True, but it's anime logic after all. Look at Kira after being shot like 30 times, Obito being crushed by boulder, Whitebeard's standing up death, etc. So Tsunade working to some degree only with her upper body is no big deal to me anywaysIf you look at it, main parts aren't destroyed (heart, brain).
Only the legs. But that's indeed a great of a blood loss.