The First 18 Months Following Food and Drug Administration Approval of Lumbar Total Disc Replacement in the United States: Reported Adverse Events Outside an Investigational Device Exemption Study Environment

BACKGROUND Introduction of a new surgical technology may result in higher rates of adverse events compared with rates reported in the study performed to gain regulatory approval. The purpose of our study was to describe the incidence of reported adverse events during the first 18 months following US Food and Drug Administration (FDA) approval of the first lumbar arthroplasty device available in the United States and to discern data trends. METHODS Reports of adverse events submitted to the FDA in patients receiving the Charité artificial disc were reviewed and pooled by similarity. We analyzed 135 medical device reports filed with the FDA regarding the Charité artificial disc between October 26, 2004, and April 26, 2006. Sixteen reports were excluded for lack of information regarding cause or because described events were vague or unrelated to the procedure. RESULTS Rate of adverse events reported to the FDA as a percentage of devices of which the device manufacturer was aware had been dispensed at 6, 12, and 18 months following approval was 0.58%, 2.34%, and 2.13%, respectively. The adverse event reported most frequently through 18 months was anterior migration with reoperation (0.65%); other reported adverse events were, in decreasing order, sizing and malposition errors resulting in reoperation (0.36%), posterior element fracture resulting in reoperation (0.30%), major vascular injury requiring a blood transfusion (0.23%), and subsidence requiring reoperation (0.20%). Three non-device-related patient deaths were reported following FDA approval. The reported rate of sizing/malposition errors leading to reoperation of 0.36% was the same rate as that seen in the investigational device exemption (IDE) study of the Charité artificial disc. All other reported rates were lower than rates of the same events reported in the study. CONCLUSIONS Medical device reporting is an important yet highly anecdotal and incomplete event-tracking process. However, it is the principal means available in the United States for obtaining information on the clinical performance of a device after its approval for sale and does provide some data, albeit imperfect, in this regard. The cumulative medical device reports through the 18 months following FDA approval, measured against the number of devices dispensed, suggests a rate of adverse events that either tracks or is somewhat less than that reported in the IDE study. This suggests that a repeat of the "cage rage," a "lumbar arthroplasty rage," has not yet occurred.