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 Disposable Energy Sources and Operating Room Time for Laparoscopic Hysterectomy (NCT02065453), a randomized na study. The primary outcome is The Primary Endpoint of This Study is Time Difference Between Cauterizing One Side of the Uterine Attachments, From the Round Ligament to the Uterine Artery on One Side, to the Time Detaching the Same Tissues on the Other Side.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02065453 |
| Phase | NA |
| Condition | Benign Uterine Disease |
| Allocation | Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 52 |
| Arms in the primary outcome | 2 |
| Lead sponsor | St. Louis University |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns people undergoing laparoscopic hysterectomy for benign uterine disease. The registry reports enrollment of 52, while the outcome entries list 45 observations for each device group. The record does not explain the difference between the enrollment figure and the reported outcome counts.
Intervention
The intervention was the disposable Ligasure device from Covidien, used to transect one side of the uterine attachments. The stated rationale was that a disposable energy source might control bleeding with little surrounding-tissue damage and potentially save operating-room time. Those statements describe the investigators’ rationale, not findings established by the posted outcome.
Comparator
The comparator was reusable energy equipment: a Robi bipolar instrument and Storz laparoscopic shears. The arm descriptions assign the disposable device to one side and reusable devices to the other, with the device sides reversed in the other description. The registry labels allocation randomized and masking none.
Primary question
The primary endpoint concerns time associated with cauterizing and detaching uterine attachments on the two sides. The posted medians are 8.4 minutes for the disposable device and 14.6 minutes for the reusable devices. A Wilcoxon (Mann-Whitney) analysis is reported with p < 0.001. This is evidence of a difference under that test, but the record does not provide a confidence interval for the contrast or enough detail to determine precisely how the within-operation side comparison was handled.
3. Trial Design
The registry describes a randomized study with no masking and a single-group model. It lists 52 participants as enrolled and identifies benign uterine disease as the condition. The status is completed. The record gives a start date of 2012-01 and a primary completion date of 2014-01. The phase is listed as not applicable.
The intervention descriptions indicate that each operation involved uterine attachments transected using disposable equipment on one side and reusable equipment on the other. A second description reverses which side received each device. That setup suggests a comparison within the surgical procedure, but the registry's model label is single group. It does not explain how the randomization was implemented, whether side order was randomized, or whether the analysis treated the measurements as paired within each participant.
The outcome entries list 45 observations for the disposable device and 45 for reusable devices. The registry does not explain why those counts differ from the enrollment figure or whether all enrolled participants contributed outcome data. It also does not report the number excluded from the analysis or reasons for any exclusions.
The study compares two device strategies for a defined surgical task. The stated timeframe for the primary outcome begins with the first incision and ends with skin closure, while the outcome description refers to uterine vessel desiccation and electrosurgical cutting time. The registry does not further reconcile those descriptions. The analysis listed for the outcome is a Wilcoxon (Mann-Whitney) test. No detailed statistical analysis plan is 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
| Stage | Disposable Device - Left & Reusable Devices - Right | Disposable Device - Right & Reusable Devices - Left |
|---|---|---|
| STARTED | 27 | 25 |
| COMPLETED | 24 | 21 |
| NOT COMPLETED | 3 | 4 |
Analysis population for the primary outcome, as defined in the registry: Uterine Vessel Desiccation and Electrosurgical Cutting Time (min)
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 | Disposable Device Left and Resusable Devices Right | Disposable Device Right and Reusable Devices Left | Total |
|---|---|---|---|---|
| Participants analysed | 24 | 21 | 45 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 24 | 21 | 45 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Continuous | years | 39 (24 to 48) | 39 (24 to 48) | 39 (24 to 48) |
| Sex: Female, Male: Female | Participants | 24 | 21 | 45 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | participants | 24 | 21 | 45 |
6. Primary Endpoint
The registry lists the primary outcome as The Primary Endpoint of This Study is Time Difference Between Cauterizing One Side of the Uterine Attachments, From the Round Ligament to the Uterine Artery on One Side, to the Time Detaching the Same Tissues on the Other Side, measured over Primary outcome study data is collected with the first incision and completed with skin closure at the completion of the surgery..
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | minutes |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is described as a time difference associated with cauterizing one side of the uterine attachments, from the round ligament to the uterine artery, and detaching the corresponding tissues on the other side. The outcome is measured in minutes. Its listed population label refers to uterine vessel desiccation and electrosurgical cutting time, and the stated timeframe runs from the first incision through skin closure.
Time is relevant to the study’s stated question because the investigators’ rationale was that disposable equipment might save operating-room time compared with reusable equipment. The record also notes that operating-room time is expensive. This rationale does not establish that the reported endpoint measures total operating-room cost or that a time difference would translate into a particular financial effect.
