As a general comment, I have often encountered people frustrated by trying to interpret success rates. If someone speaks of a procedure having a 98% success rate a few other issues come into play. The first is how success is defined. A procedure to improve mobility may have a 98% success rate, but what if success is regarded as a 1% gain in mobility? Another problem that people seldom realize until they are on the wrong end is that even if a procedure does have a 98% success rate, if you end up in the 2%, then the procedure, for you, had a 100% failure rate.
I found myself dealing with a woman who was very upset the doctors lied to her. Her husband had a stroke and heart failure. He had spent 10 days in intensive care. The primary physician, the day after her husband was admitted, told her it would take a miracle for him to recover. Her complaint was that the doctors had spoken with her about pulling the life support. She insisted they had never told her how serious the situation was. You see, she regarded miracles as happening all the time.