This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Pediatric Tonsillectomy Pain Reduction Study (NCT00678379), a randomized phase 3 study. The primary outcome is Total Number of Post-operative Doses of Analgesics..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00678379 |
| Phase | Phase 3 |
| Condition | Postoperative Pain |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 120 |
| Arms in the primary outcome | 3 |
| Lead sponsor | Vanderbilt University Medical Center |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned children undergoing tonsillectomy and postoperative pain. The registry reports 120 randomized participants, with 40 assigned to each of the three groups. Further eligibility criteria and participant characteristics are not reported in the registry record.
Intervention
Before tonsillectomy, participants received a submucosal injection into the tonsillar fossa containing lidocaine (1%) and bupivacaine (0.5%) with clonidine (25 µg). The registry describes the injected volume as 1.5 mL.
Comparator
The registry lists two comparison groups: normal saline injection into each tonsillar fossa, and lidocaine (1%) plus bupivacaine (0.5%) without clonidine. Both injections were given before tonsillectomy, and the registry describes a volume of 1.5 mL.
Primary question
The primary endpoint was the total number of postoperative analgesic doses, with the listed timeframe extending through day 7. The endpoint description specifically refers to intravenous fentanyl doses given in the post-anesthesia care unit. The registry’s objective also refers more broadly to postoperative morbidity, including pain and poor oral intake, but does not report results for those outcomes.
In statistical terms, the trial set out to compare the distribution of analgesic-dose counts across three randomized groups. The posted primary results are medians and full ranges for each group. They describe the observed dose counts in each arm, but do not establish whether the groups differed statistically: no p-value, confidence interval, or other inferential comparison is reported. The registry also does not report a prespecified contrast identifying one treatment group as the sole comparison of interest.
3. Trial Design
The registry classifies this as a completed, randomized, parallel-group Phase 3 trial with 120 participants enrolled. It lists three groups, each with 40 participants: normal saline, lidocaine (1%) plus bupivacaine (0.5%), and the same local anesthetics with clonidine (25 µg). Each injection was administered into the tonsillar fossa before tonsillectomy. The registry lists the masking classification as quadruple, while the official study title describes the trial as double-blind. The registry does not explain the difference between those descriptions or specify which roles were masked.
The registry gives a start date of 2008-04 and a primary completion date of 2009-11. These dates describe the study’s recorded timeline, not necessarily the timing of every follow-up or analysis. The primary outcome timeframe is described as postoperative through day 7. The record does not give a more detailed schedule for assessment or explain how the day 7 period relates to the primary endpoint description of fentanyl doses in the post-anesthesia care unit.
Random assignment supports a comparison of groups by their assigned interventions, but the registry does not report the sequence-generation method, allocation concealment, or whether treatment assignment was analyzed as randomized. The number enrolled is reported, as are the number in each arm for the primary results. Details about withdrawals, exclusions, adherence, and the number contributing data to each endpoint are not reported in the registry record. The registry lists six secondary outcomes, including pain, medication use, discharge time, and diet tolerance, but does not post their results in the registry record for this analysis.
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
| Stage | Normal Saline | Lidocaine (1%) + Bupivacaine 0.5% | Lidocaine 1% + Bupivacaine o.5% + Clondine 25mcg |
|---|---|---|---|
| STARTED | 40 | 40 | 40 |
| COMPLETED | 34 | 37 | 36 |
| NOT COMPLETED | 6 | 3 | 4 |
Reasons for not completing this period:
| Reason | Normal Saline | Lidocaine (1%) + Bupivacaine 0.5% | Lidocaine 1% + Bupivacaine o.5% + Clondine 25mcg |
|---|---|---|---|
| Injection performed after tonsillectomy | 2 | 0 | 1 |
| Incomplete Data | 4 | 3 | 3 |
Analysis population for the primary outcome, as defined in the registry: Number of patients randomized to each group
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.
