Pudendal Nerve Block for Hemorrhoidectomy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Pudendal Nerve Block for Hemorrhoidectomy (NCT04251884), a randomized na study. The primary outcome is Postoperative Pain on the Visual Analogue Scale (VAS).

2. Clinical Question

The clinical question is narrow: it concerns a pain score at a specified postoperative time, in patients having a particular operation under spinal anaesthesia. It is not a comparison of the block as a replacement for spinal anaesthesia; both groups are described as receiving spinal anaesthesia. The registry record also lists opioid consumption, hospital stay, complications related to the block, and cost analysis among secondary outcomes. These outcomes address other aspects of the postoperative course, but they do not change the definition of the primary question.

The record identifies enrollment of 49 and reports 23 participants in the block group and 26 in the group without the block for the primary outcome. The group comparison is the basis for the posted numerical result. The record does not report additional information about the patients’ clinical characteristics, the setting, or whether the results apply to other procedures or anaesthetic approaches. Those boundaries matter when interpreting the population to which the result may be relevant.

3. Trial Design

The registry describes a prospective, randomized, double-blind, controlled trial with a parallel-group model. Patients undergoing Milligan-Morgan hemorrhoidectomy under spinal anaesthesia were assigned to receive or not receive a pudendal nerve block after the spinal anaesthesia. The listed intervention is a local anesthetic, ropivacaine. The record marks the study as completed and lists enrollment as 49.

The primary outcome was postoperative pain on the visual analogue scale at 24 hours after hemorrhoidectomy. Results are reported as means and standard deviations for each group. The block group had 23 participants in the posted primary outcome results, with a mean score of 1.4 and a standard deviation of 1.4. The group without the block had 26 participants, a mean of 3.1, and a standard deviation of 2.4.

The registry lists the study phase as NA. It gives a start date of 2018-01-01 and a primary completion date of 2019-12-29. The record names Francesco Mongelli as sponsor. These administrative details describe the registered study but do not supply further information about how the trial was conducted.

Several design details that would help assess the conduct of the trial are not reported in the registry record. These include the method used to generate the random allocation sequence, how allocation was concealed, which people were masked, and whether masking was checked. The record does not describe the recruitment setting, the eligibility criteria, or the intended analysis population. The trial’s original sample-size justification, protocol-level analysis plan, and any interim analyses are also not reported in the registry record. The registry identifies the study as double-blind, but that label alone does not resolve those methodological questions.

Random allocation is intended to make treatment groups comparable on average, while masking can reduce the influence of expectations on care or outcome assessment. These are general principles; the registry’s design labels do not establish the details of their implementation. The results therefore need to be read alongside the information the record actually documents, rather than as a complete account of trial conduct.

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 Postoperative Pain on the Visual Analogue Scale (VAS), measured over at 24 hours after the hemorrhoidectomy.

The primary endpoint is postoperative pain measured on the visual analogue scale 24 hours after hemorrhoidectomy. The registry describes the scale as running from 0, meaning no pain at all, to 10, meaning the strongest pain. Each participant’s recorded value is a score on that scale, and the posted group summaries are means with standard deviations.

A pain scale turns a subjective experience into a score that can be summarized and compared between groups. In general, this makes it possible to describe both the average level of reported pain and the spread of scores among participants. It does not make pain fully objective: a score remains a participant’s report, interpreted through the scale and the time at which it is collected.

The 24-hour assessment gives the comparison a defined time point. It does not, by itself, describe pain at other times or the full course of recovery. A single mean can also conceal differences between individual experiences, which is why the standard deviations and confidence interval are useful alongside the group means. The registry does not report further details about how the score was collected, who collected it, or how missing 24-hour scores were handled.

This endpoint addresses the trial’s primary question about pain after the operation. It should not be treated as a direct measure of opioid use, length of stay, complications, or costs; those are separate outcomes listed in the record. Nor does the endpoint alone capture all dimensions of postoperative recovery.

7. Results Posted in the Registry

• Not Receiving the Pudendal Nerve Block: mean 3.10 versus 1.40 on control; difference 1.70 (95% CI 0.61 to 2.79), standardized effect d = 0.85; z-test p = 0.002.

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.

Opioids Consumption

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Not Receiving the Pudendal Nerve Block: 38.5% (10/26) versus 21.7% (5/23) on control; risk difference 16.7 percentage points (95% CI -8.5 to 41.9), risk ratio 1.77 (0.71–4.42); unadjusted two-proportion z-test p = 0.205.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Not Receiving the Pudendal Nerve Block and the control. The interval gives the range of effects that remain compatible with the data.

