A Prospective, Single-center, Single-arm, Pivotal Trial of the Medtronic Hugo™ Robotic Assisted Surgery (RAS) System: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Prospective, Single-center, Single-arm, Pivotal Trial of the Medtronic Hugo™ Robotic Assisted Surgery (RAS) System (NCT05715827), a na phase not stated study. The primary outcome is Completion Rate.

2. Clinical Question

The registry record frames the study as an evaluation of safety and effectiveness in participants having one of two procedures. Its primary endpoint combines a measure of procedural completion with the absence of specified events in the first 24 hours after surgery. It is therefore not simply a measure of whether an operation began or was completed; the endpoint also depends on the reasons for conversion and on whether a major complication occurred during the stated window.

The two procedure groups are described separately, but they are not randomized treatment arms or like-for-like controls. Prostatectomy and cholecystectomy are different procedures in different clinical contexts. The record does not establish a comparative question about the device versus another surgical approach. It instead describes an evaluation of the device system in these procedures, without an external or concurrent control group.

3. Trial Design

The registry describes a prospective, single-center, single-arm pivotal trial of the Medtronic Hugo RAS System. It is marked completed, with enrollment of 42 participants. The stated setting was a single site in the Republic of Korea. Participants underwent robotic-assisted prostatectomy or robotic-assisted cholecystectomy; the record describes 20 participants for each procedure as the minimum enrollment goal. The enrolled total is reported separately as 42.

There was no randomized allocation and no masking. Because the study has one arm, its procedure groups should not be interpreted as a randomized comparison. They represent different surgical procedures, and the registry does not describe one as a control for the other. Any comparison between their event counts would be descriptive rather than a controlled estimate of a treatment difference.

The primary endpoint timeframe is 24 hours after surgery. The brief summary states that participants were followed for 30 days (±7 days) after the procedure. Listed secondary outcomes include overall and major complication rates, readmission, reoperation, and device deficiency through 30 days after surgery. The registry record identifies six outcome measures and six analyses, but does not report the numerical results for these outcomes in the information available for interpretation.

The record lists a start date of 2023-02-12 and a primary completion date of 2023-06-05. It does not report the rationale for those dates, a detailed recruitment flow, or an account of deviations from the intended enrollment. The record also does not report a protocol-level statistical analysis plan or a sample-size 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.

Before assignment: After enrollment, two Cholecystectomy subjects exited the study before surgery due to a surgeon's decision and a console communication error. These two subjects did not undergo a procedure with the Hugo™ RAS System and were treated with laparoscopy as Standard-of-care treatment.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: For the analysis, we considered the Full Analysis Set (FAS), defined as all enrolled subjects who began the Hugo™ RAS procedure (first skin incision). Subjects who consented but did not reach the first incision were excluded. Those converted to open or conventional surgery, not due to the Hugo™ RAS System, were included in the safety and descriptive analyses but excluded from the primary endpoint analysis.

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: The full Analysis Set (FAS) used to evaluate the primary and secondary endpoints was defined as all enrolled subjects in whom a Hugo™ RAS procedure began. Therefore, the 2 cholecystectomy subjects who did not undergo a procedure with the Hugo™ RAS System and exited the study before surgery were excluded from the FAS.

6. Primary Endpoint

The registry lists the primary outcome as Completion Rate, measured over 24 hours.

The primary endpoint is the completion rate, defined as the proportion of participants who completed surgery without conversion due to a serious system malfunction and without any major complication within 24 hours after surgery. It combines procedural completion and early safety conditions in a single binary outcome: each participant either meets the stated definition or does not. The endpoint timeframe is 24 hours.

This kind of composite can summarize more than one clinically relevant aspect of a procedure in a single measure. In this case, it captures both a specified device-related reason for conversion and the occurrence of a major complication during the early postoperative window. Its interpretation depends on each component: a participant may fail to meet the composite because of conversion for the stated reason, a major complication, or both. The record does not report the component-level results or the number meeting the composite.

