BRIDGE Percutaneous Nerve Stimulation for Cesarean Delivery Pain Control: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for BRIDGE Percutaneous Nerve Stimulation for Cesarean Delivery Pain Control (NCT04365465), a randomized na study. The primary outcome is Pain Scores With Movement.

2. Clinical Question

The study’s brief summary describes a randomized, placebo-controlled and natural-history-controlled pilot intended to establish trial-design feasibility and acceptability. That aim is distinct from establishing a precise estimate of a treatment effect. The posted primary results give group averages and comparisons, but the registry record does not report feasibility or acceptability results, or subgroup findings by opioid-use-disorder status. The numerical pain comparisons therefore address the posted outcome summaries, not every aim described for the pilot.

3. Trial Design

This was a randomized, parallel-group trial with quadruple masking. The registry lists three arms: an active device, a placebo device and an active control. The active NSS-2 BRIDGE device and inactive sham device were placed immediately following cesarean delivery. The active-control group received no device and standard postpartum pain control. The registry describes the study as placebo-controlled and natural-history-controlled, while the arm descriptions clarify what participants in each group received.

The record lists an enrollment of 60, with 20 participants in each arm. The study status is completed. Its recorded start date is 2020-08-17, and its primary completion date is 2021-06-30. The phase is listed as NA. The sponsor is Grace Lim, MD, MS.

The stated population includes postpartum women with and without opioid-use disorder. The record does not give the number enrolled in each subgroup, explain the subgroup allocation, or report separate outcome estimates for these groups. It also does not report the original sample-size justification, the details of the randomization procedure, or how masking was maintained. Those design details should not be inferred from the labels alone.

The registry identifies pain scores with movement on post-operative day 3 as the primary outcome. The posted results provide arm-level means and standard errors, and comparisons of the active-device and active-control arms with the placebo-device arm. Formal sponsor-reported analyses are not reported in the registry record. The study is described as a pilot focused on feasibility and acceptability, but results for those aims are 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 Pain Scores With Movement, measured over post-operative day 3.

The primary endpoint is mean pain score with movement on post-operative day 3. The score runs from 0, indicating no pain, to 10, indicating most pain; a higher score represents a worse outcome. Measuring pain during movement captures pain in a context involving activity, rather than only pain at rest. The registry does not describe further details about the movement task or the score’s measurement procedure.

A group mean describes the average recorded score among participants in that arm. The posted values are 4.57 for the active-device arm, 4.61 for the placebo-device arm and 4.19 for the active-control arm. The comparisons use the placebo-device mean as their reference. The active-device mean difference is -0.04; the active-control mean difference is -0.42. A negative difference means that the relevant arm’s posted mean was lower than the placebo-device mean, which corresponds to a lower average pain score on this scale.

The endpoint is clinically interpretable as a pain score, but a difference in group averages does not describe every participant’s experience. Nor does the registry establish a threshold for what would constitute an important difference. No such threshold is reported in the registry record. The endpoint is one outcome at a specified post-operative time point; it does not by itself summarize pain at other times, overall recovery or the pilot’s feasibility and acceptability aims.

7. Results Posted in the Registry

• Active Device: mean 4.57 versus 4.61 on control; difference -0.04 (95% CI -0.68 to 0.60), standardized effect d = -0.04; z-test p = 0.903.
• Active Control: mean 4.19 versus 4.61 on control; difference -0.42 (95% CI -1.06 to 0.22), standardized effect d = -0.41; z-test p = 0.200.

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.

PROMIS Pain Intensity Survey

• 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:
  • Active Device: mean 8.23 versus 7.90 on control; difference 0.33 (95% CI -0.94 to 1.60), standardized effect d = 0.16; z-test p = 0.610.
  • Active Control: mean 7.80 versus 7.90 on control; difference -0.10 (95% CI -1.29 to 1.09), standardized effect d = -0.05; z-test p = 0.869.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Active Device and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Active Control and the control. The interval gives the range of effects that remain compatible with the data.

