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 Injecting Botulinum Toxin A Underneath the Skin to Treat Spinal Cord Pain in Patients With Spinal Cord Injury (NCT02736890), a randomized phase 2 study. The primary outcome is Numeric Pain Rating Scale (NPRS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02736890 |
| Phase | Phase 2 |
| Condition | Neuropathic Back Pain, Spinal Cord Injury |
| Allocation | Randomized |
| Design model | Crossover |
| Masking | Double |
| Enrollment | 8 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Icahn School of Medicine at Mount Sinai |
| Results posted | Yes |
2. Clinical Question
The trial asked whether subcutaneous botulinum toxin A could reduce at-level back pain in people with spinal cord injury, compared with placebo. The pain condition of interest was neuropathic back pain near the level of injury. The primary measure was participant-rated pain intensity on the Numeric Pain Rating Scale (NPRS), where higher scores indicate more pain. The registry record describes an evaluation extending up to 12 weeks after injection, over a total of 24 weeks from baseline.
Population
People with spinal cord injury and back pain near the level of injury were the intended population. The primary outcome description says that only participants who completed the crossover were included. The registry record lists enrollment of 8.
Intervention
Subcutaneous injections of botulinum toxin A were the active intervention. The study description frames the treatment as a potential approach to pain relief; that rationale is not itself evidence of an outcome.
Comparator
The comparison was placebo, described in the registry record as normal saline administered subcutaneously. The study was randomized and double-masked, with a crossover model.
Primary question
The primary question was whether NPRS pain intensity differed across the treatment conditions during follow-up. The registry record does not report a primary-outcome estimate or statistical test, so the direction and precision of any treatment difference cannot be assessed from the recorded results.
3. Trial Design
This was a Phase 2 randomized, double-masked, placebo-controlled crossover trial. In a crossover design, participants receive more than one treatment condition in sequence, allowing comparisons within participants. General: within-participant comparisons can account for stable differences between people, but interpretation also depends on how treatment order, timing, and possible carryover are handled. The registry record does not report the treatment sequence, any washout interval, or methods for assessing carryover.
The interventions were subcutaneous botulinum toxin A and placebo. The registry record describes saline as the placebo. Masking means that treatment knowledge was intended to be restricted, but the record does not report how masking was assessed or whether it was maintained throughout the study.
Enrollment was 8. The study began in 2016-03, had a primary completion date of 2018-07-17, and is listed as terminated. The reason for termination is not reported in the registry record. The status alone does not establish whether termination was related to safety, recruitment, feasibility, or any other cause.
The primary outcome was mean NPRS score, with standard deviation as the stated measure of dispersion. The outcome description specifies that only participants who completed the crossover were included. That restriction is important when considering how representative the primary analysis population may be of all enrolled participants. The registry record does not describe the number completing each treatment condition or the analysis method used to compare conditions.
Secondary outcomes included patient-reported change, pain interference with daily activities, mood and sleep, mechanical allodynia testing, and a patient-generated index. The registry record reports no analyses. It therefore does not establish how those outcomes were analyzed or whether findings were consistent across measures.
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.
