Bilateral; Flank Study With Crown Cooling Insert: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Bilateral; Flank Study With Crown Cooling Insert (NCT02554760), a na na study. The primary outcome is Percentage of Correctly Identified Pre-treatment Photos by a Panel of Blinded Independent Reviewers.

2. Clinical Question

The endpoint concerns reviewers’ recognition of pre-treatment images in paired photo series, not a direct measurement of fat volume or a participant-reported change. Reviewers were to assess changes in surface contour and/or fat volume from pre-treatment and post-treatment images. The stated success criterion required at least 70% correct identification of the pre-treatment images for flanks treated with each treatment parameter by at least 2 of 3 reviewers.

The central statistical question is whether the photographic assessment met that criterion for each treatment parameter. The record describes the assessment procedure but does not report the observed identification results or whether the criterion was met. It also does not report a numerical estimate of the difference between the two flank treatments. Thus, the clinical question is identifiable, but the posted record does not provide the primary result needed to answer it.

3. Trial Design

This was a completed, single-group split-body study of the CoolSculpting System. All participants received bilateral flank treatment: the investigator determined one flank for treatment with the CoolCore applicator without an accessory, and the contralateral flank was treated using the Crown Cooling Insert. The registry record reports enrollment of 19 participants. Because each participant received both treatments, the two treatment conditions are paired within participants; the number of participants should not be interpreted as separate independent groups.

The record gives allocation as NA and explicitly notes that this is not a randomized comparison. It therefore does not establish that treatment side was randomly assigned. Randomization is described for the order in which photo images would be presented, but that is part of the reviewer assessment procedure and should not be mistaken for random assignment of treatment to flank. The record lists masking as NONE. Separately, it says independent reviewers were blinded to post-treatment versus baseline untreated area when assessing the photographs. Those statements concern different aspects of the study and should not be collapsed into a claim that the entire study was blinded.

The study start date was 2015-09-15, primary completion was 2015-12-17, and status is COMPLETED. The primary endpoint timeframe was 12 weeks post-treatment. The registry record does not report the protocol-defined temperature, and the description of the contralateral treatment is incomplete in the available record. A study phase is listed as NA. The record identifies subject satisfaction as a secondary outcome, but does not give its results or detailed measurement method.

Because both sides were treated and treatment allocation was not randomized, this is not a conventional comparison of an intervention group against an untreated control group. The treated flanks permit a within-participant comparison of treatment conditions, but side-related differences and other design features may affect interpretation. The posted information does not describe adjustment for such factors.

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: All subjects received bilateral flank treatments.

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 Percentage of Correctly Identified Pre-treatment Photos by a Panel of Blinded Independent Reviewers, measured over 12 weeks post-treatment.

The primary endpoint is titled as the percentage of correctly identified pre-treatment photos by a panel of blinded independent reviewers. Its stated unit is photos, and its timeframe is 12 weeks post-treatment. Reviewers were to examine pre-treatment and post-treatment images and select the baseline, pre-treatment photos for each subject photo series. The assessment focused on changes in surface contour and/or fat volume in treated areas.

The endpoint is used as a photographic assessment of whether treatment-associated changes are distinguishable in images. Independent review and blinding to post-treatment versus baseline untreated area are intended to limit the influence of reviewer expectations. The record also says image order would be randomized and baseline photo placement randomized within each subject’s image pair. These procedures concern how images were presented to reviewers; they do not establish randomized treatment assignment.

The specified success rule was at least 70% correct identification of the pre-treatment images for flanks treated with each treatment parameter by at least 2 of 3 reviewers. This threshold defines the record’s stated criterion; it does not, by itself, provide evidence that the criterion was reached. The registry record does not report the number or percentage of correct identifications, reviewer-level results, an uncertainty interval, or whether the success criterion was met. The endpoint’s name therefore describes what was intended to be measured, not a result that can be inferred from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

General: What does a split-body design contribute? In a split-body study, the same participant receives different treatments on different body sites. This creates paired observations: each participant can serve as their own comparator for features that remain relatively stable across the study. In general, paired analyses account for the dependence between measurements from the same person rather than treating them as unrelated observations. This design feature does not guarantee that the sites are equivalent. Differences between left and right sides, treatment-side assignment, and local conditions can still matter. In this study, the record says one flank received the standard CoolCore treatment and the contralateral flank received the Crown Cooling Insert, but allocation is NA and the registry explicitly says this was not a randomized comparison.

General: What does the photo-review endpoint measure? The endpoint uses reviewer judgments about which images were taken before treatment. Reviewers were practicing dermatologists or plastic surgeons, according to the record, and were to be blinded to post-treatment versus baseline untreated area. Image presentation order and baseline-photo placement were to be randomized. These measures describe the assessment procedure. The endpoint is not a direct physical measurement of fat volume: it records whether reviewers correctly identify pre-treatment images from photo series. The registry’s success rule requires at least 70% correct identification for each treatment parameter by at least 2 of 3 reviewers. A defined threshold makes the intended decision rule clearer, but evaluation still requires the actual observed identification results, which are not reported in the registry record.

