Breakfalls are very, very, very dangerous, no matter who you are, no matter how good you are at taking them. Terry Dobson once told me that he thought one of the reasons he was sick was due to taking so many when he was younger. That's part of the danger - the effects later in life. They are hard on the body, even when you do them right. Especially if you have spinal concerns, I personally would not do them.
Sensei, how do you handle those throws that entail a lock of the joint that would seem to require a break fall as defensive reaction?