ON-Q Pump Infusion of Ketorolac and Ropivacaine at the Wound Site for Postoperative Pain Management: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for ON-Q Pump Infusion of Ketorolac and Ropivacaine at the Wound Site for Postoperative Pain Management (NCT00638508), a randomized phase 4 study. The primary outcome is Pain Scores at Rest.

2. Clinical Question

The question concerns the relative results of two local infusion regimens, not a comparison of either regimen with no treatment or with morphine alone. Both arms include ketorolac; the additional drug in the combination arm is ropivacaine. The primary outcome is a reported pain score at rest one hour after surgery. The registry record describes the scale as ranging from 1 to 10, with 1 indicating minimal pain intensity and 10 indicating maximal pain intensity.

The posted primary results give an arm mean and standard deviation for each regimen, along with an estimated mean difference and confidence interval. These summaries describe the observed group results and the uncertainty around their comparison. They do not by themselves establish how the regimens would compare in other populations, surgical procedures, or time points. The registry record does not report detailed eligibility criteria, the exact gynecologic procedures, or other population characteristics that would help assess how broadly the results apply.

3. Trial Design

The registry record describes a randomized, triple-masked, parallel-group Phase 4 study. It is listed as completed and names Maimonides Medical Center as sponsor. The recorded study start is 2007-06 and the primary completion date is 2008-08. Registry enrollment is 67. The posted primary outcome summaries list 30 participants in each arm; the record does not explain the relation between these outcome counts and the enrollment figure.

The comparison was between ketorolac and ketorolac with ropivacaine, administered by infusion at the wound site. The ketorolac arm description gives a dose of 5 mg/hr, not to exceed 120 mg/day. The combination-arm description gives ketorolac 5 mg and ropivacaine 0.5% via an infusion catheter at the incision site. The registry record does not report further details about the infusion duration or the timing and procedures for placing or removing the catheter.

The primary outcome was pain scores at rest one hour after surgery. The registry record also lists secondary measures concerning morphine equivalents, drowsiness, nausea, and vomiting. Numerical summaries are posted for morphine equivalents at one hour, morphine equivalents at 12 hours, and drowsiness at one hour. The record lists 20 outcome measures and reports 11 secondary outcomes as posted, but the details of all measures are not included in the numerical results presented.

Specific information about the masking procedures, allocation concealment, treatment adherence, participant flow, exclusions, and analysis populations is not reported in the registry record. The record also does not report the original sample-size justification or the study’s prespecified statistical analysis plan. Those omissions limit how completely the design and conduct can be assessed from the registry information alone.

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

Reasons for not completing this period:

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: Overall number of participants: 35 in Ketorolac group and 32 in Ketorolac with Ropivacaine group. Number of participants analyzed: 30 in each group. 5 participants from the ketorolac and 2 participants from the Ketorolac with Ropivacaine group were omitted from the study. Reason for omission- Physician decision.

6. Primary Endpoint

The registry lists the primary outcome as Pain Scores at Rest, measured over 1 hour after the surgery.

The primary endpoint is pain at rest one hour after surgery, reported as a mean score on a Visual Analog Scale. The registry description says the scale ranges from 1 to 10, with 1 representing minimal pain intensity and 10 representing maximal pain intensity. A pain score converts a participant’s rating of symptom intensity into a numerical measure that can be summarized across a group and compared between treatment arms.

Reporting the mean gives a measure of the group’s average score; the standard deviation describes how spread out the individual scores are around that average. The endpoint’s stated timing focuses the comparison on an early postoperative assessment. It does not describe pain at other times, pain during movement, or longer-term recovery. The registry record does not report the instrument’s administration details, whether the score was collected by a blinded assessor, or how missing pain assessments were handled.

The primary result is a comparison of group means, rather than a count of participants above or below a threshold. The posted results therefore estimate the average difference in reported scores and give a confidence interval to show the uncertainty around that estimate. Such a summary can help readers distinguish the estimated direction and size of the group difference from the precision of that estimate. It does not, on its own, establish the importance of a difference to individual participants; the registry record does not report a threshold for a clinically meaningful change.

7. Results Posted in the Registry

• Ketorolac With Ropivacaine: mean 6.20 versus 6.70 on control; difference -0.50 (95% CI -1.80 to 0.80), standardized effect d = -0.19; z-test p = 0.452.

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.