General: Why does blinding matter, and what does it not address? Blinding an outcome assessor can reduce the risk that knowledge of treatment status affects judgment. It can be especially relevant when an outcome includes visual interpretation. However, blinding does not ensure that photographs are equally informative, remove differences between treatment sites, or establish that treatment assignment was unbiased. The registry record reports masking as NONE while also describing blinded independent reviewers. These statements can coexist because reviewer masking is a specific feature of outcome assessment; the record does not say that participants or treating personnel were masked.

General: How should estimates and uncertainty be read? An effect estimate would describe the observed outcome or contrast under a specified analysis. A confidence interval, when reported, would describe a range of values compatible with the data under the assumptions of the method. A narrow interval generally indicates greater precision than a wide interval, but neither an estimate nor an interval establishes causality on its own. The registry record does not report a primary estimate, confidence interval, or primary statistical test. Therefore, precision and statistical compatibility with different possible effects cannot be evaluated from the posted results.

General: Why can over-dispersion matter? For count outcomes, some statistical models assume that variability follows a particular relationship to the mean. If observed variability is greater than that assumption allows, standard errors can be too small and tests or intervals can appear more certain than warranted. Analysts may use methods that allow extra variability when supported by the data and design. This is general statistical context only: the primary endpoint is described as a percentage based on photo identification, and the registry record does not report a count model, a dispersion estimate, or an analysis method for this endpoint. There is no basis in the record for claiming that over-dispersion was assessed or required a correction.

General: What do planning sample-size illustrations mean? The record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect; time-to-event illustrations use total events, while other illustrations use participants per arm. These assumptions describe a hypothetical planning calculation, not the trial’s own design or evidence about the study’s achieved power. Sample-size illustrations are not observed power, and they should not be used as a substitute for the actual outcome estimate and its uncertainty. Specific calculated sample-size values and the observed effect needed to interpret such illustrations are not reported in the registry record.

The record does not report a statistical analysis plan, model specification, handling of paired observations, adjustment for treatment side, or method for the reviewer-level data. Those details matter because different analysis choices can produce different estimates and uncertainty. In their absence, the stated endpoint and review procedure can be described, but the inferential method and its assumptions cannot be reconstructed.

10. Multiplicity, Missing Data and Analysis Populations

The registry record names a primary endpoint and lists subject satisfaction as a secondary outcome. It does not report how many endpoints were formally tested, whether a hierarchy was prespecified, or whether any adjustment for multiple testing was planned. The record also does not report whether the photo endpoint involved a single prespecified summary across reviewers or additional reviewer-level comparisons. Without those details, the approach to multiplicity is not reported in the registry record.

General statistical explanation: when several outcomes or comparisons are tested, the chance of at least one apparently unusual result can increase if each test is interpreted separately. A prespecified primary endpoint and a clear testing hierarchy can help readers distinguish confirmatory analyses from exploratory ones. The record’s stated success rule is a decision criterion for photo identification, but it does not reveal how the study handled all possible comparisons or secondary outcomes.

Missing-data handling is not reported in the registry record. It does not state how unavailable photographs, incomplete reviewer assessments, or participants without evaluable images were handled. The analysis population is also not described beyond the statement that all subjects received bilateral flank treatments. The enrollment figure is 19, but the record does not give the number included in the primary endpoint analysis or explain any exclusions.

These omissions limit assessment of how complete the outcome data were and whether the reported analysis, if any, followed a prespecified plan. The primary result itself is not reported, so it is not possible to judge whether missingness or multiple testing affected the estimate.

11. 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 0% reporting threshold.

The registry lists two treatment groups, each with 19 participants at risk. For both groups, the serious adverse event count is zero, the other adverse event count is zero, and deaths are zero. These figures are the safety entries reported in the registry record.

The study is described as split-body: participants received both treatment conditions on opposite flanks. Therefore, the two group entries represent treatment-specific records for the same participant cohort, not two independent sets of participants. The repeated at-risk count should not be interpreted as evidence that 38 distinct people took part.

General statistical explanation: an event count of zero in a study does not establish that an event is impossible or that a treatment has no safety risk. How much can be learned depends on the amount and duration of observation, event definitions, ascertainment, and completeness of reporting. The record gives the primary endpoint timeframe as 12 weeks post-treatment but does not provide additional detail on safety follow-up or event collection. It also does not report serious adverse event terms, because none are listed. The zero counts should therefore be read as the posted registry figures, not as a comprehensive guarantee about safety.

