Erector Spinae Plane vs. Paravertebral Nerve Block for Thoracic Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Erector Spinae Plane vs. Paravertebral Nerve Block for Thoracic Surgery (NCT03758261), a randomized phase 4 study. The primary outcome is Total Opioid Consumption.

2. Clinical Question

The study addresses a practical comparative-effectiveness question: whether the two continuous regional analgesia approaches are associated with different opioid consumption following VATS. The registry describes a prospective randomized study, with participants assigned to one of the two infusion approaches. The central comparison is not against no block or no analgesia; it is between two active approaches used in the study setting.

The primary posted outcome is a continuous measure: total opioid consumption in MME. Lower consumption describes less opioid use in the recorded period, but the table alone does not establish why consumption differed or whether any observed difference is important to patients. The result needs to be read alongside the variation between participants and the width of the posted confidence interval.

The question also includes safety and other recovery measures, such as incentive spirometry, hospital stay, catheter duration, and adverse events. Those measures add context but do not replace the primary comparison. Their results are limited by the amount of information recorded for each outcome and by the absence of a reported multiplicity plan.

3. Trial Design

The registry record describes a randomized, parallel-group, phase 4 study with no masking. The study summary characterizes it as prospective and states that participants were to be assigned in a 1:1 ratio to continuous paravertebral infusion or continuous erector spinae plane infusion. The registry lists the study as completed, with an enrollment of 35. The study summary describes an intended enrollment of 60, so the enrollment recorded in the completed study is below that stated intention; the reason for the difference is not reported in the registry record.

The comparison was between two active catheter-based analgesia approaches in people having VATS. According to the summary, participants in both groups could receive multimodal adjunctive therapy for breakthrough pain according to routine practice. This shared background treatment is relevant: the posted results describe outcomes under each block strategy in the context of the accompanying care, not the isolated effect of a block without other pain-management measures.

The primary result table reports 15 participants in each group. The recorded primary timeframe is 1 day post catheter removal. It reports mean total opioid consumption and standard deviation for each group, with a mean difference, confidence interval, and unadjusted p value for the comparison. These are group summaries; the registry record does not describe the individual-level analysis or how the reported confidence interval and p value were generated.

The registry also lists secondary outcomes covering spirometry, length of hospital stay, time the catheter remained inserted, narcotic use, and adverse events from catheter placement. Numerical summaries are posted for some, but not all, of these outcomes. The method used to randomize participants, allocation concealment, masking procedures beyond the listed absence of masking, and the detailed statistical analysis plan are not reported in the registry record. The original sample-size justification is also not reported in the registry record.

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

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 Total Opioid Consumption, measured over 1 day post catheter removal.

The posted primary endpoint is total opioid consumption, expressed in mg morphine equivalent (MME), measured at 1 day post catheter removal. Morphine-equivalent units put opioid use onto a common scale, allowing the total amounts of different opioids to be summarized in a single measure. The registry describes the measure as total OME and reports the mean and standard deviation for each group.

Opioid consumption is used as one measure of analgesic treatment use after surgery. In a comparison of two regional block strategies, it can help describe how much additional opioid medication participants used during the specified period. It is not, by itself, a direct measurement of pain intensity or of the full quality of recovery. A lower group mean would describe lower average recorded consumption, but interpretation also depends on pain scores, other care, participant-to-participant variation, and the time window being assessed.

The study summary says the primary efficacy assessment was intended to include both total opioid consumption and pain scores on a numeric pain rating scale. The posted primary outcome result, however, is total opioid consumption. A numerical result for pain scores is not reported in the registry record. The result should therefore be understood as evidence about the recorded opioid-consumption endpoint, not as a complete report of every element of the efficacy question described in the summary.

As a continuous outcome, the endpoint is summarized using a mean and standard deviation. The mean describes the group average; the standard deviation describes how spread out individual observations are around that average. Here, the variability is substantial relative to the group means, which is important when judging how precisely the group contrast is estimated.

7. Results Posted in the Registry

• Paravertebral Nerve Block: mean 164.70 versus 187.36 on control; difference -22.66 (95% CI -140.62 to 95.30), standardized effect d = -0.14; z-test p = 0.707.

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.

Amount Achieved on Incentive Spirometer

• 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:
  • Paravertebral Nerve Block: mean 1,188 versus 1,221 on control; difference -33.65 (95% CI -400.02 to 332.72), standardized effect d = -0.07; z-test p = 0.857.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Paravertebral Nerve Block and the control. The interval gives the range of effects that remain compatible with the data.

