Epidural Neuroplasty for the Treatment of Herniated Lumbar Disk: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Epidural Neuroplasty for the Treatment of Herniated Lumbar Disk (NCT03101033), a non-randomized na study. The primary outcome is Pain Assessed by Visual Analogue Scale.

2. Clinical Question

3. Trial Design

The registry record describes a completed, single-center, controlled clinical trial with a parallel-group model and non-randomized allocation. It lists 92 participants and the condition as herniated lumbar disk. The record gives a start date of 2015-05 and a primary completion date of 2016-02. The phase is listed as NA.

The two described arms are an epidural neuroplasty group and a transforaminal steroid injection group. The neuroplasty group description says participants would receive epidural neuroplasty once enrolled. In the injection group, participants would receive transforaminal betamethasone injection once enrolled; if no obvious pain relief was reported, another epidural injection would be given one week later. The criterion for obvious relief, the follow-up schedule, and the exact implementation of that additional injection are not reported in the registry record.

Although the intervention list also includes caudal epidural compound betamethasone injection and epidural hyaluronidase injection, the record does not explain how those interventions relate to the two arm descriptions. Masking is listed as single, but the identity of the masked party and the masking procedures are not reported. Allocation was not randomized, so the groups may differ in ways other than the assigned treatment. The registry record itself cautions that the arms are not a like-for-like control comparison. These design features matter when interpreting any apparent group difference: a non-randomized comparison does not by itself separate treatment effects from differences in who entered each arm or how care was delivered.

The registry record reports no analysis entries. It does not provide a statistical analysis plan, a sample-size justification for the trial, or details of the enrolled participants beyond the listed condition and enrollment. These absences limit what can be concluded about how the planned comparison was intended to be conducted.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: Ninety-four participants were excluded before assignment. Sixty-three of them did not meet the inclusion criteria. Twenty-four of them refused to participate. Seven participants were excluded as other reasons such as the physician was uncertain about the diagnosis or the participants was difficult to communicate with.

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 Assessed by Visual Analogue Scale, measured over before treatment.

The primary outcome is pain assessed by the Visual Analogue Scale, reported in units on a scale. The record describes a scale with 0 representing no pain and 10 representing the most severe pain a person could experience; higher scores indicate more severe pain. A VAS is a continuous measure, meaning that its recorded value can take a range of possible values rather than being restricted to categories such as “pain” or “no pain.” It is used to quantify a person’s reported pain intensity in a form that can be summarized and compared statistically.

The stated time frame for this primary measure is before treatment. That makes it a pre-treatment assessment: it describes pain at the point before the interventions, rather than reporting pain after treatment or change from baseline. A baseline measure can describe the groups’ starting status and may be useful in interpreting later outcomes. On its own, however, a pre-treatment score cannot show whether pain changed after treatment or whether the groups differed in treatment response.

The registry record does not report VAS values, variability, follow-up VAS assessments, or an analysis comparing groups. It therefore supplies the scale definition but not numerical evidence about the primary outcome after treatment.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies the primary measure as a continuous outcome: pain assessed using the VAS. It describes the outcome using a mean and standard deviation. A mean is a measure of the center of a set of observations, while a standard deviation describes how spread out observations are around that mean. These summaries can help characterize a group’s scores, but they do not by themselves establish a treatment effect. To compare arms, an analysis would also need to define the contrast of interest and report an estimate with its uncertainty. No such primary-outcome analysis is reported in the registry record.

What does the VAS measure?

The scale is defined from 0, meaning no pain, to 10, meaning the most severe pain one could experience; higher scores represent more severe pain. Treating the measure as continuous makes it possible to summarize scores with means and standard deviations and to use methods designed for continuous outcomes. The registry entry says the primary assessment was before treatment. It does not report a follow-up time for the primary outcome, or whether an analysis was planned using post-treatment scores, change from baseline, or another approach.

Why does allocation matter?

Allocation is listed as non-randomized. Random allocation, when used, is intended to make treatment groups comparable on average with respect to measured and unmeasured characteristics. Without randomization, group membership may be associated with participant characteristics, clinical decisions, or other influences. This creates a risk of confounding: a measured difference between groups may not be attributable to the intervention alone. The registry record explicitly cautions that the arms are not a like-for-like control comparison. It does not report a method for adjusting for potential confounding or the variables that such an adjustment might include.

Masking is listed as single, but the record does not identify who was masked or describe how masking was maintained. Masking can reduce the influence of knowledge of treatment assignment on some aspects of care, outcome assessment, or reporting, depending on who is masked and how outcomes are collected. Without those details, the implications of the masking designation cannot be evaluated for this trial.

