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 Clinical Outcomes of the Trinica(R) Anterior Lumbar Plate: Fixed Screws vs. Variable Screws (NCT00762723), a randomized na study. The primary outcome is Clinical Outcomes (Oswestry Disability Index, SF-12, Numeric Pain Rating Scale, Surgeon Assessment, Patient Self Assessment, Radiological Assessment).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00762723 |
| Phase | NA |
| Condition | Degenerative Disc Disease, Spinal Stenosis, Spondylolisthesis |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 19 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Zimmer Biomet |
| Results posted | Yes |
2. Clinical Question
Population
The registry lists degenerative disc disease, spinal stenosis and spondylolisthesis as the conditions of interest. The device is described as a supplemental fusion device for the lumbar or sacral spine, from L1-S1, used with an interbody device to address instability. Eligibility criteria and participant characteristics are not reported in the registry record, so the enrolled population cannot be described more specifically.
Intervention
Participants were assigned to a configuration of the Trinica Anterior Lumbar Plate System. The fixed-screw group received fixed screws only; the variable-screw group received variable screws only; and the hybrid group received 2 fixed-angle screws with 2 variable-angle screws.
Comparator
The comparison was among the three screw configurations: fixed only, variable only, and hybrid. The registry describes a randomized, parallel-group study with no masking. The randomization procedure and any allocation concealment methods are not reported in the registry record.
Primary question
The primary question was whether clinical outcomes differed by screw configuration. The registry names the Oswestry Disability Index, SF-12, Numeric Pain Rating Scale, surgeon assessment, patient self-assessment and radiological assessment, and describes fusion assessment. Outcomes were scheduled from pre-operative and operative assessments through follow-ups at 3 Months, 6 Months, 12 Months, and 24 Months. The registry states that the data were not analyzed because the study stopped due to slow enrollment, so it does not establish a comparative outcome result.
3. Trial Design
This was a randomized, open-label, parallel-group device study sponsored by Zimmer Biomet. The registry lists the phase as NA. Its title identifies a comparison of fixed-angle, variable-angle and hybrid screw configurations for the Trinica Anterior Lumbar Plate System. The device is described as a commercially available supplemental fusion device for use in the lumbar or sacral spine, intended to supplement an interbody device with anterior plate fixation.
The three groups received the same named plate system with different screw configurations. Group 1 used fixed screws only. Group 2 used variable screws only. Group 3 used a hybrid configuration of 2 fixed-angle screws with 2 variable-angle screws. The registry describes randomization, but the sequence-generation method, allocation concealment, and details of how participants were assigned are not reported in the registry record. Masking was listed as none; the record does not describe whether any particular outcome assessor was masked.
Enrollment was 19. The study start is listed as 2008-02, and primary completion as 2012-09. Its status is terminated. The registry attributes the lack of analyzed outcome data to the study stopping because of slow enrollment. It does not report the reason for termination in greater detail, or how many participants completed each scheduled assessment.
The clinical outcome schedule included pre-operative and operative assessments and follow-ups at 3 Months, 6 Months, 12 Months, and 24 Months. The listed clinical domains included disability, general health status, pain, surgeon and patient assessments, and radiological assessment. The registry does not report a detailed protocol, eligibility criteria, participant demographics, or the statistical analysis plan. Consequently, the design can be described at the level of its randomized groups and intended assessments, but not in terms of operational or analysis procedures that are absent from the 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 | ALP With Fixed Screws | ALP With Variable Screws | ALP With Hybrid Screws |
|---|---|---|---|
| STARTED | 5 | 11 | 3 |
| COMPLETED | 0 | 6 | 0 |
| NOT COMPLETED | 5 | 5 | 3 |
Reasons for not completing this period:
| Reason | ALP With Fixed Screws | ALP With Variable Screws | ALP With Hybrid Screws |
|---|---|---|---|
| Study Terminated slow enrollement | 5 | 5 | 3 |
Analysis population for the primary outcome, as defined in the registry: Data not analyzed because study was stopped due to slow enrollment.