The endpoint description contains more than one time frame: a side-specific task is described, while the outcome timeframe spans the operation from incision to skin closure. The registry does not clarify how the recorded device-specific times relate to total operating time. Readers should therefore interpret the posted values according to the listed outcome and its stated unit, without treating them as a measure of cost or of all aspects of the procedure.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The reported median time is 8.4 minutes for the disposable device, with a listed full range of 8.4 to 8.7. For the reusable devices, the median is 14.6 minutes, with a listed full range of 12.5 to 16.7. The registry reports a Wilcoxon (Mann-Whitney) test with p < 0.001. These figures show that the posted device-group summaries differ and that the reported test found strong evidence against its null comparison. They do not by themselves establish the size or precision of a population-level contrast.
No confidence interval for the comparison is reported. A p-value does not quantify the magnitude of a difference, nor does it give the probability that a hypothesis is true. Without a confidence interval or a reported estimate of the contrast, the precision of the comparison cannot be assessed directly from the inferential result. The medians and listed ranges describe the observed data, but they do not substitute for an uncertainty interval around the difference between devices.
The registry reports 45 observations for each device group. The arm descriptions indicate that each participant could have contributed a device-specific measurement from each side of an operation. If observations are paired or otherwise linked within a procedure, the analysis needs to account for that structure to represent uncertainty appropriately. The reported method is Wilcoxon (Mann-Whitney), a rank-based test commonly used to compare two groups; the registry does not state whether the analysis accounted for a within-participant pairing.
The result concerns the recorded time outcome under the study’s device comparison. It does not directly establish an effect on total operating-room time, costs, bleeding, surrounding tissue, recovery, or other outcomes. The investigators’ summary describes potential reasons to consider disposable equipment, but the posted primary result is a time comparison, not a finding about those other endpoints.
The record lists 52 enrolled participants and outcome counts of 45 for each device. It does not explain the difference, describe missing outcome data, or define the analysis population. That limits assessment of how representative the analyzed observations are of all enrolled participants. The posted p-value should therefore be read alongside the missing information on analysis structure, endpoint definitions, and participant flow.
9. Statistical Methods Explained
The primary analysis reported by the registry is a Wilcoxon (Mann-Whitney) test. This is a rank-based method for comparing observations from two groups. Rather than requiring normally distributed measurements, it uses the ordering of the observed values. In general, rank-based methods can be useful when data are skewed or when a comparison is not well represented by a normal-model analysis. They do not automatically answer every possible question about group medians: interpretation depends on the distributions and on how the measurements were collected.
What does the reported p-value say?
The reported p-value is p < 0.001. In general, a p-value describes how incompatible the observed data are with a specified null model, assuming that model and the analysis assumptions are appropriate. A small p-value is not the probability that the null hypothesis is true, and it is not a measure of clinical importance. It also does not give the estimated difference or the precision of that estimate. Here, no confidence interval for the device comparison is reported, so the p-value cannot stand in for a range of plausible effect sizes.
Why does the comparison structure matter?
The arm descriptions state that one side of the uterine attachments used the disposable device and the other side used reusable instruments, with the device-side assignment reversed in the alternate description. If each procedure contributes a measurement for both devices, those two observations may be linked because they come from the same participant and operation. In general, paired data call for an analysis that preserves the within-participant relationship. Treating linked measurements as independent can misrepresent uncertainty. The registry labels the model single group and reports a Mann-Whitney test, but does not explain whether pairing, side order, or any other within-procedure structure was accounted for. The record does not report enough detail to resolve that question.
What do the medians and ranges describe?
The registry identifies the outcome parameter as a median and the dispersion as a full range. The posted median is 8.4 minutes for the disposable device and 14.6 minutes for the reusable devices. The listed ranges are 8.4 to 8.7 and 12.5 to 16.7, respectively. A median is the central value when observations are ordered; a full range describes the lowest and highest recorded values. In general, summaries of each group do not directly provide an estimate or confidence interval for the contrast between groups. They also do not reveal the shape of the full distributions.
What information would help assess precision?
In general, a confidence interval for a contrast communicates both the estimated direction and the uncertainty around its magnitude, under the assumptions of the chosen method. The registry does not report such an interval for the primary comparison. It also does not state whether the test was one-sided or two-sided, how ties were handled, or whether there was any adjustment for paired observations. Those details are not reported in the registry record. Without them, readers can describe the result of the reported test but cannot independently evaluate all of its assumptions.
How should planning estimates be read?
General sample-size planning uses assumptions about the effect to detect, the allocation, the significance level, and the statistical model. A planning illustration is conditional on those assumptions; it is not a measure of the power actually achieved in a completed study. The record does not report the trial’s own sample-size justification. It also does not report interim analyses or a detailed statistical plan. Any planning illustration associated with the result should therefore be treated as a hypothetical planning calculation, not as observed power or as evidence that the trial was designed around the posted outcome.
