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 Efficacy of Ketamine for Improvement in Postoperative Pain Control After Spinal Fusion for Idiopathic Scoliosis (NCT02651324), a randomized phase 4 study. The primary outcome is Patient Satisfaction.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02651324 |
| Phase | Phase 4 |
| Condition | Idiopathic Scoliosis, Post-operative Pain |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 50 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Albany Medical College |
| Results posted | Yes |
2. Clinical Question
Population
The registry describes pediatric patients under 18 years of age undergoing spinal fusion for idiopathic scoliosis. It reports total Femle 39 and total male 10. The meaning of the recorded term “Femle” is not clarified in the registry record.
Intervention
The treatment group was assigned ketamine in addition to usual postoperative pain management. The planned regimen began with a ketamine bolus of 0.5mg/kg, followed by an infusion of 0.2 mg/kg/hr initiated before incision.
Comparator
The control group received saline placebo in place of ketamine. The registry describes the comparison as placebo-controlled.
Primary question
The stated question is whether adding ketamine improves postoperative pain control after spinal fusion for idiopathic scoliosis. The registered primary endpoint is patient satisfaction with postoperative pain management, measured on a score scale. The registry record does not report a primary comparison or its result.
The trial description frames the hypothesis around improvement in postoperative pain scores, while the registered primary outcome is satisfaction with pain management. Pain score is also named among the secondary outcomes, alongside opioid use and length of stay. These measures address related but distinct aspects of postoperative care: a satisfaction rating is a patient-reported assessment, whereas pain scores and opioid use describe other aspects of the experience and its management.
The registry identifies the study population as pediatric patients with idiopathic scoliosis, but does not give further eligibility details in the record. The results available in the registry do not establish whether the groups differed in satisfaction, pain scores, opioid use, or length of stay. Accordingly, the clinical question can be described from the planned comparison, but its answer cannot be determined from the outcome information recorded there.
3. Trial Design
The record describes a Phase 4, randomized, triple-masked, parallel-group controlled trial. The listed interventions are ketamine and placebo. The registry records enrollment of 50 and marks the study as completed. Its recorded start is 2013-05, and primary completion is listed as 2017-12.
In the treatment group, a ketamine bolus of 0.5mg/kg was to be followed by an infusion of 0.2 mg/kg/hr, initiated before incision. Intra-operative opioid use was left to the discretion of the attending anesthesiologist. The placebo description identifies saline as the substitute for ketamine. The treatment-group description also refers to continuation of study drug after surgery and usual postoperative management, but the available description ends before the full postoperative regimen is specified. Further procedural details are not reported in the registry record.
Randomized allocation is intended to assign participants to groups by chance, reducing the influence of deliberate selection on group assignment. A parallel design means the groups receive their assigned strategies rather than crossing over between them. Triple masking indicates that the registry records masking at three levels, but it does not identify the specific people or roles masked. The exact allocation procedure, concealment process, and masking procedures are not reported in the registry record.
The registry includes a total enrollment figure but does not report the number analyzed for the primary outcome or the number contributing data at each measurement. It also does not state the statistical plan or provide outcome comparisons. Thus, the design features identify how the study was intended to compare the interventions, but they do not establish the results or the precision of any treatment-effect estimate.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: randomized
Overall Study
| Stage | Treatment Group | Placebo |
|---|---|---|
| STARTED | 25 | 25 |
| COMPLETED | 24 | 25 |
| NOT COMPLETED | 1 | 0 |
Reasons for not completing this period:
| Reason | Treatment Group | Placebo |
|---|---|---|
| drug not administered, due dispensing issue | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: pediatric patient under 18yrs of age, total Femle 39 and total male 10
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 | Treatment Group | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 24 | 25 | 49 | |
| Age, Customized: mean age | years | 13.4 (SD 1.72) | 14.7 (SD 2.19) | 14.05 (SD 1.945) |
| Sex: Female, Male: Female | Participants | 22 | 17 | 39 |
| Sex: Female, Male: Male | Participants | 2 | 8 | 10 |
| Race and Ethnicity Not Collected | Participants | — | — | 0 |
| Region of Enrollment: United States | Participants | 24 | 25 | 49 |
6. Primary Endpoint
The registry lists the primary outcome as Patient Satisfaction, measured over Through study completion, 48 hours.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | score on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is patient satisfaction with postoperative pain management. The registry describes a score on a scale from 1 to 4: 1 is unsatisfied, 2 is moderately satisfied, 3 is generally satisfied, and 4 is very satisfied. No other subscales were included. The stated timeframe is through study completion, 48 hours.
