Clinical Outcomes of Deep Brain Stimulator (DBS) Electrodes Placed Using Intraoperative Computed Tomography (CT) and Frameless Stereotaxis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Outcomes of Deep Brain Stimulator (DBS) Electrodes Placed Using Intraoperative Computed Tomography (CT) and Frameless Stereotaxis (NCT01703598), a na na study. The primary outcome is Change in Motor OFF Ldopa UPDRS.

2. Clinical Question

The registry describes a study intended to determine whether deep brain stimulation surgery using intraoperative imaging and frameless stereotaxis is noninferior to surgery using frame-based stereotaxis and microelectrode recording. The outcome selected for that question is change in motor UPDRS while participants are in the OFF Levodopa state, assessed at baseline and 6 months. However, the study is recorded as single-group, with allocation listed as NA. The record therefore does not describe a concurrent comparator group from which to estimate a direct difference between the surgical approaches.

Noninferiority is a comparative claim: it asks whether an intervention is not worse than a specified alternative by more than a prespecified margin. It cannot be answered from an outcome in a single group alone. Without a reported comparator and margin, the intended question and the recorded design do not align in a way that permits assessment of noninferiority from this record. The enrollment figure describes the study overall, not necessarily the number with an observed endpoint.

3. Trial Design

The registry marks the study as completed and describes a single-group model. Enrollment is listed as 69. Allocation is NA, masking is none, and phase is NA. The listed condition is Parkinson's disease, and Oregon Health and Science University is the sponsor. The record gives a start date of 2011-09 and a primary completion date of 2017-03.

The title and brief summary frame the work as a comparison between deep brain stimulation surgery using intraoperative imaging and frameless stereotaxis and surgery using frame-based stereotaxis with microelectrode recording. Yet the arm description identifies a single arm, and the model is single-group. No like-for-like control arm is described. This means the study question should not be read as proof that the two approaches were directly compared within this record. Details about how participants came to receive the recorded procedure are not reported in the registry record.

The registry lists deep brain stimulation as a device intervention and DBS surgery as a procedure. It records one primary outcome measure, change in motor OFF Levodopa UPDRS, with baseline and 6 months as the timeframe. The record identifies the mean as the summary parameter and standard deviation as the dispersion measure. It does not give numerical outcome values or a statistical analysis for the endpoint.

Masking is listed as none. The record does not specify whether outcome assessors were masked, how measurements were collected, or how the surgical procedures were standardized. Further information about eligibility criteria, participant flow, and analysis populations is not reported in the registry record. Although the study status is completed, that status alone does not establish that all enrolled participants completed follow-up or contributed outcome data.

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.

Population: The analysis population is the same as the baseline population

6. Primary Endpoint

The registry lists the primary outcome as Change in Motor OFF Ldopa UPDRS, measured over Baseline and 6 months.

The primary endpoint is change in motor UPDRS in the OFF Levodopa state, with assessment at baseline and 6 months. The record identifies the measure as motor UPDRS and gives its range as 0 to 108; a higher number indicates a worse clinical state. The outcome is expressed in units on this scale. The registry specifies a mean and standard deviation as the intended summary statistics.

Change from baseline is used to describe how a measurement differs over time for the participants being assessed. A group mean change can summarize the direction and average size of that shift, while a standard deviation describes how spread out individual values are around the mean. These are distinct quantities: the standard deviation is not the precision of the mean or a confidence interval. The registry record does not report the actual baseline or 6-month measurements, a mean change, or a standard deviation.

In general, a motor scale can serve as a clinical outcome when the question concerns motor status, and measuring at baseline and follow-up makes it possible to characterize change over that interval. Here, the endpoint is relevant to the stated surgical comparison, but a single-group endpoint cannot by itself estimate how change would differ under the alternative procedure. Details of the endpoint calculation, including whether the reported change is defined as follow-up minus baseline or the reverse, are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the single-group design allow?

