Harmonic Versus Electro Surgery in Lower Body Lift Procedures: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Harmonic Versus Electro Surgery in Lower Body Lift Procedures (NCT00522171), a registered phase not stated study. The primary outcome is Total Volume (mL) From the Time of Drain Placement to Time of Drain Removal.

2. Clinical Question

3. Trial Design

The official title describes a randomized, prospective, parallel-group study comparing Harmonic™ with Electro Surgery in lower body lift procedures. The registry record lists an enrollment of 30 and a status of terminated. It gives a study start of 2007-09 and a primary completion date of 2009-02. These are record details, not an account of why the study ended; a reason for termination is not reported in the registry record.

The record names two arms: Electro Surgery and Harmonic® Technology. It describes the Electro Surgery instruments and identifies the Harmonic ultrasonic scalpel as the intervention. However, allocation is not stated in the registry record, and the record flags this as not being a randomized comparison, with the arms not being a like-for-like control comparison. The title alone therefore does not establish that participants were actually allocated at random or that the arms can be interpreted as equivalent apart from the device used.

The primary outcome population is listed as ITT, but the record does not explain how that population was defined or how participants were handled if they did not complete follow-up or have an endpoint measurement. The posted safety figures list 15 participants at risk in each arm. These safety counts should not be assumed to describe the number contributing primary-outcome data: that information is not reported in the registry record.

The endpoint schedule is described relative to drain placement and removal, rather than as a fixed visit date. The primary measure is total drainage volume during that period, with a stated upper timeframe of <= 770 hours. The secondary measure is total hours between drain placement and removal. Other design details, including the protocol, eligibility criteria, allocation procedures, masking, and reasons for termination, 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

Analysis population for the primary outcome, as defined in the registry: ITT

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 Total Volume (mL) From the Time of Drain Placement to Time of Drain Removal, measured over From the time of drain placement to time of drain removal (</= 770 hours).

The primary endpoint is the total volume, in milliliters, of postoperative serous fluid collected in wound drains from drain placement until drain removal. The record defines the fluid as serous drainage from wound drains installed after the study procedure. The measurement period is described as running from placement to removal, with a stated maximum timeframe of <= 770 hours.

This endpoint captures the amount of fluid collected during the specified drainage period. As a direct measured quantity, it can describe drainage burden without reducing the outcome to a yes-or-no event. The registry record presents the endpoint as a mean with standard deviation, which would describe the group average and the spread of individual measurements if results were reported.

The associated secondary outcome is total hours from drain placement to drain removal. This describes the duration of drainage, a distinct feature from the amount collected. Volume and duration should not be treated as interchangeable: two groups could differ in one measure without the other moving in the same way. The registry record reports no analyses for either outcome, so no group means, standard deviations, or comparative estimates are available. The endpoint’s stated purpose is to address the study objective; the record does not report a separate justification for choosing it as primary.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record characterizes the primary outcome as a continuous measure summarized by a mean and standard deviation. These summaries describe different aspects of a distribution. The mean is the arithmetic average of participants’ measured drainage volumes. The standard deviation describes how widely individual measurements vary around that average. Neither summary is reported by arm in the registry record, so the outcome distributions and average volumes cannot be evaluated.

What would a group comparison estimate?

In general, a two-group comparison of a continuous endpoint can estimate how far apart the groups’ average outcomes are. The estimate’s direction indicates which group has the higher mean, while its size describes the contrast in the measurement’s units. For this endpoint, those units are milliliters. A comparison is more informative when its uncertainty is also reported, because the estimate alone does not show how precisely the effect has been measured. The registry record does not provide a comparison estimate or its uncertainty.

How should variability be understood?

In general, the standard deviation concerns variation among individual observations, not uncertainty in the estimated group mean. A confidence interval instead expresses uncertainty around an estimate, under the assumptions of the method used. A wider interval indicates less precision than a narrower interval. No confidence interval for the primary outcome is reported in the registry record. Without group means and variability information, readers cannot reconstruct a credible comparison from the posted record.

What does the allocation information imply?

In general, random allocation is intended to make treatment groups comparable, on average, with respect to factors that could affect outcomes. That purpose depends on allocation actually being random and implemented as intended. Here, although the official title uses the term randomized, the allocation method is not stated, and the record flags the comparison as not randomized and not like-for-like. The registry therefore does not support treating the title as sufficient evidence of random allocation. The record also does not describe adjustment for differences between groups or provide characteristics that would allow their comparability to be assessed.

What can the sample-size illustrations say?

