Radial Reload Laparoscopic LAR Case Series: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Radial Reload Laparoscopic LAR Case Series (NCT01706822), a na phase 4 study. The primary outcome is The Surgeon's Ability to Achieve a Staple Line at the Desired Level of the Rectum. The Reported Value Represents the Number of Participants in Whom the Criteria Was Met.

2. Clinical Question

The record also lists surgeon usability outcomes for access, visibility, and maneuverability. These are described as percentages of cases in which the surgeon agreed or strongly agreed with questionnaire statements, but their results are not reported in the registry record. The design can describe observations from the enrolled case series; it cannot establish how outcomes would compare with another device or approach.

3. Trial Design

The registry describes a prospective multicenter case series evaluating the Covidien Radial Reload Stapler with Tri-Staple Technology during laparoscopic low anterior resection or anterior proctosigmoidectomy for rectal cancer. The listed study phase is phase 4. The study has a single-group model, allocation is not applicable, and masking is listed as none. Enrollment is 8.

The study start is recorded as 2013-04 and primary completion as 2013-11. The current registry status is terminated. The record does not explain why the study was terminated, whether enrollment reached its planned target, or whether the primary completion date reflects completion of all planned follow-up. Those details are not reported in the registry record.

Because all participants are described under the device intervention and no concurrent comparator group is listed, this design is suited to reporting procedural experience and observed outcomes in this series. It does not provide a randomized comparison or a direct estimate of the difference between the stapler and an alternative. The absence of masking is also recorded, but the registry does not describe whether outcome assessment was standardized or independently reviewed.

The registry lists 5 outcome measures and 0 analyses. It names the primary endpoint as the surgeon’s ability to achieve a staple line at the desired level of the rectum, measured as a participant count during the operative timeframe. The listed secondary outcomes concern surgeon ratings of access, visibility, and maneuverability. Outcome values beyond the adverse-event figures are not reported in the registry record. The intended sample-size rationale, detailed analysis plan, eligibility criteria, and any planned follow-up procedures are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

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 The Surgeon's Ability to Achieve a Staple Line at the Desired Level of the Rectum. The Reported Value Represents the Number of Participants in Whom the Criteria Was Met, measured over Operative.

The primary endpoint asks whether the surgeon achieved a staple line at the desired level of the rectum. It is defined as the number of participants in whom the criterion was met, with the timeframe listed as operative. This is a procedural, binary outcome: for each participant, the criterion is either recorded as met or not met, and the registry describes the endpoint as a count of participants meeting it.

In general, a procedural endpoint can document whether a specified technical objective was achieved during an operation. It is relevant to this case series because the device is being evaluated in the context of stapling during laparoscopic rectal surgery. However, the endpoint alone does not describe every aspect of the operation, nor does it establish comparative performance. Its interpretation depends on how the desired level was defined and assessed, and those operational details are not reported in the registry record.

The registry record does not report the observed primary-endpoint count. As a result, the endpoint’s result and its precision cannot be assessed from the posted results. No confidence interval or other uncertainty estimate for this outcome is reported in the registry record. The endpoint definition therefore indicates what the study intended to count, but it does not supply the outcome needed to judge how often the criterion was met.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the design permit?

In general, a single-group case series describes outcomes among people who received the intervention under study. Here, the registry lists one intervention group and no separate comparator. Allocation is not applicable, and the study is not described as randomized. These design features mean the posted data can describe the recorded experience in the series, but they cannot isolate a difference between the stapler and another device, technique, or usual-care group.

The record identifies the study as prospective and multicenter. In general, prospective data collection means outcomes are planned for collection as participants proceed through the study, while multicenter indicates participation across more than one site. Those design labels do not, by themselves, show whether outcome definitions were applied consistently across sites. The registry record does not report site-specific enrollment, procedures for harmonizing assessments, or whether outcome assessments were reviewed independently.

How should the primary outcome be understood?

The primary endpoint is a count of participants meeting a procedural criterion: the surgeon’s ability to achieve a staple line at the desired level of the rectum. The outcome is recorded for the operative timeframe. For a binary outcome, the underlying observation for each participant is whether the criterion was met. A count is useful as a direct description of how many participants met the criterion, but interpretation also requires knowing the number assessed and how missing or indeterminate assessments were handled. Those details, and the observed primary-endpoint count, are not reported in the registry record.

In general, binary outcomes can be presented as counts and proportions. A proportion needs a clear denominator, and uncertainty estimates can help show how much an observed estimate might vary. No proportion, confidence interval, or analysis result for the primary endpoint is reported in the registry record. No further calculation can be made from the reported enrollment alone because the endpoint result and analysis denominator are absent.