| Characteristic | Unit | Normal Saline | Lidocaine (1%) + Bupivacaine 0.5% | Lidocaine 1% + Bupivacaine o.5% + Clondine 25mcg | Total |
|---|---|---|---|---|---|
| Participants analysed | 40 | 40 | 40 | 120 | |
| Age, Continuous | years | 6 (5 to 9) | 7 (5 to 11) | 8 (5 to 12) | 7 (5 to 12) |
| Sex: Female, Male: Female | Participants | 24 | 20 | 23 | 67 |
| Sex: Female, Male: Male | Participants | 16 | 20 | 17 | 53 |
| Region of Enrollment: United States | participants | 40 | 40 | 40 | 120 |
6. Primary Endpoint
The registry lists the primary outcome as Total Number of Post-operative Doses of Analgesics., measured over Post-operative thru day 7.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | number of doses |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled “Total Number of Post-operative Doses of Analgesics.” It is a count: each participant’s outcome is the number of analgesic doses during the stated postoperative period. The registry identifies the unit as number of doses and specifies that results are summarized by the median and full range. Its description says that the total number of intravenous fentanyl doses given in the post-anesthesia care unit will be compared across the three randomized groups, while its timeframe is stated as postoperative through day 7. The registry does not clarify whether the endpoint includes only those PACU fentanyl doses or all analgesic doses through day 7.
Medication-use counts can help describe how much rescue or postoperative analgesia participants received under the study conditions. They are not a direct measure of pain intensity: dose counts may be affected by pain, prescribing and administration practices, and the period over which doses are counted. The registry separately lists visual analog scale pain and several diet-tolerance outcomes as secondary measures, but their results are not reported in the record.
General statistical explanation: a median describes the central position of observed values, while a full range gives the lowest and highest reported values. Neither alone describes the precision of a treatment-group contrast. A range is not a confidence interval, and the reported medians do not indicate whether any difference between groups is distinguishable from random variation.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary results are median analgesic-dose counts of 12 for normal saline, 12 for lidocaine (1%) plus bupivacaine (0.5%), and 14 for lidocaine, bupivacaine, and clonidine (25 µg). The corresponding full ranges are 9 to 15, 10 to 16.5, and 9 to 16.8. Each group has 40 participants reported. These are descriptive summaries of the recorded endpoint, not estimates of a treatment effect with quantified uncertainty.
The medians indicate that the central reported count was the same in the saline and local-anesthetic-only groups. The median in the group that also received clonidine was reported as 14. The ranges overlap: values within the reported intervals occur across all three groups. This overlap is descriptive and does not itself determine whether group distributions differ. The registry reports no statistical test, p-value, confidence interval, adjusted estimate, or other inferential result for the primary endpoint. It therefore does not report evidence with which to assess the precision or statistical significance of a between-group contrast.
The posted outcome is a count, and the registry reports it using medians and ranges rather than means and standard deviations. This gives a compact description of the center and observed extent of the data. It does not show the distribution of individual counts, how many participants had each count, or whether the distributions were skewed. Those details are not reported in the registry record. The reported ranges also should not be read as uncertainty intervals around the medians.
There is a scope ambiguity in the primary endpoint description. The title and timeframe refer broadly to postoperative analgesic doses through day 7, while the description specifies intravenous fentanyl doses in the post-anesthesia care unit. The registry does not clarify whether these refer to the same counting period or whether the endpoint was operationalized more broadly. This matters when interpreting what the median counts represent and how they relate to later postoperative medication use.
The record lists six secondary outcomes, but results for them are not reported in the registry record. The registry entries therefore do not establish whether the groups differed in pain scores, discharge time, medication doses as measured by another definition, or tolerance of liquids, soft foods, or a regular diet. No treatment conclusion follows from the descriptive primary summaries alone. The registry’s posted results support a description of the counts in these groups, but not a definitive statistical comparison or a claim about clinical benefit.
9. Statistical Methods Explained
What do the reported summaries describe?
The primary endpoint is a count of analgesic doses, and the registry reports the median and full range for each randomized group. A median is the middle value when observations are ordered. It is useful as a summary of the center, particularly when a distribution may be asymmetric or include unusually large values. The full range reports the lowest and highest observed values. It shows the extent of the recorded observations, but is sensitive to extreme observations and does not show how values are distributed between the endpoints.
