This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Lidocaine Injection and Ischemic Compression on Chronic Pelvic Pain Treatment (NCT00628355), a randomized phase 4 study. The primary outcome is Intensity of Pain.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00628355 |
| Phase | Phase 4 |
| Condition | Pelvic Pain |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 30 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Sao Paulo |
| Results posted | Yes |
2. Clinical Question
Population
Women with chronic pelvic pain caused by abdominal myofascial pain syndrome are the population identified in the trial title and intervention descriptions. The condition is listed as pelvic pain. The registry record does not report further eligibility criteria or describe the characteristics of the women enrolled, so the population cannot be characterized more narrowly from the record.
Intervention
The intervention was lidocaine injection at a trigger point. The description specifies 2 milliliters of lidocaine 0,5% without vasoconstrictor, injected directly and perpendicularly, once a week for 4 weeks.
Comparator
The comparator was ischemic compression. Its description begins with transcutaneous electrical stimulation on the trigger point for 30 minutes, using 100 Hertz frequency and a pulse of 250ms. The description is incomplete in the registry record, so the full compression procedure and its remaining parameters are not reported in the registry record.
Primary question
The primary question was whether pain intensity differed between the two treatment groups at the stated assessments immediately, 1, and 3 months after treatment. Pain was to be measured in millimeters using a visual analogue scale. The registry record does not report the group means, standard deviations, or a statistical comparison for these assessments, so it does not establish how the groups compared on the primary outcome.
3. Trial Design
The registry lists this as a randomized, double-masked, parallel-group phase 4 clinical trial sponsored by the University of Sao Paulo. The listed enrollment is 30. The two groups were lidocaine injection and ischemic compression. A parallel design assigns participants to one treatment group and follows the groups over the specified assessment period; randomization is intended to reduce systematic differences between groups at the point of assignment. These are general features of the design, not evidence that every potential source of bias was eliminated in this trial.
The record gives a start date of 2008-02, a primary completion date of 2009-10, and a status of terminated. It does not report why the trial was terminated or whether termination changed the planned follow-up or analysis. The record also does not identify who was masked, how masking was maintained, or whether masking was assessed. Those details are not reported in the registry record.
The lidocaine description specifies a dose, injection approach, and schedule. The ischemic compression description includes an initial TENS procedure, but ends before the full treatment protocol is given. Consequently, the complete comparator procedure cannot be reconstructed from the registry record. The record lists two outcome measures but no analysis entries. Although the trial design can support a randomized comparison in principle, the posted results do not include the primary outcome data needed to interpret that comparison.
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
| Stage | TENS Plus Ischemic Compression | Anesthesia Injection |
|---|---|---|
| STARTED | 15 | 15 |
| COMPLETED | 14 | 14 |
| NOT COMPLETED | 1 | 1 |
Reasons for not completing this period:
| Reason | TENS Plus Ischemic Compression | Anesthesia Injection |
|---|---|---|
| Withdrawal by Subject | 1 | 1 |
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.
| Characteristic | Unit | Ischemic Compression | Anesthesia Injection | Total |
|---|---|---|---|---|
| Participants analysed | 14 | 14 | 28 | |
| Age, Categorical: Between 18 and 65 years | Participants | 14 | 14 | 28 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Continuous | years | 36.8 (SD 3.2) | 38.5 (SD 2.8) | 37.6 (SD 3.1) |
| Sex: Female, Male: Female | Participants | 14 | 14 | 28 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 |
| Region of Enrollment: Brazil | participants | 14 | 14 | 28 |
6. Primary Endpoint
The registry lists the primary outcome as Intensity of Pain, measured over immediately, 1, 3 months after treatment.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | millimeters |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is intensity of pain, measured in millimeters on a visual analogue scale. The record describes a straight line of 100mm, with one end representing absence of pain and the other representing the worst pain experienced or imagined. Participants’ marks on such a line are intended to express the intensity of their pain as a continuous measurement rather than as a choice among a few categories.
In general, a continuous pain measure can capture gradations in a participant’s reported experience, and it can be summarized using a mean and standard deviation. The mean describes the group’s average score; the standard deviation describes how much scores vary among participants. Neither summary on its own gives the full distribution of responses.