The record identifies one outcome measure and one analysis. That is useful context, but it does not establish that the analysis was prespecified, that no other analyses were conducted, or that all outcomes collected were reported. Such details are not reported in the registry record. General interpretation of a statistical test depends not only on the formula used but also on the study design, the analysis population, missing data, and the extent to which the reported method matches the way observations were generated.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| Wilcoxon (Mann-Whitney) | not reported | < 0.001 |
The registry’s reported analysis is a Wilcoxon (Mann-Whitney) test with p < 0.001. It does not report a confidence interval or an inferential estimate for the device contrast. The posted outcome summaries give medians and ranges by device, but a recalculated two-group comparison is listed as missing or not estimable. Consequently, there is no recalculated contrast or confidence interval to set alongside the sponsor-reported test result.
The registry does not mark a discrepancy between the sponsor analysis and a recalculation. The sponsor’s reported test is therefore the available inferential result, but its scope remains limited to the comparison and analysis described in the record. The reported method does not reveal whether the within-operation relationship between the two device measurements was modeled. Nor does the p-value give the size or precision of the difference.
The group summaries are descriptive: the disposable median is 8.4 minutes and the reusable median is 14.6 minutes. The test result adds evidence of a difference under the stated analysis, but does not answer questions about total operating time, costs, or other outcomes. Further information about the analysis population and handling of paired measurements is not reported in the registry record.
11. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure and one analysis, and it reports no secondary outcomes. This identifies what is posted in the record, but does not establish that only one outcome or analysis was planned or conducted. The statistical analysis plan and any prespecified hierarchy of outcomes are not reported in the registry record.
Multiplicity arises when several outcomes, time points, subgroups, or analytic choices are examined. In general, repeated testing can increase the chance of obtaining a nominally small p-value even when no real effect exists. Whether any adjustment was appropriate depends on what was planned and tested. The available record does not describe additional analyses or a multiplicity strategy, so the impact of any such analyses cannot be assessed.
Missing-data handling is also not reported. The record lists enrollment of 52 and outcome counts of 45 for each device. It does not explain why those counts differ, whether outcome data were unavailable for some participants, or how any missing observations were treated. It does not identify an intention-to-treat population, a per-protocol population, or another analysis population. The registry record therefore does not make clear which participants contributed to the primary test or how the analysis population was defined.
The side-specific device descriptions suggest that measurements could be paired within an operation, yet the analysis is described as Wilcoxon (Mann-Whitney). The record does not say whether the pairing was considered or whether any participants contributed only one device measurement. These issues matter because assumptions about independence and missing paired measurements affect how uncertainty is estimated. No detailed statistical analysis plan, interim analysis information, or sample-size justification is reported in the registry record.
12. 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 |
|---|---|---|---|
| Disposable or Reusable Energy Sources | 0 | 45 | 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 |
|---|---|
| Disposable or Reusable Energy Sources | 0 of 45 |
The adverse-event entry combines the groups under the label “Disposable or Reusable Energy Sources.” For serious adverse events, 45 were listed as at risk and zero as affected. For other adverse events, 45 were listed as at risk and zero as affected. The deaths field is not populated, so deaths are not reported in the registry record.
These figures describe the posted event counts for the combined device category. They do not provide separate counts for disposable and reusable equipment, and they do not show whether participants were followed for different periods or whether all events were collected in the same way. The registry also lists no serious adverse-event terms. A zero count in the posted entry means no events of that category were recorded in that entry; it does not establish that the risk is absent.
The at-risk count in the adverse-event entry is 45, while the study enrollment is 52 and each device outcome count is 45. The record does not explain the relationship between those figures. Safety interpretation is therefore limited to the event counts and group label actually reported, without inferring a device-specific comparison or a broader safety conclusion.
13. What the Result Does, and Does Not, Mean
The posted results describe a shorter median time for the disposable device group than for the reusable devices in the recorded endpoint: 8.4 minutes compared with 14.6 minutes. The reported Wilcoxon (Mann-Whitney) test gives p < 0.001. The ranges listed in the record are 8.4 to 8.7 for the disposable device and 12.5 to 16.7 for reusable devices. These are the observed summaries in this record, not guarantees about results in other settings.
The result does not by itself establish how large or precise the underlying difference is. No confidence interval for the contrast is reported, and the reported analysis does not provide an estimate with uncertainty. The p-value is evidence against the null comparison under the test’s assumptions; it is not a measure of practical importance and does not establish that the null is false with certainty.
