"Laparoscopic" Cystoscopy Versus Traditional Cystoscopy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for "Laparoscopic" Cystoscopy Versus Traditional Cystoscopy (NCT01261819), a randomized na study. The primary outcome is Time Required to Perform Procedure (in Seconds).

2. Clinical Question

The study’s stated aim was to compare use of a transurethral laparoscope with traditional cystoscopy for bladder and ureter evaluation at the time of laparoscopic hysterectomy. The brief summary also states a hypothesis that visual inspection could be performed safely with the transurethral laparoscope, in less time, and at lower cost. The registered primary outcome, however, is procedure time. The registry record does not post a primary cost outcome or a formal between-group analysis of safety.

The population is described broadly as patients undergoing minimally invasive hysterectomy. The specific inclusion and exclusion criteria, clinical setting, and baseline characteristics are not reported in the registry record. The randomized comparison enrolled 66 participants, with 33 in each arm. The posted endpoint gives the time required to perform cystoscopy after laparoscopic hysterectomy, rather than a measure of later urinary tract injury or a longer-term patient outcome. The clinical question can therefore be read narrowly: how the recorded procedure times compare between the two assigned cystoscopy approaches in this study.

3. Trial Design

The registry describes a randomized, parallel-group, single-masked study with an enrollment of 66. The two groups were transurethral laparoscope and traditional cystoscopy, each with 33 participants in the posted primary outcome. The study title calls it a prospective comparison study. Its status is completed. The recorded start was 2009-01 and primary completion was 2009-07. The sponsor is AdventHealth, and the registry lists the condition as lower urinary tract injury.

In a parallel-group design, participants are assigned to one of the interventions and remain in that comparison group for the outcome assessment. Random allocation is intended to reduce systematic differences between groups, although it does not guarantee balance in a study of this size. The registry does not report the random sequence method, allocation concealment, or whether assignment was stratified. It records single masking but does not identify who was masked or how masking was maintained. These details are not reported in the registry record, so the label alone does not establish which study personnel or participants were unaware of the assigned device.

The intervention is described as cystoscopy with a transurethral laparoscope. The comparator is cystoscopy with a traditional cystoscope, identified as the gold standard in the arm description. The primary endpoint is a continuous measure of procedure time, expressed in seconds, with an arm-specific mean and 95% confidence interval. The stated timeframe is during the procedure, up to 15 minutes. The registry lists one outcome measure and no secondary outcomes. It does not report a sample-size justification, detailed protocol, or statistical analysis plan. The planning illustration assumptions recorded alongside the results should not be mistaken for the trial’s original design justification.

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

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 Time Required to Perform Procedure (in Seconds), measured over During Procedure (Up to 15 minutes).

The primary endpoint is the time required to perform cystoscopy with either device after laparoscopic hysterectomy. It is recorded in seconds during the procedure, with a timeframe described as up to 15 minutes. Because time is a continuous measurement, the registry reports a mean for each arm and a 95% confidence interval. The mean describes the group’s average recorded procedure time; it does not show the full distribution of individual times or how much times varied between participants.

Procedure time is relevant to the study’s stated comparison because the brief summary hypothesizes that the transurethral laparoscope may take less time than traditional cystoscopy. A time measure can describe the efficiency of the procedure, but it does not by itself measure whether the bladder and ureters were adequately assessed, whether an injury was detected, or whether a patient experienced a later clinical outcome. Nor does it establish cost effectiveness. The registry’s primary endpoint is limited to the time required for cystoscopy.

The posted mean is 137.0 seconds for the transurethral laparoscope arm, with a 95% confidence interval from 21.1 to 249.9. For traditional cystoscopy, the posted mean is 451.0 seconds, with a 95% confidence interval from 204.6 to 697.4. The registry does not post an estimable two-arm comparison for this continuous endpoint. These arm-specific summaries describe the recorded times, but without a reported comparison they do not supply a registry-reported estimate or test of the difference between groups.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous: it records elapsed procedure time in seconds. A mean is a common summary for a continuous measure because it expresses the average observed value in a group. Means can be useful for comparing group summaries, but they do not describe every participant’s time. They can also be affected by unusually short or long observations. The registry does not provide individual observations, a measure of spread such as a standard deviation, or a distribution plot in the registry record for this analysis. It reports a confidence interval for each arm instead.

