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 Epidural Spinal Cord Stimulation for Sensory Restoration and Phantom Limb Pain in Upper-Limb Amputees (NCT02684201), a na na study. The primary outcome is Stimulation Thresholds to a Variety of Stimulus Parameters.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02684201 |
| Phase | NA |
| Condition | Phantom Limb |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 4 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Lee Fisher, PhD |
| Results posted | Yes |
2. Clinical Question
Population
People with upper-limb amputation and phantom limb sensations or pain. The registry lists an enrollment of 4 participants.
Intervention
Epidural spinal cord stimulation using a Boston Scientific stimulator lead. The lead was to be placed in the cervical epidural space and directed toward dorsal spinal roots.
Comparator
There is no comparison group. The study is recorded as single-group, with allocation listed as NA.
Primary question
What stimulation thresholds are required to evoke sensations and neurophysiological responses, and how do the resulting percepts and responses change during the study?
The study was designed to characterize sensations elicited by stimulation near the spinal cord, rather than to compare stimulation with an alternative treatment or control condition. Its stated aims also include examining phantom limb sensations and pain, as well as testing sensory identification and prosthetic-hand control outcomes listed among the secondary measures.
The primary outcome is stimulation threshold, expressed in milliamps, with a stated measurement period of 30 days. The record describes testing over multiple sessions and removal of the electrodes at the end of testing. It does not report the threshold values or results for the other outcomes. Consequently, the registry record identifies the questions the investigators intended to examine but does not establish what participants experienced or how their measurements changed.
3. Trial Design
NCT02684201 is recorded as a completed, single-group study with no masking. Allocation is listed as NA, and the study is not a randomized comparison. The registry lists 4 participants enrolled. The intervention is a Boston Scientific Stimulator Lead, and the study description outlines temporary epidural placement in the upper back and neck, with stimulation during multiple testing sessions and removal at the final testing session.
The intervention description states that a lead would be placed in the cervical epidural space of ten upper-limb amputees and steered toward the dorsal spinal roots. This planned description and the recorded enrollment of 4 are not the same figure. The registry record does not explain the difference, so the planned number in the intervention description should not be treated as the number enrolled or analyzed.
The study began on 2015-11-01, has a primary completion date of 2024-08-01, and is marked COMPLETED. The phase is recorded as NA. The sponsor is Lee Fisher, PhD. The primary outcome concerns stimulation thresholds, while the listed secondary outcomes cover elicited sensations, pain ratings, and prosthetic-hand tasks. Although the record lists ten outcome measures, it does not report outcome estimates or analysis results. The registry record does not describe a statistical analysis plan, a sample-size justification, interim analyses, or the analysis population used for the outcomes.
Because all participants received the study intervention and no control group is listed, the design is suited to describing observations during testing, not to separating stimulation-related changes from other influences through a concurrent comparison. The completed status indicates the study's registry status; it does not by itself establish that results were reported.
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: Eligibility checking ruled out participants due to congenital missing limb (not amputation), taking prescription blood thinners, or unable to refrain from physical exertion during the duration of the experiment. These individuals were either excluded, or withdrew. Others declined the surgery.
Overall Study
| Stage | Boston Scientific Cord Stimulator Lead |
|---|---|
| STARTED | 4 |
| COMPLETED | 4 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: Participants implanted with stimulator leads
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.
Population: The first participant experienced lead migration and early explant. This participant was later re-enrolled and completed study activities. Therefore, there are 4 unique individuals counted among the 5 consented participants.
| Characteristic | Unit | Boston Scientific Cord Stimulator Lead |
|---|---|---|
| Participants analysed | 4 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 3 |
| Age, Categorical: >=65 years | Participants | 1 |
| Sex: Female, Male: Female | Participants | 3 |
| Sex: Female, Male: Male | Participants | 1 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 4 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 1 |
| Race (NIH/OMB): White | Participants | 3 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 4 |
| Participants with phantom limb pain | Participants | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Stimulation Thresholds to a Variety of Stimulus Parameters, measured over 30 days.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Full Range |
| Unit | milliamps |
| Endpoint classification | not reduced to a single comparison |
The primary outcome is titled “Stimulation Thresholds to a Variety of Stimulus Parameters.” It is intended to quantify the minimum stimulus charge required to evoke a sensation and neurophysiological responses during epidural spinal nerve stimulation, and to monitor changes in those percepts and responses over the stated 30-day timeframe. The outcome is expressed in milliamps, and the registry specifies a mean with full range as the summary approach.