Length of Hospital Stay

• 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:
  • Paravertebral Nerve Block: mean 96.30 versus 101.96 on control; difference -5.66 (95% CI -38.63 to 27.31), standardized effect d = -0.12; z-test p = 0.737.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Paravertebral Nerve Block and the control. The interval gives the range of effects that remain compatible with the data.

Time Catheter Remains Inserted in Body

• 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:
  • Paravertebral Nerve Block: mean 21.94 versus 21.99 on control; difference -0.05 (95% CI -8.96 to 8.86), standardized effect d = -0.00; z-test p = 0.991.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Paravertebral Nerve Block and the control. The interval gives the range of effects that remain compatible with the data.

The secondary results present a broadly similar pattern to the primary result: group averages are relatively close in the posted summaries, while the comparisons are imprecise. For the numerical secondary outcomes shown, the posted confidence intervals include zero. Taken together, these results do not present a clear, consistent separation between the two groups across the recovery measures that have numerical summaries.

These outcomes provide context for the opioid-consumption result, but they do not resolve its uncertainty. Incentive spirometry, length of hospital stay, and catheter duration reflect different aspects of recovery and care. Agreement in a general pattern can be descriptively reassuring, but it is not equivalent to independent confirmation: the measures may be related, and the number of participants remains limited. Nor does a lack of a clear difference in the secondary comparisons establish equivalence.

The registry lists additional secondary outcomes, including averaged total narcotic usage and adverse events from catheter placement. Numerical comparisons for those outcomes are not reported in the registry record. The summary also names more outcome measures than are accompanied by a numerical comparison in the posted secondary results. Readers should distinguish listed outcome titles from outcomes for which complete results are actually available.

The reported secondary p values are unadjusted. When several outcomes are examined, chance alone can produce apparently notable results across the set, especially if no adjustment or hierarchy was prespecified. The multiplicity approach is not reported in the registry record. For that reason, secondary findings should generally be treated as descriptive and exploratory unless a prespecified analysis plan establishes a confirmatory role. The secondary data can help frame the primary comparison, but they carry less weight as evidence for a definitive difference or similarity between approaches.

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

• Amount Achieved on Incentive Spirometer
• Length of Hospital Stay
• Time Catheter Remains Inserted in Body
• Averaged Total of Narcotic Usage
• Report of Adverse Events From Catheter Placement

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous, so the registry summarizes it with a mean and standard deviation in each group. The mean is the arithmetic average of the recorded opioid consumption values. The standard deviation describes the spread of participant values around that group mean. It is a measure of variability in the observations, not a measure of the uncertainty in the mean difference. The registry reports both group summaries and a direct contrast between the groups.

The comparison is presented as a mean difference for PVB relative to ESP. The reported estimate is -22.66 mg MME. In this contrast, a negative value indicates that the PVB group mean is below the ESP group mean. The value is a sample estimate and should not be treated as an exact difference in the populations from which the participants were drawn. The confidence interval gives an indication of how uncertain the estimate is, while the p value summarizes how compatible the observed data are with a null comparison under the analysis used.

The registry posts an unadjusted p value. “Unadjusted” means the reported value is not presented as corrected for multiple comparisons. This matters because the registry lists several outcomes, and looking across many outcomes can increase the chance that at least one result appears notable by chance. The analysis plan does not state whether an adjustment was intended, and a multiplicity strategy is not reported in the registry record. The p value should therefore be read as the posted comparison for this outcome, not as evidence that the full family of outcome analyses has been controlled for false-positive findings.

What does a confidence interval describe?

In general, a confidence interval is a range of values generated by a statistical procedure to express uncertainty around an estimate. It is not a guarantee that the true effect falls inside the particular interval, and it does not show the probability that any one value is correct. The posted interval for the primary result extends from -140.6 to 95.3 mg MME. Since it includes zero, the posted interval includes no difference as one possible value under the stated contrast. The registry does not identify the confidence level or provide enough detail to reconstruct the calculation, so interpretation should stay with the interval as posted rather than assuming additional specifications.

Why do standard deviations matter?

In general, greater variation among participant observations makes a group mean less precise when the sample size is unchanged. The primary standard deviations are 184.3 mg MME for ESP and 142.6 mg MME for PVB. These values indicate substantial observed spread within both groups. The posted standard errors, 47.6 for ESP and 36.83 for PVB, reflect uncertainty in the respective mean estimates as represented in the registry results. They are not additional outcome measures and should not be confused with the standard deviations.

