Can SIS Using Air Bubbles Replace HSG for Fallopian Tubal Patency After Essure Placement: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Can SIS Using Air Bubbles Replace HSG for Fallopian Tubal Patency After Essure Placement (NCT02628873), a randomized na study. The primary outcome is Fallopian Tube Patency - HyCoSy vs HSG.

2. Clinical Question

The clinical question is about diagnostic assessment: whether the two procedures classify tubal patency similarly, not whether either procedure changes patency. The registry summary frames the comparison around observing flow of fluid or bubbles through the fallopian tubes. That framing makes agreement or disagreement between the methods important, but the posted primary-outcome information does not give the observed counts or a statistical comparison.

The trial title and summary refer to the setting of Essure confirmation testing. The registry lists contraception as the condition. It does not provide further participant characteristics in the record, so the population cannot be characterized beyond the stated setting. Likewise, the clinical question is not answerable from the enrollment figure alone: enrollment describes how many participants entered the study, not what either procedure found.

3. Trial Design

The registry describes a randomized, single-masked crossover study. Participants were assigned to one of two procedure sequences: HyCoSy followed by HSG, or HSG followed by HyCoSy. Both procedures therefore appear in each sequence, with the order differing across randomized arms. The registry does not identify who was masked, so the masking designation cannot be interpreted more specifically.

The study enrolled 21 participants and is recorded as terminated. Its start is listed as 2015-12 and its primary completion as 2018-09. The reason for termination is not reported in the registry record. The phase is listed as NA. The sponsor is Wright State University.

In a crossover design, each participant receives or undergoes the procedures in a sequence, allowing within-participant comparisons in principle. Randomizing sequence can help balance which procedure occurs first. These are general features of crossover designs; they do not establish how this study handled order effects, timing, or paired observations. Those protocol and analysis details are not reported in the registry record.

The study's primary outcome was defined as a count of fallopian tubes observed to be closed, with analysis described per fallopian tube and assessment at the time of procedure. This is a different unit of analysis from the participant-level enrollment figure. Because a participant may contribute more than one tube, tube-level observations may be related within a participant. How such dependence was handled is not reported in the registry record.

The registry lists three outcome measures and three analyses, but the primary outcome information is not reduced to one comparison. The available information therefore identifies the general design and clinical target, while leaving the details needed to reproduce the analysis and interpret a treatment contrast unavailable.

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.

First Test (1 Hour)

Break (1 Hour)

Reasons for not completing this period:

Second Test (1 Hour)

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Analysis was per fallopian tube.

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.

Population: Number of participants are those who completed all assessments. Units of analysis for evaluation of the diagnostic tests is # fallopian tubes (open versus closed). All participants had 2 fallopian tubes.

6. Primary Endpoint

The registry lists the primary outcome as Fallopian Tube Patency - HyCoSy vs HSG, measured over At time of procedure.

The primary endpoint concerns fallopian tube patency, expressed as the count of tubes observed to be closed. The description says the observation was based on flow of fluid or bubbles through the tubes, and the assessment timeframe was at the time of procedure. The population field specifies that analysis was per fallopian tube.

Patency assessment is relevant to the study's diagnostic question because the procedures are being compared as ways to determine whether tubes are open or closed after Essure placement. A count of tubes observed closed can describe the observations made using a procedure, but a comparison between HyCoSy and HSG would require the results for both methods and an appropriate analysis of their relationship. The registry record does not report those outcome values or a single comparative estimate.

As a general statistical point, an endpoint's unit matters. A tube-level outcome is not automatically equivalent to a participant-level outcome. If observations from multiple tubes in one participant are treated as independent when they are correlated, uncertainty may be understated. Whether the analysis accounted for within-participant dependence is not reported in the registry record.