PROMIS Pain Interference Survey

• 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:
  • Active Device: mean 9.47 versus 9.00 on control; difference 0.47 (95% CI -1.68 to 2.62), standardized effect d = 0.14; z-test p = 0.668.
  • Active Control: mean 9.00 versus 9.00 on control; difference 0.00 (95% CI -2.03 to 2.03), standardized effect d = 0.00; z-test p = 1.000.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Active Device and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Active Control and the control. The interval gives the range of effects that remain compatible with the data.

ObsQoR-11 Survey

• 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:
  • Active Device: mean 79.32 versus 76.90 on control; difference 2.42 (95% CI -10.70 to 15.54), standardized effect d = 0.11; z-test p = 0.718.
  • Active Control: mean 80.30 versus 76.90 on control; difference 3.40 (95% CI -8.85 to 15.65), standardized effect d = 0.17; z-test p = 0.586.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Active Device and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Active Control and the control. The interval gives the range of effects that remain compatible with the data.

The posted secondary outcomes cover pain intensity, pain interference, recovery quality, opioid consumption and other recovery measures. The registry lists 10 secondary outcome measures, but results for many listed measures are not reported in the registry record. Among the continuous secondary outcomes with posted arm summaries, the comparisons are imprecise and do not establish clear between-arm differences. The overall pattern is therefore one of uncertain estimates rather than a consistent, precisely resolved secondary-outcome signal.

These outcomes give context to the primary result because they address related but distinct aspects of pain and recovery. Pain intensity is not identical to pain with movement; pain interference and recovery quality capture other dimensions. Similar uncertainty across these measures does not prove that the approaches have the same effects, and differences across scales should not be treated as interchangeable evidence.

The secondary findings carry less weight than a prespecified primary analysis when there are many outcomes and comparisons. Each additional comparison creates more opportunity for a seemingly notable result to arise by chance. The posted p-values are unadjusted, and no multiplicity plan or adjustment is reported in the registry record. The record also does not report formal analyses for these secondary outcomes. For these reasons, secondary estimates are best treated as descriptive and exploratory rather than confirmatory.

The outcome list includes opioid consumption, surveys and recovery variables from medical records, including ICU admission and readmission. Their specific results are not reported in the registry record. That absence prevents a full assessment of whether the observed primary pattern is accompanied by similar or different findings across all outcomes. The secondary record should therefore be read as incomplete for a broad account of recovery, not as evidence that unreported outcomes showed no difference.

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

• PROMIS Pain Intensity Survey
• PROMIS Pain Interference Survey
• Opioid Consumption
• ObsQoR-11 Survey
• Recovery Variables From Med Record: ICU Admission
• Recovery Variables From Med Record: Readmission
• Recovery Variables From Med Record: Readmission Due to Pain Issues
• BPI8 Survey

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: it is a numerical score on a 0-to-10 scale. The registry reports an arm mean and standard error for each group. A mean is the arithmetic average of the scores in a group. The standard error describes uncertainty in estimating a group mean; it is not the same as the standard deviation, which describes how dispersed individual scores are around that mean. For the primary endpoint, the posted standard errors are 0.231 for the active-device arm, 0.234 for placebo and 0.229 for active control.

The posted comparisons are mean differences relative to the placebo-device group. The active-device comparison is -0.04, calculated as the active-device mean relative to the placebo mean; the active-control comparison is -0.42 relative to placebo. The sign indicates direction: a negative value means the comparison arm’s average score is lower. Because higher scores mean worse pain, a negative value points to a lower average score in that arm, but the uncertainty must be considered before interpreting the difference.

A confidence interval expresses a range of values compatible with the data under the analysis assumptions and gives a sense of precision. It is not a guarantee that the true difference lies in that range, nor does it give the probability that a particular explanation is correct. For both primary comparisons, the interval includes zero, the value representing no mean difference. The intervals also extend to values on either side of zero. This breadth means the data do not precisely distinguish a small difference from no difference or from a difference in the opposite direction.

The registry lists unadjusted p-values of 0.903 for active device versus placebo and 0.2 for active control versus placebo. A p-value describes how unusual data at least as incompatible with a specified null model would be if that model and the analysis assumptions held. It is not the probability that the null hypothesis is true. These p-values are unadjusted, so they do not account for examining multiple outcomes or comparisons. No multiplicity adjustment is reported in the registry record.