Thresholds are relevant to this study because they describe the stimulation level at which a response is elicited. Recording thresholds across stimulus parameters can characterize the relationship between stimulation settings and observed sensations or neurophysiological responses. Repeated assessment can also be useful for describing whether measured thresholds or reported perceptions vary during a testing period. These are general reasons for using threshold measures; they do not establish what happened in this study.
The registry record does not report the observed mean, the full range, or participant-level threshold values. It also does not give estimates for changes over time. Without those results, the primary endpoint's magnitude, variability, and pattern of change cannot be evaluated from the registry record. The stated purpose and measurement format are available, but the outcome findings are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes that this was a completed, single-group study of epidural stimulation in upper-limb amputees, with 4 participants enrolled. Its primary outcome was designed to measure stimulation thresholds for evoking sensations and neurophysiological responses. However, the record does not report the primary outcome values, a mean threshold, a full range, or results describing changes over the testing period. It therefore does not support a statistical interpretation of the primary outcome's magnitude or precision.
The record also lists secondary outcomes concerning spinal regions that evoked sensations, qualitative reports, pain ratings, and prosthetic-hand tasks. Their outcome results are not reported in the registry record. A list of planned measures indicates what the study intended to assess; it is not evidence that a particular response occurred or that performance changed. The record gives no estimates, uncertainty intervals, or hypothesis-test results for these secondary questions.
Study design also limits the conclusions that can be drawn. There is no randomized allocation or comparator group, and the study is unmasked. Descriptive observations from a single group can characterize responses during the testing procedure, but cannot determine what would have happened to the same participants under a different condition. Changes over time, if measured, would not by themselves distinguish effects of stimulation from other explanations.
The enrollment of 4 also means that any observed pattern would need to be interpreted in light of the limited number of participants. General statistical principle: small samples tend to leave substantial uncertainty about population-level patterns, and estimates can be sensitive to individual observations. In this case, the registry record does not provide estimates with which to assess that uncertainty.
The adverse-event record reports 0 serious adverse events among 4 participants at risk and other adverse events affecting 2 of 4 participants at risk. These counts describe the safety information recorded, but the registry does not provide serious-event terms or further details about the other events. The counts should not be interpreted as a complete account of event severity, timing, or cause.
Overall, the registry documents the study's design, aims, and limited adverse-event counts, but not the clinical outcome results needed to assess the measured sensory thresholds, pain ratings, or task performance. The findings and their precision are therefore not reported in the registry record.
9. Statistical Methods Explained
The registry describes a single-group study with no masking and no randomized allocation. These design features matter because they determine which comparisons the data can support. With no concurrent control group, the study can describe measurements made during stimulation sessions, but it cannot make a direct comparison between stimulation and an alternative condition. General statistical principle: a before-and-after pattern within one group is not equivalent to a controlled estimate of an intervention effect, because other influences may also change over time.
What does a mean and full range describe?
The primary outcome specifies a mean and full range for thresholds measured in milliamps. A mean is a summary of the observed measurements, while the full range describes the span from the lowest to the highest observed value. General statistical principle: the mean can give a compact description of a distribution, but it may not represent every participant's measurement, especially when observations vary. The range gives information about spread at the extremes, but does not show how values are distributed between those extremes.
The registry record does not report the numerical mean or range. It is therefore not possible to assess the observed threshold level or the degree of variation from this record. Nor is it possible to judge whether a mean adequately represents the individual observations.
Why do repeated measurements require care?
The study description refers to multiple testing sessions and monitoring changes in perceptions and responses over time. General statistical principle: measurements collected repeatedly from one participant are usually related to one another. They should not automatically be treated as independent observations. An analysis of repeated measures may need to account for within-participant correlation, but the registry record does not state which statistical method was planned or used.
The record also does not report the number or timing of observed measurements per participant, whether all participants completed each session, or how incomplete repeated measurements were handled. Without those details, the structure of the analyzed data and the basis for any time-related estimate are not reported in the registry record.
What can a single-group design estimate?
A single-group design can produce descriptive summaries of the measured participants' thresholds and reported sensations. If measurements at different sessions are available, they can describe observed patterns during the study period. General statistical principle: uncertainty intervals, when reported, help communicate the range of values compatible with the data under the stated statistical model. They do not eliminate design limitations or establish that a change was caused by the intervention.
