Just to offer some clarification on the entire issue of insurance in general on this issue - ( I happen to work for a carrier)
1) If you work for a large employer - chances are your group is what is called self-funded, this means that your company is actually paying the claims, not the insurance carrier. The insurance carrier is just administering the claim. The employer will actually set the rules around what is and what is not covered. The company will also approve the process that the carrier uses to determine elligiblity for this type of procedure. Only in some states are their state mandated benefits. Thus, you can have two people with the exact same situation, both with the same insurance carrier's name on their card with very different situations. (I know for a fact that Union Pacific is self-funded)
2) BCBS is mentioned a number of times - All BCBS companies are not the same, they all carry the BCBS logo, which only means that they are a part of BCBS Association. BCBS of Illinios owns the BCBS in TX and NM. Empire is a seperate BCBS of its own. Wellpoint owns BCBS in Colorado, California, MO, and 10 other states (previously known also as Anthem BCBS).
3) So- if the company that you work for, or the fully-insured policy that you have approves the surgery, then it will go to the medical review. They will often deny the claim in the first go around, but it would definetely be worth appealing in all situations. Most of the time the first refusal is automatic and NOT a decision made by an individual, but a computer that is looking at a number of different factors. Once appealed, most companies send it to a medical review board where individuals actually evaluate and make a decision about the claim.
All companies and policies are different, take the time to put some research into it!
Hope this helps to understand the insurance side a little better.