The analysis population is described as the Full Analysis Set: enrolled participants who began the Hugo RAS procedure, defined by the first skin incision. Participants who consented but did not reach that point were excluded. The registry description of how conversions were handled is incomplete, so the handling of all conversion circumstances is not reported in the registry record. The primary endpoint result itself is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record describes an observational structure in which participants received robotic-assisted surgery with the Hugo RAS System. It does not describe random allocation, masking, or a separate control arm. This design distinction is central to interpreting the statistics: a single-arm trial can describe outcomes among enrolled participants, but by itself it does not estimate a randomized contrast between the device and an alternative approach.

What does a completion rate represent?

A rate is a proportion: the number of participants who meet a defined event criterion divided by the relevant analysis population. Here, the event criterion is the primary endpoint's composite definition, and the stated analysis population is the Full Analysis Set. The record defines that set as enrolled participants who began the procedure, with the first skin incision used to identify the start. It excludes consented participants who did not reach that point. However, the primary endpoint's observed count and denominator are not reported in the registry record, so the rate cannot be reconstructed from the available information.

A binary outcome treats each participant as meeting or not meeting a specified criterion. The registry identifies the outcome type as participants with an event (counts). For this endpoint, the definition involves both a conversion condition and a major-complication condition within the stated period. General statistical principle: when an endpoint combines components, the overall result can be affected by any component, and a total composite count does not reveal which components occurred unless component-specific counts are also reported. Such component details are not reported for the primary endpoint.

Why does the analysis population matter?

The population included in an analysis determines which participants contribute to its denominator and how the result should be understood. The Full Analysis Set in this record begins with participants who reached the first skin incision, rather than everyone who may have consented. The record's description of conversion handling is cut off after stating that some conversions were not due to the Hugo RAS system; the complete rule is not reported in the registry record. Consequently, it is not possible to establish from this description how every conversion scenario was classified for the endpoint.

General statistical principle: exclusions after enrollment can affect interpretation if excluded participants differ from those analyzed. An account of how many people consented, began surgery, and entered each analysis would help readers understand the flow into the result. Such a complete flow is not reported in the registry record. Nor does the record explain how missing endpoint assessments were handled.

What does the absence of a control group imply?

Without a concurrent comparison group, an observed rate describes outcomes in the trial cohort but does not isolate the contribution of the device from other influences. General statistical principle: comparative effectiveness claims require an appropriate basis for comparing outcomes, and randomization can help make groups comparable by balancing both measured and unmeasured factors on average. This trial is listed as single-arm with allocation marked NA, so it does not offer that randomized contrast. The prostatectomy and cholecystectomy cohorts are not substitutes for control groups because they underwent different procedures.

The record lists safety outcomes and participant counts for each procedure group. These counts are descriptive. General statistical principle: differences in counts or rates between groups can reflect chance, differences in group characteristics, or differences in the procedures and their clinical context. Without a controlled design and reported uncertainty estimates, the counts do not establish a causal difference.

How should planning calculations be read?

The registry description of a planning illustration says it uses the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; for time-to-event outcomes it refers to total events, and for other outcomes to participants per arm. These are described as planning calculations, not as the trial's own design justification. The effect fractions and resulting sample-size values are not reported in the registry record. A planning illustration based on an observed effect should not be interpreted as observed power or as evidence that the design was prospectively justified. General statistical principle: sample-size calculations depend on assumptions about the effect to detect and the analysis method, so their meaning depends on those assumptions.

Confidence intervals, if reported, would convey the range of estimates compatible with the data under the chosen method. General statistical principle: wider intervals indicate less precision, while narrower intervals indicate more precision; neither alone resolves limitations in design or measurement. Confidence intervals for the primary endpoint are not reported in the registry record. The record also does not report the statistical model or inferential method used for the primary endpoint.

What can the listed analysis count tell readers?

The record identifies six outcome measures and six analyses. That count does not reveal which statistical tests were used, whether analyses were prespecified, or how multiple outcomes were handled. General statistical principle: when many outcomes or tests are examined, the chance of finding at least one apparently notable result can increase unless the analysis plan addresses multiplicity. The statistical plan and multiplicity approach are not reported in the registry record. The outcome list alone is therefore insufficient to determine the inferential framework or the strength of any reported finding.

