Prospective Evaluation of NOTES (Natural Orifice Translumenal Endoscopic Surgery) PEG "Rescue": Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Prospective Evaluation of NOTES (Natural Orifice Translumenal Endoscopic Surgery) PEG "Rescue" (NCT01119040), a na na study. The primary outcome is Number of Participants With Successful Replacements of Dislodged PEG Tubes With NOTES Procedures in Lieu of Traditional Surgical Methods..

2. Clinical Question

The study also stated broader aims: to assess urgent upper endoscopy in the setting of a dislodged PEG tube, and the feasibility and efficacy of replacing PEG tubes with NOTES instead of traditional surgical methods. These aims provide context, but the listed primary outcome is specifically framed around conversion to conventional surgery. The record does not report separate results for the broader aims, nor does it define additional outcome measures for them.

3. Trial Design

This was a prospective, single-group study of NOTES PEG rescue. The registry lists the study model as single group, allocation as NA, and masking as none. Enrollment was 1, and the study status is terminated. The record gives a study start of 2007-11 and a primary completion date of 2010-07. It lists University Hospitals Cleveland Medical Center as the sponsor.

The study was not designed as a randomized comparison. Traditional incision-based surgery appears in the description as the alternative to NOTES, but no control arm or like-for-like comparison is reported. Consequently, the record does not support a direct estimate of how outcomes differ between NOTES and conventional surgery. The fact that an alternative procedure is named does not make it a study comparator.

The stated population for the primary outcome was only 1 subject because of low accrual. The record lists one outcome measure and no analyses. It does not report a planned sample size, a sample-size justification, enrollment targets, eligibility criteria, or details of recruitment beyond the explanation of low accrual. It also does not report a protocol-level statistical analysis plan.

The registry describes the intervention as a procedure and gives a brief explanation of NOTES as an approach using natural openings in the body. A complete procedural protocol, including technical steps, operator experience, and any criteria for attempting or abandoning NOTES, is not reported in the registry record. These omissions limit what can be inferred about how the procedure was implemented, even apart from the very small enrollment.

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

Analysis population for the primary outcome, as defined in the registry: Only 1 subject due to low accrual

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 Number of Participants With Successful Replacements of Dislodged PEG Tubes With NOTES Procedures in Lieu of Traditional Surgical Methods., measured over 30 day follow-up.

The primary endpoint counts participants with successful replacements of dislodged PEG tubes using NOTES in place of traditional surgical methods. The stated timeframe is 30 day follow-up. The record defines success through the number of patients requiring conversion from NOTES PEG rescue to conventional incision-based surgery. In practical terms, conversion is the event that indicates NOTES was not completed without that conventional surgical approach under the study’s definition.

This endpoint is used to address a procedural feasibility question: whether NOTES PEG rescue can be completed without conversion. A count of participants is a direct way to express that outcome in a single-group study. It does not, by itself, establish comparative effectiveness or provide a measure of longer-term outcomes. The registry record does not report separate criteria for other dimensions of success, such as technical quality or patient experience.

Although the outcome definition and follow-up timeframe are listed, the participant’s endpoint status and the observed count are not reported in the registry record. The posted record therefore does not establish whether conversion occurred or how the primary outcome was classified.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical information is sparse because the registry lists one outcome measure and no analyses. The primary outcome is a binary participant-level event: a participant either required conversion to conventional incision-based surgery or did not, according to the stated definition. The registry’s count-based description is suited to that kind of outcome. However, the record does not give the observed result, so no effect estimate or uncertainty interval can be assessed.

What does a confidence interval express?

General statistical explanation: A confidence interval describes the uncertainty around an estimate under a specified statistical method. It is not a guarantee that the true value lies within the interval, nor does it repair limitations in the underlying data. For a binary outcome, an interval around a proportion would depend on the observed event count, the number of participants, and the interval method. The registry record does not report the primary event count or an interval, so there is no posted interval to interpret for this endpoint.

Why does the sample size matter?

General statistical explanation: Larger studies can provide more information about the range of outcomes across participants, while a very small study leaves substantial uncertainty. With only 1 subject, the study cannot characterize participant-to-participant variation. Even if an outcome count had been posted, it would describe this participant’s status rather than provide a precise estimate for a wider population. No precision estimate should be inferred from the enrollment figure alone.

What does the absence of a comparator mean?

