Efficacy of Botulinum Toxin Versus Lidocaine in Treating Masticatory Myofascial Face Pain Using Ultrasound and EMG Guided Techniques: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy of Botulinum Toxin Versus Lidocaine in Treating Masticatory Myofascial Face Pain Using Ultrasound and EMG Guided Techniques (NCT00992108), a randomized phase 4 study. The primary outcome is Clinical Response as Assessed by >20% Change From Baseline in the Jaw Functional Limitation Scale (JFLS) Global Score.

2. Clinical Question

This is a head-to-head comparison rather than a comparison with no treatment. The registry summary explains that lidocaine injections were regarded as standard care in orofacial pain practice and describes the rationale for investigating botulinum toxin. The record identifies this as a phase 4, randomized, quadruple-masked, parallel-group trial. It was terminated. The reason for termination and the detailed enrollment criteria are not reported in the registry record.

The primary question is about a response threshold on a functional measure, not about the average score in each group. The posted outcome is a count of participants meeting that threshold at the stated follow-up. It should therefore be interpreted as a binary outcome: each participant either met the recorded response definition or did not. The registry record does not report a between-group effect estimate, confidence interval, or statistical test for this outcome.

3. Trial Design

The registry identifies a randomized, quadruple-masked, parallel-group phase 4 trial comparing botulinum toxin with lidocaine. The listed enrollment is 17. The record lists 7 participants in the lidocaine group and 9 in the botulinum group for the primary outcome. These are the group sizes reported for the posted primary endpoint, whose population is described as participants who completed the 4-month follow-up. The registry record does not explain how these outcome counts relate to the enrollment figure.

Randomization indicates that treatment assignment was intended to be determined by chance, but the method used to generate or conceal the allocation is not reported in the registry record. The masking designation is quadruple; the identities of the groups of people masked, and how masking was maintained, are not reported in the registry record. The parallel design means the two groups received their assigned treatments as separate arms rather than being described as a crossover comparison.

The trial title specifies ultrasound- and EMG-guided techniques. The record lists lidocaine and chemodenervation as interventions and names the groups Lidocaine and Botulinum. The botulinum arm description is not reported in the registry record. Details such as the treatment dose, injection locations, treatment schedule, adherence, and any co-interventions are not reported in the registry record.

The listed start is 2009-10 and primary completion is 2010-10. The trial status is terminated. The reason for termination, whether follow-up ended as planned, and whether the termination affected collection of the primary outcome are not reported in the registry record. The sponsor is the University of California, Los Angeles.

The design establishes a randomized comparison, but the posted information is not enough to reconstruct its conduct or analysis. The statistical plan, analysis population beyond the stated completed-follow-up population, allocation details, and any interim analyses are not reported in the registry record. The available group counts are descriptive; they do not by themselves establish the size or precision of a treatment contrast.

4. Participant Flow and Accounting

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

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: participants who completed the 4-month follow-up

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 Clinical Response as Assessed by >20% Change From Baseline in the Jaw Functional Limitation Scale (JFLS) Global Score, measured over 4 months.

The primary endpoint is clinical response on the Jaw Functional Limitation Scale (JFLS) global score at 4 months. The registry defines response as a >20% change from baseline and reports the outcome as the number of participants meeting the definition. The JFLS has 20 items covering limitations in mastication, vertical jaw mobility, and verbal or emotional expression. Each item is rated on a 0–10 scale, where 0 means no limitation and 10 means severe limitation.

A functional questionnaire can capture the participant's experience of difficulty in activities that may be important in daily life. Using a response threshold converts a continuous score change into a binary outcome: participants are counted as meeting or not meeting the specified criterion. This can make the result more directly interpretable as a responder count, while also discarding information about the magnitude of score changes and differences between participants who fall on the same side of the threshold. That is a general feature of dichotomizing a scale; it is not a claim about what occurred in these groups.

The registry describes the threshold as a change from baseline, but does not clarify the direction of change required for response. It also does not report group-level baseline scores, follow-up score distributions, or the change in the JFLS score itself. The posted primary outcome therefore supports interpretation of the recorded responder counts, but not a fuller assessment of how much functional limitation changed or how participants' scores were distributed.

