Effect of Spinal Manipulation on Sensorimotor Functions in Back Pain Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effect of Spinal Manipulation on Sensorimotor Functions in Back Pain Patients (NCT00830596), a randomized na study. The primary outcome is Postural Sway.

2. Clinical Question

3. Trial Design

The study is registered as a randomized, double-masked, parallel trial. It enrolled 221 participants and is marked completed. The sponsor was Palmer College of Chiropractic. The registered start is 2007-07 and primary completion is 2012-06. The phase is listed as NA.

Three intervention arms are described: HVLA-SM, LVVA-SM, and Sham Intervention. The first two are lumbo-pelvic manipulation approaches distinguished by velocity and amplitude. The sham arm description specifies light effleurage and a sham mechanically-assisted chiropractic treatment for 2 weeks, followed by full spine manipulation for 4 weeks. The registry record does not explain the rationale for that sequence or provide further details on treatment delivery.

Double masking is reported, but which participants, clinicians, assessors, or other personnel were masked is not reported in the registry record. The method used to generate the randomization sequence, how allocation was concealed, and whether masking was assessed are also not reported. The parallel design means the registered arms are separate groups, but the record does not provide enough detail to reconstruct the allocation process or analysis population.

The primary outcome is postural sway at baseline and 2 weeks. The record describes changes from baseline and refers to adjusted within-group mean changes. It does not report the adjustment method or numerical outcome estimates. Five outcome measures are listed, but numerical results are not reported in the registry record. The record is marked as having zero analyses, so it does not give a statistical analysis plan or analysis-level results.

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

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 Postural Sway, measured over Baseline and 2 weeks.

Postural sway is a continuous measure expressed in millimeters. The registry description defines anterior-posterior (AP) and medial-to-lateral (ML) postural sway as mean excursion in those directions. In general, an excursion measure describes the amount of movement along a direction while a person is standing. Such measures can be used to study sensorimotor function because maintaining posture involves sensing body position and coordinating movement.

The primary outcome description specifies baseline and 2-week measurements and frames the outcome as change from baseline. Comparing measurements over time can describe how postural sway changes during the registered interval. The registry record refers to adjusted within-group mean changes, but does not identify the adjustment variables or provide the resulting estimates. It also does not provide a numerical comparison between the intervention arms.

A mean summarizes the central value of a continuous measure; it does not show the full spread or pattern of individual measurements. A 95% confidence interval, named as the dispersion measure for this outcome, is intended to convey uncertainty around an estimate. The actual interval limits are not reported in the registry record. Without the outcome values and their uncertainty estimates, the magnitude and precision of changes cannot be evaluated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record describes a continuous primary outcome, postural sway, with mean as the parameter and a 95% confidence interval as the dispersion measure. It gives no numerical outcome estimates or analysis results. The statistical concepts below are general explanations of how such measures are commonly interpreted, not claims about analyses performed in this trial.

What does a mean describe?

In general, the mean is an average that summarizes the center of a set of measurements. For a continuous outcome such as postural sway, it can provide a compact description of the group's measurements. The average does not reveal whether individuals had similar values or whether values varied substantially. It can also be influenced by unusually high or low observations. The registry record does not provide individual-level measurements or other summaries of their distribution.

The endpoint description refers to adjusted within-group mean changes from baseline to follow-up. In general, an adjusted estimate accounts for variables included in a statistical model, with the goal of estimating a mean change conditional on those variables. The variables, model form, and adjustment procedure are not reported in the registry record. The term “adjusted” alone is not enough to reproduce or evaluate an analysis.

How should a confidence interval be read?

In general, a confidence interval expresses uncertainty around an estimated quantity. A narrower interval indicates greater precision under the assumptions of the analysis; a wider interval indicates less precision. The interval is not a range containing a fixed proportion of individual participants' values. Nor does it by itself tell whether a result is clinically important. Interpretation depends on the estimate, the interval limits, the outcome scale, and the question being asked.

The registry record names a 95% confidence interval but does not report its limits. Without those limits and the corresponding estimate, precision cannot be judged. It is not possible to determine whether the interval includes values that would represent little change, substantial change, or a contrast between arms, because those numerical results are absent.

Why distinguish change within an arm from a difference between arms?

In general, a within-arm change describes how measurements in that group differ between time points. A between-arm contrast asks whether the changes, or the follow-up values accounting for baseline, differ across groups. These answer different questions. Changes within separate arms cannot simply be compared informally to infer a treatment contrast; a direct contrast and its uncertainty are needed.