First 12 Weeks
| Stage | Botulinum Toxin A Then Placebo | Placebo Then Botulinum Toxin A |
|---|---|---|
| STARTED | 5 | 3 |
| COMPLETED | 5 | 3 |
| NOT COMPLETED | 0 | 0 |
Crossover Next 12 Weeks
| Stage | Botulinum Toxin A Then Placebo | Placebo Then Botulinum Toxin A |
|---|---|---|
| STARTED | 5 | 3 |
| COMPLETED | 3 | 1 |
| NOT COMPLETED | 2 | 2 |
Reasons for not completing this period:
| Reason | Botulinum Toxin A Then Placebo | Placebo Then Botulinum Toxin A |
|---|---|---|
| Lost to Follow-up | 1 | 2 |
| Withdrawal by Subject | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: only those who completed crossover were included
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 | Botulinum Toxin A Then Placebo | Placebo Then Botulinum Toxin A | Total |
|---|---|---|---|---|
| Participants analysed | 5 | 3 | 8 | |
| Age, Continuous | years | 50.6 (SD 7.02) | 36.7 (SD 4.04) | 45.4 (SD 9.21) |
| Sex: Female, Male: Female | Participants | 2 | 0 | 2 |
| Sex: Female, Male: Male | Participants | 3 | 3 | 6 |
| Race/Ethnicity, Customized: Hispanic/Latino | Participants | 2 | 1 | 3 |
| Race/Ethnicity, Customized: Black or African American | Participants | 2 | 0 | 2 |
| Race/Ethnicity, Customized: White | Participants | 1 | 1 | 2 |
| Race/Ethnicity, Customized: Unknown/Not reported | Participants | 0 | 1 | 1 |
| DN4 screen (neuropathic >4): Burning | Participants | 4 | 2 | 6 |
| DN4 screen (neuropathic >4): Painful cold | Participants | 1 | 2 | 3 |
| DN4 screen (neuropathic >4): Electric shock | Participants | 3 | 2 | 5 |
| DN4 screen (neuropathic >4): Tingling | Participants | 4 | 3 | 7 |
| DN4 screen (neuropathic >4): Pins and needles | Participants | 5 | 3 | 8 |
| DN4 screen (neuropathic >4): Numbness | Participants | 4 | 1 | 5 |
| DN4 screen (neuropathic >4): Itching | Participants | 1 | 2 | 3 |
| DN4 screen (neuropathic >4): Hypoesthesia to touch | Participants | 2 | 1 | 3 |
| DN4 screen (neuropathic >4): Hypoesthesia to prick | Participants | 1 | 1 | 2 |
| DN4 screen (neuropathic >4): Brushing | Participants | 2 | 1 | 3 |
| SCIPI screen (neuropathic >=3): Electric shock | Participants | 3 | 2 | 5 |
| SCIPI screen (neuropathic >=3): Pins and needles | Participants | 5 | 3 | 8 |
| SCIPI screen (neuropathic >=3): Burning or freezing | Participants | 2 | 2 | 4 |
| SCIPI screen (neuropathic >=3): Sensitive | Participants | 1 | 3 | 4 |
| SCIPI screen (neuropathic >=3): Unchanged with movement | Participants | 5 | 3 | 8 |
| SCIPI screen (neuropathic >=3): All the time when awake | Participants | 5 | 3 | 8 |
| SCIPI screen (neuropathic >=3): No feeling in area | Participants | 2 | 0 | 2 |
6. Primary Endpoint
The registry lists the primary outcome as Numeric Pain Rating Scale (NPRS), measured over up to 12 weeks post-injection, for a total of 24 weeks from baseline.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | score on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was the Numeric Pain Rating Scale (NPRS), a participant-rated measure of pain intensity. Participants rated pain from 0-10, with higher scores indicating more pain. The registry record specifies a mean score and standard deviation, with assessment up to 12 weeks post-injection and follow-up extending for a total of 24 weeks from baseline. The primary outcome description limits the included population to participants who completed the crossover.
General: a numeric pain rating converts a subjective experience into a scale that can be compared across observations. A mean describes the average score in a group or condition, while a standard deviation describes how spread out individual scores are around that mean. Neither statistic alone gives the treatment contrast or how precisely it is estimated. That requires a comparison between conditions and an uncertainty measure, such as a confidence interval, together with the analysis method.
The record does not report a single primary-outcome comparison, an effect estimate, or its uncertainty. It also does not report how scores across follow-up occasions were combined or modeled. Consequently, the endpoint definition is available, but the magnitude and precision of the treatment contrast cannot be evaluated from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies NPRS pain intensity as the primary outcome, but it does not report a primary-outcome analysis. It lists no analyses, and the recorded outcome information was not reduced to one comparison because the primary outcome has several categories or time points. There is therefore no reported estimate of the difference between botulinum toxin A and placebo, no confidence interval, and no statistical test to interpret.