The endpoint is defined at the time of the procedure, but the registry information does not state a threshold or adjudication method for classifying a tube as closed, nor does it report how uncertain or discordant findings were handled. The posted definition indicates what was observed, but not the results needed to determine how the procedures compared.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Design and comparison. The study is described as randomized, single-masked, and crossover. In a crossover study, participants undergo the interventions in an assigned order. A general advantage is that the same participant may contribute observations under both procedures, which can reduce the influence of stable differences between participants in a paired comparison. However, this advantage is realized only if the analysis preserves the pairing and the design assumptions are suitable. The registry record does not state the specific statistical test or model used.

The two recorded sequences are HyCoSy followed by HSG and HSG followed by HyCoSy. Randomization of sequence is intended, in general, to make order assignment less systematically related to participant characteristics. It does not by itself show that order effects were assessed or that the procedure performed first could not affect the later assessment. The registry record does not report an order-effect analysis, a washout interval, or other details about timing between procedures.

What a crossover analysis would need to address

As a general matter, crossover analyses should account for the fact that observations from one participant are linked. A paired analysis compares the two procedures within participant, rather than acting as though the observations came from unrelated people. In this study, the endpoint is described per tube, so the analysis may also need to account for more than one tube being observed in a participant. The specific handling of participant pairing and tube-level dependence is not reported in the registry record. No statistical model, test statistic, or variance method is identified.

Masking is recorded as single, but the masked party is not identified. This prevents a more detailed assessment of how knowledge of procedure or sequence might have influenced observation, interpretation, or recording. The registry record also does not report an adjudication process for deciding whether a tube was open or closed.

Endpoint and measurement

The primary endpoint is a count of units, defined as fallopian tubes observed to be closed. The description refers to observed flow of fluid or bubbles through the tubes, and the assessment occurs at the time of procedure. Counts are often analyzed using methods that reflect their distribution and the way observations are collected. The registry does not report the distribution of the outcome, a model choice, or an estimate of variability. It is therefore not possible to determine whether a count model, a paired binary comparison, or another method was used.

In general, over-dispersion occurs when count variability exceeds what a chosen count model assumes. If present, it can make standard errors too small under an overly restrictive model. The registry record does not report a dispersion estimate or whether over-dispersion was assessed. Because the endpoint is defined per tube and a tube may be classified as open or closed, an analysis could also be framed around binary tube-level outcomes; however, the actual analysis approach is not reported and should not be presumed.

Uncertainty and interpretation

In general, a confidence interval gives a range of values compatible with the observed data and the statistical model, and communicates precision as well as the estimated effect. A p-value addresses how compatible data are with a specified null model under its assumptions; it does not express the probability that the null hypothesis is true. Neither a confidence interval nor a p-value for the primary comparison is reported in the registry record. There is therefore no reported estimate of effect or precision to interpret.

The registry's outcome description is not reduced to one comparison. The posted information does not give a single primary estimate. No equivalence or non-inferiority margin is reported, and no statistical test for those claims is specified. As a general point, failure to observe a statistically significant difference is not sufficient to establish equivalence; equivalence requires a prespecified margin and an analysis designed to evaluate it. The margin and analysis plan are not reported in the registry record.

Planning illustrations

Sample-size planning is distinct from the observed analysis. The general planning assumptions described for illustrations use a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation, with the effect to detect expressed as a fraction of an observed effect. These are planning assumptions, not evidence of the trial's original design or of its achieved power. The registry does not report the trial's own sample-size justification. Numerical planning estimates are not reported in the registry record, and no observed power should be inferred from enrollment or from a planning illustration.

In general, a sample-size illustration indicates how many participants per arm might be needed under specified assumptions; it does not show how many participants were actually analyzed or whether a study had a particular probability of detecting an effect after the data were collected. The sample-size assumptions described for the illustrations are not a substitute for a protocol or a prospective analysis plan. The registry record does not report whether these assumptions match the study's design decisions.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists three outcome measures and three analyses, and identifies pain scores and physician evaluation of the uterine cavity as secondary outcomes. The primary outcome is a count of tubes observed to be closed. The registry information does not describe which analyses correspond to which outcomes, whether there were multiple time points or categories for each measure, or which comparisons were designated as confirmatory.