Lenght 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:
  • Not Receiving the Pudendal Nerve Block: mean 1.80 versus 1.20 on control; difference 0.60 (95% CI -0.25 to 1.45), standardized effect d = 0.39; z-test p = 0.166.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Not Receiving the Pudendal Nerve Block and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes concern several different parts of the postoperative period: opioid consumption within 48 hours, hospital stay up to 2 weeks, complications related to the pudendal nerve block, and direct and indirect cost analysis in outpatients and inpatients. The record also lists postoperative pain on the visual analogue scale among the secondary outcomes, while separately identifying pain at 24 hours as the primary endpoint. These outcomes extend the scope of the question beyond the main pain comparison, but they do not measure the same thing.

The posted opioid-consumption and hospital-stay comparisons do not show the same strength of statistical evidence as the primary pain comparison: their unadjusted p values are 0.205 and 0.166, respectively, and their confidence intervals include zero. This pattern is compatible with uncertainty about whether the groups differed on those secondary measures. It is not evidence that the groups were equivalent, and it does not overturn or independently confirm the primary result.

In general, secondary outcomes are useful for building a broader description of trial results, but they often carry less confirmatory weight when many outcomes are assessed. Each additional comparison creates another opportunity to observe a seemingly notable result by chance. A multiplicity adjustment or a prespecified hierarchy can address some of that concern, but neither is reported in the registry record. The registry also lists no reported analyses for the secondary outcomes.

The results for the other listed secondary outcomes, including complications and costs, are not reported in the registry record. Consequently, the posted secondary evidence is incomplete as a description of all outcomes named in the record. The overall pattern should be read as a primary pain comparison accompanied by limited and uncertain information on some related outcomes, not as a comprehensive assessment of every aspect of recovery or resource use.

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

• Postoperative Pain on the Visual Analogue Scale (VAS)
• Opioids Consumption
• Lenght of Hospital Stay
• Complications Related to the Pudendal Nerve Block
• Direct and Indirect Cost Analysis in Out- and In-patients

9. Statistical Interpretation

10. Statistical Methods Explained

For the primary outcome, the registry reports a continuous measure as a mean and standard deviation in each randomized group. A mean gives the arithmetic average of the observed scores. A standard deviation describes how dispersed participant scores are around that average. These summaries answer different questions: the means describe the groups’ central values, while the standard deviations indicate variation among the observations.

What does the mean difference express?

The reported mean difference compares the group without the pudendal nerve block with the group receiving the block. Its direction is defined as the score without the block minus the score with the block. A positive estimate therefore corresponds to a higher average score in the group without the block. The reported estimate is 1.7. This is a contrast between group averages; it is not a statement that every participant’s score differed by that amount.

In general, a mean difference is a natural summary when an outcome is measured on the same numerical scale in both groups. It preserves the scale’s units, which makes the contrast interpretable in relation to the visual analogue scale. The standard deviations help readers judge how much participant-level spread accompanies the group means. The registry does not report an adjusted primary estimate, so the posted comparison is interpreted as the group-level contrast in the results rather than as an adjusted model estimate.

How should the confidence interval be read?

In general, a confidence interval is constructed by combining an estimated effect with its sampling uncertainty under a statistical model. A wider interval indicates less precision than a narrower interval, all else being equal. An interval that includes zero is compatible with no mean difference under the model, while an interval entirely on one side of zero indicates that the estimated contrast is not centered on zero at the interval’s stated confidence level. For the primary comparison, the reported interval lies above zero.

A confidence interval is not a range that contains every participant’s score, and it does not imply that all values inside it are equally plausible. It also does not account automatically for possible bias from trial conduct, missing data, selective reporting, or model assumptions. The registry record does not state the confidence level in the posted comparison’s description, so no confidence level should be inferred from that description alone.

What does the p value add?

The primary comparison has an unadjusted p value of 0.002. In general, a p value is calculated under a null model and expresses how unusual the observed data, or data more extreme under the test’s definition, would be if that model held. It is not the probability that the null model is true. Nor does it show whether a difference is important to patients or whether the trial’s assumptions were met.

The registry labels the comparison unadjusted. This means the displayed p value is not described as accounting for other comparisons or covariates. The trial record does not report a fuller statistical analysis plan or a multiplicity strategy. The p value should therefore be read as a result for the displayed comparison, not as proof that all possible sources of uncertainty or selection have been addressed.

Why do the secondary outcomes use different summaries?