A 95% confidence interval is an interval estimate that communicates sampling uncertainty around an estimated quantity. In general, a narrower interval indicates greater precision for that estimate, while a wider interval indicates less precision. The intervals posted for this trial are attached to the two arm-specific means, not to a between-arm contrast. A confidence interval is not a range expected to contain 95% of individual participants’ procedure times. Nor should the two arm-specific intervals be treated as a substitute for a confidence interval for the difference between arms.

The registry reports a mean of 137.0 seconds for the transurethral laparoscope and a 95% confidence interval from 21.1 to 249.9. For traditional cystoscopy it reports a mean of 451.0 seconds and a 95% confidence interval from 204.6 to 697.4. The intervals overlap, but overlap or non-overlap between separate arm intervals is not, by itself, a complete test of a treatment contrast. A direct comparative estimate would ordinarily report the contrast on an appropriate scale, its uncertainty, and possibly a test statistic or p-value. Those comparative results are not reported in the registry record; it states that a two-arm comparison for the continuous endpoint is missing or not estimable.

Random allocation is a design feature, not an analysis result. In general, randomization supports a fair comparison by making assignment independent of measured and unmeasured characteristics on average across repeated studies. In an individual study, chance imbalances can still occur. The registry does not report the allocation sequence, concealment procedure, or participant baseline characteristics. It also does not identify who was masked despite recording single masking. These limits mean the design labels do not provide enough detail to evaluate each safeguard or examine baseline comparability.

The registry lists planning assumptions for sample-size illustrations: a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect described as a portion of the observed effect. These are presented as planning illustrations computed from the observed effect, not as the trial’s own design calculation. No numerical planning results or effect portions are included in the recorded details. Such illustrations describe the hypothetical number of participants per arm that might be needed under stated assumptions. They are not observed power, do not show the probability that the trial found a result, and cannot replace a reported analysis of the trial data. The original sample-size justification is not reported in the registry record.

For a continuous outcome, a two-arm comparison might use a model or test to estimate a mean contrast and its standard error. Depending on the analysis plan and data features, the approach could account for covariates or distributional properties. These are general statistical possibilities, not descriptions of what this trial did. The registry does not report a test, model, adjustment set, standard-error method, or confidence-interval construction. It is therefore not appropriate to infer a particular analysis from the arm means and intervals alone.

Over-dispersion is a concern primarily in settings where a statistical model assumes a particular level of variability, such as count outcomes. In general, over-dispersion means observed variability exceeds what the model assumes, which can make standard errors too small and confidence intervals too narrow if ignored. The primary outcome is procedure time, a continuous measure; the record does not report a model or variability estimate that would allow an assessment of this issue. This general concept should not be confused with evidence that over-dispersion occurred in this study.

The posted results give each arm’s participant count and mean, but do not state how missing or unusable procedure times were handled, whether all randomized participants contributed to the endpoint, or which analysis population was used. In general, missing outcome data can affect an estimate if the likelihood of missingness relates to the outcome or assigned group. Methods such as complete-case analysis or imputation require explicit assumptions and reporting. No such method is described in the registry record, so none can be attributed to this trial.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure, the procedure time for cystoscopy, and no secondary outcomes. It lists no analyses. This record therefore does not document a family of multiple outcome tests or a multiplicity adjustment. That is not evidence that no other analyses were conducted; it means they are not reported in the registry record. The registry also does not describe a prespecified hierarchy of outcomes, adjustment for multiple comparisons, or an analysis plan.

