In January 2005, the oversight responsibility of the Post-Approval Studies Program was transferred to the Division of Epidemiology (DEPI) of the Office of Surveillance and Biometrics (OSB)/Center for Devices and Radiological Health (CDRH).
The CDRH Post-Approval Studies Program encompasses design, tracking, oversight, and review responsibilities for studies mandated as a condition of approval of a premarket approval (PMA) application, protocol development product (PDP) application, or humanitarian device exemption (HDE) application. The program helps ensure that well-designed post-approval studies (PAS) are conducted effectively and efficiently and in the least burdensome manner.
CDRH has established an automated, internal tracking system that efficiently identifies the reporting status of active PAS studies ordered since January 1, 2005 based on study timelines incorporated in study protocols and agreed upon by the CDRH and applicants. This system represents CDRH's effort to ensure that all PAS commitments are fulfilled in a timely manner.
In addition, CDRH launched this publicly available webpage to keep all stakeholders informed of the progress of each PAS. The webpage displays general information regarding each PAS, as well as the overall study status (based on protocol-driven timelines and the adequacy of the data) and the applicant's reporting status for each submission due.
Julie Unger
Project Manager, Post-Approval Studies Program
Food and Drug Administration
10903 New Hampshire Ave
WO66-4206v
Silver Spring, MD
20993-0002
This is continuation of the IDE study, which was a multi-center, prospective, randomized, controlled clinical
trial. The objective of PAS is to evaluate the long-term safety and effectiveness of Prodisc -L Total Disc Replacement to spinal fusion surgery in the treatment of discogenic pain associated with Degenerative Disc Disease in the lumbosacral spine.
Study Population Description
Study population is as per device indication. The study population consists of all patients from
IDE study who were enrolled and treated without major protocol violation. This device is indicated for spinal arthroplasty in skeletally mature patients with degenerative disc disease (DDD) at one levelfrom L3-Sl. DDD is defined as discogenic back pain with degeneration of the disc confirmed by patient history and radiographic studies. These DDD patients should have no more than Grade I spondylolisthesis at the involved level. Patients receiving the PRODISC -L Total Disc Replacement should have failed at least six months of conservative treatment prior to implantation of the PRODISC Total Disc Replacement.
Sample Size
A total of 286 patients (161 randomized investigational subjects, 75 randomized control subjects, and 50
non-randomized investigational subjects) enrolled in the PAS
Data Collection
The outcome measures in the PAS include patient self-assessment on Oswestry score, SF-36, Pain and
satisfaction; physical & neurological examination and radiographic evaluation of the implanted level and adjacent segments. The composite overall success is defined as: - Oswestry score improves by at least 15% over baseline value;- SF-36 score will be improved; - Maintained or improved neurological parameters, i.e., motor, sensory, reflexes and straight leg raise tests; - No re-operations were required to modify or remove the implant (Prodisc -L group); no re-operations were required to modify the fusion site or correct a complication with an implant (Fusion group). - Radiological success as assessed by independent radiographic review.
Followup Visits and Length of Followup
The subjects were followed at 6 weeks, 3 months, 6 months, 12 months, 18 months
and 24 months post-operation in the PMA study. They will be followed annually after 24 month, up to 60 month post-operation in PAS.
Final Study Results
Actual Number of Patients Enrolled
161 randomized investigational subjects, 50 training investigational subjects, and 75 control subjects. Overall 286 patients
continued participation from the IDE study.
Actual Number of Sites Enrolled
17 sites were enrolled for the Post-Approval Study.
Patient Followup Rate
60.2%, 60.1% and 82.5% were the overall follow up rates at 36, 48, and 60 months, respectively.
Final Safety Findings
During the 3 years of the PAS, there were several AEs with higher occurrence in
the ProDisc randomized group compared to the fusion randomized group: infection/other non wound (4 vs. 1); back pain (18 vs. 4), pain ¿ back and lower extremities (10 vs. 5), surgery other (16 vs. 7).
All AEs involving pain considered together look definitely higher in the ProDisc randomized group.
Final Effectiveness Findings
At month 60 non-inferiority was demonstrated for Overall Success (p=0.0099) and Overall Success (Secondary Analyses)
(p=0.0101).
Study Strengths and Weaknesses
The main strength of the study is the randomized design. The main weakness of the
study is the relatively low follow up rate, especially during follow up visits before the final visit; this may partially hamper the validity of the randomized comparison, since loss to follow up may not be independent of randomization group as well as patients outcomes.