The primary result is based on participants who completed the 4-month follow-up. The record does not state how participants without that follow-up were handled or whether the response definition was specified before analysis. Those details matter when interpreting a threshold-based endpoint and are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a binary endpoint represent?

A binary endpoint places each participant into one of two outcome categories, such as meeting or not meeting a response definition. Here, the registry reports the number of participants meeting a change threshold on the JFLS global score. Counts are useful for describing how many participants met the definition, but a count alone is not a comparative effect estimate. The group size is also needed to understand the scale of the count, and an estimate with an uncertainty interval can show the range of effects compatible with the data under the analysis method.

As a general statistical principle, a binary endpoint can be summarized by a proportion, a difference between proportions, a ratio of proportions, or an odds-based measure. These measures answer different questions and can have different interpretations. None should be inferred from the posted counts without conducting a calculation, and the registry record does not report a comparative measure for this endpoint. The observed counts are therefore best read as descriptive results, not as a standalone significance test.

What would an uncertainty interval add?

In general, a confidence interval describes the precision of an estimate by giving a range of values compatible with the observed data under a stated method. A narrow interval indicates greater precision than a wide interval, though an interval does not resolve every source of bias or uncertainty. For a randomized comparison, an interval around the between-group effect would help readers assess whether the estimate is compatible with materially different effects. No confidence interval for the primary comparison is reported in the registry record, so its precision cannot be assessed from the posted result.

The absence of a reported interval is not evidence that the groups are equivalent. It means the registry record does not provide an interval-based comparison. Likewise, the absence of a reported p-value does not establish that a difference was absent. A p-value, if reported, would address compatibility with a specified null model under an analysis plan; it would not by itself describe the size or practical importance of an effect.

How should the response threshold be understood?

The primary outcome uses a >20% change from baseline in the JFLS global score. A threshold transforms a score that can vary across a scale into a responder classification. As a general matter, this can simplify communication, but it loses detail about the amount of change and can make classifications sensitive to the choice of cutoff. A reader cannot determine whether the participants meeting the threshold had modest or large changes because the record gives no score-level results.

The registry describes a change threshold but does not specify the direction of change required for response. Therefore, interpretation should retain the registry's wording rather than assume that the counted change necessarily indicates improvement. The record also does not provide a rationale for selecting the threshold or state whether it was prespecified in a protocol.

What does randomization contribute?

Randomization is intended to make treatment assignment independent of participant characteristics, on average, and can support a fair comparison between groups. It does not guarantee that groups will be similar in every characteristic, especially when the posted group sizes are limited. Baseline characteristics, the sequence-generation method, allocation concealment, and any adjustments in analysis are not reported in the registry record. Consequently, readers cannot examine balance or determine how assignment was implemented.

Masking can reduce the influence of expectations or knowledge of treatment assignment on participant reports, clinical assessments, or other aspects of trial conduct. The record labels the study quadruple-masked, but does not identify who was masked or describe how the masking was maintained. The designation is useful design information, but it does not allow independent assessment of masking success.

What can be inferred from the safety counts?

Adverse-event counts are descriptive reports of events recorded in each group. Serious and other adverse events are listed separately, and the numbers at risk are also reported. These figures should not be combined or treated as interchangeable: the category definitions and reporting procedures determine what each count represents. General safety comparisons also depend on event definitions, observation time, completeness of ascertainment, and participant exposure. Those details are not reported in the registry record.

The record reports no serious adverse events affecting participants in either group, while other adverse events affected participants in both groups. With no event descriptions or comparative uncertainty estimates, these figures do not provide a detailed account of event type, severity beyond the serious classification, or comparative risk. Missing death values should be described as not reported rather than interpreted as zero.

How should planning calculations be read?

Sample-size calculations are planning exercises, not descriptions of observed outcomes. The stated planning assumptions use a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation; the effect to detect is expressed as a fraction of the observed effect. As a general statistical principle, such calculations depend on assumptions about the effect, variability or event frequency, analysis method, and desired power. A planning illustration does not show that a study had a particular probability of detecting its observed result, and it is not observed power.

