Portabella, did you work for a vet? This is what I am doing now. I am a part-time anesthesia technician at the biggest emergency hospital in the state. Well, I suggest you to discuss all the options with the doctor. From my own experience, I can say that cats generally do well with three legs.
I understand you are concerned with Puss Puss surviving anesthesia. Even if not... To go under the general anesthesia is actually the best way to go, the way I wish for myself when time comes.
Good luck again.