A satisfaction score captures the patient's overall assessment of pain management rather than pain intensity alone. It may reflect a broader experience of care, so it should not be treated as interchangeable with a pain score, opioid use, or length of stay. Those measures are listed separately as secondary outcomes. The registry describes patients and parents as completing a survey, but does not clarify how their responses were combined or which response constituted the primary patient-level score.
The record identifies the endpoint and its scale but does not report group-level scores, variability, an estimated contrast, or a statistical test. It also does not specify how scores were handled if a survey response was absent or incomplete. Without those results and analysis details, the endpoint's observed pattern and the precision of any comparison cannot be assessed from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record states the study question and identifies patient satisfaction as the primary outcome, but it does not report the primary outcome values or a comparison between the ketamine and placebo groups. It therefore does not establish the direction, size, or statistical precision of a difference in satisfaction. The record also does not provide outcome estimates for pain score, opioid use, or length of stay, which are listed as secondary outcomes.
The primary outcome is a score on a bounded scale with ordered response labels. A comparison of group means, if reported, would describe average scores, but interpretation would also depend on the distribution of responses and how the scale was analyzed. The registry identifies the measure as a mean with standard deviation, yet a mean and standard deviation alone would not disclose how participants were distributed across the satisfaction categories. Those category-level results are not reported in the registry record.
The record notes four outcome measures and indicates that the primary outcome has several categories or time points and was not reduced to one comparison. This is important for interpretation: without a specified single contrast, a reader cannot identify which time point or summary was intended to answer the principal question. The record has zero analysis entries. The analysis method, adjustment strategy, and any planned handling of repeated measurements are not reported in the registry record.
The adverse-event information is separate from the efficacy question. It records zero serious adverse events and zero deaths in both groups, with other adverse-event counts also listed. These counts do not supply evidence about patient satisfaction or pain control. They should be read as recorded event counts, not as a substitute for comparative outcome analysis or a complete account of safety.
Overall, the registry allows a description of the intended randomized comparison, the satisfaction scale, and the recorded adverse-event counts. It does not provide the primary outcome results needed to judge whether the groups differed, nor does it provide uncertainty estimates such as confidence intervals. Any conclusion about the magnitude or precision of the primary comparison would go beyond what is reported in the registry record.
9. Statistical Methods Explained
The registry describes the primary outcome as a mean of a continuous measure and identifies standard deviation as its dispersion measure. A mean represents the arithmetic average of recorded scores. Standard deviation describes how spread out individual scores are around that average. These are descriptive summaries; on their own, they do not test whether groups differ or quantify the uncertainty in an estimated difference.
What would a confidence interval add?
In general, a confidence interval expresses the uncertainty associated with an estimated effect under a specified statistical method. A narrow interval indicates greater precision than a wide interval, while the interval's position relative to a value representing no difference can help readers assess compatibility with different effect sizes. A confidence interval is not reported for the primary outcome in the registry record. No interval can therefore be used to assess the precision of a ketamine-versus-placebo comparison.
Why does the outcome scale matter?
The satisfaction scale has ordered labels from unsatisfied through very satisfied. Although the registry records a mean and standard deviation, an average treats score steps as if they can be summarized numerically in that way. The mean may be useful as a concise description, but it does not show how many responses fell into each category. Category distributions could reveal whether a similar mean arose from different response patterns. Those distributions and the details of the analysis are not reported in the registry record.
Repeated measurements or multiple time points can also affect analysis. If the same participant contributes more than one observation, those observations are generally related rather than independent. A suitable analysis may need to account for that relationship. The registry notes that the primary outcome has several categories or time points and was not reduced to one comparison, but it does not specify the measurements selected for analysis, the model used, or how dependence among observations was addressed.
What does over-dispersion mean in general?
Over-dispersion occurs when observed variability is greater than a statistical model assumes. When a model underestimates variability, standard errors may be too small and uncertainty may appear less than it is. It is a general concern for some outcome types and models, not a documented feature of this trial. The registry does not report a model or diagnostics that would show whether over-dispersion was assessed, so it cannot be claimed that it occurred or that a particular adjustment was made.