The analysis information has an important boundary: no formal analyses are reported in the registry record. The arm-level summaries and comparison estimates are posted, but the record does not describe a sponsor-run model, covariate adjustment, handling of missing outcomes, or analysis population. The posted comparisons should therefore be distinguished from a prespecified, fully documented inferential analysis. No discrepancy between the posted summaries and the recalculated comparisons is identified in the record.

General statistical explanation: standard errors and confidence intervals matter especially when a sample is small or observations are variable. A difference estimate alone is not enough to judge precision; an estimate near zero can be accompanied by uncertainty that allows a wider range of possible differences. The confidence intervals help make that uncertainty visible. They do not resolve possible bias from missing data, measurement choices, selective reporting or unreported analysis decisions.

The outcomes are analyzed as means, which summarizes the center of a continuous score distribution. This is useful for a direct comparison of average scores, but a mean does not show the full distribution. It cannot reveal whether scores cluster tightly, vary substantially, or differ in ways not captured by the average. The primary endpoint’s standard errors are posted, but the registry does not provide a distribution of individual primary scores or a standard deviation for that outcome.

General statistical explanation: over-dispersion matters when a model assumes less variability than is present in the data. In that situation, standard errors can be too small and intervals too narrow. The registry does not report a count model or an over-dispersion assessment for the primary endpoint; it is a continuous score summarized by means. The general issue is therefore a reminder that model assumptions should match outcome type and variability, not a claim that over-dispersion occurred in this trial.

The registry also lists planning illustrations based on observed effects. These illustrations use a two-sided significance level of 0.05, equal allocation between the two arms and a normal approximation, with the effect to detect set to a stated fraction of the observed effect. They are not the original trial’s design calculation: the original sample-size justification and assumptions are not reported in the registry record. Such planning calculations are sensitive to the effect chosen and should be read as hypothetical illustrations rather than evidence about the trial’s ability to detect an effect.

Finally, the analysis record does not specify whether the primary results follow an intention-to-treat, per-protocol or other analysis population. It also does not report how many participants contributed endpoint data, whether scores were missing, or how missingness was handled. Without those details, the posted arm counts alone do not establish the completeness of the primary outcome data or the precise estimand represented by the comparisons.

11. Confidence Intervals and Precision

Precision concerns how tightly the data locate a group difference, not whether a result is favorable or unfavorable. For active device versus placebo, the mean difference is -0.04 and the confidence interval extends from -0.684 to 0.605. For active control versus placebo, the mean difference is -0.42 and the interval extends from -1.062 to 0.222. Both intervals include zero, so neither comparison rules out no mean difference.

The active-device interval covers values indicating a lower average score as well as values indicating a higher average score than placebo. The active-control interval also covers both directions. Their span shows that the observed estimates are not highly precise. The posted group means are useful descriptions of the trial sample, but the uncertainty around the differences limits how much can be concluded about the underlying group contrast.

Confidence intervals are often more informative than looking only at whether a p-value crosses a chosen threshold. They show the range of differences that remain compatible with the data under the analysis assumptions. They do not show all possible sources of uncertainty: for example, they cannot account for missing-data bias or unreported analytic choices unless those are built into the analysis. The registry record does not report a clinically important difference threshold, so the intervals cannot be classified against such a threshold.

Each arm included 20 participants, and no sponsor-reported formal analysis is available in the registry record. Those features counsel against treating the displayed differences as definitive. The intervals describe uncertainty for the reported comparisons; they do not establish equivalence, absence of an effect or a clinically meaningful effect.

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 display is a planning illustration based on the observed effect, not the trial’s original design calculation. For these continuous outcomes, the figures are participants per arm, not a total across both arms and not total events. The listed assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect set to the stated fraction of the observed effect. The original trial’s own sample-size assumptions and justification are not reported in the registry record.

The 80% power column gives the planned number of participants per arm under the stated assumptions for an 80% chance of detecting the chosen effect at the stated significance level, if that effect and the model assumptions are correct. The 90% power column gives the corresponding planning number for a 90% chance. These are design-planning quantities, not guarantees that a study will produce a particular result.