The registry record does not report the trial's own sample-size justification or statistical plan. The planning illustration should therefore be distinguished from evidence about the design rationale actually used for this trial. The sample-size figures themselves are not reported in the registry record. No inference about the adequacy of the planned enrollment or the likelihood of detecting an effect can be made from the listed assumptions alone.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Lidocaine", "Botulinum")
n      <- c(7, 9)
events <- c(5, 7)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Lidocaine  7  5  71.4  29.0  96.3  35.9  91.8  34.9  91.5
ARM  Botulinum  9  7  77.8  40.0  97.2  45.3  93.7  44.4  93.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists three secondary outcomes: clinical response defined by a >20% change from baseline in Pressure Pain Threshold, clinical response defined by a >20% change from baseline in Jaw Opening, and the JFLS response outcome. Four outcome measures are identified overall. The posted primary endpoint is the JFLS response at 4 months. Results for the secondary outcomes are not reported in the registry record, and the record lists no analyses.

When a study evaluates multiple outcomes or makes multiple comparisons, the chance of a false-positive finding can increase if each is tested without an appropriate plan. This is a general statistical issue, not a claim that any particular adjustment was or was not used in this trial. The registry record does not report a multiplicity strategy, a hierarchy for outcomes, or which analyses were intended to be confirmatory. It is therefore not possible to determine how multiple outcome testing was handled.

The primary outcome population is described as participants who completed the 4-month follow-up. The primary result lists group sizes of 7 for lidocaine and 9 for botulinum. The record does not report the analysis population definition beyond follow-up completion, how missing endpoint data were handled, or whether any imputation or sensitivity analysis was conducted. It also does not describe adherence-based exclusions or other post-randomization exclusions.

The enrollment figure is 17, while the primary endpoint and safety listings give different group sizes. The registry record does not reconcile these figures or explain the participant flow. This does not identify the reason for any difference, and no reason should be assumed. The record also does not report whether the primary analysis followed randomized assignment regardless of treatment received. These gaps limit assessment of missing-data risk, analysis-population selection, and the potential influence of incomplete follow-up.

12. Safety Results

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

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 affecting 0 participants in the lidocaine group, with 7 at risk, and 0 participants in the botulinum group, with 10 at risk. It lists no serious adverse event terms. These are the serious-event counts posted for the two groups; they do not establish that no unrecorded event occurred or provide a comparison adjusted for observation time.

For other adverse events, 1 participant in the lidocaine group and 2 participants in the botulinum group were affected. The corresponding numbers at risk are 7 and 10. The registry does not provide event descriptions, severity details for these events, timing, duration, or information about how adverse events were collected. The counts should therefore be read as registry summaries rather than as a complete clinical characterization.

The deaths fields contain no values. Deaths are consequently not reported in the registry record; an empty field should not be read as a recorded zero. The record also does not report a statistical comparison of adverse-event outcomes or uncertainty intervals. These limited counts do not support a broader claim about comparative safety.

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

The posted primary result establishes that the registry recorded 5 JFLS responders in the lidocaine group and 7 in the botulinum group at the 4-month follow-up, using its >20% change-from-baseline definition. The primary endpoint group sizes are 7 and 9. This is a description of the registered outcome counts among participants who completed follow-up, not a complete estimate of the treatment contrast.

The result does not establish that either treatment is superior, equivalent, or ineffective. The record does not provide a between-group effect estimate, confidence interval, or test for the primary endpoint. Without these, the precision of the comparison and the degree of uncertainty around any contrast are unknown. The counts should not be converted into a claim about response rates or a calculated difference.

The threshold-based outcome also does not reveal the size or direction of score changes for individual participants. The record states that response is a >20% change, but does not clarify the required direction. It does not report the group-level JFLS scores at baseline or follow-up. As a result, the posted counts cannot show the distribution of functional changes or how close participants were to the threshold.

The listed secondary outcomes and adverse-event counts provide additional context, but the secondary outcome results are not reported in the registry record. The serious adverse-event counts are zero in both groups; other adverse events affected 1 participant in the lidocaine group and 2 in the botulinum group. These safety counts have no accompanying event descriptions or comparative uncertainty estimates.

