Where’s Ruth G?
In the pic from ‘Clover Chronicle’ the neck is not shown. She would probably have a tracheotomy to connect to the ventilator (breathing machine) which would cause a throat scar once closed. The scar would remain unless she had a clone.
Medical Coma can be induced by several different drugs of small steady doses IV like insulin or phenobarbital. The IV can be inserted into one of the central blood veins to last longer (years). The brain waves slow down. The person can be revived mentally if the underlying cause of medical condition like pneumonia, can be treated.
As long as the heart continues to beat medicine can keep a “corpse” alive indefinitely. Have attended ventilated corpses in the past.
Medicine can also keep the heart pumping with drugs but have not seen it to work more than a week or so.
But the ventilator and coma drugs can continue forever as long as the heart, kidneys and Liver are functional.