That is an interesting topic. Medical Devices are categorized based on the risk associated with the usage of the device. The categorization is based on different parameters such as
1. The general regulatory controls:
General controls are the fundamental provisions that ensure the safety and effectiveness of regulatory devices. This regulatory control includes provision for adulteration, misbranding, device registration, repair or refund etc.
2. The special regulatory controls:
These are the additional controls to the general regulatory controls for reasonable safety and usability assurance that includes specific labeling such as usage methods, guidelines, recommendation etc.
3. The need of Pre Market Approval (PMA):
PMA is a process brought in practice by FDA (Food and Drug Administration) to review a medical device for safety and effectiveness evaluation. For class III medical devices, there a high level of risk associated.