The record identifies the trial as terminated and does not state why. It also does not explain the relationship between the enrollment figure and the outcome populations. Those omissions make it difficult to assess the completeness and context of the posted results. The appropriate interpretation is therefore limited to the registry's descriptive counts and design labels; broader conclusions are not supported by the information reported.

14. Why This Trial Matters Statistically

This trial is statistically notable as a randomized, head-to-head comparison of botulinum toxin and lidocaine for masticatory myofascial face pain. The registry summary describes lidocaine trigger point injections as part of standard myofascial care and identifies a lack of previous randomized head-to-head trials as part of the rationale. A direct comparison can address a different question from a comparison with placebo: it asks how outcomes differ between two active approaches in the study setting.

The trial title also highlights ultrasound and EMG guidance. The registry summary describes concerns in earlier work about relying on surface landmarks and not confirming that medication reached the intended muscle. That context explains why guidance is emphasized in the title, but the registry record does not report enough procedural detail to evaluate how guidance was implemented in this trial.

The statistical value of a randomized design depends on more than the design label. Transparent reporting of participant flow, outcome definitions, analysis populations, treatment procedures, uncertainty estimates, and missing-data handling is important for interpreting a comparison. Much of that information is not reported in the registry record. The posted response counts are therefore informative as descriptive observations, but do not quantify the comparative effect or its precision.

The trial's terminated status and the absence of a reported reason also matter to interpretation. The record does not explain whether termination affected recruitment, follow-up, or analysis. Without that context, readers cannot determine how the posted outcome counts relate to the study's intended conduct. The record illustrates why statistical interpretation should distinguish a randomized design from the strength and completeness of the results actually reported.

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.

Several trial-specific limitations arise from information not reported in the registry record. The reason the trial was terminated is not stated. The record does not describe whether termination changed recruitment or follow-up, or whether the primary outcome was analyzed according to the original plan. The listed enrollment is 17, while the primary endpoint group sizes are 7 and 9; the participant flow and the relationship among these figures are not explained.

The primary outcome is based on participants who completed the 4-month follow-up, but the record does not describe missing primary outcomes or how they were handled. It does not report whether participants were analyzed according to randomized assignment, whether any participants were excluded after randomization, or whether a sensitivity analysis was conducted. Baseline characteristics and baseline JFLS scores are also not reported in the posted results.

For the primary comparison, no effect estimate, confidence interval, or statistical test is reported. The registry does not clarify the direction required by the >20% change response definition, and it does not provide score distributions or individual-level changes. The listed secondary outcomes have no posted results in the information available for this analysis, and the approach to multiple outcomes is not reported.

Although the record identifies quadruple masking and guided injection techniques, it does not identify who was masked or describe the treatment procedures in enough detail to assess them. The botulinum arm description, dose, schedule, and adherence information are not reported in the registry record. Adverse-event descriptions and deaths values are also unavailable. These gaps restrict assessment of outcome interpretation, trial conduct, and safety reporting; they do not establish what happened in the unreported areas.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Efficacy of Botulinum Toxin Versus Lidocaine in Treating Masticatory Myofascial Face Pain Using Ultrasound and EMG Guided Techniques — NCT00992108.
• Registry record last updated 2016-12-29; status last verified 2016-11.
• Results first posted 2016-12-29.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

The registry record describes NCT00992108, a randomized, quadruple-masked, parallel-group phase 4 trial sponsored by the University of California, Los Angeles. It compares botulinum toxin with lidocaine for masticatory myofascial face pain and is marked terminated. The listed enrollment is 17; the reason for termination is not reported in the registry record.

The primary endpoint is the number of participants meeting a >20% change-from-baseline response definition on the JFLS global score at 4 months among participants who completed that follow-up. The posted counts are 5 in the lidocaine group and 7 in the botulinum group, with primary endpoint group sizes of 7 and 9. No comparative effect estimate, confidence interval, or statistical test is reported.

The registry lists three secondary outcomes, but their results are not reported in the registry record. Serious adverse events affected 0 participants in each group; other adverse events affected 1 participant in the lidocaine group and 2 in the botulinum group. Deaths values are not reported. The record does not provide the statistical plan, missing-data methods, or an explanation of participant flow.