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 | Group 1 | Group 2 | Group 3 | Total |
|---|---|---|---|---|---|
| Participants analysed | 5 | 11 | 3 | 19 | |
| Age, Continuous | Years | 54 (45 to 66) | 51 (35 to 74) | 45 (33 to 55) | 51 (33 to 74) |
| Sex: Female, Male: Female | Participants | 1 | 6 | 1 | 8 |
| Sex: Female, Male: Male | Participants | 4 | 5 | 2 | 11 |
6. Primary Endpoint
The registry lists the primary outcome as Clinical Outcomes (Oswestry Disability Index, SF-12, Numeric Pain Rating Scale, Surgeon Assessment, Patient Self Assessment, Radiological Assessment), measured over Pre-operative, Operative; Follow-ups at 3 Months, 6 Months, 12 Months, and 24 Months.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary outcome is titled as clinical outcomes, with the Oswestry Disability Index, SF-12, Numeric Pain Rating Scale, surgeon assessment, patient self-assessment and radiological assessment named as components. The registry’s description identifies fusion assessment. These measures represent different kinds of information: disability and health-status questionnaires, a pain rating, assessments by the surgeon and participant, and radiological evaluation. Considered together, they were intended to characterize clinical status and fusion rather than a single isolated outcome.
Such domains can be relevant in a device study because a radiological finding and a participant’s reported experience are not interchangeable. Functional questionnaires and pain ratings describe patient-reported aspects of health, while surgeon and radiological assessments provide other perspectives. This is a general explanation of why trials may include multiple outcome types; the registry does not state the rationale for selecting each measure or how the measures were to be combined.
The scheduled assessment times were pre-operative, operative, and follow-ups at 3 Months, 6 Months, 12 Months, and 24 Months. The registry does not specify scoring rules, score direction, clinically meaningful thresholds, or a single summary measure. It also states that the data were not analyzed because the study was stopped due to slow enrollment. Therefore, no analyzed primary outcome estimate or comparison between screw configurations is reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The main interpretive point is the absence of analyzed clinical outcome data. The registry identifies a randomized comparison of fixed, variable and hybrid screw configurations, but explicitly says the data were not analyzed because the study stopped due to slow enrollment. No comparative estimate, confidence interval, or significance test for the named clinical outcomes is reported in the registry record. Thus, the record does not provide an estimate of how the configurations compared on disability, health status, pain, assessments, or fusion.
Enrollment was 19, and the study status is terminated. This describes a study that did not reach a reported clinical-outcome analysis; it is not evidence that the configurations had similar outcomes or that one configuration was better. When there is no analyzed effect estimate, there is no basis in the posted results for judging the direction or precision of a clinical difference. A reader should not interpret the absence of outcome results as a finding of no effect.
The posted safety counts are descriptive. In Group 1, 1 of 5 participants at risk was affected by a serious adverse event; Group 2 reports 0 of 11, and Group 3 reports 0 of 3. For other adverse events, the counts are 4 of 5 in Group 1, 4 of 11 in Group 2, and 0 of 3 in Group 3. These counts do not substitute for the missing clinical-outcome analysis. They also should not be treated as precise comparative estimates: the groups are small, and the registry does not provide inferential analyses or further event details sufficient to characterize differences reliably.
The registry lists “Cervical Disc Disease” at 20.0% as the top serious adverse event term. It does not provide enough context in the record to connect that term to a particular group or explain its relation to the affected-participant counts. Deaths are not reported in the registry record. The adverse-event data therefore require cautious, descriptive reading and cannot resolve the unanswered primary clinical question.
In general, randomized allocation is intended to support fair comparison by reducing systematic differences in how participants enter groups. That design feature does not create an outcome result when analyses are absent, and it cannot guarantee balance in a small enrolled study. The registry does not report baseline characteristics or enough analysis details to assess group balance or the consequences of incomplete follow-up.
