Da Vinci Transoral Robotic-assisted Surgery of Pituitary Gland: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Da Vinci Transoral Robotic-assisted Surgery of Pituitary Gland (NCT02743442), a na na study. The primary outcome is Number of Patients Operated Via da Vinci Robot.

2. Clinical Question

3. Trial Design

This was a prospective single-group study of transoral pituitary surgery assisted by the da Vinci Si system. The registry lists phase as NA, allocation as NA, and masking as NONE. With no comparator arm, the design can describe whether the planned robotic approach was used and record outcomes in the enrolled group, but it cannot establish how those outcomes compare with another surgical technique.

The registry lists an enrollment of 8. The study start is recorded as 2016-03 and primary completion as 2018-03; its status is TERMINATED. The reason for termination, whether recruitment stopped as planned, and whether all intended follow-up was completed are not reported in the registry record. The brief summary presents the study as an investigation of a new minimally invasive technique for pituitary adenoma using a transoral route and robotic assistance.

The primary outcome is a participant count related to robotic operation and access to the sella turcica, with a timeframe of 1 day. Secondary outcomes are duration of surgery, number of severe adverse events, and duration of hospitalization. Results for those secondary outcomes are not reported in the registry record. Although the registry lists 4 outcome measures, it reports no analyses. Statistical methods for the primary or secondary outcomes, including any prespecified estimation or comparison plan, are not reported in the registry record.

The record describes 7 patients as having undergone robotic surgery; surgery was canceled for one patient after acute coronary syndrome, which the record says was not related to the study. This is a descriptive account, not a comparison between treatment groups. The design and available reporting support a limited account of feasibility and recorded safety events, but do not provide comparative evidence about effectiveness or relative safety.

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: Among the 8 patients enrolled in this study, 7 were operated using the Vinci robot. The surgery was canceled for one patient with acute coronary syndrome (a serious adverse event not related to the 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.

Population: Patients were included between 2016 and 2018. The median age was 48 (minimum: 22 years, maximum: 69 years). The median follow-up (time between the inclusion date and the end of the follow-up) was 6 months and 10 days.

6. Primary Endpoint

The registry lists the primary outcome as Number of Patients Operated Via da Vinci Robot, measured over 1 day.

The primary outcome is titled “Number of Patients Operated Via da Vinci Robot.” Its description specifies an operative access criterion: the entire sella turcica, including its anterior face, is seen during surgery and reached by the robotic arms. The timeframe is 1 day. The endpoint is therefore a count of participants meeting a procedural milestone, rather than a measure of tumor response, long-term disease control, or patient-reported recovery.

A count of participants who undergo the planned robotic procedure can be useful in an early study of a new surgical approach. It describes whether the approach was carried out in the enrolled group and can expose practical barriers, such as a procedure not proceeding. It does not, by itself, show that the approach is better than another route or that it improves health outcomes.

The registry narrative reports that 7 patients were operated using the robot and that surgery was canceled for one patient with acute coronary syndrome, described as unrelated to the study. The record does not separately state whether all 7 operations met the endpoint’s full visualization-and-reach criterion. That distinction matters: being operated using the robot and satisfying every element of the endpoint description are related but not necessarily identical statements. A more explicit participant-level outcome definition and result are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods for the primary and secondary outcomes are not reported in the registry record. The record lists 4 outcome measures and 0 analyses. No hypothesis test, confidence interval, adjustment method, or model is specified. The appropriate interpretation is therefore descriptive: the registry reports counts and selected event proportions, but does not provide a formal estimate of comparative treatment effect.

What does a single-group result describe?

In a single-group study, outcomes are observed among participants who receive the intervention without a concurrent comparison group. A count can describe how often a procedure was performed in the enrolled group. It cannot separate the intervention’s contribution from patient selection, clinical circumstances, operator decisions, or other influences. General statistical principle: a comparator helps establish what would have happened under another approach, while a single-group study has no direct estimate of that counterfactual.

Here, the registry reports that 7 patients underwent robotic surgery and describes a cancellation after acute coronary syndrome. The endpoint description includes visualization and robotic access to the entire sella turcica. Because the registry narrative does not separately confirm that each operation met this full criterion, the procedural count should not be silently recast as a confirmed count of endpoint successes.

Why would uncertainty estimates matter?

A confidence interval is a statistical range used to express uncertainty around an estimate under stated assumptions. It does not guarantee that the true value lies in the range, and it does not address every source of bias. No confidence interval is reported for the primary outcome. Without an uncertainty estimate, readers have only the recorded count and cannot assess the statistical precision of an underlying rate estimate from this record. Given the small enrollment, any estimate based on the group would be expected to be imprecise; no numerical precision measure should be inferred where none is reported.

General statistical principle: a p-value is a measure, under a specified model, of how compatible observed data are with a stated null hypothesis. It is not the probability that a treatment works, nor a measure of clinical importance. No p-value or hypothesis test is reported, and the absence of such a result should not be interpreted as evidence for or against a treatment effect.

