I was on a different side of that equation when I was a clinic assistant in a surgery practice. A decent chunk of my job was fighting with insurance companies to get them to cover medically necessary procedures. It was a plastic surgery practice that was part of an oncology group, so one of the surgeons mostly did melanoma surgery and the other mostly did breast reconstruction after mastectomy, and they both did some cosmetic and general plastic surgeries here and there. The insurance companies would do idiotic things like not need a formal prior authorization for a melanoma excision, but because the skin graft needed to repair the excision site technically counted as a "plastic surgery" by its CPT code, they would require a prior authorization for that.

One of my favorite things is when I got the insurance companies to cough up for medically necessary panniculectomies following drastic weight loss which heavily subsidized the "upgrade" to a tummy tuck/full abdominoplasty. The patient basically just had to pay the difference instead of paying for the whole thing. Our surgeons were really good at planning and coding procedures like that to help patients as much as possible.