My surgery was on January 12th and I also had the BAHA attachment point implanted. The actual sound processor will probably not be attached until May.
My insurer is a PPO and I have received their letters, questioning pre-existing conditions and telling me that I was not eligible for coverage. In each case, I called the customer service number on the back of my insurance card, with good results. Make sure that you write down the date you called and the name of the person who talked to you. In each case, I was able to talk through the problem and receive assurance that I was eligible for insurance coverage and that they would correct their records.
After researching the on-line medical insurance contract on my office PC, I learned that sound processors were not included in the plan, but that was for 2006. Things could have changed in the 2007 contract and I am prepared to dial that customer service number as soon as I see a declination of coverage for the BAHA in any statement of benefits that is mailed to me. If this AN has taught me anything, it is to be patient and never give up hope. Hang in there!