General statistical explanation: for a count outcome, a histogram or a list of frequencies can reveal features hidden by a median and range, such as clustering, a long tail, or many tied values. The registry does not report those participant-level distributions. The recorded medians and ranges should therefore be read as concise descriptions, not complete depictions of the underlying data.
Why is a between-group estimate important?
A randomized trial’s central statistical question is whether outcomes differ between groups assigned to different interventions. A group-specific median does not, by itself, quantify the contrast between groups. An inferential analysis would ordinarily identify the comparison or comparisons, give an effect estimate appropriate to the outcome, and report uncertainty. The registry reports none of those statistical comparison results for the primary endpoint. A p-value, if reported, would address how compatible the data are with a specified null hypothesis under the test’s assumptions; it would not by itself describe the size or importance of a difference. A confidence interval would convey a range of values compatible with the data and model, but no confidence interval is reported.
The study has three groups, so there are multiple possible pairwise comparisons or an overall test of the groups. The registry does not report which approach was planned or used. It also does not identify a primary pairwise contrast. Without that information and the corresponding results, the descriptive summaries cannot be converted into a supported inference about whether one regimen differed from another.
How might count data be analyzed?
General statistical explanation: counts are often analyzed with methods designed for discrete outcomes. A Poisson model is one option when its assumptions are reasonable, including a relationship between the expected count and its variability. If observed variability is greater than that model allows, over-dispersion can make conventional standard errors too small and uncertainty appear narrower than it should. Alternatives may be appropriate depending on the data and study question. These are general considerations only; the registry does not report the model, test, or distributional assumptions used for the primary outcome.
The posted summaries use medians and ranges, but that reporting choice does not establish which analysis method generated a comparison. Nor does it show whether the analysis accounted for other variables, repeated observations, or the trial’s three-arm structure. Such methods are not reported in the registry record. No adjusted estimates are posted, and no unadjusted recalculation is available in the registry record for this endpoint.
What does randomization contribute?
General statistical explanation: random assignment is intended to make groups comparable, on average, with respect to both measured and unmeasured characteristics at the point of assignment. It does not ensure that every characteristic is balanced in a particular trial, especially when groups are limited in size. Reporting baseline characteristics and the analysis population helps readers assess how the randomized comparison was carried out. Baseline characteristics and a participant flow account are not reported in the registry record.
The registry gives 40 participants in each arm for the primary results, matching the randomized allocation described in the record. It does not report whether every randomized participant contributed an endpoint value, how missing values were handled, or whether the analysis followed assignment regardless of treatment received. Therefore, the group summaries cannot establish the completeness or analysis population underlying the endpoint.
How should planning calculations be understood?
General statistical explanation: sample-size planning estimates how many participants may be needed to detect an effect under stated assumptions about the effect size, variability, significance level, allocation, and analysis. Such calculations are planning illustrations rather than observed power, and they depend on assumptions that may not match the trial’s actual data. The registry entries describe an illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects defined as fractions of the observed effect. They do not include the resulting participant counts for any such illustration. These assumptions do not establish the trial’s original design rationale or its planned power. The sample-size justification for the actual trial is not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The trial includes three randomized groups and lists one primary outcome plus six secondary outcomes. Comparing three groups can involve more than one statistical contrast, and assessing several outcomes also raises the general issue of multiplicity: when many hypotheses are tested, the chance of at least one apparently positive result can increase. General statistical approaches include identifying a primary comparison in advance, using a hierarchical testing plan, or adjusting for multiple comparisons. The registry does not report a multiplicity strategy, a prespecified ordering of outcomes, or the intended family of comparisons. Since no primary inferential analysis is posted, there are no reported p-values to assess for multiplicity.
The registry lists six secondary outcomes: median number of pain medication doses, time until hospital discharge, mean visual analog scale pain number, and the numbers and percentages able to tolerate liquids, a soft diet, or a regular diet. Their results are not reported in the registry record. The record also does not provide inferential results for the primary endpoint. It is therefore not possible to judge how missing or multiple outcome results might affect the overall interpretation.