9. Statistical Methods Explained
The statistical interpretation is constrained first by the status of the outcome analysis. The registry says the clinical outcome data were not analyzed because the study was stopped due to slow enrollment. Consequently, there is no reported treatment-effect estimate for the named primary outcome, and no reported confidence interval or hypothesis-test result to interpret. Statistical methods can explain how such results would ordinarily be assessed, but those general concepts must not be mistaken for analyses conducted in this study.
What randomization contributes
In general, randomization assigns participants to groups using a chance-based process. Its purpose is to reduce systematic differences between groups, including differences related to measured and unmeasured characteristics. It does not ensure that groups will be identical, particularly when enrollment is limited. Baseline characteristics and the randomization procedure are not reported in the registry record, so the effectiveness of allocation cannot be assessed from the available information. The study is described as open-label, meaning masking was listed as none; the record does not give further details about who knew each assignment or whether outcome assessors had separate procedures.
What an outcome estimate would describe
For an analyzed comparison, an estimate would quantify the observed difference between configurations for a defined outcome and assessment time. A confidence interval is a range calculated by a statistical method to express the uncertainty around an estimate. In general, a narrower interval indicates greater precision, while a wider interval indicates less precision. Neither an estimate nor an interval is reported for the clinical outcomes in this record. The outcome title covers multiple measures and the record gives several assessment times, so a complete analysis would need to specify which measure and time point each estimate addressed. Those specifications are not reported.
Multiple outcomes and time points
In general, evaluating many outcomes or time points creates multiplicity: the more comparisons made, the greater the chance of finding an apparently unusual result purely through repeated testing. Statistical plans may address this by identifying a primary comparison in advance or by adjusting interpretation across tests. The registry record lists several outcome domains and follow-up times but does not report a multiplicity strategy. Because the outcome data were not analyzed, there are no reported tests to which an adjustment could be applied or assessed.
Planning illustrations and observed evidence
The registry includes a planning-illustration description based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects expressed as a stated fraction of the observed effect. It explicitly distinguishes this illustration from the trial’s own design. Such calculations are planning exercises, not results from participants and not observed power. The record does not report the trial’s own sample-size justification or the output needed to interpret any particular planning scenario. Since the clinical outcome data were not analyzed, the record does not establish an observed clinical effect to serve as an outcome finding.
Why over-dispersion can matter
As a general statistical concept, over-dispersion occurs when observed variability is greater than a model assumes. If a model understates variability, its uncertainty estimates may be too small and its tests may appear more decisive than warranted. The registry record does not describe a count model, an over-dispersion assessment, or any fitted analysis of the clinical outcomes. This concept therefore does not describe a method known to have been used in this study; it is relevant only as general context for interpreting analyses when their model assumptions are reported.
What cannot be inferred
The registry does not report a detailed statistical analysis plan, analysis population, missing-data method, or handling of repeated measurements. It also does not report how clinical scores would have been summarized or how the three configurations would have been compared. These omissions matter because choices about population, missing observations, outcome definition, and repeated assessments can affect estimates and their uncertainty. Without an analyzed endpoint and those methods, a reader cannot reproduce or evaluate a comparative clinical result. The defensible interpretation is limited to the intended randomized comparison, its listed assessments, the reported safety counts, and the stated absence of analyzed clinical outcomes.
10. Multiplicity, Missing Data and Analysis Populations
The registry names several clinical outcome domains and several scheduled assessment times. In general, testing multiple outcomes and time points can increase the chance of at least one apparently noteworthy result arising by chance. A prespecified primary comparison, a hierarchy of outcomes, or an adjustment method can help define how multiple results are interpreted. The statistical plan and any multiplicity strategy are not reported in the registry record. Since the clinical data were not analyzed, no reported multiplicity adjustment or unadjusted comparison can be evaluated.
Missing-data methods are also not reported in the registry record. The record does not state how many participants completed each follow-up, whether any assessments were unavailable, or whether an approach such as imputation or a repeated-measures model was planned. Slow enrollment is given as the reason the study stopped and the data were not analyzed; it does not by itself establish how complete the measurements were for enrolled participants.
