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 Comparison of LigaSure to Conventional Electrocoagulation in Video-assisted Thoracoscopic Surgery Lobectomy (NCT03125798), a randomized na study. The primary outcome is Postoperative Chest Drainage Volume up to Chest Drain Removal, Average 3 Days..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03125798 |
| Phase | NA |
| Condition | Lung Cancer, Complication of Surgical Procedure |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 216 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Wielkopolskie Centrum Pulmonologii i Torakochirurgii |
| Results posted | Yes |
2. Clinical Question
Population
People undergoing video-assisted thoracoscopic surgery (VATS) lobectomy followed by systemic mediastinal lymphadenectomy for lung cancer. The registry record lists lung cancer and complication of surgical procedure among the conditions. It does not give further eligibility details or a description of the characteristics of participants in the outcome groups.
Intervention
LigaSure™ was used for mediastinal lymph node dissection according to standard surgical technique. The study focused on clinical and technical aspects of lymph node dissection during VATS lobectomy.
Comparator
Conventional monopolar electrocautery was used for mediastinal lymph node dissection according to standard surgical technique. The registry describes the study as randomized, with parallel groups and no masking.
Primary question
What postoperative chest drainage volume was recorded in each group up to chest drain removal? The primary endpoint is the median volume in milliliters, with an interquartile range. This measures drainage accumulated over the postoperative period until the drain was removed; the registry describes the average time to removal as 3 days.
3. Trial Design
The registry describes a prospective randomized controlled study with a parallel-group design. Participants were assigned to a LigaSure group or a monopolar electrocautery group for mediastinal lymph node dissection during VATS lobectomy. Masking is recorded as none, so the study was open-label. The registry reports enrollment of 216 and lists the study as completed.
The primary endpoint was postoperative chest drainage volume up to chest drain removal. The registry gives the outcome as a median in milliliters and reports an interquartile range. The outcome groups each have a recorded count of 100. For LigaSure, the median was 550 ml, with an interquartile range from 335.0 to 905.0 ml. For monopolar electrocautery, the median was 580.0 ml, with an interquartile range from 352.0 to 950.0 ml.
The outcome-group counts do not match the enrollment figure, and the registry record does not explain the difference or give a participant flow account. The method used to generate the random allocation sequence, concealment of assignment, eligibility criteria, and detailed baseline characteristics are not reported in the registry record. The record also does not describe a protocol for handling deviations from assigned treatment.
Two secondary outcomes are listed: acute phase proteins levels and local temperature. Detailed results for these outcomes are not included in the posted results described by the registry record. The trial dates are recorded as starting on 2018-05-03, with primary completion on 2021-11-04. The sponsor is Wielkopolskie Centrum Pulmonologii i Torakochirurgii.
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 | LigaSure | Monopolar Electrocautery |
|---|---|---|
| STARTED | 109 | 107 |
| COMPLETED | 100 | 100 |
| NOT COMPLETED | 9 | 7 |
Reasons for not completing this period:
| Reason | LigaSure | Monopolar Electrocautery |
|---|---|---|
| Lack of electrosurgical device in the operating room | 2 | 0 |
| Conversion to thoracotomy | 7 | 7 |
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 | LigaSure | Monopolar Electrocautery | Total |
|---|---|---|---|---|
| Participants analysed | 100 | 100 | 200 | |
| Age, Continuous | years | 65.9 (SD 7.4) | 66.4 (SD 7.3) | 66.2 (SD 7.3) |
| Sex: Female, Male: Female | Participants | 42 | 42 | 84 |
| Sex: Female, Male: Male | Participants | 58 | 58 | 116 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 100 | 100 | 200 |
| 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: Poland | participants | 100 | 100 | 200 |
6. Primary Endpoint
The registry lists the primary outcome as Postoperative Chest Drainage Volume up to Chest Drain Removal, Average 3 Days., measured over Total postoperative chest drainage volume.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | ml |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the volume of postoperative fluid collected in the chest drain, measured in milliliters from the postoperative period up to drain removal. The registry describes the average time to removal as 3 days. This is a cumulative measure over that period rather than a single measurement at one specified moment.
Chest drainage volume is a clinical and procedural measure of fluid collected after surgery. In this study, it was used to compare drainage between the two lymph node dissection techniques. The registry reports a median and an interquartile range for each group, rather than a mean and standard deviation. The median identifies the middle of the observed values when ordered; the interquartile range describes the middle half of those values. These summaries are useful when distributions are skewed or include observations far from the center, because the median is less affected by extreme values than the mean.
