I remember Amber stated that they used an epidural on her during her hysterectomy. She said her legs were still numb afterwards. So they probably put her under a lighter sedation. Less risky that way.As far as I know, all anaesthesia suppresses respiration, and that's in healthy people. Throw in hundreds of pounds of extra weight, the pressure that puts on respiration, and sleep apnea, and it's a fair bet that she is too high risk for a long surgery. The anaesthetic could stop her breathing.
Most hysterectomy surgeries take one to two hours, and she was probably a hundred pounds lighter then, I'm open to correction.