Random allocation can help balance participant characteristics across treatment groups, on average, but it does not ensure that every characteristic will be balanced in a small trial. The registry states that the study was randomized and parallel-group. It does not report the sequence-generation method or allocation concealment. Without those details, readers cannot assess the operational steps used to implement randomization from the registry record alone. The record also lists no masking, so participants or study personnel may have known the assigned group; who was aware of allocation and whether outcome assessors were masked are not reported in the registry record.

The outcome summaries are based on 15 participants per group. Those counts describe the primary result table. They do not explain whether all randomized participants contributed data, whether any observations were missing, or how exclusions were handled. The analysis population and missing-data procedures are not reported in the registry record. This is especially relevant for an outcome measured after catheter removal, because the registry does not explain how the timing and availability of that measurement were handled for each participant.

How should the planning illustrations be understood?

The sample-size table is a planning illustration computed from the observed effect, rather than a record of the trial's original design calculation. It assumes a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Its rows consider detecting 100%, 75%, or 50% of the observed effect. The figures describe participants per arm for these continuous outcomes. They should be interpreted as hypothetical planning quantities under those assumptions, not as actual study enrollment targets or a retrospective measure of trial success.

In general, the normal approximation simplifies the calculation by using an assumed distribution for the estimate. It may be less suitable when the outcome distribution departs from the assumptions or when influential observations are present. The registry does not report diagnostics or alternative modeling choices for the primary analysis, so the extent to which the analysis addressed the observed spread or any unusual outcome distribution is not reported in the registry record.

Several statistical details that would usually help reproduce or fully evaluate an analysis are absent. These include the exact inferential procedure, the confidence level, any covariate adjustment, the handling of missing observations, and the population included in the analysis. None should be inferred from the presence of a mean difference, interval, and p value alone. General statistical interpretation can explain what those quantities ordinarily convey, but the registry record does not support claims about unreported protocol or analysis decisions.

11. Confidence Intervals and Precision

The primary estimate is accompanied by a broad interval: the mean difference for PVB relative to ESP is -22.66 mg MME, with a confidence interval from -140.6 to 95.3 mg MME. The interval spans zero and includes values in both directions. This means the data, as summarized in the registry, do not tightly locate the underlying contrast. The interval is more informative about uncertainty than the point estimate considered on its own.

The group means are 187.4 mg MME for ESP and 164.7 mg MME for PVB. Their standard deviations, 184.3 and 142.6 mg MME respectively, show substantial variation among participants relative to the group averages. With 15 participants in each outcome group, the available summaries therefore reflect both a limited group size and appreciable spread in observed consumption. These features constrain precision, though the registry does not report enough detail to attribute the interval width to any single cause.

In general, confidence intervals are useful because they show a range of effect estimates compatible with the data under the method used. A narrow interval would indicate a more precise estimate; a wide interval indicates that materially different values remain plausible. Here, the interval includes a possible lower mean in PVB, a possible higher mean, and values around no difference. The posted result is consequently not precise enough to support a firm directional interpretation.

The registry does not state the confidence level for the interval or the exact analysis method that produced it. The interval should therefore be read as the posted uncertainty range, without attaching an unstated coverage level. It also does not quantify uncertainty about outcomes that were not reported, including the pain-score component described in the study summary.

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 sample-size table and curve are planning illustrations based on the observed effect in the posted comparison. For these continuous outcomes, the listed figures are participants per arm, not total events. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The planning rows consider detecting 100%, 75%, or 50% of the observed effect. The trial's own original design assumptions and sample-size justification are not reported in the registry record.

The 80% power column describes the number of participants per arm that the illustration estimates would be needed to have an 80% chance of detecting the specified effect under its assumptions. The 90% column uses a higher target chance of detection and therefore generally calls for more participants per arm. These are planning concepts: power depends on the assumed effect, variation, analysis, and design. A smaller effect is harder to distinguish from random variation, so the illustration requires more participants when the effect to detect is reduced.

For the primary outcome, the table shows that planning for 75% of the observed effect corresponds to 1,477 participants per arm for 80% power and 1,977 participants per arm for 90% power. Those figures are hypothetical outputs of the stated planning approach, not recommended enrollment numbers for this clinical question. They also are not the number enrolled in this trial.

This is not observed power. It is a forward-looking calculation using the observed effect as an input, and it should not be used to decide whether the completed study was capable of answering its question. The original trial design assumptions are not reported in the registry record, so the planning illustration cannot be treated as a reconstruction of the investigators' intended design.

