Needleless Jet Injected (J-Tip) Lidocaine in Children Undergoing Regional Anesthesia Prior to Knee Arthroscopy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Needleless Jet Injected (J-Tip) Lidocaine in Children Undergoing Regional Anesthesia Prior to Knee Arthroscopy (NCT02649322), a randomized na study. The primary outcome is Baseline Pain Assessment Before Knee Arthroscopy Via the Visual Analog Scale..

2. Clinical Question

The design therefore contrasts two ways of delivering lidocaine before regional anesthesia in children having knee arthroscopy. The main posted comparison concerns participants’ reported pain before the nerve block; the listed secondary outcome concerns satisfaction at follow-up, an average of one week after the procedure. This distinction matters for interpretation: a baseline measurement characterizes reported pain before the block, while the broader study purpose also refers to experiences associated with the anesthetic procedure. The registry record does not report a posted analysis of pain during needle insertion, pain after the block, or a treatment effect on a later pain outcome. The clinical question can be framed as whether the two groups had different mean scores on the stated baseline assessment, alongside a separate question about follow-up satisfaction. These outcomes describe different moments and concepts and should not be treated as interchangeable.

3. Trial Design

This was a randomized, controlled, parallel-group trial with single masking. The registry record lists 115 participants and marks the study completed. It gives a start date of 2015-09-03 and a primary completion date of 2019-08-28. The phase is listed as not applicable. The registry record does not identify who was masked, so the masking description should not be expanded into an assumption about whether participants, clinicians, assessors, or analysts were unaware of assignment.

Participants were allocated to one of two approaches for delivering plain lidocaine at the regional block site before the nerve-block needle was introduced. Group A received 0.25 mL of 1% lidocaine by J-Tip needleless injector. Group B received 2 mL of 1% lidocaine through a syringe and 25 gauge needle. Both groups were described as receiving a femoral and/or sciatic nerve block and general anesthesia for arthroscopic knee surgery.

The registry lists the primary outcome as baseline pain assessed by a visual analog scale before the nerve block. The scale is described from 0, no pain, to 10, the worst pain the patient had ever experienced. The listed secondary outcome is satisfaction on a 0 to 10 rating scale at follow-up, an average of one week after the procedure. Although three outcome measures are listed in total, only one secondary outcome is posted in the record described by these results. The registry record does not report the other outcome measure details or any outcome analyses beyond the posted summary values.

Random allocation can support a fair comparison between assigned groups when analyzed appropriately, but the registry information does not establish that every aspect of trial conduct or analysis was unbiased. Details such as sequence generation, concealment, adherence, protocol deviations, the identity of the masked party, and the original analysis plan are not reported in the registry record. The posted primary results have group summaries and a simple unadjusted comparison; no registry-reported analysis is listed.

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: Comparison of the mean pain on visual analog scale

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 Baseline Pain Assessment Before Knee Arthroscopy Via the Visual Analog Scale., measured over During Baseline Assessment, Taking Approximately 20 Minutes, Before Nerve Block.

The primary endpoint is mean pain on a visual analog scale measured during baseline assessment, before the nerve block. The registry describes a patient-reported score from 0 for no pain to 10 for the worst pain the patient had ever experienced. The assessment was made before nerve block and was described as taking approximately 20 minutes. It is therefore a measure of reported pain at baseline, not a direct score of pain caused by lidocaine delivery or of pain relief after regional anesthesia.

A continuous score preserves the degree of reported pain rather than reducing responses to broad categories. Comparing group means describes the difference in average scores, while the standard deviations describe how much individual scores varied around each group mean. These are general features of continuous-outcome summaries, not evidence about how the scale performed in this particular study.

In a randomized trial, baseline measures can describe the groups and allow assessment of their starting characteristics. A baseline outcome is not, by itself, a post-treatment outcome. The registry record labels the primary measure as a comparison of mean baseline pain, while the study purpose also discusses pain outcomes and satisfaction related to the anesthetic approaches. The timing of the posted measure limits what it can answer: it does not directly quantify pain during the block procedure, pain afterward, or the effect of either delivery method on subsequent pain. The registry record does not report a change-from-baseline endpoint or a later pain score as the posted primary result.

