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 Treatment of Cranial Molding Deformities in Preterm Infants (NCT02366936), a na na study. The primary outcome is Cranial Index (CI).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02366936 |
| Phase | NA |
| Condition | Preterm Infants, Dolichocephaly, Positional Scaphocephaly |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 32 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Duke University |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns preterm infants during their hospital stay, when dolichocephaly may develop. The conditions named in the registry record are preterm infants, dolichocephaly, and positional scaphocephaly. The arm description says the study was to include 30 preterm infants; the enrollment field reports 32. The record does not explain this difference, and it does not provide further eligibility details or a participant flow.
Intervention
The intervention is the Tortle Midliner positioning system, listed as a device. The study description frames its use as a strategy for prevention and/or treatment of dolichocephaly. The registry record does not describe the positioning schedule, duration of use, adherence, or whether use varied among infants.
Comparator
The brief summary states an aim of comparing the Tortle Midliner with the current standard of care intervention in the Duke Intensive Care Nursery. However, the registered design is single-group, and the listed arm is use of the Tortle Midliner. A separate standard-care comparison arm is not reported in the registry record. The study therefore does not furnish a like-for-like controlled comparison in the information recorded.
Primary question
The primary outcome is cranial index at 34 weeks gestational age. The study intended to assess whether cranial index could describe head shape in the setting of prevention or treatment of dolichocephaly. The record defines dolichocephaly as a cranial index below 76% and gives a normative range of 76-85% for prone and supine sleeping infants. Outcome values and a statistical comparison are not reported in the registry record, so the registered information does not establish how cranial index changed or whether any difference from standard care occurred.
3. Trial Design
This is an interventional, longitudinal study listed as single-group, with the Tortle Midliner as its intervention. The record identifies Duke University as sponsor and gives the study status as completed. The start is recorded as 2015-06 and primary completion as 2016-06. Phase and allocation are listed as NA, and masking is listed as none.
The arm description refers to 30 preterm infants using the Tortle Midliner, while the enrollment field reports 32. The registry record does not explain the difference between these figures. It lists no separate standard-care arm, even though the brief summary states that the study's specific aim was to determine whether the device was more effective than current standard of care intervention in the Duke Intensive Care Nursery. Consequently, the design recorded does not provide a concurrent, like-for-like comparison for that stated aim.
The primary outcome is cranial index at 34 weeks gestational age. The record describes the study as longitudinal, but does not report the timing or number of measurements before that endpoint. It also does not report the intervention schedule, participant-level follow-up, or a detailed analysis plan. There are 2 outcome measures listed, but the record does not give a count of statistical analyses; it lists 0 analyses. The study is marked completed, which does not itself mean that numerical results or analysis details have been entered in the registry.
The design information allows the study's intended population, intervention, and primary measurement to be identified. It does not allow the effect of the intervention to be separated from changes over time, usual care, or other influences, because a comparator arm is not recorded. Recruitment details, the final analyzed population, and reasons for any difference between planned and reported enrollment are not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Use of Tortle Midliner |
|---|---|
| STARTED | 32 |
| COMPLETED | 24 |
| NOT COMPLETED | 8 |
Reasons for not completing this period:
| Reason | Use of Tortle Midliner |
|---|---|
| Withdrawal by Subject | 2 |
| Lost to Follow-up | 4 |
| Physician Decision | 2 |
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 | Use of Tortle Midliner |
|---|---|---|
| Participants analysed | 32 | |
| Age, Categorical: <=18 years | Participants | 32 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 18 |
| Sex: Female, Male: Male | Participants | 14 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 2 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 29 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 1 |
| 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 | 23 |
| Race (NIH/OMB): White | Participants | 8 |
| Race (NIH/OMB): More than one race | Participants | 1 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 32 |
| Gestational age | weeks | 27 (25 to 30) |
| Birth weight | g | 975 (590 to 1430) |
6. Primary Endpoint
The registry lists the primary outcome as Cranial Index (CI), measured over 34 weeks gestational age.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | cranial index |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is cranial index (CI) at 34 weeks gestational age. The record defines CI as the ratio of biparietal diameter (BiPD) to occipitofrontal diameter (OFD), multiplied by 100. BiPD is the widest transverse diameter of the head, measured between the most prominent lateral points in the area of the parietal and temporal bones. OFD is the head diameter from the glabella to the occipital protuberance.
CI expresses head width in relation to head length and is used in this study to characterize cranial shape. The registry record defines dolichocephaly as CI below 76%. It also states that the normative CI range is 76-85% for prone and supine sleeping infants, while noting that various reported ranges for cranial molding norms exist. These definitions give context for interpreting the measure; they do not substitute for outcome data or establish a treatment effect.