The analysis population is not reported in the registry record. It is not specified whether analyses would have included all randomized participants, only participants who received the device, or a different defined population. The record also does not describe exclusions, protocol deviations, or how participants would have been handled if they did not complete follow-up. These details affect what a result would represent. With no analyzed clinical outcome and no stated analysis population or missing-data plan, the intended comparisons cannot be reconstructed from the registry information.
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 |
|---|---|---|---|
| Group 1 | 1 | 5 | 20.0% |
| Group 2 | 0 | 11 | 0.0% |
| Group 3 | 0 | 3 | 0.0% |
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 |
|---|---|
| Group 1 | 4 of 5 |
| Group 2 | 4 of 11 |
| Group 3 | 0 of 3 |
Most frequent serious adverse event terms
| Event term | Organ system | Group 1 | Group 2 | Group 3 |
|---|---|---|---|---|
| Cervical Disc Disease | Musculoskeletal and connective tissue disorders | 1 of 5 | 0 of 11 | 0 of 3 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Group 1 | Group 2 | Group 3 |
|---|---|---|---|---|
| Fall | General disorders | 2 of 5 | 1 of 11 | 0 of 3 |
| Low Back Pain | Musculoskeletal and connective tissue disorders | 1 of 5 | 2 of 11 | 0 of 3 |
| Illeus | Gastrointestinal disorders | 1 of 5 | 0 of 11 | 0 of 3 |
| Spinal Stenosis | Musculoskeletal and connective tissue disorders | 1 of 5 | 0 of 11 | 0 of 3 |
| Infection | Infections and infestations | 0 of 5 | 1 of 11 | 0 of 3 |
Serious events with the highest arm-level rate: cervical disc disease (20.0%).
The adverse-event figures are participant counts, not comparative estimates adjusted for differences among groups. For serious adverse events, Group 1 reports 1 affected participant among 5 at risk, Group 2 reports 0 among 11, and Group 3 reports 0 among 3. For other adverse events, Group 1 reports 4 among 5, Group 2 reports 4 among 11, and Group 3 reports 0 among 3. These figures describe what the registry reports for the listed groups; they do not establish that event experience differs because of screw configuration.
The number at risk varies across groups, and the group counts are small. A count of zero in a group is not proof that an event could not occur, while a count in another group does not by itself establish a comparative safety pattern. No uncertainty intervals or statistical comparisons are reported in the registry record. The record lists “Cervical Disc Disease” at 20.0% as the top serious adverse event term, but does not specify its group in the information recorded. Deaths are not reported in the registry record. These safety entries should therefore be read descriptively, alongside the record’s statement that the clinical outcomes were not analyzed.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized, open-label study was planned to compare three screw configurations for the Trinica Anterior Lumbar Plate System. It also establishes that enrollment was 19, that the study was terminated, and that the registry attributes the lack of analyzed clinical outcome data to slow enrollment. The intended clinical assessments covered disability, health status, pain, surgeon and patient assessments, and radiological assessment, with fusion assessment described.
What the record does not establish is a comparative clinical result. It reports no analyzed estimate showing how fixed, variable, or hybrid configurations compared on the named measures. There is no reported confidence interval or hypothesis test for those outcomes. The absence of an analysis should not be interpreted as evidence that the configurations performed alike, nor as evidence that one was superior. It means the primary clinical question remains unanswered by the results recorded.
The adverse-event entries provide descriptive counts for participants affected, but do not supply the detail or statistical comparison needed to draw a robust comparative conclusion. The number at risk differs by group, the groups are small, and the record does not report uncertainty estimates. The listed serious-event term and the absence of a reported death count should be interpreted as registry entries, not as a complete characterization of risk.
In general, a randomized comparison can support causal interpretation when the analysis is adequately reported and the design and follow-up are handled appropriately. Here, the lack of analyzed outcomes and missing analysis details prevent such an interpretation for clinical benefit or comparative safety. The record is informative about the study’s question, design, assessments, termination, and posted adverse-event counts, but not about whether any screw configuration produced better clinical outcomes.