The registered description emphasizes adjusted within-group mean changes. It does not report the corresponding between-group contrasts, confidence intervals, or tests. The trial is randomized, but randomization alone does not supply the missing estimates or specify how the primary outcome was analyzed. The analysis method matters for defining the comparison and accounting for repeated measurements.

What does the registered design tell us about analysis?

The study is described as randomized and parallel, with double masking. Those features describe planned design characteristics, not the statistical model. The registry record does not report the randomization procedure, concealment method, identity of masked parties, or the analysis population. It also does not report how measurements at baseline and follow-up were modeled, how adjustment was handled, or how missing observations were treated.

For repeated measurements, a statistical analysis needs to account appropriately for the fact that measurements from the same participant are related. In general, a model can use baseline and follow-up information together, or a follow-up comparison can adjust for baseline. Different approaches can yield different estimates and uncertainty. The record does not identify which approach, if any, was used.

What is over-dispersion, and is it relevant?

In general, over-dispersion means that observed variability is greater than a statistical model expects. It is especially discussed for count outcomes, where a model's variance assumptions may not match the data. Postural sway is registered as a continuous outcome summarized by a mean, so a count-model over-dispersion issue is not established by the information in this record. The observed outcome distribution and model diagnostics are not reported; no claim about whether any model assumption was met can be made.

What can planning assumptions tell us?

The registry record states that a planning illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect expressed as a specified proportion of the observed effect. It also states that non-time-to-event illustrations are expressed as participants per arm. These are planning assumptions, not a description of the trial's own design justification. Numerical planning outputs are not reported in the registry record, and the record does not state that these assumptions were used to choose enrollment of 221.

Sample-size illustrations are not observed power. In general, a planning calculation describes the sample size associated with chosen assumptions; it does not measure the probability that a completed study has detected a true effect. Since numerical outcome effects and analysis results are not reported, the planning assumptions cannot fill the gap in evidence about the observed primary outcome.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists five outcome measures and describes the primary outcome as having several categories or time points. It does not reduce that outcome to one comparison, and no numerical outcome analyses are reported. The record does not state how many formal hypotheses were tested, which comparisons were considered primary beyond the outcome designation, or whether any adjustment for multiple testing was planned or performed.

In general, multiplicity arises when several outcomes, time points, directions, or group comparisons are tested. Considering many tests can increase the chance of obtaining a nominally notable result by chance. Statistical plans may address this through a prespecified hierarchy or adjustment, but neither a multiplicity strategy nor its rationale is reported in the registry record. It would be inappropriate to infer that one was or was not used in the completed study.

Missing-data methods are also not reported. The record does not give follow-up completion counts for the postural-sway measurements, reasons for missing observations, or assumptions and procedures used to handle missing values. Enrollment of 221 does not establish how many participants contributed endpoint data.

The record does not identify the analysis population, such as whether analyses followed original randomized assignment or used another population. Nor does it report interim analyses, sensitivity analyses, or a statistical analysis plan. In general, these details help readers assess whether analyses followed prespecified choices and how robust results may be to alternative assumptions. Their absence means those aspects cannot be evaluated from the registry record.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry record reports serious adverse events in groups at risk of 74 for HVLA-SM, 74 for LVVA-SM, and 73 for Sham Intervention. The serious adverse event count is 0 in each group. Deaths are also reported as 0 in each group. These are the counts as recorded; the registry record does not provide serious-event terms or further event descriptions.

For other adverse events, the counts are 50 of 74 for HVLA-SM, 57 of 74 for LVVA-SM, and 46 of 73 for Sham Intervention. These are counts of participants affected as presented in the record, not a measure of event severity or causal relationship. Definitions of the “other” category and details such as event types, timing, duration, and attribution are not reported in the registry record.

These counts should be read separately from the primary postural-sway outcome. They do not establish comparative safety, and the registry record does not report analyses of differences between arms. A recorded count of zero serious events does not demonstrate that no such events could occur; it describes only the recorded count in the listed group. The record also does not explain the asterisk attached to each group title.

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

The registry record documents a randomized, double-masked, parallel study of two spinal manipulation approaches and a comparator intervention in patients with low back pain. It identifies postural sway as the primary outcome and specifies baseline and 2-week assessment. These details clarify the trial's intended question and the type of measurement used.

What the record does not provide is equally important. Numerical postural-sway changes, confidence interval limits, between-group estimates, and statistical tests are not reported. Therefore, it is not possible to determine from the record whether the measured outcome changed, in which direction it changed, how large any change was, or how precise an estimate might be. Lack of registered results is not a finding of no effect.

