical plan are not reported in the registry record. These details affect how confidently readers can connect the posted summaries to the intended randomized comparison.
Finally, the study's limited counts make careful description especially important. An endpoint summary and safety counts can be reported without implying a confirmed effect. For researchers planning a larger study, the distinction between descriptive observations, inferential estimates, and planning illustrations is central: planning assumptions are not the trial's own sample-size rationale, and they are not observed power.
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 leaves important design and analysis details unreported. It does not describe the eligibility criteria beyond identifying patients undergoing split-thickness skin grafting, nor does it report the random-sequence method, allocation concealment, or procedures for maintaining the assigned dressing. The study is unmasked, and no masking procedure is described. Because pain is participant-reported, the absence of masking is relevant when interpreting the subjective outcome, although the record does not report how this issue was addressed.
The standard-of-care dressing arm has no detailed intervention description in the record. The primary endpoint is reported at postoperative day 1 only; other pain time points are not posted. No secondary outcome measures are posted. The record also does not provide individual scores, additional summaries of the score distribution, or a formal between-group estimate with uncertainty.
Enrollment is reported as 17, while the primary outcome summaries include 7 participants in the Promogran Prisma arm and 9 in the standard-of-care arm. The reason for the difference is not reported in the registry record. The record does not report the analysis population, missing-data handling, participant flow, adherence, or protocol deviations. It also does not provide the trial's sample-size justification or a statistical analysis plan.
The registry reports no statistical analyses, so there is no posted inferential result to evaluate. Feasibility criteria and whether they were met are not reported. Safety details are limited to group counts; event timing, event definitions beyond the listed categories, and the causal assessment of the death are not reported. These limitations restrict interpretation to the descriptive information entered in the registry.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Impact of Prisma on Donor Site Pain — NCT04050124.
- Registry record last updated 2024-04-16; status last verified 2024-03.
- Results first posted 2024-04-16.
- 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
NCT04050124 is a completed, randomized, parallel-group study with no masking, sponsored by NYU Langone Health. The registry reports enrollment of 17 and describes the study as an assessment of the feasibility of evaluating Promogran Prisma for split-thickness skin graft donor-site pain compared with standard-of-care dressings.
The primary outcome is a visual analogue scale pain score on postoperative day 1, ranging from 0 to 10, with lower scores indicating lower pain. The median was 2 in both groups, and the full range was 0 to 8 in both. The endpoint summaries include 7 participants assigned to Promogran Prisma and 9 assigned to standard-of-care dressings.
No statistical analyses or secondary outcome measures are posted. The registry reports zero serious adverse events and zero other adverse events in each group, along with one death in the Promogran Prisma group and none in the standard-of-care group. A causal assessment of the death is not reported.