7. Results Posted in the Registry

• Group B Lidocaine Syringe: mean 0.43 versus 0.25 on control; difference 0.18 (95% CI -0.26 to 0.62), standardized effect d = 0.15; z-test p = 0.427.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Satisfaction Via a 0 to 10 Rating Scale at Follow up

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Group B Lidocaine Syringe: mean 2.39 versus 2.38 on control; difference 0.01 (95% CI -0.82 to 0.83), standardized effect d = 0.00; z-test p = 0.987.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Group B Lidocaine Syringe and the control. The interval gives the range of effects that remain compatible with the data.

The posted secondary outcome is satisfaction on a 0 to 10 rating scale at follow-up, an average of one week after the procedure. Its group means are close, and the unadjusted confidence interval for the comparison includes zero. The group standard deviations differ, indicating that the observed spread of satisfaction scores was not the same in the two groups. The registry record does not report a further analysis that accounts for this or other participant characteristics.

At a broad level, the secondary result follows the same general pattern as the baseline primary comparison: the posted group averages are close, and the uncertainty around the estimated difference does not rule out zero. That shared pattern does not mean the outcomes are replications of one another. Baseline pain and follow-up satisfaction are distinct measures taken at different stages, and they answer different questions. In particular, the primary measure is taken before the block, whereas the secondary measure is taken after the procedure.

Unadjusted secondary comparisons carry less weight when several outcomes or comparisons may be examined, because the chance of finding an apparently notable result can increase across multiple tests. This is a general statistical concern. The registry record does not report a multiplicity strategy, a hierarchy among secondary outcomes, or whether the posted satisfaction comparison was prespecified. The registry lists three outcome measures but only one secondary outcome with posted results, and it reports no analyses in the analyses field. These gaps make it difficult to place the secondary result within a complete outcome-reporting plan.

The secondary data can be read as descriptive evidence about reported satisfaction in the observed groups, with uncertainty around the comparison. They do not establish that the interventions are equivalent, and they do not answer whether pain during or after block placement differed. The result is best considered alongside the endpoint definition and the limitations in the registry record, rather than as a standalone confirmatory finding.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Satisfaction Via a 0 to 10 Rating Scale at Follow up

9. Statistical Interpretation

10. Statistical Methods Explained

What does a mean summarize?

A mean is the arithmetic average of the observed scores in a group. For a continuous measure such as the visual analog scale, the mean provides a compact description of the group’s central score. It does not describe every participant’s experience or show the full distribution of individual scores. In this trial, the posted baseline means were 0.25 for Group A and 0.43 for Group B. The secondary satisfaction means were 2.385 and 2.391. Those values describe the group averages at the times specified for each outcome; they are not interchangeable because the outcomes measure different things and were assessed at different times.

The standard deviation describes variability among scores around the mean. A larger standard deviation indicates more spread in the observed scores, while a smaller one indicates scores more concentrated around the mean. The baseline standard deviations were 1.243 for Group A and 1.185 for Group B. For follow-up satisfaction, the respective standard deviations were 1.796 and 2.624. Standard deviations are not standard errors: the former describe variation among participant scores, while a standard error describes uncertainty in an estimate such as a mean.

What does the mean difference represent?

The reported primary mean difference is the syringe-group mean minus the J-Tip-group mean. Its positive value of 0.18 follows from that direction of comparison; it indicates that the syringe group’s posted baseline average was higher. The direction is descriptive and does not establish a treatment effect. Because the endpoint is measured before the nerve block, the mean difference is a comparison of baseline reports rather than a direct comparison of post-treatment pain.

The comparison also reports a standardized effect size, d, of 0.148. A standardized effect expresses a mean difference relative to a pooled measure of variability, allowing effects measured on different scales to be placed on a common scale. It can help describe magnitude, but it does not supply a clinical-importance threshold. The registry record does not report a prespecified threshold for interpreting this effect size.

How should a p-value be read?

The unadjusted p-value for the primary comparison is 0.427. In general, a p-value describes how compatible the observed data, or data more extreme, are with a statistical model that assumes no difference and the other assumptions of the test. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of an effect. The value is unadjusted, meaning the posted comparison is not reported as corrected for multiple testing. The registry record does not report the test’s full specification, any adjustment for covariates, or a broader multiplicity plan.