Morphine Equivalents Utilization

• 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:
  • Ketorolac With Ropivacaine: mean 4.00 versus 6.30 on control; difference -2.30 (95% CI -3.54 to -1.06), standardized effect d = -0.94; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Ketorolac With Ropivacaine than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Morphine Equivalents

• 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:
  • Ketorolac With Ropivacaine: mean 1.50 versus 2.10 on control; difference -0.60 (95% CI -1.24 to 0.04), standardized effect d = -0.48; z-test p = 0.065.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Ketorolac With Ropivacaine and the control. The interval gives the range of effects that remain compatible with the data.

DROWSINESS

• 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:
  • Ketorolac With Ropivacaine: mean 4.40 versus 4.00 on control; difference 0.40 (95% CI -0.97 to 1.77), standardized effect d = 0.15; z-test p = 0.566.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Ketorolac With Ropivacaine and the control. The interval gives the range of effects that remain compatible with the data.

The secondary results span measures of morphine equivalents at different assessment times and drowsiness at one hour. Their pattern is not uniform across outcomes: the posted comparison for morphine equivalents at one hour differs in precision from the 12-hour comparison, while the drowsiness comparison has an interval spanning values on either side of zero. These measures address related but distinct aspects of postoperative experience and medication use, so they should not be combined into a single overall claim.

These outcomes provide context for the primary pain-score comparison, but they do not replace it. The primary endpoint concerns pain at rest at one hour; the secondary measures concern opioid use or drowsiness and, in one case, a later assessment time. A result on a secondary measure does not establish a corresponding difference in pain, and a primary result does not determine the pattern for every secondary outcome. The registry record also lists nausea and vomiting among secondary outcomes, but numerical results for those measures are not reported in the posted summaries.

Unadjusted secondary results carry less weight when several outcomes or time points are considered. With multiple comparisons, the chance of finding an apparently notable result by chance can increase. This is a general statistical concern, not evidence that any particular result is false. The registry record does not report a multiplicity adjustment, a testing hierarchy, or a prespecified distinction between confirmatory and exploratory secondary outcomes. As a result, individual secondary p-values should be treated as descriptive evidence rather than as a complete, controlled set of confirmatory tests.

The record lists more secondary outcomes than the numerical summaries that are available for interpretation. The reason for this difference is not reported in the registry record. Without full outcome reporting, a prespecified plan, and information about missing assessments, it is not possible to assess whether the posted secondary measures represent all planned analyses. The most defensible reading is therefore to consider the secondary pattern alongside the primary estimate while avoiding selective emphasis on any single unadjusted comparison.

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

• Morphine Equivalents Utilization
• Morphine Equivalents
• Morphine Equivalents
• DROWSINESS
• DROWSINESS
• NAUSEA
• NAUSEA
• VOMITING

9. Statistical Interpretation

10. Statistical Methods Explained

The posted continuous outcomes are summarized with means and standard deviations. A mean describes the average observed score or amount in an arm. A standard deviation describes the spread of observations around that arm’s mean; it is not the same as the uncertainty around the mean or the uncertainty around the between-arm comparison. The primary outcome is a mean pain score, and the secondary numerical outcomes are also reported as means.

What does a mean difference represent?

A mean difference compares the arm averages by subtracting the comparator mean from the intervention mean. In the primary comparison, the registry record reports the combination arm relative to ketorolac alone. A negative estimate therefore means the observed average was lower in the combination arm; a positive estimate would mean it was higher. The mean difference retains the original outcome’s units, so the pain-score contrast is expressed in score units and the morphine-equivalent contrasts in the reported milligram units.

A group-level mean difference is not a statement about every participant. Individual values can vary around each arm’s mean, as the reported standard deviations indicate. A mean comparison also does not show the distribution’s shape or whether a small number of observations strongly influenced the mean. The registry record does not report individual-level data, distributional diagnostics, or adjusted model estimates.

What does a confidence interval add?

A confidence interval gives a range of values compatible with the observed data under the statistical method used, and conveys the estimate’s precision. A narrower interval indicates greater precision than a wider interval on the same scale. If an interval for a mean difference includes zero, the data are compatible with no average difference as well as with differences on either side of zero. If it excludes zero, that is evidence against a zero difference under the assumptions of the analysis. This interpretation does not determine whether an effect is clinically important.

The posted comparisons include confidence limits, but the registry record does not identify the specific inferential procedure used to obtain them or report an adjusted analysis. The primary comparison’s interval ranges from -1.803 to 0.803. Its inclusion of zero means the posted result does not precisely resolve the direction of the average difference. The interval should be considered alongside the point estimate and the outcome scale, not reduced to a binary label.