The specified assessment times are immediately, 1, and 3 months after treatment. These time points make the intended outcome comparison dependent on when pain was assessed. The registry record does not report actual scores, group summaries, or results at any of these time points. It also does not give a more detailed account of how the scale was administered or how missing assessments were handled.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clinically interpretable comparison: pain intensity after lidocaine injection versus pain intensity after ischemic compression in women described as having chronic pelvic pain caused by abdominal myofascial pain syndrome. It also specifies a continuous primary measure and three post-treatment assessment times. However, the record contains no reported primary outcome analysis. Group means, standard deviations, estimated differences, confidence intervals, and p-values for pain intensity are not reported in the registry record.
As a result, the posted results do not show the magnitude or direction of any difference in pain scores between the groups. They also do not show how precisely a difference was estimated. Random assignment is a feature of the design; it is not itself an outcome. Without the outcome data and an analysis, the design description cannot answer the primary question.
The registry lists enrollment of 30, but enrollment alone does not establish how many participants completed each assessment or contributed to any analysis. The record lists zero analyses, and the primary outcome is not reduced to a single comparison because it has several assessment times. The registry record does not report which time point, if any, was selected as the main basis for an inferential conclusion, or how results across the assessment times were handled.
The safety entries report zero serious adverse events among 15 participants at risk in each group. They report zero other adverse events among 15 at risk in the ischemic compression group and 2 among 15 at risk in the anesthesia injection group. These are descriptive counts, not a statistical test of the primary endpoint. The record does not give enough detail to assess event definitions, reporting completeness, or the uncertainty around comparisons.
Thus, the most defensible interpretation is limited: the registry describes a randomized comparison and records some safety counts, but it does not report the primary pain results. No conclusion about relative pain outcomes can be drawn from the posted results. The absence of a reported estimate is not evidence that the groups had the same outcome; it means the relevant comparison is unavailable in the registry record.
9. Statistical Methods Explained
The design is randomized and parallel-group. In general, randomization uses an allocation process intended to make treatment groups comparable with respect to both measured and unmeasured characteristics, on average. It does not guarantee exact balance in a small trial, and it cannot correct problems that occur after assignment, such as incomplete follow-up or selective outcome reporting. The record does not describe the randomization sequence or concealment procedure, so those implementation details are not reported in the registry record.
Parallel-group means participants are assigned to one of the treatments and the groups are compared over time. The record calls the trial double-masked, but does not specify which people were masked or how the two interventions were made to appear similar. Because the interventions are different in form, the practical details of masking matter for assessing possible bias; those details are not reported in the registry record. The recorded design label alone is not enough to establish how successful masking was.
The primary outcome is continuous and is specified as a mean with standard deviation. In general, the mean is a measure of the central location of scores, while the standard deviation describes their spread around the mean. A comparison of group means can summarize an average difference, but interpretation also depends on uncertainty, the analysis population, and whether the method’s assumptions are reasonable. The registry record does not report group means or standard deviations, an estimated between-group difference, a confidence interval, or a test result.
In general, a confidence interval gives a range of estimates compatible with the data and the method used, reflecting statistical uncertainty. A narrow interval indicates more precise estimation than a wide interval, but neither width nor location can be assessed without a reported interval. A p-value, when reported, addresses compatibility of the data with a specified null model; it does not measure the size or clinical importance of an effect. No primary endpoint p-value or interval is reported in the registry record, so neither can be interpreted for this trial.
The endpoint has several scheduled assessment times: immediately, 1, and 3 months after treatment. Repeated assessments can describe how scores vary over follow-up, but they introduce an analytic choice about whether to compare groups at each time, model the trajectory, or designate one time as primary for inference. In general, repeated measurements on the same participant are related and should not automatically be treated as independent observations. The registry record does not report the statistical method used for repeated measurements, how a primary comparison across time was chosen, or whether any adjustment was made for multiple comparisons.
The sample-size assumptions describe a planning illustration using a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect expressed as a stated fraction of the observed effect. These are planning assumptions, not a report of the trial’s original design justification. The registry record does not report the trial’s own sample-size justification. A planning calculation based on an observed effect is also not observed power: it illustrates the sample size that might be needed under specified assumptions and does not establish the probability that the completed trial detected an effect.