What does the sample-size information mean?

The registry record describes a planning illustration based on an observed effect, using a two-sided significance level of 0.05, equal allocation between the arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. These are assumptions for a planning calculation, not a report of the trial’s own design justification. The record does not report a sample-size justification for the trial itself, and it does not provide the observed primary-outcome effect needed to interpret such planning illustrations in context.

General statistical context: a sample-size calculation estimates the number of participants needed to detect a specified effect under stated assumptions about variability, significance level, allocation, and analysis. It is prospective planning, not evidence that a study actually had a given probability of finding a result. A planning illustration based on a trial’s observed effect is especially dependent on that estimate and should not be read as observed power. No calculated participant counts or observed primary-outcome estimates are reported in the registry record.

What can a p-value or confidence interval tell a reader?

General statistical context: a p-value measures how incompatible the observed data are with a specified null model, under the assumptions of the analysis. It does not measure the probability that a treatment works, nor does it quantify the size or importance of an effect. A confidence interval places an estimate in context by showing its uncertainty under the analysis assumptions. It is important to consider both the estimate and its precision rather than relying on a threshold alone. The registry record does not report a primary-outcome p-value, estimate, or confidence interval, so these interpretations cannot be applied to an efficacy result for this trial.

What analysis details are absent?

The registry record lists eight outcome measures and zero analyses. The secondary outcomes are listed as Functional Status Assessed by Oswestry Disability Index, repeated four times, but the record does not provide the corresponding results or explain the repeated entries. It does not report the statistical model, treatment contrast, handling of repeated measurements, missing-data approach, analysis population, or adjustment for multiple outcomes. These details affect how estimates should be interpreted and how robust a comparison may be. Their absence means the statistical procedures used for the registered outcomes cannot be reconstructed from the registry record.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Epidural Neuroplasty Group", "Transforaminal Steroid Injection Group")
n   <- c(27, 51)
m   <- c(5.63, 5.92)
sp  <- c(1.24, 1.2)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Epidural Neuroplasty Group  27  5.630  1.240  5.139  6.121
CARM  Transforaminal Steroid Injection Group  51  5.920  1.200  5.582  6.258

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists eight outcome measures, including the primary VAS measure and four repeated entries for functional status assessed by the Oswestry Disability Index. It does not explain why the secondary outcome appears repeatedly, specify the time points associated with those entries, or report results for them. The record lists zero analyses.

When a study evaluates multiple outcomes or multiple time points, the chance of obtaining an apparently notable result can increase if many comparisons are made. General statistical approaches can address this issue, for example by defining a primary comparison in advance or adjusting inference across multiple comparisons. The registry record does not report whether a multiplicity strategy was planned or used. With no analysis results and no statistical plan reported, it is not possible to assess how outcome multiplicity was handled.

Missing-data methods and analysis populations are also not reported in the registry record. It does not state how unavailable measurements, withdrawals, or protocol deviations were handled, nor does it describe which participants were included in efficacy analyses. These choices can affect estimates, particularly if missingness differs between groups or is related to participant outcomes. No assumptions about missing data or participant inclusion can be inferred from the registry entries.

The record’s planning illustration does not fill these gaps: it describes assumptions for sample-size planning, not the analysis of missing outcomes or multiple endpoints. Without outcome values and analysis details, readers cannot determine whether the reported groups, outcomes, or procedures align with a prespecified analysis plan.

12. 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 2% reporting threshold.

Most frequent non-serious adverse event terms

The registry safety entries list 60 participants at risk in the transforaminal steroid injection group and 32 in the epidural neuroplasty group. Serious adverse events are recorded as 0 in each group, and deaths are recorded as 0 in each group. Other adverse events are recorded as 0 in the injection group and 2 in the neuroplasty group.

These are registry counts, not a detailed safety analysis. The record does not name the two other events, describe their severity or timing, or state whether they were considered related to treatment. It also does not explain how adverse events were collected or define the observation period. The counts therefore should not be read as a complete account of all possible harms or as a comparison adjusted for differences between groups.

The at-risk counts are the denominators listed for these safety entries. The record does not establish that those denominators are the same as the participants included in any efficacy analysis. With non-randomized allocation and no reported efficacy analyses, the safety entries should be interpreted descriptively. A zero count in the serious-event or death fields means no such events are recorded in these entries; it does not establish that the interventions have no safety risks.

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

The registry record supports a limited descriptive account: this was a completed, single-center, non-randomized comparison of epidural neuroplasty with transforaminal steroid injection in people with herniated lumbar disk. Enrollment is listed as 92, and pain measured before treatment on the VAS is the registered primary outcome. The record also describes the two arms and lists safety counts.