How should a p-value be read?

A p-value describes how unusual data at least as inconsistent with a specified null model would be if that model and the statistical assumptions were correct. It is not the probability that the null hypothesis is true, the probability that the observed result arose by chance, or a measure of effect size. The primary comparison has an unadjusted p-value of 0.452. The secondary p-values are also unadjusted. Because the registry record does not report a multiplicity plan, these values should not be interpreted as if they were the only tests conducted.

Statistical significance and practical importance are different questions. A small p-value does not establish that a difference matters to participants, and a larger p-value does not demonstrate that the regimens are equivalent. An equivalence conclusion would require a prespecified equivalence margin and an analysis designed for that purpose; neither is reported in the registry record.

Why does variability matter?

Variability affects how precisely an arm mean and a between-arm difference can be estimated. When observations are more dispersed, a given number of observations generally provides less precise information about the average. This is why the standard deviations are relevant to interpreting the means and why the same estimated difference can have different precision in studies with different variability or sample sizes. These are general statistical principles; the registry record does not report diagnostics showing whether the assumptions for the posted comparisons were assessed.

The posted summaries use standard deviations, but they do not provide enough information to evaluate the full distribution of the outcomes. For example, they do not show whether values were skewed, whether there were influential observations, or whether a normal approximation was appropriate for every measure. The sample-size illustration explicitly uses a normal approximation, but the original trial’s analysis method is not reported in the registry record.

What is and is not reported about the analysis?

The record identifies a randomized, triple-masked, parallel design, but does not report the statistical analysis plan, the original sample-size justification, interim analyses, or the analysis populations. It does not describe adjustment for baseline values or other covariates, handling of missing observations, or whether all randomized participants were analyzed according to their assigned arm. Those details can affect how a comparison should be interpreted.

The record’s reported-analysis field is empty, while outcome summaries and comparison statistics are posted. The posted values can be described as reported results, but the absence of analysis documentation prevents a full audit of how estimates and p-values were obtained. No discrepancy between the reported comparison and a recalculated result is flagged in the registry record. Accordingly, the discussion should focus on the posted summaries and their uncertainty, without attributing an unreported model or analysis strategy to the investigators.

In general, randomization aims to make groups comparable at the start of a trial, and masking can reduce some risks of biased care or assessment. These design labels do not establish that allocation was concealed or that masking was maintained; those operational details are not reported in the registry record. The design information is relevant context, but it does not replace details about conduct, outcome completeness, and analysis.

11. Confidence Intervals and Precision

The primary mean difference is -0.5 pain-score units for ketorolac with ropivacaine relative to ketorolac alone. Its confidence interval extends from -1.803 to 0.803. Because the interval includes zero, the observed data do not pin down the direction of the average difference with high precision. The estimate is compatible with a lower average score in the combination arm and also with a higher average score. The interval does not prove that the treatments are the same.

Precision is distinct from the point estimate. The point estimate is the single value that best summarizes the observed comparison under the reported calculation; the interval describes uncertainty around it. The two arm standard deviations are 2.2 and 2.9, and the posted outcome summaries list 30 participants in each arm. These figures give context for the variability and size of the posted outcome groups, but do not remove the uncertainty shown by the interval.

The registry record does not report a clinically meaningful difference threshold for the pain scale. Therefore, the interval cannot be used to decide whether all values it contains would be trivial or important to participants. Nor does the record report an equivalence margin. A nonsignificant unadjusted p-value of 0.452 does not establish equivalence; it indicates that the comparison did not provide strong evidence against a zero difference under the reported test.

Confidence intervals also depend on the statistical method and its assumptions. The registry record posts limits but does not describe the method used to calculate them, whether the analysis adjusted for other factors, or how missing outcomes were handled. The interval is useful evidence about the uncertainty represented by the posted comparison, while the lack of analysis details limits independent assessment of that uncertainty.

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 participants per arm, not a total across arms or a count of total events. The sample-size illustration assumes a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It uses the stated fraction of the observed effect as the effect to detect. These are assumptions for the planning illustration; the registry record does not report the original trial’s sample-size assumptions or justification.

