What does this mean?

I am looking into lapband surgery.  I called my insurance company, gave them my group and member number and the CPT code for lapband surgery.  "Is it covered under my plan?"  Answer:  "Yes, as long as it's medically necessary."  Fine, great! Then I request my plan booklet from HR and here's what it says under "Exclusions": Treatment for obesity or services performed primarily for weight loss or control (including gastric bypass and gastric staplings); but this shall not exclude procedures that are necessary due to a specific condition caused by another disease. I have no idea what this means, and I'm an attorney and deal with arcane stuff all day long Does this mean it's excluded and what they told me on the phone was incorrect?  Does it mean I need a co-morbidity?  Or what?

Thanks, Paul.  It does seem very oddly worded to me.  It almost appears to say that if you have a disease that causes your obesity, then you are covered.  Which doesn't seem right.  I mean, obesity IS a disease that complicates or causes other conditions.  If I had a disease that caused obesity, then wouldn't they want me to treat the underlying disease? Guess it's time to call the insurance company back and figure it all out!