For a randomized parallel-group trial, an unadjusted comparison would ordinarily contrast outcomes between the assigned groups. Adjusted analyses may account for prespecified participant characteristics or other design features. Neither an adjusted nor an unadjusted primary analysis is reported in the registry record. The registry also does not describe a covariate set, the treatment of baseline measurements, or whether the analysis followed assigned groups regardless of treatment received. Those details matter because analysis choices can affect both the estimate and its uncertainty.
How should planning calculations be read?
Sample-size planning illustrations are calculations for a hypothetical future study under stated assumptions; they are not observed trial results and are not observed power. In general, such an illustration depends on an assumed effect, variability, allocation, significance level, and statistical approximation. The registry's planning description refers to a two-sided significance level of 0.05, equal allocation, a normal approximation, and effects expressed as fractions of an observed effect. However, no planning illustration values or observed primary effect are reported in the registry record. The trial's own sample-size justification and design assumptions are not reported there, so the planning description cannot establish what guided the original enrollment.
Zero analysis entries means the registry does not contain an analysis record for the reported outcomes. It does not establish that no analyses were performed outside the registry, nor does it provide evidence about their results. The statistical test, model, multiplicity approach, missing-data method, and analysis population are not reported in the registry record. These omissions prevent a complete assessment of whether the analysis matches the design and outcome structure.
10. Multiplicity, Missing Data and Analysis Populations
The registry identifies multiple outcomes: patient satisfaction is primary, while pain score, opioid use, and length of stay are listed as secondary outcomes. It also records four outcome measures and notes that the primary outcome has several categories or time points, without reducing them to one comparison. When a study evaluates several outcomes, time points, or contrasts, the chance of finding at least one apparently notable result can increase if each is tested separately. A prespecified hierarchy or adjustment can address that issue, but neither is described in the registry record.
The record does not identify which satisfaction time point or contrast was intended as the decisive primary analysis. It does not report whether secondary outcomes were confirmatory or exploratory, whether any multiplicity adjustment was planned, or how the several categories or time points were to be summarized. Those details are important for interpreting any collection of tests, but no test results are reported.
Missing-data methods are also not reported in the registry record. The number of participants with a completed satisfaction survey, the amount and pattern of missing data, and any method for handling absent responses are not stated. The record does not report an analysis population, such as whether all randomized participants were included according to assigned group, or how withdrawals and protocol deviations were handled.
These gaps do not show that missing data or multiplicity problems occurred. They mean that the registry record does not provide enough information to evaluate how those issues were handled. A reader cannot determine whether the primary analysis preserved the randomized comparison, whether incomplete outcome data could have affected the estimate, or how selective emphasis among outcomes and time points was avoided.
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 |
|---|---|---|---|
| Treatment Group | 0 | 24 | 0.0% |
| Placebo | 0 | 25 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Treatment Group | 0 of 24 |
| Placebo | 0 of 25 |
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 |
|---|---|
| Treatment Group | 3 of 24 |
| Placebo | 9 of 25 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Treatment Group | Placebo |
|---|---|---|---|
| GI symptoms | Gastrointestinal disorders | 3 of 24 | 9 of 25 |
| GI symptoms | Gastrointestinal disorders | 3 of 24 | 3 of 25 |
| cardiac | Cardiac disorders | 1 of 24 | 0 of 25 |
The registry records serious adverse events for the treatment group and placebo group separately. In the treatment group, 24 were at risk and 0 were affected by a serious adverse event; in the placebo group, 25 were at risk and 0 were affected. The recorded death count is 0 in each group. The record lists no top serious-event terms.
For other adverse events, the registry records 3 affected among 24 at risk in the treatment group and 9 affected among 25 at risk in the placebo group. These are registry counts; the record does not provide event descriptions, severity grading, timing, or an explanation of how events were collected. It also does not report a statistical comparison or uncertainty estimate for these counts.
Counts should be interpreted in light of the definitions and surveillance methods used, which are not reported in the registry record. The absence of recorded serious events or deaths does not establish that no event could occur, and counts of other adverse events alone do not establish a causal effect of either assigned intervention. These safety figures do not answer the primary satisfaction question.
12. What the Result Does, and Does Not, Mean
The record supports a description of a randomized, triple-masked comparison of ketamine and saline placebo in pediatric patients undergoing spinal fusion for idiopathic scoliosis. It identifies the planned ketamine regimen, the satisfaction scale, and several secondary outcomes. It also provides separate counts for serious and other adverse events and deaths.
