Erector Spinae Block for Spine Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Erector Spinae Block for Spine Surgery (NCT05417113), a randomized phase 4 study. The primary outcome is Postoperative Opioid Consumption During First 72 Hours.

2. Clinical Question

The registry describes the study’s hypothesis as lower opioid use and improved pain scores with the liposomal formulation compared with plain bupivacaine. That is a proposed effect, not a reported finding. The primary outcome is opioid consumption; change in pain score is listed as a secondary outcome. Other secondary outcomes concern quality of recovery, postoperative nausea and vomiting, time to ambulation, and hospital length of stay.

The primary outcome’s timeframe lists 12 hours, 24 hours, 48 hours, and 72 hours. The registry record does not provide the values at those time points or a single combined comparison. It therefore does not establish from the posted results whether the groups differed in opioid consumption or how precisely any difference was estimated.

3. Trial Design

This is a phase 4, randomized, parallel-group trial with quadruple masking, sponsored by Icahn School of Medicine at Mount Sinai. The registry lists an enrollment of 13. It describes two arms: bupivacaine alone and liposomal bupivacaine added to bupivacaine. Both are administered in erector spinae plane blocks for lumbar spinal fusion surgery.

The study start date is 2022-08-31, and the listed primary completion date is 2024-02-27. Its status is terminated. The reason for termination, the date of termination, and whether the listed enrollment represents the final number analyzed are not reported in the registry record. Details about how randomization was generated or concealed are also not reported.

Quadruple masking indicates that the registry classifies the study as masked at four levels, but the identities of the masked groups or roles are not reported. The registry also does not specify the procedure for maintaining masking, whether it was assessed, or whether any unmasking occurred. These details matter because knowledge of treatment assignment can affect care, outcome assessment, and reporting, but their absence does not establish that masking failed.

The record lists six outcome measures and zero analyses. The primary outcome is postoperative opioid consumption during the first 72 hours, while the listed secondary outcomes include pain, quality of recovery, postoperative nausea or vomiting, ambulation time, and hospital length of stay. No protocol details, treatment schedules beyond the arm descriptions, participant flow, or reasons for withdrawal are reported. The word “terminated” describes the registry status; by itself, it does not explain why the trial stopped or what results were available when it did.

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.

6. Primary Endpoint

The registry lists the primary outcome as Postoperative Opioid Consumption During First 72 Hours, measured over 12 hours, 24 hours, 48 hours, 72 hours.

The primary endpoint is postoperative intravenous opioid consumption during the first 72 hours, expressed as total morphine milligram equivalents (MME). The record describes the measure as the amount of intravenous opioid consumed and lists a mean with standard deviation as its statistical form. Its timeframe includes 12 hours, 24 hours, 48 hours, and 72 hours.

MME expresses opioid exposure on a common morphine-equivalent scale, allowing consumption of different opioids to be represented in a shared unit. In general, a consumption measure can describe medication use, but it does not directly measure pain intensity, quality of recovery, or longer-term outcomes. Those are distinct outcomes, and pain score and quality of recovery appear separately among the secondary measures.

The endpoint is relevant to the registry’s stated hypothesis about opioid use after surgery. However, the record does not report the group means, standard deviations, between-group estimates, confidence intervals, or statistical tests for this outcome. It also does not specify whether the time points represent separate measurements, cumulative consumption, or a particular summary comparison. The listed timeframe alone is not a result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary endpoint as a continuous measure summarized by a mean and standard deviation. In general, a mean describes the center of a set of measurements, while a standard deviation describes how spread out individual measurements are around that center. They answer different questions: the mean concerns the average level, and the standard deviation concerns variability among observations. Neither one alone describes the uncertainty in a comparison between treatment groups.

To compare group means, an analysis would usually estimate a difference and quantify its uncertainty, for example with a confidence interval. In general, a confidence interval gives a range of values compatible with the data and the method’s assumptions. It is not a guarantee that the true effect lies in that range. The registry record does not report a mean for either group, an estimated group contrast, a confidence interval, or a test result, so none can be interpreted for this trial.

The endpoint’s timeframe lists 12 hours, 24 hours, 48 hours, and 72 hours. These may represent multiple measurements or summaries, but the registry does not clarify their relationship or identify one as the sole analysis. Repeated measurements on the same participant are generally related rather than independent. In general, methods for repeated outcomes need to account for that relationship if observations across time are modeled together. The registry record does not report whether such a model was used, whether each time point was analyzed separately, or whether a particular time point was designated as the main comparison.