The endpoint should not be equated with total operating-room time without further information. Although the registry’s rationale discusses potential time savings and operating-room expense, the primary outcome description focuses on uterine-attachment and electrosurgical cutting time, while its timeframe is stated as the operation from first incision to skin closure. The record does not clarify this relationship or report a cost analysis.
The findings also do not establish an effect on bleeding, tissue injury, recovery, or other outcomes. The summary describes those as possible considerations, but the posted outcome does not measure them. The adverse-event entry reports zero serious and zero other events in its combined device category, but does not give separate device-specific counts; the deaths field is not reported.
Finally, the study’s randomized label does not resolve the analytical questions created by the side-by-side device descriptions. The record does not say whether within-participant pairing was included in the analysis, explain the outcome counts, or describe missing-data handling. These limitations qualify the interpretation of the test and its relevance beyond the observations recorded.
14. Why This Trial Matters Statistically
This trial raises a useful statistical issue in surgical-device comparisons: a device may be assigned to one side of a procedure while another device is used on the other side. Such a design can produce closely linked measurements from the same operation. In general, recognizing that structure is essential because methods for independent groups and methods for paired measurements answer related but distinct questions and can yield different uncertainty estimates.
The record makes that issue visible through its descriptions of disposable and reusable devices on opposite sides, alongside a single-group model label and a Wilcoxon (Mann-Whitney) analysis. It does not explain whether the analysis preserved the within-operation relationship. That gap illustrates why reporting the design and analysis connection is important, even when the group summaries and a p-value are available.
The endpoint also highlights the importance of precise outcome definitions. A side-specific transection time and an operation-wide interval from incision to skin closure are not necessarily interchangeable measures. The registry’s rationale discusses operating-room time, whereas its outcome description refers to uterine vessel desiccation and electrosurgical cutting time. Clear alignment between the scientific question, recorded measurement, and analysis helps readers understand what a result can support.
Finally, the record illustrates why a p-value alone is an incomplete account of a comparison. The medians and ranges describe the observed groups, while the reported test assesses evidence under a statistical model. Without an effect estimate and confidence interval, the precision of the contrast remains unclear. That distinction is central to interpreting clinical research responsibly: statistical evidence, effect magnitude, and practical relevance are separate considerations.
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 registry does not explain the difference between enrollment of 52 and the outcome entries of 45 observations for each device. It does not report participant flow, reasons for unavailable outcomes, exclusions, or the analysis population. The influence of missing or excluded data therefore cannot be assessed from the record.
The arm descriptions indicate that the devices were used on different sides during an operation, but the registry does not describe the randomization procedure, side assignment, or order of device use. It also does not clarify whether the statistical analysis accounted for paired measurements within each participant. The reported Wilcoxon (Mann-Whitney) method may be read as a two-group comparison, but the record does not document how the method was applied to the apparent within-operation design.
The primary endpoint description refers to time between steps on different sides, the outcome label refers to uterine vessel desiccation and electrosurgical cutting time, and the timeframe runs from first incision to skin closure. The registry does not reconcile these descriptions. This makes it difficult to determine precisely which elapsed time is represented by the reported device-specific values.
No confidence interval for the comparison is reported, and the recalculated two-group comparison is listed as missing or not estimable. The test result therefore lacks a reported interval estimate that would communicate precision. The registry does not report the sample-size justification, a detailed statistical analysis plan, interim analyses, or a multiplicity strategy. Those omissions limit assessment of prespecification and the broader analysis process.
Safety reporting is also limited: the adverse-event entry combines disposable and reusable energy sources, and the deaths field is unreported. Separate device-specific event counts are not available. The record does not provide results for other outcomes such as cost, bleeding, tissue injury, or recovery, so the primary time comparison cannot answer those questions.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Disposable Energy Sources and Operating Room Time for Laparoscopic Hysterectomy — NCT02065453.
- Registry record last updated 2017-06-14; status last verified 2017-05.
- Results first posted 2017-06-14.
- 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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19. Record Summary
NCT02065453 is a completed randomized study of disposable Ligasure and reusable energy instruments during laparoscopic hysterectomy for benign uterine disease. The registry lists no masking, a single-group model, and enrollment of 52. The outcome entries list 45 observations for each device.
The primary outcome is a time measure in minutes related to uterine-attachment cauterization and detachment. The reported medians are 8.4 for disposable equipment and 14.6 for reusable equipment, with listed ranges of 8.4 to 8.7 and 12.5 to 16.7. The reported Wilcoxon (Mann-Whitney) test has p < 0.001.
No confidence interval for the comparison is reported. The registry does not explain the outcome counts, missing-data handling, or whether the analysis accounted for measurements from both sides of the same procedure. The adverse-event entry reports zero serious and zero other events in a combined device group, while the deaths field is unreported.