Missing-data handling is not reported in the registry record. The record does not describe whether any participants withdrew, missed outcome assessments, or were excluded from particular analyses. It gives 40 participants per group for the primary summaries, but does not state explicitly whether this represents all randomized participants with observed endpoint data or another analysis population. The analysis population, handling of missing endpoint values, and any sensitivity analyses are not reported in the registry record. These details matter because conclusions can depend on who is included and how absent observations are treated.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Normal Saline | 0 | 40 | 0.0% |
| Lidocaine (1%) + Bupivacaine 0.5% | 0 | 40 | 0.0% |
| Lidocaine 1% + Bupivacaine o.5% + Clondine 25mcg | 0 | 40 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Normal Saline | 0 of 40 |
| Lidocaine (1%) + Bupivacaine 0.5% | 0 of 40 |
| Lidocaine 1% + Bupivacaine o.5% + Clondine 25mcg | 0 of 40 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Normal Saline | 4 of 40 |
| Lidocaine (1%) + Bupivacaine 0.5% | 6 of 40 |
| Lidocaine 1% + Bupivacaine o.5% + Clondine 25mcg | 6 of 40 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Normal Saline | Lidocaine (1%) + Bupivacaine 0.5% | Lidocaine 1% + Bupivacaine o.5% + Clondine 25mcg |
|---|---|---|---|---|
| Dehydration | General disorders | 1 of 40 | 3 of 40 | 3 of 40 |
| Bleeding | Blood and lymphatic system disorders | 3 of 40 | 1 of 40 | 1 of 40 |
| Emergency Department admission | General disorders | 0 of 40 | 1 of 40 | 1 of 40 |
| Lingual nerve palsy | Nervous system disorders | 0 of 40 | 0 of 40 | 1 of 40 |
| Severe pain | General disorders | 0 of 40 | 1 of 40 | 0 of 40 |
The registry reports zero serious adverse events in each of the three groups, with 40 participants at risk in each group. It also reports zero deaths in each group. These are counts in the posted safety record; they do not establish that no adverse events of any kind occurred, nor do they rule out uncommon events.
For other, non-serious adverse events, the record lists 4 participants affected in the normal saline group, 6 in the lidocaine and bupivacaine group, and 6 in the group receiving those local anesthetics with clonidine. The record gives 40 participants at risk in each group. These counts are not accompanied by inferential comparisons or confidence intervals. No percentages need to be inferred from the counts to read the registry’s report.
The serious adverse event terms list is empty. That means no serious-event terms are listed in the registry record; it should not be treated as a detailed description of the kinds of events monitored or as a full account of ascertainment. The registry does not report event definitions, severity grading, timing, relatedness assessments, or whether participants could experience more than one event. Consequently, the counts are a limited summary of posted safety information and do not permit a detailed comparison of safety profiles.
12. What the Result Does, and Does Not, Mean
The primary results describe the number of postoperative analgesic doses recorded in each randomized group. The median was 12 for saline, 12 for lidocaine plus bupivacaine, and 14 for the combination that also included clonidine. The reported ranges were 9 to 15, 10 to 16.5, and 9 to 16.8, respectively. Each group is reported as having 40 participants. These summaries show the central values and observed ranges recorded by the registry; they do not quantify the uncertainty around differences between groups.
The registry does not report a statistical test or an estimate with a confidence interval for the primary comparison. It also does not report results for the listed secondary outcomes. Thus, the posted record does not establish whether differences in analgesic use are compatible with random variation, whether any difference is clinically important, or how the interventions relate to pain scores, hospital discharge, or diet tolerance. The data should not be interpreted as proof that a regimen does or does not reduce postoperative pain or medication use.
The endpoint’s definition also limits interpretation. Its title and timeframe refer to postoperative analgesic doses through day 7, while its description specifies intravenous fentanyl given in the post-anesthesia care unit. Without clarification of the precise dose-counting period, readers cannot be certain whether the posted values represent PACU fentanyl use alone or a broader interval and set of analgesics.