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 = -22.660; pooled standard deviation σ = 164.820.
2. n = 2 × (1.96 + 0.842)² × 164.820² / -22.660² = 830.5, rounded up to 831 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 <- -22.66                      # observed difference in means
sigma <- 164.819738047359                     # 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(3758261)
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 = 831 (80% power), 1,112 (90% power)
 75% of observed effect: n per arm = 1,477 (80% power), 1,977 (90% power)
 50% of observed effect: n per arm = 3,322 (80% power), 4,448 (90% power)
power.t.test: 831.5 
Simulated power at n = 831 per arm: 0.802 (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

The registry lists a primary outcome and several secondary outcomes, but a plan for handling multiple comparisons is not reported in the registry record. No hierarchy among secondary outcomes, adjustment procedure, or decision rule for interpreting the full set is described. The posted p values are identified as unadjusted. This means they should be considered individual comparisons rather than results shown to control the chance of false-positive conclusions across all outcomes.

The registry record does not report the statistical analysis plan in sufficient detail to establish whether the posted outcomes and analyses were prespecified, whether additional analyses were conducted, or whether any outcome definitions changed. It also does not report an analysis population such as intention-to-treat or per-protocol. These omissions do not demonstrate that a particular procedure was or was not used; they mean that the relevant information is not reported in the registry record.

Missing-data handling is also not reported in the registry record. The outcome summaries show 15 participants per group for the primary and numerical secondary outcomes, but the record does not explain whether these counts include everyone randomized, how many participants had missing measurements, or what methods were used for any unavailable values. There is no reported sensitivity analysis for missing data. Readers therefore cannot determine from these summaries whether the results might be affected by incomplete outcome measurement.

Other details that would inform interpretation are not reported, including the exact test or model used for the primary comparison, the confidence level, covariate adjustment, and checks of model assumptions. No interim analysis information or stopping rule is reported in the registry record. It would be inappropriate to infer that such procedures were planned or absent. The registry supports a description of the posted results, but not a full audit of the analysis decisions behind them.

These limitations matter particularly because several outcomes are considered and the groups are small. Transparent reporting of prespecified outcome priorities, missingness, analysis populations, and multiplicity procedures would help distinguish confirmatory findings from exploratory patterns. In the absence of that information, the primary result should be read with its own uncertainty, and secondary comparisons should be interpreted cautiously.

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.

Most frequent non-serious adverse event terms

The registry reports serious adverse events for 0 of 17 participants at risk in the ESP group and 0 of 16 participants at risk in the PVB group. It also reports 0 deaths in each group. These are the serious-event figures in the record; they should not be interpreted as evidence that serious events cannot occur, particularly in a study of this size.

For other adverse events, the record reports 0 of 17 participants at risk in the ESP group and 4 of 16 in the PVB group. The registry does not provide serious-event terms, and the list of top serious-event terms is empty. It also does not provide enough detail to characterize the nature, timing, severity, or relationship to the block of the other reported events. The category should therefore be read as a count in the registry’s adverse-event summary, not as a full clinical description.

The number at risk in these safety summaries differs from the group count in the primary outcome table. The reason for that difference is not reported in the registry record. Safety summaries also do not establish whether the groups have equivalent risk: absence of reported serious events in these groups cannot rule out uncommon harms or differences that this study could not estimate precisely.

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

The posted primary result describes mean opioid consumption in the two randomized groups during the period ending 1 day post catheter removal. It estimates a lower mean in the PVB group than in the ESP group, but the confidence interval is broad and includes values in both directions. The result is therefore uncertain, and the available registry data do not establish a clear difference between the strategies on this endpoint.

That interpretation is not the same as saying that the approaches are equivalent. Equivalence requires a specified margin and an analysis designed to assess whether the effect lies within that margin. Neither is reported in the registry record. The result also does not establish that one method is superior, because the estimate is imprecise and the interval includes no difference. A non-small p value is not proof that there is no effect.

The outcome is opioid consumption, not a direct measure of every dimension of pain relief or recovery. The study summary describes pain scores as part of the intended primary efficacy assessment, but no numerical pain-score result is reported in the registry record. Other recovery and safety outcomes provide useful context where results are posted, but not all listed outcomes have numerical comparisons available. The registry summaries therefore do not answer every question posed by the study description.