The registry record describes planning illustrations based on fractions of an observed effect, using a two-sided significance level of 0.05, equal allocation, and a normal approximation. They are planning illustrations, not the study’s own design justification and not observed power. The registry record does not report the protocol’s sample-size justification. Nor does it provide primary outcome estimates from which readers could assess the observed effect behind those illustrations. A planning calculation cannot replace reported results or show what the trial actually found.

Why does the measurement window matter?

In general, an outcome measured over a participant-specific interval can depend on how that interval begins and ends. Here, the endpoint is defined from drain placement until drain removal, and the record states a maximum timeframe of <= 770 hours. The secondary outcome is the total hours in that interval. The record does not explain how measurements were handled if drain removal did not occur within the stated timeframe, or if a participant’s drainage measurement was incomplete. Such handling details are not reported in the registry record.

Can the analysis method be identified?

No specific inferential method is reported for the primary comparison. The record names the outcome summary but does not identify a statistical test, model, adjustment strategy, confidence interval method, or diagnostic checks. General methods for continuous outcomes can make different assumptions about distribution shape, variance, and independence. Those are considerations for interpreting a specified analysis, not evidence about what this study used. Since the analysis method and outcome results are absent, no method-specific conclusion can be drawn.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Electro Surgery", "Harmonic® Technology")
n   <- c(15, 15)
m   <- c(2163.03, 1863.6)
sp  <- c(756.295, 1471.39)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Electro Surgery  15  2163.030  756.295  1744.208  2581.852
CARM  Harmonic® Technology  15  1863.600  1471.390  1048.771  2678.429

11. Multiplicity, Missing Data and Analysis Populations

The record lists two outcome measures: total drainage volume as the primary outcome and total hours from drain placement to drain removal as a secondary outcome. It does not report a statistical analysis plan, a testing sequence, or a method for handling multiple comparisons. The registry record also lists no analyses. It is therefore not possible to determine whether either outcome was tested, whether additional outcomes were assessed, or how any multiplicity was addressed.

In general, multiplicity arises when several outcomes or comparisons are examined. Without an analysis plan, readers cannot know whether a reported statistical finding would have been the prespecified primary test or one among several opportunities to observe a result. No adjustment or other multiplicity strategy is reported in the registry record; this does not establish that none was used outside the record.

The primary endpoint population is named as ITT. The registry record does not define the population further, identify who was analyzed, report the number of participants with observed primary outcome values, or explain how missing measurements were handled. It also does not report whether any participants withdrew, whether follow-up was incomplete, or whether missingness differed between arms. These details are necessary to understand how the stated population relates to the analyzed data.

In general, missing outcome data can affect both the estimate and its precision, especially when the reasons for missingness are related to the outcome. The record does not provide enough information to assess that possibility. The study’s terminated status does not itself establish that data were missing or explain any missingness. The reason for termination and its consequences for data collection or analysis are not reported in the registry record.

12. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: dyspnoea, meddra version 10.0 (6.7%), wound dehiscence, meddra 10.0 (6.7%).

The registry record lists 15 participants at risk for serious adverse events in each arm. It reports 1 affected participant in the Electro Surgery group and 1 affected participant in the Harmonic® Technology group. These are counts of participants, not a complete description of the number, timing, duration, or severity of every event. The record does not provide enough detail to infer whether the affected participants experienced one event or multiple events.

The record also lists other adverse-event counts: 14 of 15 participants in the Electro Surgery group and 11 of 15 in the Harmonic® Technology group were affected. These figures are distinct from the serious-adverse-event counts and should not be conflated with them. No further event-level detail is included in the record.

The listed top serious terms are dyspnoea, MedDRA Version 10.0, at 6.7%, and wound dehiscence, MedDRA 10.0, at 6.7%. The record does not attribute these terms to a particular arm, so they should not be assigned to either group. Death counts are not reported in the registry record; the absence of a numerical value does not establish that there were no deaths. With limited event detail and no reported outcome analyses, the safety figures are descriptive and do not establish a comparative safety effect.

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

The registry record specifies a comparison of Harmonic ultrasonic technology with Electro Surgery during lower body lift procedures. It defines the primary endpoint as total serous drainage volume collected from drain placement to drain removal and lists the duration of drainage as a secondary outcome. It also provides limited adverse-event counts. These details clarify what the study was intended to examine and what safety information was posted.

The record does not report primary or secondary outcome analyses. It therefore does not show whether average drainage volume or drainage duration differed between the arms, nor does it establish the direction or size of any difference. No confidence interval or inferential result is reported to indicate the precision of a comparison. It would be incorrect to interpret missing results as a finding of no difference.

