How Often does this happen with Auvi-Q?

https://www.youtube.com/watch?v=AerwbhkJjB8

Needle becomes lodged into the thigh.

 

The needle retracts back into the device.

 

It is difficult to determine how often the needle does not retract and stays inside the thigh of the injectee, since the majority of injectors are disposed and never administered due to epi drug expiration. Only in an emergency situation will the patient know if it works as designed.