@jimrichards . I don't know the cause of my left paralyzed diaphragm for sure, and it's not something I spend a lot of time thinking about. The damage to my phrenic nerve that caused it to be paralyzed might have been an auto accident, fall down a flight of stairs, chiropractic manipulation, another operation, a virus, immunizations, etc. If you haven't joined, I really recommend you join the facebook group for people with paralyzed diaphragms. There are over 950 people on it with paralyzed diaphragms, which is actually a pretty rare condition. I've learned so much from them about the condition, how to deal with symptoms, etc... and gotten wonderful support. Please let me know if you have other questions. Good luck! Nancy