The 80% power column gives the estimated participants per arm for a future study to have an 80% chance of detecting the specified effect under those assumptions, if that effect and the assumptions are correct. The 90% power column gives the corresponding planning figure for a 90% chance. For example, planning for 100% of the observed primary effect gives 416 participants per arm for 80% power and 557 participants per arm for 90% power. Planning for 75% of the observed effect gives 740 participants per arm for 80% power and 991 participants per arm for 90% power; planning for 50% gives 1,664 and 2,228 participants per arm, respectively.

Smaller effects are harder to distinguish from random variation, so the planning figures rise as the target effect becomes a smaller fraction of the observed effect. The figures depend on the assumptions and the observed estimate used as their starting point; a different true effect or variability could lead to different planning needs. This is not observed power: it is a planning illustration, not a measure of how likely the completed trial was to detect an effect after its results were known.

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 = -0.500; pooled standard deviation σ = 2.574.
2. n = 2 × (1.96 + 0.842)² × 2.574² / -0.500² = 416.0, rounded up to 416 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 <- -0.5                      # observed difference in means
sigma <- 2.57390753524675                     # 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(638508)
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 = 416 (80% power), 557 (90% power)
 75% of observed effect: n per arm = 740 (80% power), 991 (90% power)
 50% of observed effect: n per arm = 1,664 (80% power), 2,228 (90% power)
power.t.test: 417 
Simulated power at n = 416 per arm: 0.800 (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, or comparisons. Even when each individual test uses a conventional threshold, examining many results can increase the chance that at least one appears statistically notable by chance. This is a general statistical issue. It does not mean that a particular secondary result is necessarily spurious, but it affects how much weight should be placed on isolated unadjusted findings.

The registry record lists multiple outcome measures, including pain, morphine equivalents, drowsiness, nausea, and vomiting. Numerical comparison results are posted for the primary pain outcome and for three secondary summaries. The record does not report a multiplicity correction, a prespecified hierarchy among outcomes, or which secondary comparisons were intended to be confirmatory. The posted secondary p-values are unadjusted, so they should be interpreted with this uncertainty in mind.

Missing-data handling is also not reported in the registry record. It does not state how many participants had each outcome measured beyond the posted arm-level counts, whether any observations were missing, why they might be missing, or how missing measurements were treated in the analyses. Missingness can affect both the precision and the validity of a comparison, particularly if the reasons for missingness differ between arms or are related to the outcome. The available record does not allow those possibilities to be evaluated.

The analysis populations are not described. The registry record does not say whether the posted comparisons use all randomized participants, only those with observed outcome measurements, or another population. It also does not report exclusions after randomization or whether analyses followed assigned treatment. These details matter because different analysis populations can answer different questions and can affect the protection afforded by randomization.

The original statistical analysis plan, interim analyses, and sample-size justification are not reported in the registry record. Without these details, it is not possible to determine whether the posted outcomes and analyses were prespecified, whether any interim decisions affected the study, or whether the trial was designed around a particular target difference. These are limitations of the registry information and should not be filled in by assumption.

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 serious-adverse-event summaries list 30 participants at risk in each arm and zero serious events in each. The summaries also list zero other adverse events and zero deaths in each arm. No serious adverse-event terms are listed. These figures describe the events recorded in the registry’s safety fields for the listed groups.

Zero recorded events should not be interpreted as proof that an intervention has no risk. The registry record does not provide event definitions, collection procedures, the duration of safety follow-up, or details about how completely adverse events were ascertained. It also does not report additional context that would allow the safety figures to be compared across different follow-up periods or populations. The registry record’s spelling of the combination-arm name differs in the adverse-event entry, but the listed regimen is the ketorolac-and-ropivacaine arm.

The safety summaries are separate from the pain and morphine-equivalent outcomes. They do not establish that the regimens have the same safety profile, and the absence of listed events does not rule out uncommon or unrecorded events. These counts should be read as registry-reported observations, with the limited safety detail in the record kept in view.

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

The result describes a randomized comparison of two wound-site infusion regimens after gynecologic surgery. The primary posted estimate is a mean pain-score difference of -0.5 at rest one hour after surgery, with a confidence interval from -1.803 to 0.803. The interval includes zero and allows for differences in either direction. The posted data therefore do not precisely settle the direction or size of the average difference in pain scores.

This result does not establish that the two regimens are equivalent. Equivalence requires a defined margin and an analysis designed to test whether the plausible differences fall within that margin. Neither is reported in the registry record. The result also does not establish that either regimen is ineffective, or that the observed group averages apply to every participant. It is a summary of the posted trial comparison at a specific outcome and time point.