The trial is randomized, which supports a fair comparison in principle, but the number of participants represented in the primary results is limited and masking is listed as none. The registry does not report the randomization details, analysis population, missing-data methods, or full statistical plan. Those gaps restrict assessment of how the reported result was produced and how broadly it can be generalized.

The results apply to the participants and care context represented in this record: VATS procedures, continuous block infusions, and the multimodal adjunctive therapy described in the study summary. They should not automatically be generalized to other operations, settings, or analgesia regimens. The findings are best viewed as a small randomized comparison with substantial uncertainty, rather than a definitive ranking of the two approaches.

17. Why This Trial Matters Statistically

This trial illustrates a central issue in clinical biostatistics: a point estimate can look directionally informative while remaining too imprecise to support a strong conclusion. The primary contrast favors lower recorded opioid consumption in the PVB group at the point estimate, but its interval includes values on both sides of no difference. Interpreting the estimate together with its uncertainty is more informative than focusing on the direction or the p value alone.

The posted standard deviations are large, and each primary group summary includes 15 participants. That combination makes the width of the interval important to the clinical reading. A study can be randomized and still leave a broad range of effects plausible when the amount of information is limited. Randomization is a strength of design; precision is a separate question.

The registry also provides an opportunity to distinguish a trial's original design from a retrospective planning illustration. The sample-size calculations use the observed effect and stated assumptions. They do not explain why the study was designed for its intended enrollment, nor do they measure the probability that the completed trial detected a true effect. Keeping those concepts separate prevents planning calculations from being mistaken for evidence about the success of the completed study.

Finally, the record shows why complete outcome reporting and transparent statistical methods matter. The study summary describes pain scores, but the posted primary result is opioid consumption; the registry lists secondary outcomes without numerical comparisons for all of them; and analysis details such as missing-data handling and multiplicity procedures are not reported. These omissions constrain synthesis and make careful distinctions between posted findings, unreported results, and general statistical interpretation essential.

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.

The primary result includes 15 participants in each group, while the registry lists overall enrollment as 35 and the study summary states an intended enrollment of 60. The reason for the difference between intended enrollment and recorded enrollment is not reported in the registry record. The record also does not explain the relationship between enrollment and the outcome-specific counts.

Masking is listed as none. In a comparison of analgesia approaches, awareness of group assignment could influence care or outcome reporting, although the registry does not specify who knew assignments or how any such influence was assessed. The randomization method and allocation concealment are not reported in the registry record, so those implementation details cannot be evaluated from the posted information.

The primary outcome is one part of the efficacy question described in the study summary. Pain scores are mentioned there but numerical pain-score results are not reported in the registry record. Some secondary outcomes have numerical summaries, while other listed outcomes do not have numerical comparisons posted. This limits the completeness of the clinical picture and makes it difficult to compare all planned measures.

The primary confidence interval is broad, and the observed standard deviations are substantial. The record does not provide individual-level data, outcome distributions, sensitivity analyses, or enough analysis detail to assess the influence of unusual observations. Missing-data procedures, analysis populations, multiplicity handling, and the original sample-size justification are not reported in the registry record.

The safety summary reports no serious adverse events in either group, but the numbers at risk are limited, and the registry does not provide serious-event terms. The other adverse-event count is not accompanied by detailed descriptions. Consequently, the record cannot rule out uncommon events or give a complete account of event characteristics. These limitations are specific to the information available for this trial and should be considered alongside the uncertainty in the primary estimate.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Erector Spinae Plane vs. Paravertebral Nerve Block for Thoracic Surgery — NCT03758261.
• Registry record last updated 2023-07-03; status last verified 2023-06.
• Results first posted 2023-07-03.
• 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

NCT03758261 is a completed, randomized, parallel-group, phase 4 study comparing continuous erector spinae plane and paravertebral nerve block infusions for VATS. The registry lists no masking and an enrollment of 35; the study summary describes an intended enrollment of 60.

The posted primary outcome is total opioid consumption in mg MME at 1 day post catheter removal. Each group has 15 participants in the primary summary. The estimated mean difference for PVB relative to ESP is -22.66 mg MME, with a confidence interval from -140.6 to 95.3 and an unadjusted p value of 0.707. The interval is broad, leaving substantial uncertainty about the direction and size of the contrast.

Numerical summaries are available for some secondary outcomes, and adverse-event summaries are posted. Pain-score results and several analysis details are not reported in the registry record. The study therefore offers a randomized comparison, but the posted results do not establish a clear difference or equivalence between the approaches.