The reported median was 550 ml for LigaSure and 580.0 ml for monopolar electrocautery. The interquartile range was 335.0 to 905.0 ml for LigaSure and 352.0 to 950.0 ml for monopolar electrocautery. These summaries describe the observed outcome groups. The registry record does not report a confidence interval, a test of the between-group difference, or a clinical threshold for interpreting the size of a difference. It also does not specify whether drain-removal decisions followed a standardized rule.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted results describe the primary endpoint as a median and interquartile range in each treatment group. The LigaSure group had a median postoperative drainage volume of 550 ml, with an interquartile range from 335.0 to 905.0 ml. The monopolar electrocautery group had a median of 580.0 ml, with an interquartile range from 352.0 to 950.0 ml. These figures convey the central outcome and the spread of the middle half of the observations in each group.
The two interquartile ranges overlap substantially. That observation is descriptive; it is not a formal test and does not establish whether the groups differ statistically. Nor does overlap or non-overlap of interquartile ranges, by itself, determine the result of a hypothesis test. The registry record does not report an inferential analysis for this endpoint, such as a confidence interval or p-value. It therefore does not establish the precision of an estimated between-group effect or quantify uncertainty around that effect.
The outcome-group counts are 100 in each group. The registry reports enrollment of 216, but does not explain how enrollment relates to the participants included in these outcome summaries. It does not report reasons for exclusions, missing endpoint values, or whether the reported groups include all randomized participants. This limits interpretation of how representative the summaries are of the full randomized population.
The primary endpoint is a volume accumulated until drain removal, and the registry describes the average time to removal as 3 days. Because the observation period ends at a clinical event, interpretation depends on how and when drains were removed. Criteria for removal, variation in observation duration, and any adjustment for such differences are not reported in the registry record. The reported endpoint should therefore be read as the registry-defined drainage outcome, not as a standardized measurement over an identical duration for every participant.
The registry identifies randomization, which is a design feature intended to support fair comparisons between groups. However, details of the allocation process and an analysis plan are not reported. The record does not provide a statistical estimate adjusted for other factors or identify an analysis population. The posted medians and interquartile ranges can be described directly, but they do not alone support a claim about causation, statistical significance, or clinical importance.
The safety record reports no serious adverse events in either group and lists other adverse events for 24 of 100 at risk in the LigaSure group and 22 of 100 at risk in the monopolar electrocautery group. No deaths are recorded in either group. These safety counts are descriptive and should be interpreted separately from the drainage endpoint. The registry does not provide detailed event terms for serious events or a statistical comparison of adverse-event rates.
9. Statistical Methods Explained
The primary outcome is summarized by medians and interquartile ranges. These statistics describe observed distributions rather than the precision of a treatment effect estimate. A median is the central observation in an ordered set of values. The interquartile range spans the middle half of the observations, from the lower quartile to the upper quartile. In this record, the reported intervals are 335.0 to 905.0 ml for LigaSure and 352.0 to 950.0 ml for monopolar electrocautery. An interquartile range is not a confidence interval: it describes variability among observed outcomes, whereas a confidence interval describes uncertainty around an estimated quantity.
What can the medians tell us?
The medians are 550 ml for LigaSure and 580.0 ml for monopolar electrocautery. They identify the centers of the reported group distributions. A median does not show every participant’s outcome, and it does not reveal the shape of the full distribution. Different distributions can have similar medians but differ in their tails, clustering, or spread. The interquartile ranges add information about the central spread, but they do not describe all observations. The registry does not report a full distribution or an inferential comparison, so the summaries should not be treated as a complete account of the outcome.
Why is the analysis method important?
Outcome values may be asymmetric or influenced by unusually high observations. In general, a median can be a suitable descriptive measure in such circumstances. A statistical comparison must still account for the question being asked and the properties of the observed data. For example, a model based on means and a method based on ranks answer different statistical questions and rely on different assumptions. The statistical method selected for this endpoint, any transformations, and checks of model assumptions are not reported in the registry record.
General statistical interpretation also distinguishes an estimate from its uncertainty. A confidence interval is a range of values compatible with the data under a specified method and gives information about the precision of an estimate. A p-value, when used, measures how unusual data at least as extreme as those observed would be under a specified null model and its assumptions. Neither quantity is reported for the primary outcome in the registry record. Without an effect estimate and an uncertainty measure or test result, the posted summaries do not support a conclusion about statistical significance or the precision of a between-group effect.
What does randomization contribute?
In general, random allocation is intended to make treatment groups comparable on average with respect to both measured and unmeasured characteristics. This supports causal interpretation when allocation is properly implemented and participants are analyzed in a way that preserves the randomized comparison. The registry identifies the study as randomized, but the sequence-generation and concealment procedures are not reported. It also does not state whether the primary analysis followed intention-to-treat principles, used a per-protocol population, or followed another approach. The analysis population therefore cannot be determined from the registry record.
