Q7 Modifier

“We are inquiring about the use of the Q7 modifier when billing nail and callus debridement with Medicare. We are aware of the changes to the LCD with diagnosis codes. When billing nail debridement CPT 11721 and callus debridement CPT 11056, we are submitting diagnosis codes Z89.412 and Z89.422, (acquired absence of toe) with a Q7 modifier to show “non-traumatic amputation of a foot or an integral skeletal part of the foot.” Now we are being told by Medicare that per the LCD, we cannot bill those diagnosis codes even with a Q7 modifier. Should we be billing with a different modifier?”