Why does the FDA take a long time to approve needed medical devices?
The types of medical devices you mention (artificial discs and stents) are surgically placed in patients' bodies for long periods of time. While in a person's body, the device is expected to withstand conditions within the body without deteriorating, breaking down, causing complications to the person's condition or causing a reaction or new health condition, all while serving the purpose for which it was implanted. Given the expectations and performance standards that are present by the physicians, surgeons, therapists, patients, and families, the Food and Drug Administration requires extensive testing and approvals before allowing any device to be put into use. To grant permission for a new design of device to be used without giving it detailed evaluations under all the circumstances it might be expected to encounter under use would go against the Food and Drug Administration's stated purpose - to act as "a team of dedicated professionals working to protect, promote and enhance the health of the American people."