The registry outcome groups each include 100 participants, while enrollment is reported as 216. The record does not explain the relationship between these counts. Without a flow description and information about missing outcome values, it is not possible to assess from the registry whether participants were excluded after randomization, whether endpoint data were unavailable, or how those situations were handled. These details matter because exclusions or missing measurements can compromise the comparability created by randomization.
How should planning calculations be read?
In general, a sample-size calculation is a prospective planning tool. It depends on the target effect, variability assumptions, significance level, allocation, and analysis method. A planning illustration based on an observed effect is not evidence of the trial’s original design rationale and is not observed power. The registry record does not report the trial’s own sample-size justification or a prespecified statistical plan. Any planning illustrations should therefore be understood as illustrative calculations under stated assumptions, not as a retrospective measure of whether the trial was adequately powered.
For this study, the registry record does not report an inferential analysis of the primary endpoint, an adjusted model, a confidence interval, or a p-value. It also does not report interim analyses or how multiplicity was handled. Statistical methods beyond the descriptive summaries cannot be reconstructed from the posted outcome figures alone. General statistical principles can clarify what the summaries mean, but they cannot substitute for unreported analysis decisions.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists two secondary outcomes: acute phase proteins levels and local temperature. It does not include detailed results for these outcomes in the posted results. The record lists three outcome measures in total, but does not report a multiplicity strategy for testing the primary and secondary outcomes. When several outcomes or statistical tests are considered, the chance of at least one apparently notable result can increase; general approaches to address this include prespecifying a primary outcome or adjusting inference across tests. The record does not state whether or how any such approach was used.
Missing-data procedures are not reported in the registry record. The primary outcome counts are 100 in each group, while registry enrollment is 216. The record does not explain the participant flow from enrollment to the outcome summaries, report missing endpoint values, or describe any imputation or sensitivity analysis. It is therefore not possible to determine whether the outcome summaries include every randomized participant or how unavailable measurements were handled.
The analysis population is also not reported. The record does not identify an intention-to-treat, per-protocol, or other population for the primary comparison. It gives no details about adherence, crossovers, exclusions, or deviations from assigned intervention. These omissions make it difficult to assess whether the analysis, if conducted, retained the benefits of randomization.
No statistical analyses are recorded. The registry does not report a prespecified analysis plan, adjustment for covariates, interim analyses, or inferential results for the primary endpoint. Consequently, the reported group summaries should be treated as descriptive rather than as a complete account of the planned or conducted statistical analysis.
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 |
|---|---|---|---|
| LigaSure | 0 | 100 | 0.0% |
| Monopolar Electrocautery | 0 | 100 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| LigaSure | 0 of 100 |
| Monopolar Electrocautery | 0 of 100 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| LigaSure | 24 of 100 |
| Monopolar Electrocautery | 22 of 100 |
Most frequent non-serious adverse event terms
| Event term | Organ system | LigaSure | Monopolar Electrocautery |
|---|---|---|---|
| Prolonged air leak | Surgical and medical procedures | 10 of 100 | 12 of 100 |
| Residual air space | Surgical and medical procedures | 8 of 100 | 7 of 100 |
| Atrial fibrillation | Surgical and medical procedures | 6 of 100 | 3 of 100 |
The registry reports serious adverse events for each group using the number at risk and the number affected. In the LigaSure group, 0 of 100 at risk were affected by a serious adverse event. In the monopolar electrocautery group, 0 of 100 at risk were affected by a serious adverse event. The record lists no serious adverse-event terms. It also reports 24 of 100 at risk affected by other adverse events in the LigaSure group and 22 of 100 at risk in the monopolar electrocautery group. Deaths are recorded as 0 in each group.
These figures are counts from the registry record and are descriptive. The record does not provide event-level details for the other adverse events, a definition of how events were grouped, or a statistical comparison between groups. A count of affected participants is not necessarily the same as a count of all events if a participant could experience more than one event; the record does not clarify that distinction. Zero reported serious events or deaths should be read as the registry’s recorded figures, not as proof that such events are impossible or that the groups have identical safety profiles. The record does not report follow-up duration for safety outcomes.
12. What the Result Does, and Does Not, Mean
The posted primary outcome provides a descriptive comparison of postoperative chest drainage volume up to chest drain removal. The LigaSure group’s median was 550 ml and the monopolar electrocautery group’s median was 580.0 ml. Their interquartile ranges were 335.0 to 905.0 ml and 352.0 to 950.0 ml, respectively. These values show the central summaries and spread of the middle half of the recorded outcomes in each group.
Those figures do not, on their own, establish whether a difference between groups is statistically significant, precise, or clinically important. The registry record does not report an estimated treatment effect with a confidence interval, a p-value, or a prespecified threshold for meaningful change. The values also do not describe the full distributions or explain how any missing outcomes were handled.