Multiplicity arises when several outcomes, time points, subgroups, or statistical tests are evaluated. As a general statistical matter, making many comparisons can increase the chance of at least one apparently unusual finding. Common approaches include designating a primary analysis in advance or adjusting inference across a defined family of tests. The registry record does not report a multiplicity strategy, hierarchy of outcomes, or adjustment method. Since the primary outcome has not been reduced to one comparison, the posted information does not support an account of how multiple primary-outcome categories or time points were handled.

Missing data are also important in a small crossover study: a participant may not complete both procedures, and some tube observations may be unavailable or uninterpretable. These are general possibilities, not reported events in this record. The registry does not state how many participants completed each sequence, how many tubes were assessed, whether any outcome data were missing, or how missing observations were handled.

The analysis population is not defined in the registry information. It does not say whether the primary analysis included all randomized participants, only those completing both procedures, or another set of observations. No protocol deviations, exclusions, or imputation methods are described. These omissions limit assessment of attrition, selection, and whether the analyzed population preserved the benefits of randomization.

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 5% reporting threshold.

The registry lists serious adverse events and deaths by sequence group. For HyCoSy followed by HSG, 13 participants are listed at risk, with 0 serious events, 0 other events, and 0 deaths. For HSG followed by HyCoSy, 6 participants are listed at risk, with 0 serious events, 0 other events, and 0 deaths. No serious-event terms are listed.

These are the safety figures recorded for the groups; they do not mean that risk is impossible or that no event could occur outside the registry's reporting period or definitions. A zero count is an observed count, not proof of zero underlying risk. The registry record does not provide further detail about safety-event definitions, collection procedures, follow-up duration, or whether the at-risk counts represent all randomized participants or a particular analysis population.

The sequence groups have different at-risk counts, and the study used a crossover design. Without participant flow and safety-analysis details, these entries should not be interpreted as a direct comparison of the safety of HyCoSy and HSG. They also do not address the diagnostic performance question, which concerns the primary tubal patency outcome.

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

The record establishes that the study set out to compare HyCoSy and HSG for assessment of fallopian tube patency after Essure placement. It identifies a randomized crossover design, the two procedure sequences, and a primary endpoint based on the count of tubes observed to be closed. Those details clarify the intended comparison and the measurement target.

What the record does not establish is the comparative result. It does not report the primary outcome counts for each procedure, a paired comparison, an effect estimate, or uncertainty around an estimate. Therefore, the posted information does not show whether the procedures gave similar classifications, whether one yielded more tubes classified as closed, or how precise any such difference might be. The clinical question of whether HyCoSy was as good as or better than HSG remains unanswered by the reported outcome information.

The study's enrollment of 21 participants and terminated status are relevant context, but neither tells readers why the trial ended or how many participants contributed usable observations to each endpoint. The reason for termination, participant flow, and analysis population are not reported in the registry record. It would be inappropriate to infer that the trial was stopped for efficacy, safety, feasibility, or any other reason.

Likewise, zero adverse events in the listed groups are limited safety observations, not a finding that establishes absence of risk. They should not be conflated with evidence about diagnostic accuracy. No sensitivity, specificity, agreement statistic, or reference-standard analysis is reported in the registry information.

In general, equivalence or non-inferiority requires a prespecified margin and an analysis designed to evaluate that margin. Neither is reported. A study's aim to test whether one diagnostic approach is as good as or better than another does not, by itself, establish that the design or analysis supported an equivalence or non-inferiority conclusion. The available record supports description of the study question and structure, but not a conclusion about comparative diagnostic performance.

13. Why This Trial Matters Statistically

This study is statistically interesting because it combines a randomized sequence with a crossover comparison. In general, crossover designs can make within-participant comparisons possible and may limit the influence of stable differences between participants. They also require attention to procedure order, paired observations, and the possibility that one observation changes how a later one is interpreted. Knowing the design is therefore important, but the registry record does not report whether these issues were addressed in analysis.