The endpoint is specified as a median with full range as its dispersion measure. A median describes the middle of the observed values after they are ordered, while the full range describes the lowest and highest observed values. These summaries can convey the distribution's center and span without assuming that values follow a symmetric pattern. The registry record does not report the median, range, number with an observed measurement, or any comparison at 34 weeks gestational age.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a completed single-group study and names cranial index at 34 weeks gestational age as its primary outcome. It does not report numerical outcome results or statistical analyses. As a result, there is no posted estimate of the cranial index distribution, no confidence interval, and no reported test of a treatment effect to interpret. The status “completed” describes the study's recorded status; it is not evidence that a result was entered or that the stated comparison was performed.
The study's brief summary describes an intended comparison with current standard of care intervention in the Duke Intensive Care Nursery. In contrast, the recorded design is single-group and lists use of the Tortle Midliner without a separate standard-care arm. Without a recorded concurrent comparator, an observed outcome in the intervention group alone could not show how outcomes would have differed under standard care. It also could not distinguish intervention effects from changes over time or other influences. This is a design limitation, not a conclusion that the device did or did not affect cranial shape.
The registry identifies 32 as enrollment, while the arm description refers to 30 preterm infants. The record does not explain the discrepancy. Enrollment is not necessarily the same as the number with an endpoint measurement or the number included in an analysis. The record does not report these analysis-population details, nor participant flow or missing endpoint data. Therefore, the enrolled count cannot be treated as the denominator for an outcome analysis without additional information.
The planned endpoint summary is a median with full range. Those choices would describe the central observed CI and its spread, but they would not by themselves establish a between-group effect, particularly when only one group is recorded. The record defines dolichocephaly as CI below 76% and gives a normative range of 76-85% for prone and supine sleeping infants. Those definitions provide interpretive context, but no observed CI values are available to assess against them.
The adverse-event record lists 0 serious events among 32 at risk and 1 affected in the other adverse-event category among 32 at risk, with 0 deaths. The record does not provide further detail about the other event, its seriousness classification, timing, or relationship to the device. These entries are counts recorded in a single study group and do not support a comparative safety estimate. Overall, the registry information describes an intended question and endpoint but does not report outcome analyses capable of answering that question.
9. Statistical Methods Explained
The statistical information in the registry record is limited. It identifies a primary endpoint, its summary format, and a study design, but lists 0 analyses. Detailed methods for estimating or testing an intervention effect are not reported in the registry record. The following concepts explain how the stated endpoint and design relate to statistical interpretation; they are general explanations, not descriptions of analyses documented for this study.
What does the single-group design allow?
A single-group study can describe measurements among participants who receive the intervention. In a longitudinal study, measurements may also describe change over time if repeated measurements and their timing are recorded. Neither feature alone establishes what would have happened under another care strategy. For a comparative treatment effect, a suitable comparator helps distinguish intervention-associated differences from natural change, co-interventions, and other influences.
Here, the brief summary states an aim to compare the Tortle Midliner with current standard of care, but the registered design is single-group and only the Tortle Midliner arm is listed. There is no recorded concurrent comparison group from which to estimate a contrast. A before-and-after contrast could sometimes be informative if measurements and analysis were specified, but the registry record does not report such a comparison or the required results. No treatment-effect estimate should therefore be inferred from the stated aim alone.
Why summarize the endpoint with a median and full range?
The median is the middle value after observations are placed in order. It is less influenced by extreme values than a mean and can be a useful description when a distribution is skewed or when unusually low or high measurements occur. The full range reports the smallest and largest observations and therefore gives a direct account of the total span. It can also be sensitive to extreme observations and does not show how values are distributed between the endpoints.
These summaries answer descriptive questions about the observed CI values. They do not, on their own, quantify uncertainty in the estimated median or establish a difference between groups. A confidence interval, when reported, expresses a range of values compatible with the data and the statistical method under its assumptions. No confidence interval is reported in the registry record. The record also does not report the CI observations, median, or full range, so none of these descriptions can be assessed empirically for this study.
How does the clinical definition relate to the measurement?
The endpoint definition makes CI a ratio of head width to head length, expressed as a percentage. The registry record defines dolichocephaly as CI below 76% and gives a normative range of 76-85% for prone and supine sleeping infants. A threshold turns a continuous measurement into a category, while retaining the continuous measure can preserve distinctions among values that fall on the same side of a threshold. The record does not report an analysis of either continuous CI or the proportion below the stated threshold. No such result can be inferred from the endpoint definition.