It does not report numerical results for the primary outcome, post-treatment pain measurements, a treatment-effect estimate, or an analysis comparing the groups. Thus, the record does not show whether pain changed after treatment, whether any change differed between groups, or how precise such a difference might be. A primary measurement taken before treatment is not itself evidence of treatment response.

The non-randomized design further limits causal interpretation. The registry record warns that the arms are not a like-for-like control comparison. Even if an outcome contrast were available, group differences other than treatment could contribute to it. No adjustment strategy or adjusted estimate is reported.

The safety entries show zero serious adverse events and zero deaths in both groups, with two other adverse events recorded in the neuroplasty group. They are counts without event descriptions or a reported causal assessment, so they cannot provide a comprehensive or comparative safety conclusion.

General statistical context: an estimate is most informative when its magnitude, uncertainty, and design limitations are considered together. Here, the primary estimate and its uncertainty are not reported. The record can therefore identify the question the trial set out to address, but it cannot answer that question from the posted results. It also cannot establish that either intervention is superior, equivalent, or ineffective.

14. Why This Trial Matters Statistically

This trial is statistically notable because its stated aim is comparative, while its allocation is non-randomized. That distinction is central to interpretation: comparisons between groups can be affected by differences in who received each intervention, not only by the interventions themselves. The registry record explicitly cautions that the arms are not a like-for-like control comparison. Recognizing this limitation is important before assigning a causal meaning to any group contrast.

The registered primary outcome also highlights the importance of timing. Pain on the VAS is specified before treatment. A baseline measurement can describe starting pain, but it does not answer whether treatment is followed by a change or whether changes differ between groups. Reporting the outcome time point and the actual analysis is therefore essential to interpreting an efficacy question.

The record further illustrates the difference between trial results and planning calculations. It describes a sample-size planning illustration based on an observed effect and stated assumptions, but does not report the trial’s own sample-size justification or the primary-outcome effect. Planning figures are not observed results and do not substitute for estimates and uncertainty from the trial analysis.

Finally, the registry record lists multiple outcome measures but reports zero analyses. Without outcome results, analysis methods, multiplicity handling, or missing-data information, readers cannot assess the statistical evidence behind the stated question. The value of careful registry interpretation lies in distinguishing what the record identifies—the design, interventions, and intended measure—from what it does not report: the efficacy estimate and the methods needed to evaluate it.

15. 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.

A key limitation is that the registry record does not report numerical primary-outcome results or any analyses. Although it defines the VAS and specifies that the primary measure was taken before treatment, it does not report post-treatment pain, change from baseline, or a group comparison. The central efficacy question therefore cannot be evaluated from the posted results.

The non-randomized allocation is an additional limitation, and the record cautions that the arms are not a like-for-like control comparison. The registry entry does not report participant characteristics, a confounding-adjustment strategy, or adjusted estimates. Differences between groups could therefore complicate interpretation of any apparent contrast.

Other design and treatment details are incomplete. The record lists single masking without identifying who was masked. It names caudal betamethasone and hyaluronidase among the interventions, but does not explain their place in the described arms. The additional injection condition in the comparator arm is described in terms of no obvious pain relief, but the criterion and its application are not specified.

The secondary outcome list repeats the Oswestry Disability Index entry, without explaining the repetitions or reporting time points and results. The registry record also does not report missing-data procedures, analysis populations, multiplicity handling, or a trial sample-size justification. Safety reporting is limited to counts, without event descriptions or causal assessments. These omissions constrain interpretation and make it difficult to reconstruct the intended or conducted statistical analysis.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Epidural Neuroplasty for the Treatment of Herniated Lumbar Disk — NCT03101033.
• Registry record last updated 2018-09-04; status last verified 2017-11.
• Results first posted 2018-09-04.
• 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.

19. Record Summary

The registry record describes a completed, single-center, non-randomized, parallel-group comparison of epidural neuroplasty and transforaminal steroid injection for herniated lumbar disk. Enrollment is listed as 92. The primary outcome is pain assessed by the VAS before treatment; higher values indicate more severe pain, on a scale from 0 to 10.

The record lists eight outcome measures and zero analyses. It does not report numerical primary-outcome results, a comparative estimate, or its uncertainty. It lists zero serious adverse events and zero deaths in both groups, with two other adverse events recorded in the neuroplasty group. Allocation was non-randomized, and the registry record cautions that the arms are not a like-for-like control comparison. As a result, the record describes the planned question and some design and safety details, but does not provide the efficacy analysis needed to answer that question.