General statistical explanation: a descriptive difference between group summaries is not the same as a statistically supported treatment effect. An effect estimate and its uncertainty, an account of the analysis population, and clear endpoint definitions are needed to assess how much the observed data support a comparative conclusion. Those elements are not reported in the registry record. The safest reading is therefore limited to the stated descriptive summaries and the explicit gaps in the record.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of the distinction between a randomized design and a complete report of comparative evidence. Randomization assigns participants to interventions by chance and is intended to support fair group comparisons. But a record of randomization, arm sizes, and group-specific summaries does not by itself show the result of a statistical comparison. Readers also need a clearly specified endpoint, a defined analysis population, and an estimate of the between-group contrast with an account of its uncertainty.
The endpoint illustrates why operational definitions matter. “Total number” of postoperative analgesic doses and the stated period through day 7 suggest a broad count, while the description specifies intravenous fentanyl doses in the post-anesthesia care unit. Those descriptions may be intended to align, but the registry does not explain how. A count’s meaning depends on what medications, events, and time periods are included. Clear definitions are essential for reproducibility and for comparing results across studies.
The three-arm structure is another important statistical feature. The saline group, local-anesthetic group, and local-anesthetic-plus-clonidine group allow questions about more than one contrast. The record does not identify a planned contrast or multiplicity strategy, and no inferential results are posted. That makes the descriptive medians useful for orientation but insufficient for deciding which comparisons were intended or how strongly the evidence supports them.
Finally, the registry lists outcomes beyond analgesic doses, including pain, discharge, and oral intake. Their absence from the posted results limits the range of questions that can be answered from this record. Statistical reporting is most useful when it connects a prespecified clinical question to a clearly defined outcome, the participants analyzed, and transparent uncertainty. This record documents the broad design and some results, while leaving important elements of that chain unreported.
14. 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 primary endpoint has an ambiguity between its title and timeframe, which describe postoperative analgesic doses through day 7, and its description, which specifies intravenous fentanyl in the post-anesthesia care unit. The record does not clarify whether the reported count covers the full stated period or only PACU administration, or whether other analgesics are included. This affects interpretation of the median counts.
No inferential result is reported for the primary outcome. The record contains no test, p-value, confidence interval, or effect estimate for comparisons among the three groups. The statistical analysis plan, any prespecified primary contrast, and any adjustment for multiple comparisons are not reported in the registry record. The six listed secondary outcomes also have no results reported in the registry record; their analysis methods and multiplicity handling are not reported.
The registry reports 40 participants per group for the primary results, but does not describe participant flow, missing outcome values, exclusions, adherence, or analysis populations. Baseline characteristics are not reported. The methods for random sequence generation and allocation concealment are not reported in the registry record. The registry classifies masking as quadruple, while the official title says double-blind, without explaining the difference or specifying who was masked.
Safety information is limited to counts of serious events, other events, and deaths. Event definitions, timing, severity, relatedness, and ascertainment procedures are not reported. The empty list of serious-event terms does not supply further detail. These omissions constrain interpretation of both the efficacy summaries and the safety counts. The trial’s sample-size justification and its original statistical analysis plan are not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Pediatric Tonsillectomy Pain Reduction Study — NCT00678379.
- Registry record last updated 2017-07-02; status last verified 2017-06.
- Results first posted 2017-07-02.
- 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.
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18. Record Summary
The registry describes a completed, randomized, parallel-group Phase 3 trial of pre-tonsillectomy injections in children, with 120 participants enrolled. It lists 40 participants in each of three groups: normal saline, lidocaine (1%) plus bupivacaine (0.5%), and those local anesthetics with clonidine (25 µg). The primary outcome is the total number of postoperative analgesic doses, summarized by median and full range.
Reported median counts were 12, 12, and 14, respectively, with ranges of 9 to 15, 10 to 16.5, and 9 to 16.8. No inferential comparison is reported, and the endpoint description does not clearly reconcile the stated period through day 7 with the specified PACU fentanyl doses. Six secondary outcomes are listed, but their results are not reported in the registry record. Serious adverse event counts and deaths are reported as zero in each group; other adverse event counts are 4, 6, and 6.