General statistical explanation: A single-group study can describe what happened in the group receiving an intervention, when results are reported. It cannot by itself separate the intervention’s effect from other influences or estimate how outcomes would have differed under another approach. A causal comparison generally requires a suitable comparison design and analysis. Here, traditional surgery is named as an alternative in the study aims, but the record lists a single-group model and no comparator arm.

The registry lists allocation as NA and masking as none. Allocation concerns how participants are assigned to study groups; with a single group and no randomized comparison, there is no reported assignment process between arms. Masking concerns whether participants or study personnel are kept unaware of an assigned treatment or assessment information. The record reports no masking, but does not provide additional detail about outcome assessment procedures.

How should the sample-size illustrations be read?

General statistical explanation: Planning calculations estimate the enrollment that might be needed under chosen assumptions about a target effect, significance level, allocation, and statistical model. The assumptions associated with the planning illustrations specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They also describe planning for stated fractions of an observed effect. Those are planning assumptions, not evidence that this single-group study used that design or achieved a particular probability of detecting an effect.

The record does not report the original sample-size justification or a planned enrollment target. The planning illustrations are not the study’s own design, and any sample size displayed for a hypothetical two-arm comparison should not be interpreted as the observed sample size, an observed power calculation, or a result from this trial. The record also does not report the observed primary effect needed to ground an interpretation of an effect-based planning exercise.

What analyses are reported?

The registry lists no analyses. It does not report a statistical model, adjustment factors, hypothesis test, confidence interval method, or analysis population. In general, analysis choices should be prespecified and aligned with the endpoint and design; the record does not provide enough information to assess such choices. No unadjusted or adjusted result is posted, and there is no sponsor analysis to compare with a recalculation.

Over-dispersion is a concern in some count models when observed variability exceeds what a model assumes. General statistical explanation: that issue can affect standard errors and interval estimates for count data. It is not possible to assess over-dispersion for this record: the endpoint is stated as a participant count, enrollment is 1, and no analysis or distribution of repeated counts is reported. Applying a more complex model would not resolve the lack of outcome information.

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("NOTES PEG Rescue")
n      <- c(1)
events <- c(1)
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  NOTES PEG Rescue  1  1  100.0  2.5  100.0  20.7  100.0  15.8  98.7

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure, the count of participants with successful NOTES replacements as defined by conversion to conventional surgery, with a 30 day follow-up timeframe. It does not report a multiplicity strategy, such as an order for testing several outcomes or an adjustment for multiple statistical tests. Because no analyses are listed, the record does not show whether any formal hypothesis tests were conducted.

Missing-data methods are not reported in the registry record. The posted information does not say whether the participant completed follow-up, how an unavailable endpoint would have been handled, or whether any imputation or sensitivity analysis was planned. The one-subject population is attributed to low accrual, but that does not establish whether any outcome data were missing.

The record gives no analysis population beyond stating that only 1 subject was included because of low accrual. It does not describe an intention-to-treat population, a per-protocol population, exclusions from analysis, or participant flow through follow-up. No analysis results are listed. These omissions mean readers cannot assess how the primary endpoint was handled analytically or whether missing observations affected the result.

Interim analyses, stopping criteria, and any statistical monitoring plan are not reported in the registry record. The study is marked terminated, but the reason for termination is not reported. Termination and low accrual should not be treated as evidence of a particular statistical decision or of a particular participant outcome.

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.

The registry records 1 participant at risk for serious adverse events and 0 participants affected. It also records 1 participant at risk for other adverse events and 0 affected. These are participant counts, not counts of every event episode, and the record lists no serious adverse-event terms.

These figures mean that the posted results do not record a participant with an event in either category. They do not establish that the procedure has no safety risks. With only 1 participant at risk, the figures provide little information about how often adverse events might occur in a larger group or what kinds of events might be seen. The record does not report event-level details, severity grading, attribution, or a fuller safety analysis.

The death count is not reported in the registry record. It should not be read as zero. The safety figures also do not resolve the missing primary outcome result or provide a comparison with conventional surgery.

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

This record establishes that a prospective, single-group study of NOTES PEG rescue was registered, that enrollment reached 1 participant, and that the study was terminated. It also specifies a primary outcome based on whether a participant required conversion to conventional incision-based surgery during the stated 30 day follow-up period. The registry attributes the small population to low accrual.