How should the event counts be read?

The serious adverse event summary lists 4 affected among 8 at risk in the Transoral Surgery group. The other adverse event summary lists 7 affected among 8 at risk, and the deaths count is 0. These are descriptive counts. The record does not report whether the same participant contributed to both adverse-event categories, how many events each participant experienced, or how the categories were operationally defined. Counts of participants affected should not be treated as counts of unique events, and categories should not be summed to create a total.

The record also lists serious-event terms with percentages: Injury, poisoning and complications of interventions, 25.0%; Complication of neurological intervention, 12.5%; Injuries and complications related to an intervention, 12.5%; and Stroke, 12.5%. The registry does not give enough detail in this summary to determine whether terms overlap or whether their percentages use the same event-level or participant-level basis. General statistical principle: adverse-event coding terms can overlap because one event may be described at different levels of specificity. They should not be assumed to represent separate groups of participants.

What do the planning assumptions mean?

The registry’s sample-size assumptions describe a planning illustration based on the observed effect, not the study’s own design. They specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. For time-to-event outcomes, the stated convention is a total number of events; for other outcomes, it is participants per arm. These assumptions do not describe the single-group study design, and the registry does not report that the study was planned or powered using them.

Such sample-size illustrations are hypothetical planning tools, not observed power. They do not show that a study had a particular probability of detecting an effect after the data were observed. For a small, uncontrolled study, planning from an observed effect is especially vulnerable to uncertainty in that effect. No numerical planning results are reported in the registry record, so there is no basis to state a required sample size from this information.

What does the absence of analyses imply?

The registry lists no analyses, so it does not identify an analysis population, an approach to missing observations, a model, or a prespecified handling of multiple outcomes. These omissions do not prove that no analysis was performed outside the registry, but the registry record does not document one. Statistical interpretation should stay with the recorded descriptions and avoid attributing undocumented methods to the investigators.

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("Transoral Surgery")
n      <- c(7)
events <- c(7)
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  Transoral Surgery  7  7  100.0  59.0  100.0  64.6  100.0  63.1  99.7

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 4 outcome measures, including the primary measure and secondary outcomes for duration of surgery, number of severe adverse events, and duration of hospitalization. It lists 0 analyses. A statistical plan for handling multiple outcomes, including whether any outcome was designated for formal hypothesis testing or whether adjustments were planned, is not reported in the registry record. In general, when multiple outcomes are examined, the chance of at least one apparently notable finding can rise; adjustment or a prespecified hierarchy may help control that issue. No such procedure can be attributed to this study from the registry information.

Missing-data methods and analysis populations are also not reported in the registry record. The registry gives an enrollment of 8, says that 7 were operated using the robot, and describes cancellation for one patient after acute coronary syndrome. It does not state whether all enrolled participants were included in every outcome, how outcomes were handled when surgery was canceled, or whether any follow-up observations were unavailable. Those details matter because different handling decisions can change the meaning of an outcome count.

The record does not identify an intention-to-treat, per-protocol, or safety population, and it does not state a rule for classifying participants who did not undergo surgery. It also does not report whether missingness was assessed as related to participant condition or outcome. Therefore, the primary count should be read in the terms the registry uses, rather than assumed to represent a particular analysis population. No imputation or sensitivity analysis is reported.

12. 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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: injury, poisoning and complications of interventions (25.0%), complication of neurological intervention (12.5%), injuries and complications related to an intervention (12.5%), stroke (12.5%).

For the Transoral Surgery group, the registry lists 8 participants at risk for serious adverse events and 4 affected. For other adverse events, it lists 8 at risk and 7 affected. The reported death count is 0. These figures describe recorded participants with events in this group; they are not a comparison with another surgical approach and do not establish relative safety.

The registry also lists serious-event terms and percentages: Injury, poisoning and complications of interventions at 25.0%; Complication of neurological intervention at 12.5%; Injuries and complications related to an intervention at 12.5%; and Stroke at 12.5%. The record does not clarify whether these terms refer to overlapping event descriptions or distinct participants. The percentages should be read as listed, not added together or interpreted as mutually exclusive risks.

The acute coronary syndrome that led to cancellation is described as a serious adverse event not related to the study. The registry does not provide detailed event narratives, timing, resolution, or attribution procedures. General statistical principle: adverse-event summaries are most informative when definitions, exposure time, event counts, participant counts, and relatedness assessments are clearly specified. Those details are not reported in the registry record, so the safety figures have limited interpretability beyond their descriptive counts.

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

The record documents a single-group study of transoral pituitary surgery assisted by the da Vinci Si system. It reports that 7 of the 8 enrolled patients were operated using the robot, while surgery was canceled for one patient after acute coronary syndrome, described as unrelated to the study. The primary outcome is framed around seeing and reaching the entire sella turcica during surgery, but the record does not separately confirm that every robotic operation met all parts of that definition.

