We have had a few kids come through it. The journey is very individual. Some have recovered quickly and successfully, with no further pain again. Others have had a hard time recovering, it we have never had a kid driven from the sport because of it.
The problem with stress fractures in the back, is they are often a result of long term stress on the back, not an acute injury. This means that there is an underlying problem and if the underlying problem in not addressed then it will not heal because as soon as activity starts again, the problems will begin again.
Quite often the cause is not gymnastics at all, but posture, especially when sitting at school. The gymnastics then adds to the stress on the back, which leads to the fractures. This is so hard to deal with because every day they will continue to sit and stand with poor posture, which will continue to aggravate the problem. These kids need to do vigilant exersices to improve their posture and often wear a brace at school.
Often the problem is caused by a weakness somewhere in their body such as a lack of flexibility in their shoulders or hip flexors, meaning every time they do a bridge or walkover, there is more pressure on their lumber spine. Or a lack of strength in the glutes. These issues need to be continually addressed.
Sometimes there is an underlying cause in the body itself, such as an inborn bone abnormality, which is minor but only comes to light after years of gymnastics.
As a coach, once you have had a kid with a stress fracture in their back, you have to always be vigilent and limited arching skills.