A p-value above a conventional significance threshold is not proof that groups are equal. A failure to detect a difference can occur when the underlying difference is small, when the data are imprecise, or when other assumptions are not met. Equivalence or non-inferiority would require an appropriate design and prespecified margin; the registry record does not report such a margin or analysis.

Why do confidence intervals matter?

A confidence interval gives a range of estimates compatible with the data under the method used and its assumptions. It communicates both the direction and the precision of an estimated difference. The primary interval includes zero, so values representing a difference in either direction, as well as no difference, remain compatible with the posted comparison. A wide interval indicates less precision than a narrow interval. The interval should not be interpreted as a range containing a fixed proportion of individual participant scores.

The registry record posts a confidence interval for the mean difference, but it does not describe the interval method or report an adjusted interval. As with the p-value, the interval is tied to the stated comparison and the assumptions of its calculation. It does not resolve the limitation that the primary endpoint was collected before the nerve block.

What is over-dispersion, and does it apply?

In general, over-dispersion refers to observed variation greater than a model expects. It can matter for outcomes modeled with a particular probability distribution, especially counts or binary outcomes, because underestimating variability can make uncertainty look too small. The posted primary and secondary outcomes are continuous scores summarized by means and standard deviations, not counts analyzed with a count model. The registry record does not report an over-dispersion assessment or a model for these outcomes. It would therefore be inappropriate to assert that over-dispersion was present or that a specific correction was needed.

More generally, statistical conclusions depend on the design, outcome distribution, missingness, and analysis choices. The registry record gives summary statistics and unadjusted comparisons but does not report sufficient detail to verify all modeling assumptions or reconstruct an original analysis plan. The posted summaries are useful descriptions of the recorded outcomes, but they do not substitute for a full protocol and statistical analysis report.

11. Confidence Intervals and Precision

The primary estimated mean difference is 0.18, comparing the syringe group with the J-Tip group. Its confidence interval spans zero, so the data do not pin down the direction of the difference with high certainty. The interval also permits differences away from zero, rather than concentrating only on a single precise value. Thus, the posted results are compatible with no mean difference and with some nonzero differences under the interval’s assumptions.

Precision is about how narrowly the data locate an estimate, not whether the estimate is important to patients or clinicians. The primary group means are close, and the standard deviations show variation among individual scores. The confidence interval is the key summary of uncertainty around the estimated difference; the p-value alone does not show the range of plausible values. The unadjusted p-value of 0.427 is consistent with the interval including zero, but neither statistic establishes equality.

The registry record does not give a threshold for a clinically important difference on the baseline visual analog scale. Consequently, the interval cannot be classified as excluding all clinically meaningful differences based on the registry information. It also does not report an equivalence margin or a non-inferiority framework. A reader should distinguish the observed estimate, the uncertainty around it, and the clinical interpretation that would require a prespecified meaningful threshold.

The secondary satisfaction comparison also has a confidence interval that includes zero. It is a separate estimate with its own precision and should not be combined with the primary result as if both assessed the same construct. The posted record does not describe multiplicity adjustment or adjusted confidence intervals. Precision should therefore be understood as applying to each stated unadjusted comparison, not as a comprehensive claim across all outcomes.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are illustrative calculations based on the observed effect, rather than the trial’s original design assumptions. The registry record does not report the original sample-size justification or the assumptions used when planning enrollment. For these continuous outcomes, the displayed planning quantities are participants per arm, not total events. The stated calculation assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The calculation uses the stated fraction of the observed effect as the effect to detect.

The 80% power column describes the number of participants per arm that the illustration estimates would be needed to have an 80% chance of detecting an effect of the specified size under those assumptions, if that effect were real. The 90% power column gives the corresponding planning quantity for a higher probability of detecting that effect. These are design calculations, not a description of the probability that the completed trial found a real effect.

The rows illustrate planning for 100%, 75%, and 50% of the observed effect. For both posted comparisons, the illustrated participant requirements rise as the effect to detect becomes smaller. This is a general consequence of planning to detect smaller differences: smaller signals are harder to distinguish from random variation, so more participants are generally needed under otherwise similar assumptions. The very large figures for the satisfaction comparison reflect the very small observed difference used in that calculation; they should not be read as a recommendation or a trial requirement.

