The review process for FDA registration of medical devices in the United States typically involves the following steps:

1. Device Classification: The FDA first determines the classification of the device (Class I, II, or III) based on its intended use and the level of risk associated with it. This classification affects the regulatory pathway and requirements.

2. Establishment Registration and Device Listing: Manufacturers and importers must register their establishments with the FDA and list the devices they are producing or importing. This is done annually and through the FDA's FDA Establishment Registration and Device Listing systems.

3. Premarket Submission:

   • Class I Devices: Most Class I devices are exempt from premarket notification (510(k)) and approval.
   • Class II Devices: Most Class II devices require a 510(k) Premarket Notification, where the manufacturer must demonstrate that the device is substantially equivalent to a device already on the market.
   • Class III Devices: Class III devices generally require Premarket Approval (PMA), which involves a comprehensive review of clinical data, manufacturing processes, and labeling to ensure the device is safe and effective.

4. FDA Review of Submission:

   • 510(k) Review: If the device requires a 510(k) submission, the FDA will review the provided data to assess substantial equivalence to a legally marketed device. If the FDA agrees, the device can be marketed.
   • PMA Review: For Class III devices, a more extensive review process is involved. The FDA evaluates clinical trial data, manufacturing processes, and labeling. The device undergoes a more thorough evaluation before approval.

5. FDA Decision:

   • If the device meets all the necessary regulatory requirements, the FDA issues an FDA clearance (for 510(k)) or FDA approval (for PMA).
   • If the submission is incomplete or insufficient, the FDA may request additional information or reject the submission.

6. Postmarket Requirements: After approval or clearance, manufacturers must comply with ongoing FDA regulations, including reporting adverse events, maintaining manufacturing quality, and following recall procedures if necessary.

The overall process can vary in length depending on the device classification, the complexity of the device, and the submission type (510(k) or PMA).