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

The record supports a description of the intended comparison: bilateral flank treatment within participants, with CoolCore without an accessory on one side and the Crown Cooling Insert on the contralateral side. It also specifies a photographic primary endpoint at 12 weeks post-treatment and a success rule based on correct identification by blinded independent reviewers. These details describe the study question and its planned assessment.

The record does not report the primary endpoint outcome. It therefore cannot establish whether the photo-review criterion was met, what the observed result was, or how precisely any treatment contrast was estimated. The absence of a posted result is not evidence that the endpoint was negative, nor is it evidence that it was positive. The secondary outcome of subject satisfaction is also named without a reported result.

The nonrandomized, split-body design can provide paired information, but the record does not document randomized treatment-side assignment. It cannot, on the information reported, rule out side-related influences or other sources of bias. Reviewer blinding is a feature of the endpoint assessment, not a substitute for random allocation. The photographic measure also captures reviewers’ identification judgments rather than a direct quantitative measurement of fat reduction.

The adverse-event entries report zero serious events, zero other events, and zero deaths in each treatment group, with 19 at risk per group. These entries should be interpreted in light of the split-body structure and the information recorded about safety follow-up. They do not prove that risk is absent. Overall, the posted record permits a careful account of design, endpoint definition, and recorded safety counts, but not a conclusion about efficacy or a quantified comparison between treatment conditions.

13. Why This Trial Matters Statistically

This study is statistically notable for using a split-body structure to compare two treatment conditions within the same participant. General statistical explanation: paired designs can reduce the influence of participant-level differences because each participant contributes observations under both conditions. That potential advantage depends on valid measurement, appropriate treatment-side assignment, and analysis that respects the paired structure.

The registry record makes the allocation limitation explicit: allocation is NA, and the comparison is not randomized. This matters because a within-participant design does not automatically remove all confounding. Treatment side, local anatomy, or other site-level features can be associated with outcome. The record does not describe random assignment of treatment to side or a method of accounting for side effects.

The endpoint also illustrates the distinction between an outcome definition and an observed result. A threshold of at least 70% correct identification by at least 2 of 3 reviewers defines a success rule, but interpretation requires the actual reviewer outcomes. Those results are not reported in the registry record. A detailed endpoint description cannot replace the estimate, uncertainty, and analysis needed to evaluate what was observed.

Finally, the safety figures demonstrate why trial structure matters when reading group totals. Both treatment groups list 19 at risk, but the same participants received both conditions. Treating the entries as separate cohorts would misstate the design. Taken together, the record offers useful design and measurement details while leaving the primary efficacy result and inferential analysis unavailable.

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 primary limitation for interpretation is that the registry record does not report the primary endpoint result. It gives the endpoint definition and success criterion but no observed photo-identification percentage, reviewer-specific outcome, treatment contrast, or uncertainty interval. The record therefore does not permit assessment of the direction, magnitude, or precision of the primary outcome.

The comparison was not randomized according to the registry record. Although the split-body design means both treatment conditions were used in each participant, treatment-side assignment is listed as NA. Any side-related differences could affect the comparison, and the record does not describe an adjustment for them. The image-order randomization described for reviewers does not address treatment allocation.

The record reports masking as NONE while describing blinded independent photo reviewers. It does not clarify masking for participants or treatment personnel. It also does not report a statistical analysis plan, the method used to account for paired observations, or the analysis population for the primary endpoint. Missing-data procedures and the number of evaluable photo assessments are not reported in the registry record.

Further details are limited for the treatment procedure: the available arm description says the standard CoolCore treatment lasted 60 minutes at a protocol-defined temperature, but the protocol-defined temperature is not reported in the registry record, and the contralateral-flank description is incomplete. The record lists subject satisfaction as a secondary outcome without its result. Safety follow-up details beyond the reported group counts are not reported in the registry record. These limitations constrain interpretation even though the study status is COMPLETED.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Bilateral; Flank Study With Crown Cooling Insert — NCT02554760.
• Registry record last updated 2020-10-26; status last verified 2020-10.
• Results first posted 2020-10-26.
• 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.

18. Record Summary

This completed single-group study enrolled 19 participants and used bilateral flank treatments in a split-body design. One flank received CoolSculpting with the CoolCore applicator without an accessory; the contralateral flank received treatment using the Crown Cooling Insert. The primary endpoint was correct identification of pre-treatment photographs by blinded independent reviewers at 12 weeks post-treatment, with a stated threshold of at least 70% correct identification for each treatment parameter by at least 2 of 3 reviewers.

The registry reports allocation as NA and states that the comparison was not randomized. It lists zero serious adverse events, zero other adverse events, and zero deaths in each treatment group, with 19 at risk per group. The primary endpoint result, secondary outcome result, analysis method, confidence interval, and missing-data handling are not reported in the registry record. The posted information describes the study design and intended assessment but does not quantify the primary outcome.