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("RAS Prostatectomy", "RAS Cholecystectomy")
n      <- c(20, 20)
events <- c(20, 19)
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  RAS Prostatectomy  20  20  100.0  83.2  100.0  83.9  100.0  83.9  99.9
ARM  RAS Cholecystectomy  20  19  95.0  75.1  99.9  76.4  99.1  76.2  98.8

11. Multiplicity, Missing Data and Analysis Populations

The registry lists several outcomes, including the primary completion rate and secondary measures of complications, readmission, reoperation, and device deficiency. It identifies six outcome measures and six analyses, but the statistical analysis plan is not reported in the registry record. The record does not state whether a formal hierarchy was used, whether any outcomes were designated as confirmatory, or whether adjustments were made for testing multiple outcomes.

General statistical principle: examining multiple outcomes can increase the chance of observing an apparently unusual result by chance. Prespecification and a clear multiplicity strategy help readers understand how to interpret multiple tests. Without those details, the inferential meaning of any nominal significance result would be uncertain. No primary endpoint result or p-value is reported in the registry record in the information available for this interpretation.

The record defines the Full Analysis Set as participants who were enrolled and began the procedure, identified by the first skin incision. Consented participants who did not reach incision were excluded. The available description of the conversion rule is incomplete. The record does not report how missing assessments, withdrawals, or participants with incomplete follow-up were handled, nor does it provide a complete participant flow for each outcome.

General statistical principle: missingness can affect estimates when the probability of missing data is related to a participant's outcome or characteristics. The extent and handling of missing data are therefore important to interpreting a proportion. Since those details and the endpoint result are not reported in the registry record, the robustness of the primary analysis cannot be evaluated from the available information.

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: asthenia (5.0%), vomiting (5.0%), small bowel nos perforation (5.0%), abdominal wall hematoma (5.0%), biliary tract disorder (5.0%).

The registry lists serious and other adverse events by procedure group. Among participants at risk in the RAS prostatectomy group, 1 of 20 is recorded as affected by a serious adverse event and 4 of 20 by other adverse events. In the RAS cholecystectomy group, 3 of 20 are recorded as affected by a serious adverse event and 2 of 20 by other adverse events. Zero deaths are listed for each group.

These are participant counts, not a randomized comparison of two treatments. The groups underwent different procedures, and no control group is described. The counts should therefore be read as descriptive entries rather than evidence that one procedure or device use has a higher or lower risk than another. The registry record does not provide confidence intervals or detailed event-level information needed to assess the precision or clinical context of these counts.

The record lists serious-event terms including Asthenia, Vomiting, Small Bowel Nos Perforation, Abdominal wall hematoma, biliary tract disorder, and Hypertension, each with a listed frequency of 5.0%. The record does not clarify the group attribution for these terms in the information, nor does it explain whether one participant could contribute more than one event. The listed terms should not be added together or treated as mutually exclusive categories. The event figures also do not replace the primary endpoint result, whose composite definition is distinct.

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

The registry record establishes the trial's purpose and design: a prospective, single-center, single-arm evaluation of the Hugo RAS System in participants undergoing prostatectomy or cholecystectomy. It also defines a primary endpoint that combines a specified system-related conversion condition with the absence of a major complication within 24 hours. Those design details clarify what the study set out to assess.

The available information does not report the primary endpoint count or rate, so it does not show how many participants met the definition. Numerical results for the listed secondary outcomes are also not reported in the registry record. The posted safety counts give a limited descriptive account of adverse events and deaths, but they do not supply a controlled comparison or detailed uncertainty estimates. Thus, the record does not establish comparative benefit or harm relative to another surgical system or approach.

General statistical principle: a result from a single-arm study describes outcomes in the observed cohort, while a causal comparison requires a suitable reference group and an analysis that accounts for the study design. The two procedure groups cannot be treated as comparable treatment arms because they underwent different operations. Even if a result were reported for each, their contrast would not by itself isolate the effect of the device.

The record's safety counts also need to be considered alongside the follow-up windows and endpoint definitions. The primary endpoint uses 24 hours, while the brief summary says all participants were followed for 30 days (±7 days) and several secondary outcomes extend through 30 days. Without the numerical outcome results, completeness of follow-up, and analysis details, the extent of evidence over those periods cannot be judged. The study's reported completion status does not resolve these result-reporting gaps.