The registry identifies the study as single-group, with one arm and no allocation description. In general, a single-group design can describe observed outcomes within the group over time. If baseline and follow-up values are available, an analysis can summarize average within-group change and its variability. Such a change does not, on its own, show what would have happened to the same participants under another procedure. Changes over time may reflect multiple influences, and a concurrent comparison is needed to estimate a between-approach difference under the study design.

The stated objective uses noninferiority language, but noninferiority is inherently comparative. In general, the analysis needs an estimate contrasting the intervention with an alternative and a prespecified noninferiority margin. The margin defines the largest disadvantage that would still be considered compatible with the question. It must be set before interpreting the results; choosing it after seeing an estimate would not provide the same safeguard. A comparator group and a margin are not reported in the registry record. Thus the design information in this record is insufficient to evaluate the stated noninferiority objective.

What do the mean and standard deviation describe?

The registry specifies a mean for the continuous motor UPDRS change and a standard deviation for dispersion. In general, the mean is an average that describes the center of a set of measurements. The standard deviation describes how much individual measurements vary around that average. A standard deviation does not describe uncertainty in the estimated mean; that is a different inferential quantity, often conveyed with a confidence interval. Neither the mean nor the standard deviation for the primary outcome is reported in the registry record.

Change scores require a defined calculation, such as follow-up minus baseline or baseline minus follow-up. That choice determines how the sign of a change is interpreted. The record identifies the outcome as change and gives baseline and 6 months as the timeframe, but does not define the subtraction order. It also does not report the baseline and follow-up values or the resulting change. The higher-score-worse direction is stated for the scale itself, but the direction convention for the change score cannot be inferred from that description.

How would a comparative estimate be interpreted?

In general, a comparative analysis would estimate a difference between the two approaches on the chosen outcome. Precision would be assessed using an uncertainty measure such as a confidence interval. For noninferiority, interpretation would depend on whether the interval rules out a disadvantage larger than the prespecified margin, using the analysis conventions set out in the protocol. No comparative estimate, confidence interval, margin, or analysis result is reported in the registry record. A within-group mean change, even if it were available, would not substitute for this comparison.

Statistical significance and clinical interpretation are not interchangeable. In general, a p-value describes how compatible data are with a specified null model under the assumptions of a test; it does not measure the size or importance of an effect. A confidence interval adds information about the range and precision of plausible effects. The registry record does not report a test, p-value, or interval for the primary endpoint, so none can be interpreted.

Why can dispersion affect analysis?

In general, the spread of individual outcomes affects the precision of a group estimate. Greater variability can make an estimate less precise when other features of the data are unchanged. Some outcome distributions may also be asymmetric or have unusual values, in which case a mean and standard deviation may not fully describe their shape. This is a general statistical consideration, not a claim about the distribution in this study: the registry record gives no participant-level data, outcome values, or distributional assessment.

For count outcomes, over-dispersion means that observed variability exceeds what a simple model assumes. It can make standard errors too small if the model does not account for the extra variation. That concept is not directly applicable to the continuous motor UPDRS endpoint as, and no such analysis is reported. The record does not list a statistical model or diagnostic procedure for the primary outcome.

What do planning illustrations mean?

In general, a sample-size calculation depends on assumptions about the target effect, variability, significance level, allocation, and analysis. A planning illustration based on an observed effect is a hypothetical design exercise, not evidence of the study's power as conducted. It must not be interpreted as observed power or as a test of whether the trial succeeded. The registry record does not report its own sample-size justification or the assumptions used to plan enrollment. Any planning illustration should therefore be kept separate from the study's actual design and outcomes.

The assumptions described for a planning illustration refer to a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of an observed effect. Those are illustration assumptions, not documented features of this single-group study. The record does not provide the outcome estimates needed to interpret an observed-effect-based illustration, and no trial-specific sample-size rationale is reported.

What analysis details remain unknown?