This is not observed power. It is a planning illustration derived from the observed effect, and it should not be used to infer whether the study was adequately powered according to its original plan. The registry record does not report that original plan, a target effect chosen before enrollment, or the trial’s own sample-size justification. The figures also rely on simplified assumptions and do not document possible design features or analysis choices beyond those stated.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 0.180; pooled standard deviation σ = 1.215.
2. n = 2 × (1.96 + 0.842)² × 1.215² / 0.180² = 714.8, rounded up to 715 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 0.18                      # observed difference in means
sigma <- 1.21460286309734                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(2649322)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 715 (80% power), 957 (90% power)
 75% of observed effect: n per arm = 1,271 (80% power), 1,702 (90% power)
 50% of observed effect: n per arm = 2,860 (80% power), 3,828 (90% power)
power.t.test: 715.7 
Simulated power at n = 715 per arm: 0.801 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when a study evaluates several outcomes, time points, groups, or statistical comparisons. In general, making many inferences without a planned adjustment can increase the chance that at least one result appears unusual by chance. A prespecified outcome hierarchy or an adjustment procedure can help clarify how such results should be interpreted. The registry record lists three outcome measures, but only one secondary outcome is detailed with posted results. It does not report a multiplicity strategy, an outcome hierarchy, or whether any adjustment was planned. The posted p-values should therefore be understood as unadjusted comparisons, not as results corrected across all outcomes.

The registry record does not report how missing data were handled. The posted primary and secondary summaries include 58 participants in Group A and 57 in Group B, but the record does not explain whether these numbers represent all randomized participants, the number with available outcome data, or an analysis subset. It does not describe reasons for missing observations, imputation, or sensitivity analyses. Without that information, the possible influence of missingness on the estimates cannot be assessed from the posted summaries alone.

The analysis population is also not reported in sufficient detail. The registry record does not say whether the results follow an intention-to-treat approach, a per-protocol approach, or another defined population. It does not give information about exclusions after randomization, protocol deviations, or treatment adherence. These details matter because excluding participants or analyzing them according to treatment received rather than assigned can affect what a randomized comparison estimates.

The registry lists zero reported analyses, although outcome summary values and comparisons are posted. It does not provide a full statistical analysis plan, the method used for the primary comparison, or the handling of baseline characteristics. These absences do not show that such procedures were not performed; they mean that they are not reported in the registry record. Interpretation should accordingly remain limited to the posted unadjusted summaries and their stated outcome definitions.

15. 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.

The registry reports zero serious adverse events in Group A among 58 participants at risk and zero in Group B among 57 participants at risk. It also reports zero other adverse events in both groups, and zero deaths in each group. No serious adverse event terms are listed.

These figures should be read as the adverse event counts recorded for the stated groups and risk sets. They do not establish that an event was impossible, nor do they rule out uncommon events or events not captured in the registry record. The record does not provide additional detail about event definitions, collection procedures, duration of safety follow-up, or whether all participants had the same opportunity for adverse event reporting. It also does not report a formal comparative safety analysis.

A count of zero is not the same as proof of no risk. The number of participants represented in these summaries is limited, and the registry record gives no further safety detail that would support a broader conclusion. These counts describe what was posted and should not be interpreted as medical advice or as a complete safety assessment.

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

The posted results describe a randomized comparison of two lidocaine delivery approaches before regional anesthesia for knee arthroscopy. The primary endpoint is a baseline pain score taken before the nerve block. The observed group means were close, and the estimated mean difference had a confidence interval that included zero. The follow-up satisfaction comparison also had a confidence interval that included zero. These results indicate uncertainty about the direction and size of the group differences in the posted comparisons.

They do not prove that the methods produce identical experiences, establish equivalence, or show that no difference exists. Such claims would require an appropriate design, prespecified margin, and analysis, none of which is reported in the registry record. The results also do not establish that either method changes pain during the injection, pain after the block, or postoperative pain, because the posted primary score was measured before the nerve block and no such analysis is posted in the stated results.

The baseline score is useful as a description of the groups’ starting pain reports, but its timing limits its relevance to treatment effects. The secondary satisfaction result concerns a later and different concept, and the registry does not report multiplicity handling. The posted adverse event figures are zero counts for the listed categories, not proof that adverse events cannot occur or a complete safety assessment.

