Is nephrectomy a very common procedure?

Nephrectomy. It is done quiet often by urologists. They have many ways of doing it, including robotically, traditionally with an incision and even laprascopically (small incisions using a scope and other tools).
Yes. Nephrectomies are done for many reasons (most common is probably kidney cancer) and are done on a daily basis in nearly all large hospitals in the us. Many are done via laparoscope (no big incision, minimally invasive) and is generally a safe procedure, although not one i would wish anyone to have.