The study is identified as randomized, but randomization alone does not resolve all concerns about bias or interpretation. The allocation procedures and analysis population are not reported, and the registry does not explain why outcome counts differ from enrollment. Because drainage is measured up to drain removal, the removal criteria and variation in measurement duration could also affect the observed volumes; those details are not reported.
The safety record lists no serious adverse events and no deaths in either group, along with other adverse events affecting 24 of 100 participants at risk in the LigaSure group and 22 of 100 at risk in the monopolar electrocautery group. These figures do not constitute a formal safety comparison, and event details are limited. In short, the registry supports a description of the posted outcome summaries, but does not report enough statistical or participant-flow information to establish a definitive comparative effect or its uncertainty.
13. Why This Trial Matters Statistically
This trial addresses a statistical challenge common in procedural research: the outcome is measured during a clinical process that can vary in duration. Postoperative drainage volume is accumulated until chest drain removal, and the registry describes the average time to removal as 3 days. Because the endpoint depends on when observation ends, its interpretation is linked not only to the amount collected but also to drain-removal practice. Clear reporting of measurement rules and removal criteria is important for judging whether outcomes are comparable across participants and groups.
The choice to report medians and interquartile ranges also matters. These summaries describe the center and central spread without assuming a symmetric distribution. They allow readers to inspect the observed group outcomes, but they do not replace an estimate of the between-group effect with an uncertainty interval. Reporting both descriptive summaries and inferential estimates would help distinguish the distribution of observed outcomes from the precision of the comparison.
The registry identifies randomization, which is intended to support a fair comparison. Yet the usefulness of that design depends on transparent reporting of allocation, participant flow, missing data, and analysis populations. Here the outcome groups each have a count of 100, while enrollment is 216, and the registry does not explain the relationship. This gap is relevant to whether the posted summaries represent the randomized groups as a whole.
The record also lists secondary outcomes and safety data but does not provide a multiplicity approach or detailed statistical analysis. That makes it harder to understand how different outcomes were prioritized and how uncertainty was handled. These reporting issues are statistically important even when group summaries appear straightforward: they determine what conclusions the data can support and how reproducible the analysis is.
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 several trial-specific details unresolved. It reports enrollment of 216, while the primary outcome groups each have a count of 100, but does not describe participant flow or explain this difference. Reasons for exclusions, withdrawals, and missing outcome measurements are not reported. Without those details, the completeness of the primary outcome data and the relationship between randomization and analysis cannot be assessed.
Allocation is described as randomized, but the sequence-generation method and concealment of assignment are not reported. Masking is recorded as none. The record does not describe whether outcome measurement or drain-removal decisions were standardized, nor whether the people assessing drainage were aware of treatment assignment. Because the endpoint accumulates until drain removal, unreported removal criteria and measurement duration are particularly relevant to interpretation.
The outcome record gives medians and interquartile ranges but no inferential comparison, confidence interval, p-value, or adjusted analysis. The statistical plan, sample-size justification, analysis population, and handling of deviations from assigned treatment are not reported in the registry record. The two listed secondary outcomes do not have detailed results in the posted results, and no multiplicity strategy is reported.
Safety reporting is also limited: the record provides affected counts but no detailed terms for serious events and no event-level descriptions for other adverse events. It does not report safety follow-up duration. These limitations restrict interpretation of both the comparative endpoint and the broader clinical record; they do not establish that unreported procedures or analyses were not conducted.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Comparison of LigaSure to Conventional Electrocoagulation in Video-assisted Thoracoscopic Surgery Lobectomy — NCT03125798.
- Registry record last updated 2024-09-03; status last verified 2021-11.
- Results first posted 2024-09-03.
- 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
NCT03125798 is a completed, prospective randomized controlled study comparing LigaSure with conventional monopolar electrocautery for mediastinal lymph node dissection during VATS lobectomy. It used a parallel-group design with no masking. The registry reports enrollment of 216, a study start date of 2018-05-03, and primary completion on 2021-11-04.
The primary outcome was postoperative chest drainage volume up to chest drain removal, reported as a median and interquartile range. The LigaSure group had a median of 550 ml and an interquartile range of 335.0 to 905.0 ml; the monopolar electrocautery group had a median of 580.0 ml and an interquartile range of 352.0 to 950.0 ml. The registry record does not report an inferential comparison or explain the relationship between enrollment and the outcome-group counts.
Acute phase proteins levels and local temperature are listed as secondary outcomes. The record reports no serious adverse events or deaths in either group and lists other adverse events affecting 24 of 100 at risk in the LigaSure group and 22 of 100 at risk in the monopolar electrocautery group. Detailed statistical methods and analysis populations are not reported in the registry record.