The rows that plan for 100%, 75% or 50% of the observed effect illustrate how the assumed target changes the required sample size. A smaller effect is harder to distinguish from random variation and therefore requires more participants. In some comparisons, the observed effect is very small, so basing a future planning figure on that estimate produces a large requirement. Because estimates from a pilot can be unstable, these figures should not be treated as validated targets for a later study.

The planning figures are not observed power. They do not describe the probability that this completed trial detected an effect after seeing its results. The trial enrolled 20 participants per arm; the illustration instead asks how many would be planned per arm under its stated assumptions and chosen effect.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -0.040; pooled standard deviation σ = 1.040.
2. n = 2 × (1.96 + 0.842)² × 1.040² / -0.040² = 10,607.5, rounded up to 10,608 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -0.04                      # observed difference in means
sigma <- 1.03979324867976                     # 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(4365465)
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 = 10,608 (80% power), 14,201 (90% power)
 75% of observed effect: n per arm = 18,858 (80% power), 25,246 (90% power)
 50% of observed effect: n per arm = 42,430 (80% power), 56,802 (90% power)
power.t.test: 10608.4 
Simulated power at n = 10,608 per arm: 0.801 (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 multiple secondary outcomes, and the primary comparisons include active device versus placebo and active control versus placebo. Considering many outcomes and contrasts increases the chance that at least one result may appear notable by chance. The reported p-values are unadjusted. A prespecified testing hierarchy, family-wise error procedure, false-discovery approach or other multiplicity strategy is not reported in the registry record. Consequently, the secondary comparisons should not be treated as independent confirmatory tests.

The record does not report whether any interim analyses were planned or performed, or whether the primary analysis plan specified the test, covariate adjustments or handling of protocol deviations. The statistical analysis plan is not reported in the registry record. These omissions do not show that such procedures were absent; they mean that their details cannot be assessed from the registry record.

Missing-data information is also not reported in the registry record. It does not state whether all randomized participants contributed post-operative day 3 scores, how many observations were missing, why data might be missing, or how missing values were handled. The group sizes listed for the endpoint are 20 per arm, but that does not by itself describe whether every randomized participant provided an evaluable score.

The analysis population is not reported in the registry record. It is therefore unclear whether the comparisons include all randomized participants, participants who received the assigned intervention, or another defined group. The record also does not report subgroup analysis by opioid-use-disorder status, despite the stated inclusion of women with and without that condition. These details matter for interpreting what population the posted estimates represent and whether the analysis could be affected by missingness or exclusions.

These are limits on interpretation, not proof of bias or error. They make it harder to judge how robust the reported estimates are to analysis decisions, outcome availability and the number of comparisons. The registry’s feasibility-and-acceptability objective is described, but its corresponding results and analysis methods are not reported in the registry record.

15. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The adverse-event record lists 20 participants at risk in each arm. It reports zero serious adverse events in the active-device, placebo-device and active-control groups, and zero deaths in each group. The registry also records zero other adverse events in each arm. These are the posted event figures for the groups and do not establish that the risks are identical.

With 20 participants at risk per arm, the absence of recorded events is a limited safety observation in this trial. It does not rule out uncommon events or establish what might occur in a larger population or over a different period of follow-up. The registry record does not list serious adverse-event terms, and it does not provide additional detail about event definitions, collection procedures or duration of safety follow-up. The zero counts should therefore be read as an account of what was recorded in this study, not as proof that no risk exists.

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

The posted results describe average movement-pain scores on post-operative day 3 among participants assigned to an active device, a sham device or standard postpartum pain control without a device. The active-device mean was 4.57 and the placebo-device mean was 4.61; the active-control mean was 4.19. The estimated differences relative to placebo were -0.04 and -0.42, respectively. Both confidence intervals include zero, and the estimates are imprecise.

These findings do not establish a difference between the groups, but they also do not establish that the groups are equivalent. A lack of strong evidence against no difference can reflect uncertainty, especially with small group sizes; it is not proof that effects are absent. Equivalence would require an appropriate design and a prespecified margin, neither of which is reported in the registry record.