Here, the record contains no outcome estimates or uncertainty intervals. It also does not report inferential test results for the primary or secondary outcomes. The analysis approach, including any adjustment for participant characteristics or repeated observations, is not reported in the registry record.
How should planning illustrations be read?
Any sample-size illustrations associated with observed effects are planning scenarios, not observed power and not a substitute for the study's missing outcome results. They do not show that the study had a particular probability of detecting an effect after the fact. General statistical principle: planning calculations depend on assumptions about the effect, variability, allocation, and statistical procedure. The registry record does not provide a sample-size justification for this study or identify a protocol-based target sample size.
The intervention description's reference to ten upper-limb amputees is not a statistical analysis result. Enrollment is separately recorded as 4, and the registry does not explain the discrepancy or state how many participants contributed data to each outcome.
What is absent from the statistical record?
The registry record does not report a statistical analysis plan, the model or tests used, criteria for handling outliers, or the approach to missing observations. It also does not report which participants were included in each outcome analysis. These omissions do not show that no analysis occurred; they mean the methods and results are not reported in the registry record. With neither outcome estimates nor a described analysis method, the precision and robustness of any effect estimate cannot be evaluated.
10. Multiplicity, Missing Data and Analysis Populations
The record lists ten outcome measures, including the primary threshold outcome and secondary measures of sensations, pain, and prosthetic-hand tasks. Considering multiple outcomes raises the general statistical issue of multiplicity: when many questions are tested, the chance of at least one apparently notable result can increase if no adjustment or interpretive strategy is specified. This is a general explanation, not a claim about analyses performed in this study.
The registry record does not report a multiplicity adjustment, a hierarchy for interpreting secondary outcomes, or a statistical analysis plan. It also does not report results or hypothesis tests for the listed measures. It is therefore not possible to determine whether multiplicity was addressed or how the investigators intended to distinguish primary from exploratory findings beyond the outcome labels.
Missing-data handling and analysis populations are also not described. The record gives an enrollment of 4, but does not state how many participants contributed data to each endpoint, whether any measurements were missing, or how missing observations were handled. It does not identify an intention-to-treat, per-protocol, or other analysis population. These details are not reported in the registry record.
General statistical principle: incomplete measurements can affect estimates when the reason for missingness is related to outcomes or participant characteristics. The direction and size of any such effect depend on the pattern of missingness and the analysis approach. Since neither is documented in the registry record, the potential influence of missing data cannot be assessed. The absence of these details should be treated as a reporting limitation, not as proof that data were missing or that an analysis was conducted incorrectly.
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 |
|---|---|---|---|
| Boston Scientific Cord Stimulator Lead | 0 | 4 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Boston Scientific Cord Stimulator Lead | 0 of 4 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 1% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Boston Scientific Cord Stimulator Lead | 2 of 4 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Boston Scientific Cord Stimulator Lead |
|---|---|---|
| Lead migration | Surgical and medical procedures | 2 of 4 |
The registry reports 0 serious adverse events among 4 participants at risk in the Boston Scientific Cord Stimulator Lead group. It reports other adverse events affecting 2 participants among 4 at risk. These are participant counts as recorded; they do not provide event-level detail or describe the nature, timing, duration, or severity of the other events.
The record lists no serious adverse-event terms. It also does not report a causal assessment linking events to the lead or stimulation. The counts alone cannot establish whether an event was related to the intervention, and the absence of a recorded serious event does not describe every aspect of safety or tolerability.
General statistical principle: with a small group, event counts provide limited information about how frequently events might occur in a broader population. In addition, an adverse-event count is distinct from an efficacy outcome. These registry figures should be read as the recorded safety counts for this study, not as a comparative safety estimate, because there is no control group. Further event detail is not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The record documents a study intended to characterize sensory and neurophysiological responses to epidural spinal stimulation in people with upper-limb amputation. It specifies a threshold-based primary outcome and lists additional measures related to evoked sensations, pain ratings, and prosthetic-hand tasks. It also records that the study is completed and reports limited adverse-event counts.
Those design details do not reveal the study's primary findings. The registry record does not report threshold values, summaries of change over time, or results for the listed secondary outcomes. Consequently, it does not show what sensations participants experienced, whether pain ratings changed, or how participants performed on the prosthetic-hand tasks. It is not possible to judge the size or precision of an outcome from the registry record.
The single-group, unmasked design also does not provide a randomized comparison. Even if outcome measurements had been reported, observed changes within the group would not alone identify what caused those changes. A controlled comparison would address a different question from this study's stated descriptive and exploratory aims.