What does a confidence interval communicate?

In general, a confidence interval gives a range of values compatible with an estimate under a specified statistical procedure. It conveys precision: a wider interval indicates less precision than a narrower interval, all else being equal. It does not remove the limitations of the study design, and it cannot correct for bias or replace a suitable comparator. No confidence interval for the primary endpoint is reported in the registry record, so the precision of that result cannot be described.

What can the usability outcomes show?

The registry names access, visibility, and maneuverability as secondary outcomes measured using a surgeon usability questionnaire. Each is described as the percentage of cases in which the surgeon agreed or strongly agreed. In general, such ratings summarize reported perceptions under the questionnaire’s response categories. Their interpretation depends on the wording of the questions, the response process, and the number of cases assessed. The questionnaire items, observed values, and denominators are not reported in the registry record. These outcomes therefore cannot be interpreted numerically from the listed descriptions alone.

How should the planning illustrations be read?

In general, sample-size calculations are planning tools: they describe the sample size associated with assumptions about an effect, significance level, allocation, and statistical method. They are not evidence that a study had a particular probability of detecting an effect after the results are observed. The planning assumptions described for this study use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect set as a stated fraction of the observed effect. For time-to-event outcomes, the stated convention is a total event count; for other outcomes, it is participants per arm.

Those planning assumptions describe an illustration rather than the trial’s own design, and the registry record does not report a trial-specific sample-size justification. The study itself is a single-group case series, not a two-arm comparison. No numerical planning results are reported in the registry record. Any planning illustration should therefore be distinguished from observed study evidence; it is not observed power and does not supply a missing endpoint result.

Why does over-dispersion matter in general?

Over-dispersion is a general statistical issue that arises when observed variability is greater than a model assumes. If a model underestimates variability, its uncertainty estimates may be too narrow and its statistical evidence may appear stronger than warranted. The registry record does not report an over-dispersion assessment or a model-based analysis for this case series. Since no outcome analysis is listed, there is no basis to infer which statistical model or variance assumptions were used.

What is the role of the reported analysis count?

The registry lists 0 analyses. This indicates that no analysis entries are listed in the record; it does not establish that no analysis was conducted outside the registry. The statistical analysis plan, any model specifications, and any analysis populations are not reported in the registry record. As a result, the posted information does not allow readers to assess adjustment choices, handling of repeated or site-level data, or whether outcome definitions changed during the study.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Covidien Radial Reload Stapler With Tri-Staple Tec")
n      <- c(8)
events <- c(6)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Covidien Radial Reload Stapler With Tri-Staple Tec  8  6  75.0  34.9  96.8  40.9  92.9  40.0  92.5

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 5 outcome measures, including the primary procedural endpoint and secondary usability outcomes for access, visibility, and maneuverability. It does not report a statistical analysis plan or an account of how multiple outcomes were handled. Multiplicity refers, in general, to the interpretive issue that can arise when several outcomes or statistical tests are considered: the chance of observing apparently notable findings can depend on how many analyses were conducted and how they were selected. No adjustment method or hierarchy beyond the designation of a primary endpoint is reported in the registry record.

The registry lists 0 analyses. No analysis populations, endpoint-specific denominators, missing-data procedures, or imputation methods are reported in the registry record. The enrollment of 8 does not establish that all enrolled participants contributed to every outcome. For the primary endpoint and usability outcomes, the number of participants with assessable data is not reported.

Missing outcome data can affect interpretation because the observed cases may not represent all enrolled participants. In general, the consequences depend on how much information is missing and why it is missing. The registry does not report whether data were incomplete, how incomplete observations were treated, or whether any sensitivity analyses were performed. The reason for the terminated status is also not reported in the registry record. Without these details, completeness and possible selection effects cannot be evaluated.

12. Safety Results

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

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: ileus (12.5%), pneumoperitoneum (12.5%), postoperative ileus (12.5%), procedural complication (12.5%), ureteric obstruction (12.5%).

The registry reports 8 participants at risk for serious adverse events and 4 affected. For other adverse events, it reports 8 at risk and 2 affected. These are participant counts in the intervention group. The registry also lists Ileus, Pneumoperitoneum, Postoperative ileus, Procedural complication, and Ureteric obstruction among the serious adverse-event terms, each with a reported value of 12.5%.

These figures are descriptive, not comparative. The term-level percentages should not be added or assumed to represent distinct participants: the registry does not report whether participants experienced more than one event or how events mapped to individuals. The record does not state whether the listed events were judged related to the device or procedure. It also does not report a death count; the death field is null, so deaths are not reported in the registry record.