The secondary outcome for opioid consumption is a participant count, so its comparison is expressed as a risk difference. The posted results record 5 participants in the block group and 10 in the group without the block within 48 hours. A risk difference expresses the difference between the proportions with an event or characteristic in the two groups. In general, it is an absolute contrast, unlike a ratio measure, which compares relative levels.

Length of hospital stay is reported as a continuous measure in days, using group means and standard deviations. The registry reports a mean difference of 0.6 days, with a confidence interval that includes zero and an unadjusted p value of 0.166. The measure is listed for up to 2 weeks. These summaries describe a different outcome and time frame from the primary pain endpoint.

Different outcome types call for different statistical summaries. Counts and proportions describe binary outcomes, while means and standard deviations describe continuous outcomes. General statistical considerations include whether a continuous outcome is sufficiently well represented by a mean-based model and whether binary-outcome estimates are stable when event counts are limited. The record does not describe diagnostic checks, alternative models, or sensitivity analyses, so those aspects of the analysis are not reported in the registry record.

What does randomization contribute?

In general, random assignment is intended to balance both measured and unmeasured characteristics across groups on average. This helps support a causal interpretation of a between-group contrast, provided assignment was implemented as intended and subsequent analysis is appropriate. The registry labels the trial randomized, but the sequence-generation and concealment methods are not reported in the registry record. Randomization does not guarantee that the groups will be identical in a trial, especially when the number of observations is limited.

The record also labels the study double-blind. Masking can reduce bias related to expectations or outcome assessment, but its value depends on who was masked and whether masking was maintained. Those details are not reported in the registry record. The statistical summaries cannot resolve these questions about conduct.

Finally, the registry lists no reported analyses for the secondary outcomes and zero analyses in its analysis count. The displayed comparisons should not be confused with a complete protocol-driven statistical report. Details about covariate adjustment, missing-data methods, prespecified analysis populations, interim monitoring, and multiplicity are not reported in the registry record. The posted summaries can still be described, but the absent details constrain how confidently their analysis choices can be evaluated.

11. Confidence Intervals and Precision

For the primary mean difference, the registry reports an estimate of 1.7 and a confidence interval whose lower and upper limits are both above zero. This indicates that the interval does not include a zero difference under the reported comparison. The interval gives more information than the point estimate alone: it communicates uncertainty around the estimated contrast, rather than presenting 1.7 as an exact or universally applicable value.

Precision is about the range of estimates compatible with the data under the statistical model, not the certainty that the result will repeat in another sample. In general, estimates from smaller groups tend to be less precise than estimates from larger groups when other factors are similar. The primary outcome results include 23 participants in the block group and 26 in the group without the block. The record does not report whether any randomized participants lacked a primary outcome observation or how such observations were handled.

The observed standard deviations, 1.4 and 2.4, show that scores varied within both groups. A mean difference describes the separation of group averages, while participant-level variation helps determine how precisely that separation is estimated. The confidence interval reflects sampling uncertainty under the analysis assumptions, but it cannot capture unreported sources of bias or uncertainty about trial conduct.

The secondary results are less precise in their own ways. The opioid-consumption risk-difference interval spans zero, and the hospital-stay mean-difference interval also includes zero. These intervals do not provide clear evidence of a nonzero difference at their reported interval level, but they should not be interpreted as proving equality. Their breadth and the available outcome counts matter when judging what size of differences remain compatible with the data. The registry does not report a clinically important threshold for these outcomes.

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 figures are planning illustrations based on the observed effect, not the trial’s original design calculation. The original sample-size assumptions and justification are not reported in the registry record. For the continuous primary outcome, the figures are participants per arm. The same per-arm convention applies to the binary opioid-consumption outcome and the continuous hospital-stay outcome; these are not total-event counts.

The planning calculation uses a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It considers effects at 100%, 75%, and 50% of the observed effect. The 80% power column means the projected number of participants per arm for a design intended to have an 80% chance of detecting the stated effect under those assumptions. The 90% power column gives the corresponding projection for a design intended to have a 90% chance. These are design targets under the calculation’s assumptions, not guarantees about a future study.

For the primary outcome, planning for 100% of the observed effect gives 22 participants per arm for 80% power and 29 participants per arm for 90% power. Planning for 75% of the observed effect gives 39 participants per arm for 80% power and 52 participants per arm for 90% power. Planning for 50% of the observed effect gives 87 participants per arm for 80% power and 116 participants per arm for 90% power.