The record does not report the primary outcome count, an analysis, or an estimate of precision. It therefore does not show whether conversion occurred for the participant, and it cannot provide a reliable estimate of the outcome across a broader group. The absence of a posted result is not evidence that the procedure succeeded or failed.

The design also does not support a direct comparison with traditional surgery. Although that approach appears in the study’s aims as the alternative to NOTES, the record describes a single group and does not list a control arm. Any differences between methods, including differences in success or safety, are not estimated in the registry record.

The adverse-event counts describe no participants affected among the 1 participant at risk in each listed category. These counts are limited observations, not a demonstration that adverse events cannot occur. Deaths are not reported. The record also does not provide results for the broader stated aims concerning urgent endoscopy, feasibility, or efficacy.

The study is therefore best understood as a very small, terminated evaluation with a defined procedural endpoint but no posted primary outcome analysis. It documents the question that investigators set out to address, but the available record does not answer that question with an interpretable outcome estimate.

14. Why This Trial Matters Statistically

This study matters statistically because it illustrates the gap between a clinically motivated question and the information needed to estimate an outcome. The registry poses a focused feasibility question about whether NOTES PEG rescue can be completed without conversion to conventional surgery. It defines a binary endpoint and a follow-up timeframe, but enrollment of 1 participant and the absence of a posted endpoint result leave the question unanswered by the available record.

A single-group design can be useful for describing an initial procedural experience when results are fully reported. It cannot establish comparative performance without a comparison group, and a single participant cannot describe the range of outcomes across patients. These are design and information limits, not conclusions about the underlying procedure.

The case also shows why a zero adverse-event count needs its denominator and context. The registry records zero affected participants among 1 at risk for both serious and other adverse events, but that observation is too limited to characterize safety in a larger population. The death count is not reported.

Finally, the record distinguishes an endpoint definition from an endpoint result. Specifying how success would be assessed does not tell readers whether success occurred. With no listed analyses and no posted primary outcome count, the record supports a careful account of design, accrual, and reporting gaps rather than a treatment-effect conclusion.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The principal limitation is enrollment of only 1 subject, which the registry attributes to low accrual. This is insufficient to characterize variation in outcomes among participants and sharply limits the precision of any possible estimate. In addition, the registry does not report the participant’s primary outcome status, so even a descriptive success count cannot be interpreted.

The study is single group, with no reported comparator arm. Traditional surgery is mentioned as the alternative method, but no comparative results are available. The record lists no analyses, statistical model, confidence interval, or test. It also does not report an original sample-size justification or statistical analysis plan.

The registry does not provide full eligibility criteria, participant characteristics, procedural details, operator information, or the reason for termination. It does not say whether follow-up was completed, whether data were missing, or how the endpoint would be handled if it could not be assessed. These details are not reported in the registry record and should not be inferred from the stated endpoint definition.

Safety reporting is limited to participant counts: zero affected for serious events and zero for other events, with 1 participant at risk in each category. No event terms are listed, and deaths are not reported. The available record also does not provide results for the broader aims concerning urgent upper endoscopy, feasibility, and efficacy. Together, these gaps prevent a fuller assessment of outcome reporting, procedural implementation, and safety.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Prospective Evaluation of NOTES (Natural Orifice Translumenal Endoscopic Surgery) PEG "Rescue" — NCT01119040.
• Registry record last updated 2015-01-05; status last verified 2014-12.
• Results first posted 2012-12-03.
• 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.

19. Record Summary

The registry describes a prospective study of Natural Orifice Translumenal Endoscopic Surgery for PEG rescue. Its stated aims concerned urgent upper endoscopy for a dislodged PEG tube and replacing PEG tubes with NOTES instead of traditional surgical methods. The listed primary outcome counts successful replacements, defined by whether conversion to conventional incision-based surgery was required, at 30 day follow-up.

The study was single group, unmasked, and terminated. Enrollment was 1; the record attributes this to low accrual. The study start is listed as 2007-11 and primary completion as 2010-07. University Hospitals Cleveland Medical Center is listed as sponsor. One outcome measure and no analyses are reported.

The primary outcome result, reason for termination, analysis plan, missing-data approach, and death count are not reported in the registry record. The adverse-event figures record zero affected participants among 1 at risk for serious events and zero among 1 at risk for other events.