Modifier 59 for Add-On codes?

[JAMETH345]

When billing for 64490, 64491, and 64492, because the 91 and 92 are add-on codes, same procedure as 64490, but different levels of the spine, should modifier 59 be necessary? Aetna is saying 59 is necessary for 64492, but not necessary for 64490 or 64491, which doesn't make sense to me. I would appreciate any clarification for the general rules. I understand it can vary from one payer to another.

Thank you.

John Methgen, BS, CPC-A, CPB

 

[lindsey.hansen]

I think it's an Aetna issue because running it through encoder doesn't bring up any edits. And I have never seen an instance where a 59 gets added to an add on.