The other outcomes have their own planning figures because their observed effects and outcome types differ. The opioid-consumption projections range from 117 participants per arm for 80% power and 157 for 90% power when using 100% of its observed effect, to 430 and 576 when using 50%. The hospital-stay projections range from 105 and 140 when using 100% of its observed effect, to 419 and 560 when using 50%.

Smaller effects require more participants to detect under otherwise fixed assumptions because they are harder to distinguish from random variation. The displayed figures are not observed power: they are planning illustrations calculated from the observed effects, and they do not show the probability that this completed trial detected its effects. The sample-size curve should be read as a visual representation of the same planning relationship, not as a separate estimate of trial findings.

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 = 1.700; pooled standard deviation σ = 1.995.
2. n = 2 × (1.96 + 0.842)² × 1.995² / 1.700² = 21.6, rounded up to 22 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 <- 1.7                      # observed difference in means
sigma <- 1.99531365848698                     # 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(4251884)
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 = 22 (80% power), 29 (90% power)
 75% of observed effect: n per arm = 39 (80% power), 52 (90% power)
 50% of observed effect: n per arm = 87 (80% power), 116 (90% power)
power.t.test: 22.6 
Simulated power at n = 22 per arm: 0.788 (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 record identifies a primary outcome and lists several secondary outcomes. It does not report a multiplicity strategy, such as a hierarchy of hypotheses or a procedure for adjusting significance thresholds across outcomes. When many outcomes are tested, the chance of at least one apparently notable result can increase even if none of the underlying effects is real. This is a general statistical concern, not evidence that any particular reported result is false.

The primary pain comparison has an unadjusted p value of 0.002. The registry does not report whether this comparison was selected in advance in a protocol or analysis plan, although it is designated as the primary outcome in the record. The registry does not report a broader plan for interpreting the set of outcomes together. Unadjusted secondary comparisons should therefore be treated as less confirmatory than a result interpreted under a prespecified multiplicity plan.

Missing-data handling is also not reported in the registry record. The posted outcome groups have different reported participant counts, but the record does not explain whether those counts reflect all randomized participants, outcome availability, or another analysis population. It does not state how missing pain scores, opioid-use data, or hospital-stay observations were handled. Without those details, it is not possible to assess whether missingness could have affected the estimates.

The analysis populations are not reported in the registry record. In general, an intention-to-treat analysis retains participants in their assigned groups, while other analysis populations may use different inclusion rules. The record does not say which approach was used, or whether there were protocol deviations or exclusions. Randomized assignment is most informative when the analysis and participant flow are transparent, so the absence of this information limits appraisal.

The record lists zero analyses and no reported analyses for the secondary outcomes. It does not report interim analyses, stopping rules, covariate adjustment, or sensitivity analyses. These omissions do not prove that such procedures were absent in the conduct of the study; they mean that they are not reported in the registry record. The posted results can be described, but the completeness of the statistical reporting cannot be established from the registered information alone.

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 5% reporting threshold.

The registry reports serious adverse events for 0 of 23 participants in the group receiving the pudendal nerve block and 0 of 26 in the group without the block. It also reports other adverse events for 0 of 23 and 0 of 26, respectively. Deaths are reported as 0 in both groups. These figures describe the safety information recorded for the groups in the registry.

Zero reported events should not be read as proof that the risk of an event is zero. In general, when no events are recorded in a study, the data still leave uncertainty about events that could occur in a larger population or over a longer period. The registry does not describe the adverse-event collection procedures, the observation period for these safety summaries, or whether all participants were assessed in the same way.

The record lists complications related to the pudendal nerve block as a secondary outcome, but the adverse-event figures alone do not give a detailed account of specific complications. No serious adverse event terms are listed. These data are a limited report of recorded events, not a comprehensive determination of safety across settings or patient groups.

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

The result is a comparison of average pain scores at 24 hours after hemorrhoidectomy in the two randomized groups described in the registry. The posted means were 1.4 for participants receiving a pudendal nerve block and 3.1 for participants not receiving the block. The reported mean difference was 1.7 in the direction of a higher average score without the block, and the registry reports an unadjusted p value of 0.002. The confidence interval for that difference lies above zero.

These findings describe the observed results in this trial. They do not mean that every participant experienced a lower score, and they do not provide a prediction for an individual. A group mean can coexist with a broad range of personal scores. The standard deviations reflect variation in the observed scores, and the confidence interval reflects uncertainty in the estimated group contrast under the model.

The result does not establish the clinical importance of the difference. The registry does not report a threshold for a meaningful change on the visual analogue scale, so statistical evidence and clinical importance cannot be treated as interchangeable. It also does not answer whether a similar contrast would occur with other operations, anaesthetic approaches, patient groups, or outcome times.