The registry lists one outcome measure and no analyses. It does not report an analysis population, missing-data method, covariate adjustment, treatment of repeated measurements, or sensitivity analyses. These choices can affect how an estimate is defined and how robustly it is interpreted. Their absence from the record does not establish that no methods were used elsewhere; it means they are not reported in the registry record. No statistical plan should be inferred from the endpoint label, design label, or completed status.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("DBS Surgery")
n   <- c(69)
m   <- c(14.8)
sp  <- c(8.9)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  DBS Surgery  69  14.800  8.900  12.662  16.938

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome measure, change in motor OFF Levodopa UPDRS, and no analyses. It therefore does not provide reported test results across which multiplicity can be assessed. In general, multiplicity arises when several hypotheses or outcomes are tested: repeated opportunities to declare a finding can increase the chance of a misleading positive result unless the analysis plan addresses that issue. A single listed primary measure does not establish that no other outcomes or analyses were conducted; those details are not reported in the registry record.

Missing data are also not described. The record does not state how many participants had baseline measurements, how many had 6-month measurements, or how many contributed to a change score. It does not report reasons for missing observations, whether missingness was handled by an imputation method, or whether any sensitivity analyses were undertaken. Enrollment of 69 should not be assumed to equal the endpoint analysis population.

In general, missing-data methods rely on assumptions about why observations are absent and how the missing values relate to observed information. Different assumptions can lead to different estimates, so transparent reporting of participant flow and analysis populations is important. No such details are reported in the registry record. The primary outcome population field is blank, leaving unclear which participants the intended mean and standard deviation would describe.

The record also does not identify an intention-to-treat, per-protocol, or other analysis population. Such populations can be especially consequential in noninferiority evaluations, where different approaches to inclusion and adherence may affect interpretation. This is a general methodological point; it does not indicate which analysis was used or which would have been appropriate for these data. The registry record provides no basis for resolving it.

12. 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.

For the DBS Surgery group, the registry lists 69 people at risk for serious adverse events and zero affected. It also lists 69 at risk for other adverse events and zero affected, with zero deaths. These are the recorded counts for the group. No serious adverse event terms are listed.

Counts should be read with their denominators: the at-risk figures identify the group size used in the registry's safety entry, while the affected figures give the number recorded with each event category. The record does not state the observation period, event definitions, collection procedures, or whether the safety figures cover the same follow-up as the primary outcome. Further safety detail is not reported in the registry record.

A zero recorded count does not establish that an event is impossible, nor does it describe the frequency of events beyond the recorded group and definitions. It also does not answer the primary clinical question, which concerns motor UPDRS change and a comparison between surgical approaches. The safety counts should therefore be interpreted separately from efficacy or noninferiority claims.

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

The record documents a completed study with enrollment of 69 and an intended primary endpoint of motor OFF Levodopa UPDRS change from baseline to 6 months. It states that the scale ranges from 0 to 108 and that a higher score indicates a worse clinical state. It also records zero serious adverse events, zero other adverse events, and zero deaths in the DBS Surgery group, with 69 at risk for each listed adverse-event category.

These registry entries do not reveal the observed motor outcome. No mean change, standard deviation, confidence interval, or comparative result is reported in the registry record. As a result, the direction, magnitude, and precision of the endpoint cannot be described. The completed status and enrollment figure do not provide those missing estimates.

The record's study question concerns noninferiority of one surgical approach relative to another. Yet the recorded design is single-group, with no comparator arm described, and the noninferiority margin is not reported. A noninferiority conclusion cannot be established from a single group's change alone. In general, that conclusion requires a direct comparative estimate interpreted against a margin defined in advance. The record does not provide those elements.

Accordingly, the registry record can be read as documenting the intended comparison, a single-group design, the selected endpoint, and the listed adverse-event counts. It cannot establish whether the approaches differ, whether one is noninferior to the other, or how precisely any motor outcome was estimated. It also cannot establish that every enrolled participant contributed follow-up data. These limits concern the information reported in the registry, not a claim about what may have been analyzed or reported elsewhere.