Without an estimated contrast, the posted results do not show whether average pain ratings were higher, lower, or similar under either condition. They also do not establish how precisely any difference was estimated. The enrollment of 8 gives context for the scale of the trial, but enrollment alone cannot establish the size or uncertainty of a treatment effect. The outcome population is described as participants who completed the crossover, and the number of such completers is not reported in the registry record.
General: statistical interpretation depends on both an estimated effect and its uncertainty. A confidence interval communicates a range of values compatible with the data and analysis assumptions; it is not a guarantee that the true effect lies within that range. A p-value, if reported, would describe how unusual the observed data or more extreme data would be under a specified null model. Neither can substitute for the size and clinical meaning of an effect. No such primary-outcome statistics are reported in the registry record.
The study is listed as terminated, but the reason is not reported in the registry record. Termination does not by itself indicate the direction or quality of an outcome, and it should not be treated as evidence for or against a treatment effect. Likewise, the study's stated aim and rationale describe why the intervention was investigated, not what the outcome analysis found.
The listed safety counts are descriptive and do not resolve the missing efficacy analysis. In this crossover trial, participants could be exposed to both conditions, so group-specific risk entries should be read as registry entries for the respective treatment groups, not as proof of independent participant sets. The serious-event information is too limited to establish causation or comparative risk. Overall, the available record supports a description of the question, design, outcome, and recorded safety counts, but not a quantitative conclusion about pain outcomes.
9. Statistical Methods Explained
What does a crossover design compare?
In a crossover trial, the same participant receives multiple treatment conditions at different times. General: this permits a within-participant comparison, which can reduce the influence of stable characteristics that differ between people. It does not remove every source of bias. Treatment order, changes over time, missing periods, and effects that persist after a treatment period can affect the comparison. Appropriate interpretation therefore depends on the sequence and timing of treatment and on the analysis model. The registry record does not report the sequence, washout arrangements, or a carryover assessment.
Randomization is intended to reduce systematic differences in treatment assignment, and masking is intended to limit influence from knowledge of assigned treatment. Here the registry record identifies the trial as randomized and double-masked. It does not report the randomization procedure, who was masked, or any assessment of whether masking remained effective. These missing details should not be filled in by assuming a particular implementation.
What does the reported mean and standard deviation describe?
The endpoint is a continuous score, summarized as a mean with standard deviation. General: the mean is an average, whereas the standard deviation describes variability among observed scores. A standard deviation is not the uncertainty of the mean and is not an estimate of the difference between treatment conditions. To estimate a treatment contrast, an analysis must compare observations across conditions while accounting for the crossover structure and the outcome timing. The registry record does not report that model or its results.
For repeated observations, an analysis may need to account for correlation among measurements from the same participant. General: observations from one person are often more alike than observations from different people, so treating every measurement as independent can misstate uncertainty. The registry record does not state whether repeated measurements were modeled, how time points were handled, or whether the primary outcome was summarized at a particular visit.
How should uncertainty be understood?
General: a confidence interval gives a range of estimates compatible with the data under the model and its assumptions. A narrow interval indicates greater precision than a wide interval, but neither guarantees that the estimate is unbiased or clinically important. A p-value addresses compatibility with a null hypothesis under a statistical model; it does not measure the probability that a treatment works. The record contains no primary-outcome confidence interval or p-value, so neither statistical precision nor evidence against a null hypothesis can be assessed.
General: small studies often yield imprecise estimates, but precision cannot be quantified from enrollment alone. It depends on the observed variability, the analysis population, the within-participant correlation, missing observations, and the treatment contrast. Those outcome and analysis details are not reported in the registry record.
What do the sample-size planning assumptions mean?
The planning illustrations are described as calculations based on the observed effect, not as the trial's original design justification. Their stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a fraction of the observed effect. General: such illustrations ask how many participants per arm might be needed under specified assumptions to detect a target effect with a chosen power. They are planning scenarios, not observed power and not evidence that the trial was adequately powered.
The trial itself is described as a crossover study, whereas the planning assumptions describe equal allocation between two arms. Those assumptions should be understood as the basis of the planning illustration, not as a complete description of the trial's analysis. No sample-size justification or statistical plan for the trial is reported in the registry record. Because no primary-outcome estimate is reported, the illustrations cannot be interpreted as a validation of the result or as a substitute for an effect estimate with uncertainty.