In general, serious adverse events and other adverse events are separate reporting categories, and their counts should be interpreted using the registry’s definitions and follow-up procedures. Those definitions and the follow-up duration are not reported in the registry record. With no comparison group, these counts cannot show whether event occurrence differed from another treatment or setting.

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

The record documents a prospective, multicenter evaluation of the Radial Reload Stapler in laparoscopic low anterior resection or anterior proctosigmoidectomy for rectal cancer. It identifies a primary procedural question: whether the surgeon achieved a staple line at the desired level of the rectum. It also specifies surgeon-rated usability outcomes and reports adverse-event counts for the intervention group. These features clarify what the study set out to observe.

The posted results do not include the primary endpoint value or numerical results for the listed usability outcomes. Therefore, the registry record does not show how many participants met the primary criterion, how surgeons rated the usability domains, or how precise those outcome estimates might be. The adverse-event counts and listed event terms provide descriptive information, but the registry does not report event relatedness or a death count.

In general, an uncontrolled case series can describe outcomes among participants treated in the observed setting. It cannot establish what would have happened to similar participants under a different device or approach. This design has no randomized comparator, and the record does not provide a basis for estimating a comparative effect. The observations also should not be interpreted as proof of general performance beyond the enrolled series.

The record reports enrollment of 8 and a terminated status, but does not explain the reason for termination or whether the planned data collection was complete. The study’s analysis plan, missing-data handling, and endpoint-specific denominators are not reported in the registry record. Taken together, the entry describes the study question and some safety information, but it does not supply the primary outcome result needed to answer the central procedural question.

14. Why This Trial Matters Statistically

This study is statistically notable because its registry entry illustrates the difference between defining an endpoint and reporting its result. The primary endpoint is stated in concrete procedural terms and has a specified timeframe, but the observed count is not reported in the registry record. Without the result and its denominator, readers cannot assess either the observed frequency of meeting the criterion or its precision.

The case-series design also matters for interpretation. A single intervention group can describe recorded experience, but it cannot provide a concurrent estimate of what would have occurred under a comparator. The absence of allocation to a control group is not a minor technical detail: it limits the questions that can be answered by the data. The record should therefore be read as a descriptive study entry, not as a comparative trial result.

Enrollment of 8 places the reported safety counts in the context of a small series. General statistical reasoning cautions that counts from a small sample can be imprecise and may not characterize outcomes in a broader population. The registry does not report confidence intervals for these observations, and the primary result is absent. The listed serious-event terms are useful as event descriptions, but their percentages do not establish causality or comparative risk.

Finally, the record lists 5 outcome measures and 0 analyses, while important details about missing data, analysis populations, and multiplicity are not reported. These omissions limit reproducibility and assessment of selective reporting. They also underscore why a clearly defined outcome is not enough on its own: interpretation requires the observed data, denominator, analysis approach, and context appropriate to the study design.

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.

Several limitations are specific to the registry information for this study. The primary endpoint is defined, but its result is not reported in the registry record. Numerical results for the surgeon usability outcomes are also not reported. Although the record lists 5 outcome measures, it provides no analysis entries. The absence of those results prevents assessment of the central procedural outcome and the stated secondary outcomes.

The study enrolled 8 participants and has no separate comparator group. It therefore offers no direct basis for comparing the device with another stapler, surgical approach, or usual care. The record does not report participant characteristics, detailed eligibility criteria, site-level enrollment, or endpoint-specific denominators. It also does not describe how the desired staple-line level was defined or assessed.

The registry status is terminated, but the reason for termination and its effect on study completion are not reported. The record does not describe missing-data procedures, the analysis population, the statistical analysis plan, or any multiplicity approach. The relationship of adverse events to the device or procedure is not reported, and the death count is not reported in the registry record. These gaps constrain interpretation of both the outcome and safety information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Radial Reload Laparoscopic LAR Case Series — NCT01706822.
• Registry record last updated 2015-03-18; status last verified 2015-03.
• Results first posted 2015-03-18.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

The registry describes a prospective, multicenter, single-group case series of the Covidien Radial Reload Stapler with Tri-Staple Technology during laparoscopic low anterior resection or anterior proctosigmoidectomy for rectal cancer. It lists phase 4, enrollment of 8, no masking, a study start of 2013-04, primary completion of 2013-11, and a terminated status.

The primary endpoint is the number of participants in whom the surgeon achieved a staple line at the desired level of the rectum. The record lists 5 outcome measures and 0 analyses, but does not report the primary endpoint result or numerical usability results. It reports serious adverse events in 4 of 8 participants and other adverse events in 2 of 8 participants. No comparator group is listed, and the reason for termination, analysis plan, missing-data handling, and event relatedness are not reported in the registry record.