The trial record does not report details of random-sequence generation, allocation concealment, missing-data methods, or analysis populations. Those gaps limit assessment of possible bias and of how completely the posted comparison represents randomized participants. The record also does not report a multiplicity plan, so secondary findings should be interpreted cautiously.

The result does not establish that the intervention changes all aspects of postoperative recovery. Opioid consumption and hospital stay are separate outcomes, and their posted comparisons are less conclusive. Complication and cost results are not reported in the registry record. The most direct conclusion is therefore bounded: the posted primary data show a difference in mean pain scores at the specified time, with statistical uncertainty reported, while important details needed to assess broader effects and trial conduct remain unavailable in the record.

17. Why This Trial Matters Statistically

This trial is statistically interesting because it pairs a clearly defined primary outcome with a randomized comparison and reports group-level summaries, an effect estimate, a confidence interval, and an unadjusted p value. Readers can distinguish the estimated size and direction of the pain-score contrast from the uncertainty around it, rather than relying on a significance label alone.

The result also illustrates why a confidence interval matters. The primary interval lies above zero, while the intervals for the posted secondary comparisons include zero. Those patterns convey different levels of information about the estimated contrasts. Neither pattern alone establishes clinical importance, and intervals should be considered alongside study size, outcome variability, and the design and reporting details.

The registry also makes visible the challenges of interpreting a collection of outcomes. Pain, opioid consumption, hospital stay, complications, and costs address different questions. Without a reported multiplicity plan and without reported analyses for the secondary outcomes, a reader cannot treat all posted comparisons as equally confirmatory. The record’s missing information about analysis populations and missing data further demonstrates that numerical results are only part of an evidence assessment.

Finally, the planning illustrations show how sample-size requirements depend on the effect a future study aims to detect. They are based on observed effects and specified planning assumptions, not on the original design rationale. This distinction is important: a planning projection can help frame future study design, but it cannot retrospectively establish whether the completed trial was adequately designed or powered. The record gives a useful statistical contrast, while also showing why transparent protocol and analysis reporting matters.

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 registry record leaves important trial details unreported. It does not describe eligibility criteria, participant characteristics, recruitment setting, random-sequence generation, allocation concealment, or which people were masked. These omissions limit assessment of how participants entered the study, whether group assignment could have been anticipated, and how the double-blind designation was implemented.

The record does not explain the analysis population or the handling of missing outcome data. The posted group counts identify the participants included in the results, but do not establish whether all randomized participants were analyzed or whether any outcome measurements were unavailable. Without a participant-flow account or missing-data methods, the potential influence of missingness cannot be evaluated.

The record does not report the trial’s original sample-size calculation or the assumptions behind it. Planning illustrations based on the observed effects do not fill that gap. The record also does not report a protocol-level statistical plan, multiplicity adjustment, covariate adjustment, sensitivity analyses, interim analyses, or stopping rules. These details are relevant to judging whether the analyses were prespecified and how robust the findings may be.

The primary outcome is a pain score at one specified time. The registry does not provide additional time points for interpreting the course of pain, nor does it report a threshold for clinical importance. Some named secondary outcomes, including complications and cost analysis, do not have results reported in the registry record. The available results therefore offer a limited view of outcomes beyond the primary comparison.

These reporting limitations do not establish that the study procedures or analyses were deficient. They indicate that the registry record does not contain enough information to assess those aspects. The interpretation should remain tied to the posted group summaries and comparison, rather than extending to unreported outcomes or settings.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Pudendal Nerve Block for Hemorrhoidectomy — NCT04251884.
• Registry record last updated 2022-03-11; status last verified 2022-03.
• Results first posted 2020-06-05.
• 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

The registry describes a completed, prospective, randomized, double-blind, parallel-group trial of pudendal nerve block after spinal anaesthesia for Milligan-Morgan hemorrhoidectomy. Enrollment is listed as 49. The primary outcome was visual analogue scale pain at 24 hours after surgery.

The posted primary results report mean scores of 1.4 for the block group and 3.1 for the group without the block. The reported mean difference is 1.7, with an unadjusted p value of 0.002 and a confidence interval lying above zero. Secondary results include opioid consumption and hospital stay; the registry does not report analyses for the other listed secondary outcomes.

Information about the original sample-size rationale, missing-data handling, analysis populations, and multiplicity is not reported in the registry record. The results are therefore most directly interpreted as the posted group comparison for pain at the stated time, with the reported uncertainty and limitations in registry detail kept in view.