In general, absence of a reported outcome estimate is not evidence of no change or of no difference. It leaves the estimate unknown from this record. Likewise, the listed zero safety counts describe the registry's entries and should not be converted into a broader assurance about safety.

14. Why This Trial Matters Statistically

This trial is statistically notable because its stated objective and its recorded design do not match cleanly. The study description asks whether one surgical approach is noninferior to another, while the record identifies a single-group model and one arm. Recognizing that distinction is essential: a within-group change and a between-group comparison answer different questions.

The endpoint itself is clearly identified as motor OFF Levodopa UPDRS change at baseline and 6 months, with a defined scale range and direction. Yet the record contains no numerical outcome estimate or analysis. This illustrates why a named endpoint is not the same as a reported result. Without the mean change and its variability, readers cannot describe the observed outcome or assess its precision; without a comparator estimate and margin, they cannot evaluate noninferiority.

The registry also lists enrollment and safety counts, but those figures do not substitute for outcome reporting. Enrollment does not establish the size of the endpoint population, and zero recorded adverse events do not answer a comparative motor-outcome question. Keeping these quantities distinct helps prevent conclusions that the data in the record cannot support.

More broadly, clear reporting of analysis populations, missing outcomes, and comparative methods is important when a study's objective is framed as noninferiority. Those details let readers understand what was estimated, for whom, and under what assumptions. Their absence from this record limits statistical interpretation, even though the study is marked completed. This is a reason to distinguish the registry's documented design and results from the question the study was intended to address.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main limitation for interpretation is that the record describes a single-group study while the stated purpose is a noninferiority comparison. A comparator arm is not described, and the noninferiority margin is not reported in the registry record. The intended comparative question therefore cannot be evaluated from the design and results recorded.

The primary endpoint is named, but its numerical results are absent. The record does not report baseline or 6-month values, mean change, standard deviation, confidence interval, or an inferential test. It also does not define the subtraction convention for the change score. This prevents interpretation of the endpoint's direction, size, and precision.

Enrollment is listed as 69, but the number of participants with endpoint data is not reported. The outcome population field is blank, and missing-data handling and participant flow are not described. The record does not state whether outcome assessors were masked or how measurements were standardized; masking overall is listed as none. These omissions limit assessment of potential sources of bias and the population represented by any estimate.

Safety information is limited to the recorded counts of zero serious adverse events, zero other adverse events, and zero deaths in the DBS Surgery group. Event definitions, ascertainment methods, and observation period are not reported. The record also lists no analyses, so statistical methods beyond the mean and standard deviation summary are not available for review. These are limitations of what the registry record reports and should not be taken as evidence that additional information does not exist elsewhere.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Clinical Outcomes of Deep Brain Stimulator (DBS) Electrodes Placed Using Intraoperative Computed Tomography (CT) and Frameless Stereotaxis — NCT01703598.
• Registry record last updated 2019-08-13; status last verified 2019-07.
• Results first posted 2019-08-13.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

The registry record describes NCT01703598, a completed single-group study sponsored by Oregon Health and Science University. It lists Parkinson's disease as the condition, enrollment of 69, no masking, allocation as NA, and phase as NA. The recorded dates are a start in 2011-09 and primary completion in 2017-03.

The stated objective concerns noninferiority of deep brain stimulation surgery using intraoperative imaging and frameless stereotaxis compared with frame-based stereotaxis and microelectrode recording. The recorded arm description is single arm. One primary outcome is listed: change in motor OFF Levodopa UPDRS at baseline and 6 months, summarized as a mean with standard deviation. The record does not report numerical outcome results or analyses.

For DBS Surgery, the record lists 69 at risk and zero affected for serious adverse events, 69 at risk and zero affected for other adverse events, and zero deaths. No serious event terms are listed. The registry does not report an outcome-analysis population, missing-data methods, or a comparative estimate. Consequently, the record documents the study's stated aim and selected endpoint but does not provide the evidence needed to assess its intended noninferiority question.