The primary outcome has arm-specific means and confidence intervals, but the registry flags the two-arm comparison as missing or not estimable for the continuous endpoint. No comparative p-value or confidence interval for a between-group effect is posted. That leaves the central randomized contrast without a registry-reported inferential result. The arm-level summaries remain descriptive even though the outcome measure is identified as primary.

Missing-data methods and analysis populations are not reported in the registry record. It does not say whether all randomized participants were analyzed in their assigned groups, whether any endpoint times were unavailable, how unavailable times were treated, or whether exclusions occurred after randomization. The posted arm counts are 33 and 33, but the counts do not, by themselves, establish the population used for every analysis or the completeness of outcome data.

For general interpretation, missingness can matter when the chance of an unavailable measurement is related to the assigned intervention or to the unobserved value. Different handling assumptions can change both estimates and their uncertainty. Without participant flow and a stated approach to missing outcomes, the consequences cannot be assessed for this trial. The registry record also does not report interim analyses, stopping rules, or monitoring procedures; these should not be inferred from the completed status.

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 3% reporting threshold.

Most frequent non-serious adverse event terms

The posted safety figures list 33 participants at risk in each arm. Serious adverse events affected zero participants in the transurethral laparoscope group and zero in the traditional cystoscopy group. Other adverse events affected one participant in the transurethral laparoscope group and six in the traditional cystoscopy group. Deaths are listed as zero in each group. The registry provides no serious adverse-event terms.

These are descriptive counts, not a formal comparison of safety. The record does not post a statistical test, comparative estimate, or confidence interval for adverse events. A count of zero serious adverse events in both groups means none were recorded in these groups in the posted results; it does not establish that serious events cannot occur. The other-event counts likewise do not establish that assignment caused a difference. The definitions, collection procedures, severity details for other events, and follow-up period for these safety figures are not reported in the registry record.

The safety counts should also be kept distinct from the primary endpoint. Procedure time does not measure adverse events, and the adverse-event counts do not answer whether cystoscopy identified urinary tract injuries. The record’s stated study hypothesis mentions safe visual inspection, but the limited safety summaries cannot resolve that broader question. They describe only the figures posted for this comparison.

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

The results describe a randomized, parallel comparison of two cystoscopy approaches among patients undergoing minimally invasive hysterectomy. The transurethral laparoscope arm has a posted mean procedure time of 137.0 seconds, with a 95% confidence interval from 21.1 to 249.9. The traditional cystoscopy arm has a mean of 451.0 seconds, with a 95% confidence interval from 204.6 to 697.4. These are arm-specific summaries of the time required for cystoscopy during the procedure.

The registry does not provide an estimable two-arm comparison for this continuous outcome. Thus the posted information does not include a direct estimate of the between-group effect or its uncertainty. The difference in the displayed means should not be described as a registry-reported treatment effect, and the summaries do not establish statistical significance. The confidence intervals for the individual means do not answer the same question as a confidence interval for a contrast.

The figures also do not establish that either method is more accurate in evaluating the bladder or ureters. No diagnostic accuracy outcome, injury detection result, or later urinary tract outcome is listed among the posted measures. Cost effectiveness is part of the study’s stated hypothesis, but a cost endpoint or economic comparison is not reported. The safety figures are limited to the adverse-event counts and do not provide a formal comparative safety analysis.

In general, trial design and outcome reporting determine which claims the data can support. Randomization describes how treatment assignment was intended to occur; it cannot compensate for the absence of a reported primary comparative analysis. The record does not provide enough information to judge missing data, analysis populations, baseline balance, or analytic adjustments. These are boundaries on interpretation rather than evidence for or against either approach.

The narrow conclusion supported by the posted results is that the registry records arm-specific procedure-time means and confidence intervals, alongside limited adverse-event counts, in a completed randomized comparison. It does not report a direct statistical comparison for the primary continuous outcome. The time summaries can be described as observed group summaries, but conclusions about comparative effectiveness, detection performance, cost, or safety go beyond what this record establishes.