For a continuous outcome, such a planning calculation generally depends on the assumed effect size and variability, as well as the selected error rate, allocation, and statistical approximation. If variability is greater than assumed, estimates may be less precise than anticipated. In general, over-dispersion means the data vary more than a model assumes; this can make standard errors too small and confidence intervals too narrow if not addressed. The registry record does not report a fitted model, a dispersion assessment, or an adjustment for such a concern. No model-specific conclusion can therefore be made.
The registry lists zero analysis entries. It does not state whether the primary outcome was analyzed but omitted, whether data were unavailable, or whether no analysis was performed. The analysis population, treatment of deviations from assigned treatment, and handling of missing measurements are not reported in the registry record. Without those details and without the outcome summaries, the intended statistical method cannot be reconstructed. The randomized design and the stated outcome scale describe what a comparison could address, but they do not substitute for a reported estimate and its uncertainty.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome is measured at multiple post-treatment times: immediately, 1, and 3 months after treatment. Testing the groups separately at multiple times can increase the chance of finding at least one apparently noteworthy result even when there is no underlying difference. In general, a statistical plan can address this by identifying one primary time point, using a model that considers the repeated measurements together, or adjusting inference for multiple comparisons. The registry record does not report which approach was planned or used.
The registry identifies two outcome measures and lists zero analyses. It does not report a hierarchy of primary and secondary outcomes beyond naming intensity of pain as primary, nor does it describe any multiplicity adjustment. The multiplicity strategy is therefore not reported in the registry record. Without it, a reader cannot determine how the multiple assessment times or outcomes were incorporated into inferential claims.
The record also does not report participant flow by assessment time, the number of observed pain scores, reasons for missing assessments, or a missing-data method. In general, missing data can affect a comparison when the likelihood of missingness is related to participants’ outcomes or treatment experiences. Complete-case analysis, imputation, or model-based approaches rely on different assumptions; no such approach can be attributed to this trial from the registry record.
The analysis population is also not reported in the registry record. It is therefore unclear whether the intended analysis included all randomized participants, only participants who completed treatment, or another defined group. These omissions matter because both the handling of missing measurements and the definition of the analysis population can influence the interpretation of a randomized comparison.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Ischemic Compression | 0 | 15 | 0.0% |
| Anesthesia Injection | 0 | 15 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Ischemic Compression | 0 of 15 |
| Anesthesia Injection | 2 of 15 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Ischemic Compression | Anesthesia Injection |
|---|---|---|---|
| Ecchymosis | Skin and subcutaneous tissue disorders | 0 of 15 | 2 of 15 |
The registry lists serious adverse event counts of 0 among 15 participants at risk in the ischemic compression group and 0 among 15 at risk in the anesthesia injection group. For other adverse events, it lists 0 among 15 at risk in the ischemic compression group and 2 among 15 at risk in the anesthesia injection group. These are the registry’s reported counts, and they should be read as descriptive safety information rather than as a formal comparison.
The entries do not identify the specific non-serious events, their timing, severity, or relationship to treatment. The deaths field is not populated with a count; deaths are not reported in the registry record. The record also does not explain how adverse events were defined, collected, or verified, or whether all participants had the same duration of safety follow-up.
In general, zero recorded events do not establish that an event cannot occur, and small groups provide limited precision for comparing uncommon harms. The counts do not establish whether the groups differ in safety. A comparative interpretation would require fuller event descriptions, follow-up information, and an appropriate analysis, none of which is reported in the registry record.
12. What the Result Does, and Does Not, Mean
The trial record establishes that investigators planned a randomized, double-masked, parallel comparison of lidocaine injection and ischemic compression for chronic pelvic pain attributed to abdominal myofascial pain syndrome. It identifies pain intensity on a visual analogue scale as the primary outcome and specifies assessments immediately, 1, and 3 months after treatment. These details define the intended research question, but they do not supply the results needed to answer it.
The primary pain outcome results are not reported in the registry record. There is no reported group mean, standard deviation, between-group estimate, confidence interval, or p-value for the scheduled assessments. It is consequently not possible to determine from the posted results whether pain scores differed, in what direction they may have differed, or how precisely an effect was estimated. Missing results should not be interpreted as proof of either benefit, harm, or no difference.