What can the listed analyses establish?
The registry record lists no analyses. The primary measure is identified, but the statistical test, model, handling of multiple time points, and treatment of incomplete crossover data are not reported in the registry record. Without those details and numerical results, it is not possible to reproduce or judge a treatment-effect estimate. General: transparent reporting of the analysis population, model, effect estimate, and uncertainty is needed to distinguish the observed data from assumptions used to analyze them.
10. Multiplicity, Missing Data and Analysis Populations
The registry record identifies NPRS as the primary outcome and lists secondary measures involving global change, pain interference with daily activities, mood and sleep, mechanical allodynia, and a patient-generated index. It reports 8 outcome measures and no analyses. The registry record does not describe a multiplicity procedure, an outcome hierarchy beyond identifying the primary measure, or which secondary comparisons were intended to be confirmatory.
General: when researchers examine multiple outcomes, time points, or contrasts, the chance of at least one apparently notable result can increase if each is tested separately. A prespecified hierarchy or multiplicity adjustment can address this issue, but no such approach is reported in the registry record. With no analyses reported, there are no outcome-specific estimates to compare or interpret for consistency.
The primary endpoint description says that only participants who completed the crossover were included. The number completing the crossover, reasons for missing data, and amount of missing outcome information are not reported in the registry record. It also does not report whether incomplete observations were excluded, imputed, or handled by a model. General: complete-case analysis can be vulnerable to bias if completion is related to outcomes or treatment experience; imputation and model-based approaches also depend on assumptions that should be described.
The record does not report an intention-to-treat analysis or another named analysis population. The available wording supports only that completers were included in the primary outcome population; it does not establish how all randomized participants were treated analytically. These omissions limit interpretation of both the primary endpoint and any possible secondary findings.
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 |
|---|---|---|---|
| Botulinum Toxin A | 1 | 8 | 12.5% |
| Placebo | 0 | 8 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Botulinum Toxin A | 0 of 8 |
| Placebo | 0 of 8 |
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 |
|---|---|
| Botulinum Toxin A | 1 of 8 |
| Placebo | 0 of 8 |
Most frequent serious adverse event terms
| Event term | Organ system | Botulinum Toxin A | Placebo |
|---|---|---|---|
| thrombosed IVCF | Vascular disorders | 1 of 8 | 0 of 8 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Botulinum Toxin A | Placebo |
|---|---|---|---|
| fever | Infections and infestations | 1 of 8 | 0 of 8 |
Serious events with the highest arm-level rate: thrombosed ivcf (12.5%).
The registry record lists serious adverse events affecting 1 participant in the botulinum toxin A group and 0 in the placebo group. It lists other adverse events affecting 1 participant in the botulinum toxin A group and 0 in the placebo group. Deaths are recorded as 0 in each group. The number at risk is listed as 8 for each treatment group.
The record also lists “thrombosed IVCF” as a serious adverse event term, with 12.5%. It does not establish from this term alone whether the event was considered related to treatment. No causal attribution should be inferred from a count or event label. The registry record does not report event timing, severity details beyond the serious classification, or an assessment of relatedness.
General: adverse-event counts are descriptive. In a crossover study, participants may contribute exposure to more than one condition, so the risk entries for each group should not be treated as evidence that the groups are independent participant populations. These sparse counts do not provide a precise comparison of safety, and zero recorded events in a group does not prove that the risk is absent. The registry record does not describe how adverse events were collected or whether follow-up was complete.
12. What the Result Does, and Does Not, Mean
The record documents a randomized, double-masked crossover study designed to compare subcutaneous botulinum toxin A with placebo for at-level back pain in people with spinal cord injury. It identifies a participant-rated pain-intensity scale as the primary outcome and gives the scale direction, summary measure, follow-up description, and completer population. It also records adverse-event counts for the two treatment groups.