13. Why This Trial Matters Statistically

This trial illustrates a key distinction in clinical statistics: reporting an outcome for each group is not the same as reporting the randomized comparison. A reader can see an arm-specific mean and confidence interval for each approach, but the record does not report an estimable two-arm analysis of procedure time. The comparison is the central question in a randomized study, so the absence of a contrast and its uncertainty limits interpretation even when group summaries are available.

It also shows why the endpoint’s scope matters. Procedure time addresses how long the cystoscopy took. It does not directly assess the accuracy of bladder or ureter inspection, detection of injury, downstream clinical outcomes, or costs. A study hypothesis may mention several potential benefits, but conclusions should follow the outcomes actually defined and reported. Here, the registry lists one primary outcome and no secondary outcomes.

The record is also a useful example of separating study design from statistical evidence. Randomized allocation and a parallel-group structure describe the intended comparison. They do not tell the reader how the sequence was generated, who was masked, how missing measurements were handled, or which analysis population was used. Those details are not reported in the registry record. Likewise, sample-size planning illustrations based on an observed effect are not a substitute for a design justification or a direct trial analysis.

Finally, the safety counts demonstrate the difference between descriptive reporting and comparative inference. Counts of adverse events provide basic context, but without event definitions and a comparative analysis they cannot establish a difference in risk. Careful reading keeps each statistic attached to the question it actually addresses and distinguishes recorded findings from conclusions the registry does not support.

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 main limitation for interpreting the primary outcome is that the registry posts arm-specific means and confidence intervals but no estimable two-arm comparison. It therefore does not report a direct contrast, its uncertainty, or a p-value for procedure time. The descriptive figures alone cannot establish the magnitude or statistical precision of the between-group effect.

The record does not report a sample-size justification, detailed statistical analysis plan, allocation sequence method, or allocation concealment. Although masking is described as single, the masked parties and practical masking procedures are not identified. Baseline characteristics and eligibility criteria are not reported, limiting assessment of the enrolled population and group comparability.

The registry does not state how missing procedure times were handled or which participants were included in each analysis. It lists 33 participants per group for the outcome, but does not provide participant flow or explain whether those counts represent all randomized participants with available outcomes. Variability summaries beyond confidence intervals, individual observations, model specifications, and adjustment methods are not reported.

The posted primary endpoint measures time, not diagnostic performance, urinary tract injury, patient outcomes, or economic value. Although the study summary states hypotheses about safety and cost effectiveness, the registry does not list a cost outcome or a direct comparative safety analysis. Adverse-event definitions and collection details are not reported. The completed status and recorded study dates do not resolve these reporting limitations or provide evidence about outcomes beyond those posted.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: "Laparoscopic" Cystoscopy Versus Traditional Cystoscopy — NCT01261819.
• Registry record last updated 2020-10-08; status last verified 2020-09.
• Results first posted 2020-10-08.
• 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

The registry record describes a completed, randomized, parallel-group, single-masked comparison of transurethral laparoscope cystoscopy with traditional cystoscopy in patients undergoing minimally invasive hysterectomy. Enrollment was 66, with 33 participants in each arm for the posted primary outcome. The stated study aim was to compare evaluation of the bladder and ureters at the time of laparoscopic hysterectomy.

The primary endpoint was time required to perform cystoscopy, measured in seconds during the procedure, up to 15 minutes. The transurethral laparoscope mean was 137.0 seconds, with a 95% confidence interval from 21.1 to 249.9. The traditional cystoscopy mean was 451.0 seconds, with a 95% confidence interval from 204.6 to 697.4. A two-arm comparison is not reported as estimable. The posted safety figures list zero serious adverse events in either group, other adverse events in one participant and six participants respectively, and no deaths in either group.

The registry lists no secondary outcomes or analyses. Details of the statistical plan, sample-size justification, missing-data handling, and analysis populations are not reported in the registry record.