Overall, the registry describes a clinical evaluation and reports some adverse-event counts, but the primary effectiveness-related result and several key analysis details are not reported in the registry record. The design and available counts do not support a conclusion about how the device compares with other methods or about the precision of the primary endpoint estimate.

14. Why This Trial Matters Statistically

This trial is statistically relevant because it illustrates how a clearly defined endpoint can still be difficult to interpret when its observed result is not reported. The primary definition identifies a participant-level composite and a 24-hour timeframe, while the analysis population is defined by reaching the first skin incision. These details are essential for understanding what a reported rate would represent. Without the numerator, denominator, or uncertainty estimate, however, the endpoint cannot be evaluated quantitatively.

The trial also highlights the distinction between a device evaluation and a comparative study. The single-arm design can document outcomes among participants undergoing the two procedures, but it does not create a randomized comparison. The procedure cohorts are clinically distinct, so placing their counts side by side does not answer whether outcomes differ because of the device or surgical approach.

The adverse-event entries provide useful descriptive context, including participant counts by procedure group and zero deaths recorded in each group. Their interpretation remains limited by the absence of a control group, uncertainty intervals, and fuller event-level reporting. The listed serious-event terms are not accompanied by enough information to establish their group attribution or whether participants experienced multiple terms.

For clinical researchers and biostatisticians, the record emphasizes the value of reporting endpoint counts, analysis populations, follow-up completeness, missing-data handling, and a prespecified analysis plan. Those details allow readers to judge both the magnitude and precision of an estimate and the extent to which the analysis answers the stated question. The absence of such information is itself important when assessing what can be learned from a registry record.

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 main limitation for interpretation is that the registry record does not report the primary completion-rate result. It also does not report numerical results for the listed secondary outcomes. This prevents assessment of the endpoint's observed frequency, its precision, or how the component events contributed to the composite.

The trial is single-arm and single-center, with no randomized allocation or control group. Its data therefore do not provide a direct comparative estimate against another surgical system or approach. The prostatectomy and cholecystectomy groups involve different procedures and cannot be treated as like-for-like arms. The registry identifies the setting as a single site in the Republic of Korea, so the record alone does not establish how broadly the findings would apply across other settings.

The endpoint combines conversion due to a serious system malfunction with absence of major complications within 24 hours. The component counts are not reported, and the registry's description of conversion handling is incomplete. This limits evaluation of how participants were classified. The Full Analysis Set excludes people who consented but did not reach the first incision; a complete participant flow and the number excluded are not reported in the registry record.

The brief summary states 30-day follow-up (±7 days), but completeness of follow-up and missing-data handling are not reported. Confidence intervals, the statistical method for the primary endpoint, and the multiplicity plan are also not reported in the registry record. Adverse-event counts are available, but event-level details and confidence intervals are absent; the record does not clarify the group attribution of the listed serious-event terms in the information available for interpretation.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Prospective, Single-center, Single-arm, Pivotal Trial of the Medtronic Hugo™ Robotic Assisted Surgery (RAS) System — NCT05715827.
• Registry record last updated 2024-11-05; status last verified 2024-10.
• Results first posted 2024-11-05.
• 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 completed, prospective, single-center, single-arm pivotal trial of the Medtronic Hugo RAS System. Enrollment was 42 participants. The stated minimum enrollment goal was 20 participants undergoing prostatectomy and 20 undergoing cholecystectomy. The primary endpoint was completion without conversion due to a serious system malfunction and without a major complication within 24 hours after surgery, analyzed in a Full Analysis Set of enrolled participants who began the procedure.

The brief summary states follow-up for 30 days (±7 days). The registry lists serious adverse events affecting 1 of 20 participants in the RAS prostatectomy group and 3 of 20 in the RAS cholecystectomy group; other adverse events affected 4 of 20 and 2 of 20, respectively. Zero deaths are listed in each group. The primary endpoint result, numerical secondary outcome results, and key statistical analysis details are not reported in the registry record.