It does not report the primary-outcome analysis, an estimated difference in NPRS scores, or uncertainty around a treatment contrast. Accordingly, the registry record cannot establish the direction, size, or precision of an effect on pain. The stated study purpose and background rationale should not be read as findings. The absence of a reported analysis is not evidence that the treatment had no effect, just as the intervention's proposed rationale is not evidence that it had an effect.
The study's terminated status is part of the record, but the reason is not reported in the registry record. It is not possible to infer from termination whether the study stopped for operational, safety, efficacy, or other reasons. Nor can the limited adverse-event counts establish a comparative safety profile or treatment causation.
General: clinical interpretation requires attention to effect size, uncertainty, population, outcome measurement, and study conduct. A statistically detectable difference, if one were reported, would not automatically establish that the difference was meaningful to patients. Here, the missing outcome estimates prevent even that initial statistical assessment. The appropriate conclusion is therefore about what the record documents and what it leaves unresolved, rather than a claim that the intervention does or does not change pain.
13. Why This Trial Matters Statistically
This trial is statistically instructive because its design and endpoint are described more fully than its outcome analysis. A randomized, double-masked crossover design raises specific analytic considerations: treatment order, repeated observations within participants, possible carryover, and incomplete treatment sequences. These features make the analysis plan important for understanding how a treatment contrast should be estimated.
The primary endpoint is a continuous participant-rated measure with a stated direction and summary approach. That information helps define what an estimate would mean, but a mean and standard deviation alone would not show the comparative effect. Interpretation also needs a defined contrast, an analysis that respects the crossover structure, and an uncertainty measure. None of those primary-outcome results is reported in the registry record.
The record also illustrates why enrollment, trial status, and safety counts cannot substitute for outcome estimates. Enrollment of 8 does not by itself reveal precision, and termination does not establish why the trial ended. The adverse-event entries provide descriptive counts but do not establish causality or a stable comparison of risks.
Finally, the distinction between a completer population and all randomized participants matters. The primary outcome is described as including crossover completers, while the number of completers and handling of missing data are not reported. Clear reporting of analysis populations and missing-data methods would help readers assess how results relate to the randomized trial. These are general reporting and interpretation issues, not conclusions about the treatment.
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 principal limitation for interpretation is that the registry record reports no analyses of the primary outcome. It gives no NPRS treatment contrast, confidence interval, or statistical test. Several outcome categories or time points are noted, but no single comparison is reported. As a result, neither the magnitude nor precision of the primary result can be evaluated.
The primary outcome population is limited to participants who completed the crossover, but the number of completers and the reasons for non-completion are not reported in the registry record. The handling of missing scores is also not reported. This leaves uncertainty about how the analyzed population relates to everyone enrolled and how incomplete observations may have affected the estimate.
Further design and analysis details are not reported in the registry record, including treatment sequence, washout arrangements, carryover assessment, the model for repeated measurements, and the method for comparing treatment conditions. The statistical plan and any multiplicity approach are also not reported. Without these details, the analysis cannot be independently assessed from the recorded information.
The study is listed as terminated, but its reason is not reported. Safety information consists of group counts and a serious-event term; event timing, attribution, and collection methods are not reported. These limits are specific to the information available in the registry record and should not be replaced with assumptions about trial conduct or results.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Injecting Botulinum Toxin A Underneath the Skin to Treat Spinal Cord Pain in Patients With Spinal Cord Injury — NCT02736890.
- Registry record last updated 2019-04-09; status last verified 2019-04.
- Results first posted 2019-04-09.
- 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
NCT02736890 is a Phase 2, randomized, double-masked, placebo-controlled crossover study of subcutaneous botulinum toxin A for at-level back pain in people with spinal cord injury. Enrollment was 8. The study began in 2016-03, had a primary completion date of 2018-07-17, and is listed as terminated.
The primary outcome was mean NPRS pain intensity, scored from 0-10 with higher scores indicating more pain. The stated follow-up extended up to 12 weeks post-injection, for a total of 24 weeks from baseline, and the primary outcome population included participants who completed the crossover. No analyses or primary-outcome estimate are reported in the registry record. Recorded safety counts include serious and other adverse events in the botulinum toxin A group, none in the placebo group, and no deaths in either group; the record does not establish causation.