The posted comparisons also do not establish that the active device is effective or ineffective, nor do they determine whether a difference would matter to patients. The registry does not report a minimal important difference for the movement-pain scale. The record describes a pilot focused on feasibility and acceptability, but results for those aims are not reported in the registry record. The pain outcome therefore addresses only part of the stated study purpose.

The results are specific to this trial’s population, intervention, comparator and measurement time. They concern a post-operative day 3 score, not pain at all times, all aspects of recovery or opioid use. The record includes postpartum women with and without opioid-use disorder but does not report subgroup estimates. Thus, the overall means cannot establish whether the pattern differed by opioid-use-disorder status.

In general, trial estimates are best understood by considering the observed difference, its uncertainty, the design and the completeness of reporting together. Here, the numerical estimates are available, but formal sponsor analyses, missing-data methods and the original sample-size justification are not reported in the registry record. The result is a descriptive, uncertain pilot comparison, not a conclusive answer about comparative treatment effects.

17. Why This Trial Matters Statistically

This trial is statistically informative because it includes both a sham-device arm and a no-device active-control arm. Those comparators represent different contrasts: one compares the active device with an inactive device, while the other compares device assignment with standard postpartum pain control without a device. The registry posts comparisons against the placebo-device arm, making the reference group explicit.

The primary endpoint is a continuous pain score with a clear direction, and the registry provides group means, standard errors, mean differences, confidence intervals and unadjusted p-values. This allows readers to distinguish the estimated direction from the precision of the estimate. In particular, the intervals include zero, so the estimates should not be interpreted from their point values alone.

The study also illustrates the limits of a small pilot sample when the goal is to estimate comparative effects precisely. The enrollment was 60, with 20 participants per arm. Planning illustrations based on observed effects can show how strongly sample-size requirements depend on the target effect, but they do not replace the trial’s original design assumptions, which are not reported in the registry record.

Finally, the stated feasibility-and-acceptability purpose is a useful reminder that a pilot may address questions beyond efficacy. Those outcomes are not reported in the registry record, leaving a gap between the stated purpose and the available outcome detail. For biostatistical interpretation, transparent reporting of analysis plans, missing data, analysis populations and multiplicity would help readers assess how much confidence to place in the posted comparisons.

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 results come from 20 participants per arm, and the confidence intervals are broad enough to include no difference and differences in either direction. The estimates therefore have limited precision. The registry does not report a threshold for a clinically important difference, preventing interpretation against a prespecified benchmark.

The registry record does not report the original sample-size justification, statistical analysis plan, interim-analysis procedures, analysis population, covariate adjustment or missing-data handling. It also does not report outcome completeness, the number of participants contributing primary endpoint data, or subgroup results for participants with and without opioid-use disorder. These omissions limit assessment of potential analysis and reporting effects.

The stated pilot purpose was feasibility and acceptability, but those results are not reported in the registry record. Although the record lists 10 secondary outcome measures, results for many listed measures are not reported. The reported secondary comparisons are unadjusted, and a multiplicity strategy is not reported. The registry also does not describe the movement task in detail or provide primary score distributions, which limits understanding of how averages relate to individual experiences.

Finally, the adverse-event figures report zero serious and other events, but the record does not provide additional detail about ascertainment or safety follow-up. These limitations do not demonstrate that the trial was conducted improperly; they identify what cannot be evaluated from the registry record.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: BRIDGE Percutaneous Nerve Stimulation for Cesarean Delivery Pain Control — NCT04365465.
• Registry record last updated 2023-01-18; status last verified 2022-12.
• Results first posted 2023-01-18.
• 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

NCT04365465 is a completed, randomized, quadruple-masked, parallel-group pilot comparing an active NSS-2 BRIDGE device, an inactive sham device and standard postpartum pain control without a device after cesarean delivery. The registry reports enrollment of 60 participants, with 20 in each arm, and describes a population of postpartum women with and without opioid-use disorder.

The primary outcome is mean pain with movement on post-operative day 3, scored from 0 to 10, with higher scores indicating worse pain. The posted mean differences versus placebo are -0.04 for active device and -0.42 for active control; both confidence intervals include zero. The study’s stated feasibility-and-acceptability aim is not accompanied by reported results in the registry record. Formal sponsor analyses, original sample-size justification, missing-data methods and analysis-population details are also not reported.