Revival

In cryonics, revival, or reanimation is successful resuscitation of a cryonics patient after their long-term care (cryostasis). Biological revival and mind uploading are proposed ways for revival. As of 2022, no cryonics patients have been revived.

Requirements
According to the Cryonics magazine, successful revival of cryonics patients will require three distinct technologies: 1) a cure for the disease that put the patient in a critical condition prior to cryopreservation, 2) biological or mechanical cell repair technologies that can reverse any injury associated with the cryopreservation process and long-term care at low temperatures, 3) rejuvenation biotechnologies that restore the patient to good health prior to resuscitation. Or it will require some entirely new approach such as 1) mapping the ultrastructure of cryopreserved brain tissue using nanotechnology, and 2) using this information to deduce the original structure and repairing, replicating or simulating tissue or structure in some viable form so the person "comes back."

According to Emil Kendziorra, in total, four types of damage will need to be repaired: 1) damage from before circulatory arrest (e.g. due to diseases or general degradation), 2) damage occurring after circulatory arrest due to ischemia (e.g. apoptotic and necrotic processes), 3) damage from the cryopreservation itself (e.g. toxicity, ice nucleation, etc.), and 4) damage from the warming and reperfusion procedures (e.g. ice nucleation). Some of the repairs probably need to be done at sub-zero temperatures.

Problems
Possible post-revival problems include culture shock, survivor guilt, and body dysmorphic disorder.