Opioid consumption is a continuous outcome, but such measurements can have features that complicate a simple comparison of means. In general, consumption data may be skewed or include many low values alongside a smaller number of high values. If a statistical model assumes a particular distribution or variance pattern, departures from those assumptions may affect the validity of uncertainty estimates. Over-dispersion, in general, means that observed variability exceeds what a model expects; accounting for it can prevent uncertainty from being understated. These are general considerations, not claims about the distribution in this trial. The registry does not report outcome distributions, diagnostic checks, transformations, robust methods, or a model specification.

The record’s sample-size assumptions describe a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. The assumed effect to detect is described as a stated fraction of the observed effect. The record distinguishes participant-per-arm planning illustrations from total-event planning for time-to-event outcomes. No planning values are reported in the registry record for interpretation, and the primary endpoint results needed to evaluate such an illustration are not reported. These planning calculations, when available, would concern hypothetical future study sizes; they would not be observed power and would not establish what the trial found.

Power is a design concept: in general, it describes the probability that a specified analysis will detect an effect of a specified size under stated assumptions. It is not a measure of the probability that a result is true, and it cannot be inferred from the outcome of a completed trial. Because the registry record gives no observed primary-outcome estimate and no analysis results, it is not possible to assess the precision of this trial’s comparison from the posted information. A planning illustration based on an observed effect does not replace the effect estimate and uncertainty interval themselves.

Randomization is intended, in general, to make treatment groups comparable on average with respect to both measured and unmeasured characteristics. It does not ensure exact balance in a particular trial, especially when enrollment is limited. The record identifies random allocation but does not report the sequence-generation procedure, concealment method, stratification factors, or baseline characteristics. It is therefore possible to describe the randomized design, but not to assess those implementation details.

Masking can reduce the influence of treatment knowledge on care decisions, participant reports, and outcome assessment. The registry classifies the study as quadruple masked, but does not state who was masked or how the masking was maintained. No conclusion about masking success or its effect on the endpoint can be drawn from that label alone. The registry also does not report a statistical analysis plan, prespecified model, adjustment variables, handling of repeated measures, or methods for checking assumptions. These items are not reported in the registry record, so the posted information does not permit a detailed review of the analysis approach.

10. Multiplicity, Missing Data and Analysis Populations

The primary outcome lists four time points: 12 hours, 24 hours, 48 hours, and 72 hours. When multiple outcomes, time points, or comparisons are tested, the chance of finding at least one apparently notable result can increase. In general, a multiplicity strategy can define a primary comparison, adjust testing, or otherwise explain how multiple results will be interpreted. The registry record does not report a strategy for handling multiplicity or clarify how the time points relate to one another.

Several secondary outcomes are listed, including change in pain score, Quality of Recovery (QOR 15), postoperative nausea or vomiting, time to ambulation, and hospital length of stay. The record does not state which secondary outcomes were prioritized, whether formal hypotheses were specified, or whether any adjustment for multiple testing was planned. Without that information and without results, the secondary outcomes cannot be used to make a confirmatory claim.

Missing-data handling is also not reported in the registry record. There is no account of missing outcome measurements, reasons for missingness, imputation, sensitivity analyses, or the assumptions used to handle incomplete observations. The registry does not identify the analysis population, such as whether the analysis followed randomized assignment or was limited to participants with observed measurements. It does not report participant flow or the number contributing to each endpoint and time point.

The listing of zero analyses means the registry contains no analysis entries. It does not determine whether analyses were performed elsewhere. Because there are no posted outcome estimates, analysis methods, or missing-data details, readers cannot assess how the primary and secondary results were selected, how incomplete data were handled, or whether the reported analysis followed a prespecified plan. Those omissions constrain interpretation, but they do not establish that any particular analytic practice occurred.

11. 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 lists separate safety figures for the two arms. For Bupivacaine Only, the at-risk count is 5 and the counts affected are 0 for serious adverse events and 0 for other adverse events; deaths are listed as 0. For Liposomal Bupivacaine and Bupivacaine, the at-risk count is 4, with 0 affected by serious adverse events and 0 affected by other adverse events; deaths are listed as 0.

These figures indicate that the posted record lists no events in those categories among the participants represented by the arm-specific at-risk counts. They do not establish that no adverse events occurred outside the recorded categories, or that no risk exists. The registry does not report event definitions, collection procedures, follow-up duration, severity grading beyond the serious-versus-other distinction, or whether all participants had complete safety follow-up.

With limited enrollment, zero recorded events provide little information about the frequency of uncommon harms. In general, an absence of observed events is not equivalent to evidence that an event cannot occur. These entries should be read as the safety counts recorded in the registry, not as a comprehensive demonstration of safety or a comparison proving that the arms have the same safety profile.

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

The registry record establishes the trial’s stated comparison: liposomal bupivacaine added to 0.25% bupivacaine in an erector spinae plane block versus 0.25% bupivacaine alone. It identifies postoperative intravenous opioid consumption during the first 72 hours as the primary outcome and lists pain and recovery-related secondary outcomes. It also records a randomized, quadruple-masked, parallel design and a terminated status.