It does not report the primary outcome scores or a statistical comparison. As a result, it cannot show whether satisfaction differed between groups, the direction of any difference, or how precisely an effect was estimated. It likewise does not report results for pain score, opioid use, or length of stay. The stated hypothesis is not itself evidence that the expected outcome occurred.
The safety counts are descriptive and do not establish that either intervention caused or prevented an event. The registry does not give the event definitions, collection procedures, or comparative analyses needed to assess those counts in greater detail. Likewise, the study's completed status does not imply that its results are available in this registry record.
More broadly, an endpoint definition and a trial design describe what investigators set out to compare; they are not a substitute for the observed results. Without effect estimates, uncertainty measures, and analysis details, the registry record cannot support a conclusion about benefit, lack of benefit, or equivalence. That limitation concerns the information reported in the record, not necessarily the existence of analyses elsewhere.
13. Why This Trial Matters Statistically
This trial illustrates why a registered research question and a reported result are different kinds of information. Randomization, masking, and a placebo comparison describe design features intended to support a fair comparison. They do not, by themselves, reveal the effect estimate or its precision. For that, readers need outcome results, a clearly defined contrast, and an account of the analysis.
The distinction between the study hypothesis and the primary endpoint is also statistically important. The summary frames the hypothesis around postoperative pain scores, while the registered primary outcome is satisfaction with pain management. Pain score is listed as a secondary outcome. These measures are related, but they answer different questions; their results should not be substituted for one another.
The record further notes several categories or time points for the primary outcome without identifying one comparison. This makes the analysis target unclear and highlights the value of prespecifying which contrast is primary, how repeated observations will be handled, and how other outcomes will be interpreted. Such clarity helps readers distinguish a central test from additional analyses and understand the scope of any conclusion.
Finally, the adverse-event counts demonstrate why descriptive counts should be accompanied by definitions, follow-up details, and comparative uncertainty when available. The registry record gives some counts, but not enough analysis detail to interpret their comparative meaning. This trial is therefore statistically informative as an example of how design information, outcome definitions, analytic reporting, and complete results each contribute distinct pieces to evidence appraisal.
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 principal limitation for interpreting this trial from the registry record is that primary and secondary outcome results are not reported. No group-level satisfaction summaries, treatment-effect estimate, confidence interval, or statistical test is available. The record therefore does not permit assessment of the size or precision of the primary comparison.
The primary outcome description has unresolved detail. It identifies a score scale and a timeframe through 48 hours, but also notes several categories or time points without reducing them to one comparison. The record does not clarify which observations formed the primary analysis, how patient and parent survey responses were combined, or how scores were handled if incomplete.
Important analysis details are absent, including the statistical model, adjustment strategy, analysis population, missing-data method, multiplicity approach, and handling of repeated observations. The record reports zero analysis entries. The treatment description is also incomplete: the postoperative description ends before the full regimen is specified. Masking is labeled triple, but the masked roles and procedures are not identified.
The registry describes pediatric patients under 18 and records total Femle 39 and total male 10, but does not clarify the recorded term “Femle” or provide further demographic detail. It does not report eligibility criteria beyond the population description, baseline characteristics, withdrawals, or outcome completion. These omissions limit assessment of the study population and the completeness of its outcome data. They do not establish that the trial itself lacked such procedures or analyses; they indicate what is not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Efficacy of Ketamine for Improvement in Postoperative Pain Control After Spinal Fusion for Idiopathic Scoliosis — NCT02651324.
- Registry record last updated 2025-02-20; status last verified 2025-02.
- Results first posted 2025-02-20.
- 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 record identifies NCT02651324 as a completed Phase 4, randomized, triple-masked, parallel-group trial of ketamine versus saline placebo after spinal fusion for idiopathic scoliosis. Enrollment is recorded as 50. The ketamine regimen is described as a 0.5mg/kg bolus followed by an infusion of 0.2 mg/kg/hr initiated before incision.
Patient satisfaction with postoperative pain management is the primary outcome, scored on a scale from 1 to 4 through study completion, 48 hours. Pain score, opioid use, and length of stay are listed as secondary outcomes. The registry does not report the primary outcome comparison, secondary outcome results, or analysis methods. It records zero serious adverse events and zero deaths in both groups, with other adverse-event counts of 3 in the treatment group and 9 in the placebo group.