These results do not establish that the approach is more effective, safer, or less burdensome than endonasal surgery or another technique. There is no comparator group and no reported analysis of comparative effects. The rationale in the brief summary describes potential reasons for a transoral route, including avoidance of certain nasal complications, but those proposed advantages are not outcomes established by this study’s results.

The recorded adverse-event counts provide limited descriptive safety information. They do not show how event risk compares with another approach, and the record does not explain overlap among event categories or provide detailed follow-up. The absence of reported deaths in this group is a registry count, not proof that a rare risk is absent.

The study’s terminated status is an administrative fact, but the reason for termination is not reported in the registry record. It would be speculative to attribute termination to the acute coronary syndrome, safety concerns, recruitment, or any other cause. Likewise, the record does not report enough about selection criteria, operator experience, follow-up, or missing outcomes to determine how broadly the findings apply.

The most defensible conclusion is narrow: the registry describes use of the robotic transoral approach in this enrolled group and records selected safety counts. It does not provide comparative evidence or a complete statistical account of the endpoint. The result is best treated as an early descriptive record, not a definitive assessment of clinical benefit or risk.

14. Why This Trial Matters Statistically

This study is statistically notable because it asks a feasibility-oriented question about a surgical approach without a comparison group. In such a setting, a count of procedures performed can document that the technique was used in enrolled patients. It cannot establish what would have occurred with another route, and it cannot isolate the effect of the robotic system from the surgical approach, patient selection, or other features of care.

The endpoint also illustrates why outcome definitions matter. Its title focuses on the number operated using the da Vinci robot, while the description includes a more specific procedural criterion: seeing and reaching the entire sella turcica. The narrative reports robotic operations but does not separately state whether every operation met that full criterion. Clear alignment between an endpoint’s title, definition, and reported result is important for interpreting whether a feasibility milestone was achieved.

The small enrollment makes the descriptive record especially limited for safety inference. Serious-event counts can alert readers to events recorded during the study, but they cannot provide a stable comparative risk estimate without a suitable comparator and clearer detail on event definitions and follow-up. General statistical principle: sparse data often yield substantial uncertainty, even when counts are presented precisely.

The record also highlights the difference between a study’s own design and a planning illustration. The stated sample-size assumptions describe a hypothetical two-arm design, whereas the study is single-group. A planning calculation based on an observed effect is not evidence that the original study had adequate power, and it is not observed power. Distinguishing design assumptions from actual methods prevents a hypothetical calculation from being mistaken for a feature of the trial.

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 registry record does not report the reason the study was terminated. Although it lists primary completion as 2018-03, the record does not clarify whether termination followed completion of planned procedures or whether any intended assessments remained outstanding. The acute coronary syndrome associated with cancellation is described as unrelated to the study, but the relationship between that event and the termination status is not reported and should not be inferred.

Eligibility criteria and detailed participant characteristics are not reported in the registry record. The brief summary identifies pituitary adenoma, but does not describe the range of disease characteristics or explain how candidates were selected. The record also does not specify the surgeon’s experience with the technique, procedural standardization, or criteria for deciding whether the approach was technically successful.

The primary outcome description and narrative result are not fully reconciled: the endpoint includes seeing and reaching the entire sella turcica, while the narrative states how many patients underwent robotic surgery. A separate result for the full access criterion is not reported. Secondary outcome results for duration of surgery and duration of hospitalization are not reported in the registry record.

Follow-up duration beyond the primary timeframe of 1 day, missing-data handling, and the analysis population are not described. There is no reported comparator, statistical analysis, confidence interval, or adjustment for multiple outcomes. The safety summary lacks event narratives and does not explain overlap among event categories. These limitations restrict interpretation to the registry’s descriptive statements rather than supporting broader claims about comparative effectiveness, long-term outcomes, or relative safety.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Da Vinci Transoral Robotic-assisted Surgery of Pituitary Gland — NCT02743442.
• Registry record last updated 2021-03-29; status last verified 2021-03.
• Results first posted 2021-03-29.
• 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 record describes a terminated, single-group study of transoral pituitary surgery using the da Vinci Si robot. It lists pituitary neoplasms as the condition, an enrollment of 8, a study start of 2016-03, and primary completion of 2018-03. Allocation is listed as NA and masking as NONE.

The primary outcome concerns the number of patients operated using the robot, with a description requiring visualization and robotic access to the entire sella turcica. The narrative reports that 7 patients were operated using the robot and that surgery was canceled for one patient after acute coronary syndrome, described as unrelated to the study. The registry lists 4 serious adverse-event participants affected, 7 participants affected by other adverse events, and 0 deaths in the Transoral Surgery group. It reports no analyses. The reason for termination, secondary outcome results, missing-data methods, and comparative estimates are not reported in the registry record.