The secondary results provide additional but distinct information. They include morphine-equivalent summaries at one hour and 12 hours and a drowsiness measure at one hour. The registry record lists nausea and vomiting as outcomes but does not provide numerical results for them in the posted summaries. Because the secondary comparisons are unadjusted and the record does not report a multiplicity plan, they should not be treated as definitive evidence based on individual p-values.

The registry record does not report detailed eligibility criteria, the original analysis plan, missing-data procedures, analysis populations, or a clinically meaningful threshold for the primary scale. These omissions limit assessment of the trial’s conduct, the robustness of the estimates, and the relevance of the results to settings beyond the study. The posted findings are statistical evidence about the recorded trial outcomes, not medical advice or a general recommendation about postoperative pain management.

17. Why This Trial Matters Statistically

This trial is statistically instructive because its primary point estimate and its uncertainty need to be read together. The estimated mean difference is modest in the scale’s units, but the confidence interval spans zero and extends in both directions. A point estimate alone can suggest a simple story; the interval makes clear that the data are less decisive about the underlying average contrast.

The trial also illustrates why outcomes and time points should not be blended. Pain at rest, morphine equivalents, and drowsiness are different measures, and the secondary estimates do not all have the same precision. A result on one outcome cannot substitute for another, and a collection of unadjusted secondary comparisons raises a multiplicity concern. Statistical interpretation requires attention to both the measurement being compared and the uncertainty attached to that comparison.

The registry information further demonstrates the importance of reporting analysis details. Randomization and masking are useful design features, but the record does not describe the analysis populations, missing-data methods, multiplicity plan, or original sample-size justification. Those omissions make it harder to assess whether the posted estimates answer the intended question under the intended analysis plan.

Finally, the planning illustration distinguishes future study design from retrospective judgment of a completed trial. Its figures use the observed effect and stated assumptions to show how target effect size and desired power influence the number of participants planned per arm. They are not evidence that the completed study had a particular probability of detecting an effect. This distinction helps prevent a planning calculation from being mistaken for a conclusion about the trial’s results.

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.

Several limitations specific to this trial affect interpretation of the posted outcomes. The primary comparison is based on mean pain scores at a single reported time point, one hour after surgery. The registry record does not provide primary pain results at other times, during movement, or over a longer recovery period. Nor does it report a threshold for a clinically meaningful change on the 1-to-10 scale, limiting interpretation of the practical importance of the estimated mean difference.

The registry record does not report detailed eligibility criteria, the types of gynecologic surgery performed, or baseline participant characteristics. Without these details, it is difficult to assess how representative the study participants were or how broadly the results might apply. It also does not explain the relationship between the registry enrollment of 67 and the posted primary outcome arm counts of 30 in each group.

The record does not describe allocation concealment, how triple masking was implemented, or whether masking was maintained. It does not report treatment adherence, infusion duration, participant flow, or reasons for any missing outcome data. The analysis populations and statistical analysis plan are also not reported, leaving uncertainty about exclusions, covariate adjustment, and the treatment of incomplete observations.

Secondary outcomes are numerous, but the record does not report a multiplicity strategy or provide numerical summaries for all listed measures. The posted secondary p-values are unadjusted. The record also does not report the original sample-size justification or interim analyses. These gaps do not invalidate the reported summaries, but they constrain evaluation of selective reporting, precision planning, and robustness. The confidence intervals describe uncertainty in the posted comparisons; they cannot resolve limitations in the available design and analysis documentation.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: ON-Q Pump Infusion of Ketorolac and Ropivacaine at the Wound Site for Postoperative Pain Management — NCT00638508.
• Registry record last updated 2018-08-07; status last verified 2018-07.
• Results first posted 2018-08-07.
• 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, triple-masked, parallel-group Phase 4 trial sponsored by Maimonides Medical Center. It compared ketorolac infused at the wound site with ketorolac plus ropivacaine after gynecologic surgery. Registry enrollment is 67; the posted primary outcome summaries list 30 participants in each arm.

The primary outcome was mean pain at rest one hour after surgery, measured on a Visual Analog Scale. The posted mean difference for the combination arm relative to ketorolac alone was -0.5, with a confidence interval from -1.803 to 0.803 and an unadjusted p-value of 0.452. Secondary numerical results include morphine-equivalent measures at one hour and 12 hours and drowsiness at one hour.

The registry record does not report the original sample-size justification, statistical analysis plan, analysis populations, or missing-data methods. The secondary results are unadjusted, and a multiplicity plan is not reported.