More complete interpretation would depend on information not reported in the registry record, including the original statistical plan, missing-data handling, analysis population, masking details, and the other listed outcome measures. The posted summaries can be described accurately without extending them to unreported endpoints or claims about clinical benefit. They are evidence about the observed group summaries and the uncertainty of the comparisons, rather than definitive evidence of equality or difference.

17. Why This Trial Matters Statistically

This trial illustrates why endpoint timing is central to statistical interpretation. The study’s stated purpose concerns pain outcomes and satisfaction related to two ways of delivering lidocaine before regional anesthesia. Yet the posted primary endpoint is baseline pain before the nerve block. A baseline score can characterize participants and their starting reports, but it does not directly measure pain caused by the block procedure or pain relief afterward. Naming the endpoint precisely prevents a comparison from being interpreted as answering a broader question than the recorded outcome supports.

The results also demonstrate the difference between a small observed group contrast and a precise conclusion. The primary means are close, but the confidence interval includes zero and the registry record supplies no clinical-importance threshold. A non-significant result is not evidence of equivalence. Readers need both the estimated difference and its uncertainty, as well as an appropriate design if the intended question is whether the approaches are sufficiently similar.

The record further highlights the importance of reporting statistical plans and analysis populations. A randomized design is valuable, but interpretation depends on knowing how assignment, missing outcomes, protocol deviations, multiple outcomes, and analysis sets were handled. Those details are not reported in the registry record. The planning illustrations are based on observed effects and cannot substitute for the original sample-size rationale.

These are general lessons for clinical trial reporting: align the claim with the actual measurement and its timing, read estimates together with intervals, and distinguish absence of statistical evidence from evidence of absence. The posted summaries offer a limited but interpretable account, while leaving key design and analysis details unresolved.

18. 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.

A central limitation is that the posted primary endpoint is baseline pain before the nerve block. Although the study purpose discusses pain outcomes related to the anesthetic approaches, the stated primary result does not directly measure pain during lidocaine delivery, during block placement, or after the block. The registry record does not post a later pain outcome analysis among the results described. This timing constrains how directly the primary comparison addresses the broader purpose.

The registry record does not report the original sample-size justification or the target effect used to plan enrollment. It also does not describe the method used for the primary analysis, any covariate adjustment, or a prespecified threshold for clinical importance. Consequently, the posted non-significant comparison cannot establish equivalence, and the planning illustrations based on observed effects cannot establish whether the trial met its original design goals.

Information about missing data, analysis populations, and protocol deviations is not reported in the registry record. Although group sizes are posted for both outcomes, the record does not explain whether all randomized participants contributed data or how unavailable scores were handled. The identity of the masked party is also not reported, despite the single-masking designation. The record does not describe allocation concealment or other implementation details.

The registry lists three outcome measures but posts only one secondary outcome with results, and it does not report a multiplicity plan. This limits assessment of selective outcome reporting and the confirmatory status of the secondary comparison. Safety reporting is also limited to event counts without detailed definitions, collection methods, or follow-up information. These are limitations of what the registry record reports; they do not establish that unreported procedures or information were absent from the full study.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Needleless Jet Injected (J-Tip) Lidocaine in Children Undergoing Regional Anesthesia Prior to Knee Arthroscopy — NCT02649322.
• Registry record last updated 2020-05-05; status last verified 2020-04.
• Results first posted 2020-04-28.
• 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.

22. Record Summary

The registry record describes a completed, randomized, controlled, parallel-group trial with single masking and 115 enrolled participants. It compares needleless J-Tip delivery of 0.25 mL of 1% plain lidocaine with delivery of 2 mL of 1% plain lidocaine by syringe and 25 gauge needle, before introduction of the nerve-block needle.

The posted primary outcome is baseline visual analog scale pain before the nerve block. The group means were 0.25 and 0.43, with a reported mean difference of 0.18 and an unadjusted p-value of 0.427. The posted secondary outcome is satisfaction at follow-up, an average of one week after the procedure; its group means were 2.385 and 2.391. The confidence intervals for both comparisons include zero.

The registry reports zero serious adverse events, zero other adverse events, and zero deaths in each group. Details of the original statistical plan, missing-data handling, analysis populations, multiplicity strategy, and the other listed outcome measures are not reported in the registry record.