What is over-dispersion, in general?
Over-dispersion is a general statistical issue in count or binary-outcome models when the observed variability is greater than the model expects. If ignored, uncertainty estimates may be too small and statistical tests may appear more decisive than warranted. It is not possible to determine from the registry information whether over-dispersion is relevant to any analysis of this study. The primary endpoint is described as a median with full range, and no model-based analysis is reported.
How should planning calculations be understood?
The record describes sample-size calculations as planning illustrations based on an observed effect, with two-sided significance level 0.05, equal allocation between two arms, and a normal approximation. It states that the effect to detect is a specified fraction of the observed effect, and distinguishes total event counts for time-to-event calculations from participants per arm for other calculations. These are planning assumptions, not evidence that the study used a two-arm design or achieved a particular power. The registered study is single-group, and the registry record does not report an observed effect estimate or a trial-specific sample-size justification.
Planning sample sizes do not measure the probability that a completed study's finding is correct. They also are not observed power, which is not a substitute for an effect estimate and its uncertainty. Without a reported effect estimate and outcome analysis, the planning illustrations cannot be used to infer the magnitude or precision of the study's result. The registry record does not report an interim analysis plan or further statistical methods.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 2 outcome measures and identifies cranial index at 34 weeks gestational age as the primary outcome. It lists 0 analyses. The other outcome measure is not described in the information recorded. A detailed statistical analysis plan, including which outcomes were tested, the order of testing, or any adjustment for multiple comparisons, is not reported in the registry record.
Multiplicity arises when several outcomes, time points, or statistical tests are examined. In general, conducting many tests can increase the chance of at least one apparently unusual result if no strategy for interpreting multiple comparisons is specified. This is a general consideration, not evidence that a particular multiplicity problem occurred in this study. Without posted analyses and a stated plan, the extent to which multiplicity was addressed cannot be evaluated.
The registry record does not report missing endpoint data, the number with a CI measurement at 34 weeks gestational age, or how missing measurements were handled. It also does not describe an analysis population, such as whether analysis included all enrolled infants or only those with a measured endpoint. The enrollment field reports 32, while the arm description refers to 30 preterm infants; the record does not explain the difference. Neither figure should be assumed to be the endpoint denominator.
Missingness can affect interpretation if participants without measurements differ from those with measurements. General methods for handling missing data require assumptions about why values are absent and should be described alongside the analysis. No such assumptions or methods are reported in the registry record. Participant flow, exclusions, and sensitivity analyses are also not reported. Accordingly, the available record does not establish how representative any analyzed group would be of the enrolled participants.
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 |
|---|---|---|---|
| Use of Tortle Midliner | 0 | 32 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Use of Tortle Midliner | 0 of 32 |
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 |
|---|---|
| Use of Tortle Midliner | 1 of 32 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Use of Tortle Midliner |
|---|---|---|
| non-blanchable pressure ulcer | Investigations | 1 of 32 |
The adverse-event record lists 0 serious adverse events among 32 at risk. It lists 1 affected in the other adverse-event category among 32 at risk, and 0 deaths. The record does not list a serious adverse-event term, and it does not identify the event in the other category. Its timing, severity details, duration, and relationship to the Tortle Midliner are not reported in the registry record.
These entries describe recorded counts in the listed Tortle Midliner group. They are not a comparison of event rates between the intervention and standard care, because no separate standard-care arm is recorded. The “at risk” counts also should not be interpreted as proof that every participant had complete safety follow-up; follow-up details are not reported in the registry record.
A count of 0 serious events does not establish that serious harms are impossible or that the intervention is safer than another approach. The count is an observation within this study record, and its interpretation depends on the participants observed and the completeness of event collection. The record does not provide enough detail to characterize the other event or make comparative safety conclusions.
12. What the Result Does, and Does Not, Mean
The registry information establishes that a completed, single-group study of the Tortle Midliner was registered with cranial index at 34 weeks gestational age as its primary endpoint. It also records the study's stated interest in prevention and/or treatment of dolichocephaly in preterm infants. The endpoint definition and category threshold are described, but numerical outcome results are not reported in the registry record.
That distinction matters: a study's question and measurement do not answer the question without observed results and an analysis. The record lists 0 analyses and does not give the median CI, full range, an estimate of change, or a confidence interval. It is therefore not possible from the registry record to determine the direction or size of any change, or the precision of an estimate. The completed status should not be mistaken for a posted finding.