The endpoint also highlights a common unit-of-analysis challenge. Enrollment is counted in participants, while the primary endpoint is described per fallopian tube. General statistical practice requires the analysis to reflect how observations are grouped and related. If tubes from one participant are correlated, treating them as independent can misstate uncertainty. The analysis method for this endpoint is not reported.

Another statistical lesson is that a clear research question and a defined endpoint are not enough to interpret effectiveness or diagnostic performance. A reader also needs the observed results, a comparison appropriate to the design, and an account of uncertainty. The registry provides the intended outcome and study structure, but not a single primary comparison or its precision. The result cannot be reconstructed from enrollment or the safety entries.

The trial's terminated status makes transparency about participant flow, planned enrollment, and reasons for ending especially useful. Those details are not reported in the registry record. Their absence limits the ability to assess completeness and the relationship between the design and the available results, without allowing any conclusion about why the trial was terminated.

Finally, the record illustrates why diagnostic claims such as similarity, equivalence, or non-inferiority require more than an aim to compare methods. A stated margin, suitable paired analysis, and reported uncertainty would be needed to support such claims. Those elements are not reported, so the statistical contribution that can be drawn from the record is primarily about the intended design and the information gaps that prevent a comparative conclusion.

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 principal limitation for interpretation is the absence of reported primary-outcome values and a single comparison. Without counts for tubes observed closed under each procedure, readers cannot assess the direction or size of any contrast, agreement between methods, or precision. The registry defines the endpoint but does not report its results.

The record does not state the number of participants who completed both procedures or the number of tubes analyzed. This makes it difficult to understand how the enrollment of 21 relates to the primary analysis. The reason for termination is also not reported, nor is the planned enrollment or the study's sample-size justification.

Details needed to judge the crossover analysis are missing. The registry does not report how procedure order was handled statistically, whether paired observations were used, whether carryover was assessed, or how possible within-participant correlation between tubes was modeled. It also does not identify the party masked or explain how tube patency was classified, including how ambiguous observations were treated.

The analysis population, missing-data approach, exclusions, and protocol deviations are not reported. These gaps prevent assessment of whether all randomized participants contributed to analysis or whether incomplete observations could have affected the comparison. The registry also does not report a prespecified equivalence or non-inferiority margin, multiplicity control, confidence interval, or p-value for the primary outcome.

Safety information is limited to the event counts and at-risk numbers listed for the two sequences. Definitions, follow-up, and ascertainment details are not reported. The listed zero counts should therefore be read as recorded observations, not as comprehensive evidence that adverse events cannot occur. Together, these limitations mean the posted record describes the question and broad design but does not permit a firm statistical interpretation of comparative diagnostic performance.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Can SIS Using Air Bubbles Replace HSG for Fallopian Tubal Patency After Essure Placement — NCT02628873.
• Registry record last updated 2024-10-22; status last verified 2024-10.
• Results first posted 2020-08-31.
• 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

NCT02628873 is a randomized, single-masked crossover study sponsored by Wright State University. It enrolled 21 participants and is recorded as terminated. The study compared HyCoSy with HSG for assessing fallopian tube patency after Essure placement, assigning participants to one of two procedure sequences.

The primary endpoint was the count of fallopian tubes observed to be closed, based on observed fluid or bubble flow and assessed at the time of procedure. The primary outcome was defined per fallopian tube, but the registry record does not report the outcome counts or a single comparison. Secondary outcomes were pain scores and physician evaluation of the uterine cavity.

The listed safety entries report 0 serious adverse events, 0 other adverse events, and 0 deaths in each sequence group. The reason for termination, participant flow, analysis population, statistical analysis details, and primary comparative result are not reported in the registry record. The study question is clear, but the posted information does not establish how the two procedures compared.