The serious and other adverse-event counts are also limited in scope. They record 0 serious adverse events among 4 at risk and other adverse events in 2 of 4 at risk, but event descriptions and causal assessments are not reported in the registry record. These counts do not establish overall safety or compare safety with another intervention.
Thus, the record describes the study question and design but does not report the clinical outcome results needed to assess sensory thresholds, phantom limb pain, or task performance. Its findings on those outcomes cannot be inferred from the study title, aims, completion status, or list of planned measures.
13. Why This Trial Matters Statistically
This trial is statistically notable for the distinction between a detailed research question and a registry record that does not report the corresponding outcome estimates. It identifies a measurable primary endpoint—stimulation thresholds in milliamps—and describes an intended assessment of sensations and neurophysiological responses over 30 days. Yet the threshold results themselves are not reported in the registry record. The design and endpoint can therefore be discussed, but the observed magnitude and precision cannot.
The single-group format is important to interpretation. It can support descriptive investigation of responses during stimulation, which is relevant when a study is exploring what kinds of sensations can be evoked and how they are characterized. It does not provide a concurrent control comparison. That distinction limits causal conclusions and should remain clear when interpreting any within-group patterns.
The enrollment of 4 also makes transparent reporting especially important. General statistical principle: in a small study, individual measurements can have substantial influence on descriptive summaries, and uncertainty about broader patterns is typically considerable. Without participant-level values, dispersion summaries, or uncertainty intervals, readers cannot assess how consistent responses were across participants.
The discrepancy between the recorded enrollment of 4 and the intervention description's reference to ten upper-limb amputees is another reason to distinguish planned descriptions from completed enrollment and analyzed data. The registry does not explain the difference. Reporting the number included in each outcome analysis would help clarify the evidence base for each result, but those analysis counts are not reported.
Finally, the listed outcomes span several kinds of measurement. Clear statistical reporting would help readers understand which questions were primary, how repeated observations were handled, whether missing data affected analyses, and how multiple outcomes were interpreted. Those methods and outcome findings are not reported in the registry record, so the study's statistical conclusions remain unavailable there.
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 central limitation for interpreting results is that the registry record does not report the primary endpoint values or results for the secondary outcomes. No threshold mean or full range is given, and no estimates of change over time are reported. Without these results, the study's sensory measurements and their variability cannot be assessed.
The study is single-group and unmasked, with allocation listed as NA. There is no concurrent comparator, so the design cannot directly distinguish intervention-associated changes from other influences. This matters particularly for outcomes such as pain ratings or task performance, where measurements may change for reasons not isolated by a single-group comparison.
The record lists an enrollment of 4, while the intervention description refers to ten upper-limb amputees. It does not explain this difference or state the number of participants included in each outcome analysis. The registry also does not report participant-level data, missing-data patterns, or the handling of incomplete observations.
Further limitations are reporting gaps in the statistical methods. The analysis plan, model, inferential procedures, multiplicity strategy, and analysis populations are not reported in the registry record. The absence of these details prevents evaluation of how repeated measurements or multiple endpoints were handled. No sample-size justification is reported, and any planning illustrations based on observed effects should not be read as observed power.
Safety interpretation is also constrained: the record gives adverse-event counts but no serious-event terms, descriptions of other events, or causal assessments. These limitations concern what can be concluded from the registry record and do not establish whether unreported analyses or additional details exist elsewhere.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Epidural Spinal Cord Stimulation for Sensory Restoration and Phantom Limb Pain in Upper-Limb Amputees — NCT02684201.
- Registry record last updated 2025-10-08; status last verified 2025-09.
- Results first posted 2025-10-08.
- 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
NCT02684201 is recorded as a completed, single-group, unmasked study of epidural spinal cord stimulation in upper-limb amputees. Enrollment is listed as 4. The intervention description refers to a Boston Scientific stimulator lead placed in the cervical epidural space and directed toward dorsal spinal roots; it also refers to ten upper-limb amputees, a figure not reconciled with the recorded enrollment.
The primary outcome concerns stimulation thresholds, expressed in milliamps, with a stated 30-day timeframe and a mean and full range as the summary approach. Secondary measures address evoked sensations, pain ratings, and prosthetic-hand tasks. Outcome results and statistical analyses are not reported in the registry record. Safety information lists 0 serious adverse events among 4 at risk and other adverse events affecting 2 of 4 at risk.