The record’s design information also calls for caution. The official title describes a randomized study, but allocation is not stated and the record flags the arms as not being a randomized, like-for-like comparison. Without a clear allocation account and outcome estimates, the record cannot establish that any possible group contrast was caused by the device rather than by other differences between the arms.

The safety figures do not resolve the missing efficacy information. They describe counts of participants affected, but the registry does not provide detailed event-level information, arm attribution for the listed serious terms, or a reported comparative safety analysis. The death information is not reported in the registry record and should not be read as zero.

Overall, this record documents a terminated trial with a stated enrollment of 30 and an intended drainage-volume comparison, but it does not contain the outcome analyses needed to answer the primary question. It cannot support a claim that either device increased or reduced drainage, or that the groups were equivalent. The record’s limits are about what it reports; they do not determine what may have been observed in unposted study data.

14. Why This Trial Matters Statistically

This study illustrates why a registered endpoint and a reported result are different things. The record defines a clinically interpretable continuous measure—total fluid collected in wound drains—and identifies its unit and measurement window. Yet without the group summaries and a comparison estimate, the endpoint definition alone cannot answer whether the groups differed. A precise measurement plan is useful, but it does not substitute for published or posted outcome data.

The record also highlights the importance of transparent design details. The official title calls the study randomized, while the registry does not state the allocation method and flags the comparison as not randomized and not like-for-like. That inconsistency matters statistically because the interpretation of a group contrast depends in part on how groups were formed. A reader needs a clear account of allocation and comparability before attributing differences to an intervention.

Terminated status and a stated enrollment of 30 are relevant context, but neither tells the reader whether the planned analysis was completed or why the study ended. The registry reports no analyses. A status label cannot stand in for an explanation of missing results, and enrollment cannot be used to infer the precision of an unreported effect.

Finally, the record shows why endpoint and safety data need separate interpretation. The primary drainage outcome is not reported as an analysis, while adverse-event counts are posted with limited detail. Counts alone do not yield a complete comparative safety assessment, just as a defined endpoint does not yield an efficacy estimate. The statistical lesson is to distinguish the question a study set out to answer from the evidence the registry actually reports.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The most consequential limitation for interpretation is the absence of reported primary and secondary outcome analyses. The registry record gives no arm-specific drainage volumes, standard deviations, estimated contrasts, confidence intervals, or inferential results. Consequently, neither the size nor the precision of a group difference can be assessed. No result should be inferred from the fact that analyses are not listed.

The design description is also incomplete and internally difficult to interpret. The official title describes a randomized, prospective, parallel-group comparison, but the record does not state the allocation method and flags the comparison as not randomized and not like-for-like. Further information about how participants entered each arm or how baseline differences were assessed is not reported in the registry record.

The record names ITT as the primary-outcome population but does not explain its operational definition, identify the number analyzed, or describe missing-data handling. Details about eligibility, outcome collection procedures beyond the drain interval, measurement reliability, masking, and the analysis plan are not reported in the registry record. The reason for termination is also not reported, so its relationship to recruitment, follow-up, and analysis cannot be assessed.

The posted safety information is limited to participant counts and a short list of serious-event terms. It does not provide detailed event descriptions or attribute the listed terms to an arm. Death information is not reported in the registry record. These limitations prevent a full comparison of safety outcomes. Finally, the planning illustrations described in the record are not a substitute for the trial’s design justification or its observed results; the protocol’s sample-size rationale is not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Harmonic Versus Electro Surgery in Lower Body Lift Procedures — NCT00522171.
• Registry record last updated 2009-12-09; status last verified 2009-11.
• Results first posted 2009-11-20.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

The registry record describes a study of Harmonic™ ultrasonic technology versus Electro Surgery in lower body lift procedures. The official title calls it randomized, prospective, and parallel group, but the record does not state allocation and flags the comparison as not randomized and not like-for-like. Enrollment is listed as 30; status is terminated. The study start is 2007-09, and primary completion is listed as 2009-02.

The primary endpoint is total serous drainage volume in milliliters from drain placement to removal, with a maximum stated timeframe of <= 770 hours. Total hours from placement to removal is listed as a secondary outcome. The record names ITT as the primary-outcome population but reports no analyses or outcome estimates. Safety counts are posted, but event detail is limited and death information is not reported in the registry record. The termination reason, statistical analysis plan, missing-data handling, and sample-size justification are not reported in the registry record.