The record's stated comparative aim is not matched by a registered comparator arm. It lists a single group using the Tortle Midliner, despite the brief summary's reference to current standard of care. A single group can describe outcomes among those receiving the intervention, but without a suitable comparison it cannot show what outcomes would have been under standard care. This limits causal interpretation even if descriptive results were available.
The endpoint threshold and normative range provide context for CI, but they do not establish a result. The record defines dolichocephaly as CI below 76% and gives a normative range of 76-85% for prone and supine sleeping infants. No observed values or counts relative to the threshold are reported. It is not possible to assess whether participants' measurements fell within either category from the registry information.
The adverse-event counts are also limited to a single group and have little accompanying detail. They should not be treated as a comparison of safety or as proof of absence of harm. In sum, the record documents an intervention, a population of interest, and a primary measure, but does not supply the analyses needed to judge effectiveness, precision, or comparative safety.
13. Why This Trial Matters Statistically
This study is statistically notable because its stated aim is comparative, while its registered design is single-group. That difference illustrates why the intended question and the structure of the data must be considered together. A study can state a comparison as its objective, but a comparison requires information from an appropriate comparator group or another clearly specified design that supports the contrast. The registry record lists no standard-care arm.
The record also distinguishes enrollment from the arm description: enrollment is 32, while the intervention description refers to 30 preterm infants. This is a reminder that a registered enrollment figure does not necessarily equal the number with a completed endpoint or the analysis population. Because participant flow and analysis denominators are not reported, the relationship among these counts cannot be resolved from the record.
The primary measure is a continuous ratio with an explicitly stated clinical threshold and normative range. That combination raises useful statistical questions about whether an analysis should describe the full distribution, assess values relative to a threshold, or both. The registry record specifies the median and full range for the primary endpoint, but does not report the outcome values or any analysis. Thus, the endpoint definition alone cannot show how participants' measurements were distributed.
Finally, the record is marked completed but lists 0 analyses. This distinction is important when reading trial registries: study status, protocol objectives, and posted results are separate kinds of information. The record can clarify what investigators intended to measure, while leaving the statistical findings unavailable. Recognizing that boundary prevents an aim, an endpoint definition, or an adverse-event count from being mistaken for an estimate of comparative benefit or harm.
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.
Several limitations specific to this study constrain interpretation of the registry record. First, the study is listed as single-group, with use of the Tortle Midliner as the only registered arm. Although the brief summary describes comparison with current standard of care, no separate comparator is recorded. This prevents a direct comparison based on the registered design and limits causal interpretation.
Second, numerical results for the primary endpoint are not reported. The record identifies CI at 34 weeks gestational age and specifies median with full range, but does not provide those values, a confidence interval, or an analysis. The record lists 0 analyses. The stated completion status therefore cannot be treated as a reported effectiveness result.
Third, enrollment is recorded as 32, while the arm description says the study will include 30 preterm infants. The registry record does not explain the difference. It also does not report how many participants had a measurement at the primary time point, whether any were excluded, or how missing measurements were handled. The analyzed population and endpoint denominator are consequently unclear.
Fourth, details about intervention delivery, adherence, participant follow-up, and measurement procedures beyond the CI definition are not reported in the registry record. The record does not provide an analysis plan, multiplicity approach, or information about interim analyses. These omissions limit assessment of how the study was conducted and how any analyses would have been selected or interpreted.
Finally, the adverse-event listing supplies counts but little descriptive detail. The other event is not identified, and timing, follow-up completeness, and attribution are not reported. With no comparator arm, these data do not support comparative safety conclusions. These limitations describe gaps in the registry information; they do not establish that a particular outcome or event occurred beyond the counts recorded.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Treatment of Cranial Molding Deformities in Preterm Infants — NCT02366936.
- Registry record last updated 2024-04-15; status last verified 2017-03.
- Results first posted 2017-04-18.
- 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
The registry record describes an interventional, longitudinal, single-group study of the Tortle Midliner in preterm infants, sponsored by Duke University. It is marked completed, with start recorded as 2015-06 and primary completion as 2016-06. Enrollment is 32, while the arm description refers to 30 infants; the difference is not explained.
The primary endpoint is cranial index at 34 weeks gestational age, summarized as median with full range. The record defines dolichocephaly as CI below 76% and gives a normative CI range of 76-85% for prone and supine sleeping infants. Although the brief summary states an aim to compare the intervention with current standard of care, no separate comparator arm is recorded.
Numerical outcome results are not reported in the registry record, which lists 0 analyses. The adverse-event record lists 0 serious events, 1 affected in the other event category, and 0 deaths. Details about that other event and comparative safety are not reported.