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| General |
| Study Status |
Completed |
Application Number /
Requirement Number |
P060018 / PAS001 |
| Date Original Protocol Accepted |
07/16/2007
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| Date Current Protocol Accepted |
07/16/2007
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| Study Name |
Long-Term Study
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| Device Name |
PRESTIGE CERVICAL DISC SYSTEM
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| General Study Protocol Parameters |
| Study Design |
Randomized Clinical Trial
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| Data Source |
New Data Collection
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| Comparison Group |
Concurrent Control
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| Analysis Type |
Analytical
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| Study Population |
Transit. Adolescent B (as adults) : 18-21 yrs,
Adult: >21
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| Detailed Study Protocol Parameters |
| Study Objectives |
This is a prospective cohort to continue follow-up of the subjects who participated in (1) the IDE premarket study and (2) the continued access arm and metal ion study.
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| Study Population |
The study include IDE, CAS and metal ion study subjects. This device is indicated in skeletally mature patients for reconstruction of the disc from C3-C7 following single-level discectomy for intractable radiculopathy and/or myelopathy. Intractable radiculopathy and/or myelopathy should present with at least one of the following items producing symptomatic nerve root and/or spinal cord compression which is documented by patient history (e.g., pain [neck and/or arm pain], functional deficit, and/or neurological deficit), and radiographic studies (e.g., CT, MRI, x-rays, etc.): 1) herniated disc, and/or 2) osteophyte formation. The PRESTIGE 9 device is implanted via an open anterior approach.
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| Sample Size |
A minimum of 200 patients (minimum of 100 patients each from control and PRESTIGE groups) at 7-year follow-up
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| Key Study Endpoints |
A patient will be considered an overall success if all of the following conditions are met:
1. Postoperative Neck Disability Index score improvement of at least a 15-point increase from preoperative;
2. Maintenance or improvement in neurological status from preoperative;
3. Functional spinal unit height success;
4. No serious adverse event classified as implant associated or implant/surgical procedure associated; and
5. No additional surgical procedure classified as a "failure".
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| Follow-up Visits and Length of Follow-up |
Postoperative data will be collected at 3, 5, and 7 years
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| Interim or Final Data Summary |
| Interim Results |
Between initial surgery and the 60 months visit, there were 1098 adverse events (AEs) reported in 249 investigational patients (90.2%) and 932 AEs reported in 227 control patients (85.7%). Among SAEs (serious adverse events) in the investigational group there were a total of 256 SAEs reported in 127 patients (46.0%) and there were a total of 185 SAEs in 110 control patients (41.5%).
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| Actual Number of Patients Enrolled |
600 (100%)
|
| Actual Number of Sites Enrolled |
31 (100%)
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| Patient Follow-up Rate |
The sponsor was expected to follow a minimum of 200 patients (minimum of 100 patients each from control and PRESTIGE groups) through 7-year follow-up, at 31 study sites. The sponsor has followed-up
228 (84.8%) investigational and 199 (80.9%) control patients through year 7. However, the follow-up is lower, when availability of data on Functional Spinal Unit (FSU) if taken into account, n=168 (62.5%) and n=135 (54.9%) for the investigational and control patients, respectively.
There were
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| Final Safety Findings |
In terms of cumulative adverse events n=259 (97.7%) of investigational patients had an adverse event
during the study as compared to n= 232 (94.5%) of control patients (pWilcoxon=0.722). For neck the time-to-event analysis, the cumulative rate is 70.2% and 64.7% for the investigational and control groups, respectively, with pWilcoxon = 0.070.
Further, no adverse local tissue reactions (ALTR) were observed in 6 explanted investigational devices. However, four (n=4) explanted devices showed greater than anticipated wear rate (derived from bench studies).
In the metal ion group of the investigational device patients (n=34), the Chromium levels were higher than pre-operative levels, but about 41 fold less than undesired level (7 ng/ml)
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| Final Effect Findings |
The primary end-point for the study was overall success-a composite of safety and effectiveness. Hundred twenty two (n=122) out of 168 or 72.6% of investigational patients have reached overall success. In comparison, 81 (60%) out of 135 control patients have reached overall success, p (non- inferiority)<0.001. Please refer to the table below for additional information.
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| Study Strengths & Weaknesses |
This study provided much needed information on the Prestige long term (7-years) performance. However, the findings and interpretation of this study are limited due to the observed high loss to the follow-up. A total of 108 study subjects in the investigational group and 130 in the control group have missing data on the overall success with FSU at 84 months. Additionally, 64 study subjects in the investigational group and 83 in the control group have missing data for overall success without FSU at
84-month. Furthermore, 48 study subjects in the investigational group and 66 in the control group have no 84-month data. The high proportion of loss to follow-up can introduce bias in the rate estimates, possibly due to differences in loss to follow-up between patients with different overall success at 24- months. For example, study subjects who completed the PAS in Prestige group were more likely to have achieved overall success at 24-month; whereas, study subjects in the control group who did not achieve overall success at 24-month were more likely to complete the PAS. This suggests differential loss to the follow-up between treatment groups, which limits the interpretation of the study results. Trends for several of the other study outcomes were similar.
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| Recommendations for Labeling Changes |
Yes: Long term data on the device safety and effectiveness is available and the labeling should include additional information on the long term device performance; (2) Higher than predicted wear during bench testing was observed in the explanted devices after long-term use.
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