The registry entry also does not describe enough of the analysis to evaluate model choices, adjustment, missing data, analysis populations, or multiplicity. Although it reports enrollment and trial design labels, those details do not substitute for results or a detailed statistical plan. The stated planning assumptions likewise do not show what was observed and should not be interpreted as observed power.

The adverse-event counts provide a limited descriptive account: no serious adverse events or deaths are listed in any arm, while other adverse events are recorded in all three arms. The record does not define those other events or provide details that would support a broader safety comparison.

Thus, the registry record can support a description of the study framework and its recorded adverse-event counts, but not a conclusion about the primary outcome or comparative effects. Any interpretation of efficacy or clinical importance would require numerical results and sufficient methodological detail, neither of which is reported in the registry record.

13. Why This Trial Matters Statistically

This trial is statistically interesting because it sets a physiological measurement, postural sway, as the primary outcome in a study of spinal manipulation approaches. The outcome is continuous and described in directional components, while the registered question concerns change from baseline to follow-up. That structure makes clear why an analysis needs to distinguish change within an arm from direct comparisons between arms.

The registry record also illustrates that design labels and enrollment totals do not answer questions about the analysis. Randomization, masking, a parallel structure, and a completed status are useful design information. They do not reveal how the endpoint was modeled, which participants contributed data, how uncertainty was quantified in practice, or how missing observations and multiple outcome components were handled.

Another statistical point is the difference between a stated precision measure and an available precision estimate. The record names 95% confidence intervals but gives no interval limits. Readers therefore cannot assess how compatible the results might be with different magnitudes of change. The endpoint's description alone is not enough to judge evidence strength.

The record further separates planning assumptions from observed findings. A planning illustration may be based on an effect assumption and specified statistical settings, but it is not a substitute for outcome estimates and does not represent observed power. Without the numerical planning outputs or trial results, neither can be evaluated quantitatively.

Finally, the safety counts are presented by arm but have little accompanying context about event definitions or attribution. Their proper statistical reading is descriptive rather than a comparative test. Together, these features show why transparent reporting needs to include estimates, uncertainty, analysis methods, and participant accounting, not only the design and outcome labels.

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 main trial-specific limitation of the registry record is the absence of numerical primary outcome results. Although the endpoint description identifies postural sway, baseline and 2-week measurement, and adjusted within-group mean changes, it does not report the estimates or confidence interval limits. The record therefore cannot support an assessment of direction, magnitude, or precision.

The outcome is described in AP and ML directions, but the record does not provide direction-specific results or clarify how the multiple outcome categories and time points relate to the primary analysis. It is not possible to determine whether all planned endpoint components were measured, analyzed, or reported.

Information needed to assess the analysis is also absent. The adjustment method, statistical model, missing-data approach, analysis population, and between-arm contrasts are not reported in the registry record. Although enrollment is listed as 221, the number contributing primary outcome data at each time point is not stated. The method of randomization and details about masking are likewise not reported.

The sham arm's description includes a change in intervention over time, from light effleurage and sham mechanically-assisted treatment for 2 weeks to full spine manipulation for 4 weeks. This is relevant context when interpreting the comparator, but the registry record does not explain the rationale for the sequence or its relation to the primary outcome's 2-week timeframe.

Safety information is limited to group counts. Serious-event terms are not listed, other adverse events are not described, and definitions or attribution procedures are not reported. The registry record also does not provide a multiplicity strategy, interim-analysis information, or a statistical analysis plan. These gaps limit evaluation of both the outcome evidence and the methods used to obtain it.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effect of Spinal Manipulation on Sensorimotor Functions in Back Pain Patients — NCT00830596.
• Registry record last updated 2017-09-25; status last verified 2017-07.
• Results first posted 2017-09-25.
• 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.

18. Record Summary

NCT00830596 is a completed randomized, double-masked, parallel trial sponsored by Palmer College of Chiropractic. It enrolled 221 participants with low back pain. The registered start is 2007-07, and primary completion is 2012-06. The phase is listed as NA.

The three arms were HVLA-SM, LVVA-SM, and Sham Intervention. The primary outcome was postural sway, described as mean excursion in AP and ML directions, measured at baseline and 2 weeks. Five outcome measures are listed, but the registry record contains no analysis entries and reports no numerical primary outcome results.

Serious adverse events and deaths are recorded as 0 in each arm. Other adverse events are recorded for 50 of 74 participants in HVLA-SM, 57 of 74 in LVVA-SM, and 46 of 73 in Sham Intervention. Further event details are not reported in the registry record.