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.
The COAST is a multi-center prospective study that will evaluate the safety and effectiveness of
the X-STOP in a population of patients with moderately impaired function. The primary study objective of the Condition of Approval Study (COAST) is to confirm that the two-year postoperative response rate in moderately impaired lumbar spinal stenosis patients who undergo X-STOP surgery will be equivalent to the overall success rates reported at two years postoperatively in a cohort of X-STOP patients in the IDE pivotal trial who were also moderately impaired at baseline. The secondary study objectives are: 1) to determine the treatment response rate at five years postoperatively, and to compare these results to the five-year results from the pivotal trial and 2) to evaluate the long-term safety outcomes compared to the results from the pivotal trial and to obtain further precision in the overall estimated percentage of rare but serious adverse events.
Study Population Description
The study population is comprised of patients aged 50 years and older who have lumbar
spinal stenosis, suffers symptoms of neurogenic intermittent claudication, have moderately impaired physical function, and are able to relieve their symptoms when they bend forward or flex their spines. This device is indicated for treatment of patients aged 50 or older suffering from neurogenic intermittent claudication secondary to a confirmed diagnosis of lumbar spinal stenosis (with X-Ray, MRI, and/or CT evidence of thickened ligamentum flavum, narrowed lateral recess and/or central canal narrowing). The X STOP is indicated for those patients with moderately impaired physical function who experience relief in flexion from their symptoms of leg/buttock/groin pain, with or without back pain, and have undergone a regimen of at least 6 months of nonoperative treatment. The X STOP may be implanted at one or two lumbar levels in patients in whom operative treatment is indicated at no more than two levels.
The sample size is 240 patients
Office visits are scheduled preoperatively, and at 6 weeks and 1, 2, 3, 4, and
5 years postoperatively. Clinical/neurological and radiographic examinations are performed during each office visit. A baseline patient history (including medication usage) is taken, and concomitant medications are recorded at each postoperative follow-up visit. In addition, patients are asked to complete the following questionnaires prior to consultation with their physicians or their staff: ZCQ, ODI, NRS, and SF-36 Health Survey. At the 2-, 3-, 4-, and 5-year office visit, patients are also asked two questions assessing the value of surgery and the overall improvement in quality of life postoperatively.
Followup Visits and Length of Followup
Safety and effectiveness data are assessed at baseline and annually through 5 years postoperatively. The
impact, if any, of the X-STOP on adjacent-level discs is evaluated by MRI at the 2- and 5-year postoperative follow-up visits. The treated and adjacent-level intervertebral discs of 200 enrolled subjects are graded using the Pfirrmann Rating System as visualized on T2-weighted spin echo MRI. The MRI images are archived by a core laboratory, and the images evaluated by two independent radiologists. Each patient will be followed for a total of 5 years.