The safety record contains the listed event counts, but the small group entries and lack of event descriptions limit what can be inferred. They do not establish that one treatment is safer than the other, nor do they provide a complete account of the kinds of events experienced. No medical conclusion should be drawn from these counts alone.
In general, a clinical trial’s randomized design can support a causal comparison when the study is conducted and analyzed appropriately. Evaluating that claim requires the outcome data, an analysis plan or a clear account of the analysis, and information about follow-up and missingness. Those elements are not reported in the registry record. The record therefore supports a description of the trial’s design and intended endpoint, but not a conclusion about the comparative effect of the two approaches.
13. Why This Trial Matters Statistically
This trial is statistically notable because it describes a randomized comparison but does not report the primary outcome analysis. That distinction is important: a well-defined research question and a suitable design do not by themselves tell readers what the data showed. Statistical interpretation requires an estimate and information about its uncertainty, not merely the name of the endpoint or treatment groups.
The outcome is continuous and scheduled at multiple times. This raises ordinary design and analysis questions about how to summarize group differences, account for repeated observations, handle missing measurements, and address multiple comparisons. These are not technical details that can be recovered from the endpoint description alone. The registry record does not report the methods or results needed to assess those choices.
The listed enrollment is 30, while the safety groups each list 15 participants at risk. These figures describe the registry entries; they do not show how many participants contributed pain scores at each assessment. For a small study, precision is especially important to interpretation: a point estimate can be uncertain, and event counts provide limited information about uncommon outcomes. Yet no primary endpoint precision estimate is reported.
The record also illustrates the difference between a planning illustration and the trial’s original design justification. A calculation based on an observed effect can help explore planning assumptions, but it is not a substitute for a prespecified design rationale and is not evidence of observed power. The trial’s own sample-size justification is not reported in the registry record.
For readers assessing clinical research, the central statistical lesson is to separate the question a study was designed to address from the evidence it actually reports. In this case, the question and measurement are identifiable, while the primary comparative result is not.
14. 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 most consequential limitation of the registry record is that it does not report the primary pain outcome results. No group summaries or inferential comparison are available for any of the stated assessment times. This prevents evaluation of effect direction, magnitude, and precision.
The record lists the trial as terminated but does not report the reason. It is not possible to determine whether termination affected recruitment, treatment delivery, follow-up, or analysis. The listed enrollment of 30 does not establish the number assessed or analyzed at each time point. Participant flow and analysis populations are not reported in the registry record.
The comparator description is incomplete. It gives some details of transcutaneous electrical stimulation but ends before the full ischemic compression procedure is described. The record also does not identify who was masked or how masking was implemented. These missing details limit assessment of treatment reproducibility and possible bias.
The record does not report the randomization method, allocation concealment, statistical analysis plan, handling of repeated measurements, multiplicity approach, or missing-data method. The trial’s sample-size justification is not reported in the registry record. The reported safety counts lack descriptions of the individual events and details of safety follow-up. These limitations mean that neither the primary comparison nor the completeness of safety reporting can be assessed from the registry information alone.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Lidocaine Injection and Ischemic Compression on Chronic Pelvic Pain Treatment — NCT00628355.
- Registry record last updated 2014-06-06; status last verified 2014-05.
- Results first posted 2014-04-25.
- 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.
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18. Record Summary
NCT00628355 is a phase 4, randomized, double-masked, parallel-group trial sponsored by the University of Sao Paulo. The registry lists enrollment of 30, a start date of 2008-02, a primary completion date of 2009-10, and a terminated status. The trial compared lidocaine injection with ischemic compression for chronic pelvic pain described as caused by abdominal myofascial pain syndrome.
The primary outcome was pain intensity in millimeters on a visual analogue scale, assessed immediately, 1, and 3 months after treatment. The primary outcome results and analysis are not reported in the registry record. Safety entries list no serious adverse events in either group and 2 other adverse events in the anesthesia injection group; the event details are not reported. The reason for termination, analysis population, missing-data handling, and full comparator procedure are not reported in the registry record.