It does not establish whether the addition changed opioid consumption. There are no posted group values, estimated treatment contrast, uncertainty interval, or analysis result for the primary endpoint. The registry’s hypothesis that opioid use would be lower and pain scores improved describes the rationale being tested, not an observed outcome. Nor does the record support a conclusion about long-term benefit: the primary endpoint is framed around the first 72 hours, and no long-term result is reported.

The safety entries report zero serious events, zero other events, and zero deaths in each arm’s recorded figures. Those entries should not be interpreted as proof of no risk, particularly without details about follow-up and event collection. The record also does not explain why the study was terminated or whether the listed enrollment reflects the final analyzed population.

Accordingly, the defensible interpretation is descriptive: the registry records a trial design, a comparison, outcome definitions, limited enrollment, and safety counts, but does not provide the primary efficacy results or analysis details needed to estimate an effect. It does not show that either approach is superior, equivalent, or ineffective. Any stronger conclusion would require results and methods that are not reported in the registry record.

13. Why This Trial Matters Statistically

This trial raises a useful statistical question because it compares an added formulation against a standard active block while focusing on postoperative opioid consumption. That endpoint is a measurable quantity expressed in MME, and the registry also lists pain and recovery outcomes that capture different aspects of the postoperative experience. Keeping those outcomes distinct is important: a difference in medication consumption would not automatically establish a difference in pain, recovery, or longer-term outcomes.

The design also makes interpretation dependent on clear reporting. Random allocation and masking are relevant features, but readers need outcome estimates, uncertainty, analysis methods, and participant flow to understand what the data say. A design label alone cannot supply that evidence. Here, the absence of reported primary results is especially consequential because the endpoint is named and its measurement window is described, yet no group-level data or contrast is available for interpretation.

The terminated status and listed enrollment make transparent reporting particularly important. The record does not state why the trial stopped, how many participants contributed to each outcome, or whether data were incomplete. These registry entries would help distinguish a study that generated an inconclusive estimate from one whose results were not entered into the registry. Neither explanation can be inferred from the status alone.

The statistical lesson is that a registry entry can document a research question and design without permitting an effect assessment. Readers need estimates and their precision, not only a hypothesis or an endpoint label. In this case, the record supports understanding what comparison was intended, while the missing results prevent judgments about the magnitude, direction, and uncertainty of the primary outcome.

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 most important trial-specific limitation for interpretation is that the registry record does not report primary outcome values or analyses. The primary endpoint has multiple listed time points, but the record does not clarify whether these are separate or cumulative measurements, identify a single principal contrast, or provide estimates and uncertainty. The absence of these details prevents assessment of the treatment comparison.

The listed enrollment is 13, and the registry does not report how many participants contributed to each endpoint. There is no participant-flow account, no arm-specific primary-outcome denominator, and no description of missing data or exclusions from analysis. The reason for termination is not reported in the registry record. These omissions limit the ability to understand completeness and representativeness of the outcome data.

Although the study is classified as randomized and quadruple masked, details about randomization, allocation concealment, who was masked, and how masking was maintained are not reported. Baseline characteristics and the statistical analysis plan are also not reported. The record lists secondary outcomes but does not describe multiplicity handling or how repeated time-point measurements were analyzed.

The safety record lists no affected participants in the reported serious or other adverse-event categories and no deaths, but gives no event definitions, follow-up duration, or collection procedures. Thus, the safety entries have limited interpretive scope. These limitations describe what is absent from the registry record; they do not establish that the trial lacked procedures or analyses that were not entered there.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Erector Spinae Block for Spine Surgery — NCT05417113.
• Registry record last updated 2024-05-29; status last verified 2024-05.
• Results first posted 2024-05-29.
• 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.

18. Record Summary

The registry record describes a phase 4, randomized, quadruple-masked, parallel-group trial of liposomal bupivacaine added to 0.25% bupivacaine in erector spinae plane blocks for lumbar spinal fusion surgery, compared with 0.25% bupivacaine alone. The listed enrollment is 13, and the status is terminated. The sponsor is Icahn School of Medicine at Mount Sinai.

The primary outcome is postoperative intravenous opioid consumption in MME, with a timeframe of 12 hours, 24 hours, 48 hours, and 72 hours. Secondary outcomes include pain score, quality of recovery, postoperative nausea or vomiting, time to ambulation, and hospital length of stay. The record lists zero analyses and does not report the primary outcome results, the reason for termination, participant flow, or analysis details.

Safety entries list zero serious adverse events, zero other adverse events, and zero deaths in each arm’s recorded counts. These figures do not establish the absence of risk. The registry record documents the study question and design but does not provide results sufficient to estimate the primary treatment effect.