13. Why This Trial Matters Statistically
This trial matters statistically because its intended comparison is clear while its clinical outcome analysis is absent. It posed a randomized comparison among fixed, variable and hybrid screw configurations, and specified multiple clinical domains across scheduled follow-up. Yet the registry states that data were not analyzed because the study stopped due to slow enrollment. That distinction is important: a well-defined question and an outcome schedule do not by themselves produce evidence about the answer.
The record also illustrates why enrollment and analysis details matter for precision. With enrollment of 19 across the study, the adverse-event counts are descriptive and the record supplies no uncertainty estimates for the clinical outcomes. Small groups can yield imprecise comparisons, and randomization does not remove uncertainty when few participants are enrolled. The registry does not report a sample-size justification for the trial, so it is not possible to assess its planned ability to estimate a clinical difference.
The multiple outcome domains and follow-up times also make a prespecified analysis plan important. In general, defining the primary comparison and handling multiple assessments helps prevent selective emphasis on whichever result appears most favorable. The record does not report these analysis details, and the absence of analysis means there is no result by which to assess them.
Finally, the registry’s explicit statement about slow enrollment distinguishes lack of evidence from evidence of no difference. That is a useful statistical lesson in reading terminated studies: the design may identify what investigators intended to learn, while the available record may not contain an estimate capable of answering the question. The posted information supports a careful description of the trial and its limitations, not a conclusion about comparative clinical performance.
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 most consequential limitation is that the registry says the clinical outcome data were not analyzed because the study stopped due to slow enrollment. There are no reported comparative results for the primary outcome, so the intended clinical question cannot be answered from this record. Enrollment was 19, and the registry lists the study as terminated. It does not report whether outcome data were collected from all enrolled participants or how many reached each follow-up.
The primary outcome title spans several distinct measures, and the registry description identifies fusion assessment. It gives assessment times from pre-operative and operative through 3 Months, 6 Months, 12 Months, and 24 Months. However, it does not specify scoring rules, outcome definitions, score direction, thresholds, or how the measures and time points would be prioritized. This makes the intended endpoint less specific than a single fully defined outcome.
Further design and analysis details are absent. Eligibility criteria, participant characteristics, the randomization procedure, allocation concealment, the analysis population, missing-data handling, and a detailed statistical analysis plan are not reported in the registry record. The record also does not report a sample-size justification or an approach to multiple outcomes and time points. These gaps prevent assessment of baseline comparability, follow-up completeness, and the planned interpretation of any possible results.
The safety figures are limited to participant counts and do not include comparative statistical analyses or uncertainty estimates. The serious adverse-event term listed at 20.0% is not linked to a group in the registry information. Deaths are not reported in the registry record. Taken together, these limits mean the posted data support only a narrow descriptive account of study conduct and reported adverse-event counts, not a comparative clinical conclusion.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Clinical Outcomes of the Trinica(R) Anterior Lumbar Plate: Fixed Screws vs. Variable Screws — NCT00762723.
- Registry record last updated 2014-04-17; status last verified 2014-03.
- Results first posted 2014-03-26.
- 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
NCT00762723 is a randomized, open-label, parallel-group device study sponsored by Zimmer Biomet. It compared the Trinica Anterior Lumbar Plate System with fixed screws only, variable screws only, or a hybrid configuration of 2 fixed-angle screws with 2 variable-angle screws. The conditions listed are degenerative disc disease, spinal stenosis and spondylolisthesis. Enrollment was 19; the study started in 2008-02, had primary completion in 2012-09, and is listed as terminated.
The intended clinical outcomes included the Oswestry Disability Index, SF-12, Numeric Pain Rating Scale, surgeon assessment, patient self-assessment and radiological assessment, with fusion assessment described. Follow-ups were scheduled at 3 Months, 6 Months, 12 Months, and 24 Months. The registry says the data were not analyzed because the study was stopped due to slow enrollment. It reports group-specific serious and other adverse-event counts, but no analyzed comparative clinical outcome or statistical test. The registry record does not report a detailed statistical plan, analysis population, or missing-data method.