Question: I'm having trouble distinguishing between codes 41010 and 41520. In what circumstances should I use each code? New Jersey Subscriber Answer: Each of these are surgical procedures on the lingual frenum. Similarly, each procedure involves an incision into the lingual frenum. The way to differentiate the two via an operative report is to examine both the type of incision and the reason for the incision. The physician will opt to perform 41010 (Incision of lingual frenum [frenotomy]) as a means of offering the patient a greater range of motion within the tongue. Physicians will most often perform this procedure on patients with a diagnosis of ankyloglossia, also known as tongue-tie. This is a congenital disease in which the lingual frenum is abnormally short and/or thick, resulting in restricted the movement of the tongue. A 41010 procedure simply involves an incision into the lingual frenum with or without the use of sutures. The provider might also perform a 41520 (Frenoplasty [surgical revision of frenum, eg, with Z-plasty]) procedure on patients with a diagnosis of ankyloglossia. With this procedure, the physician will make an incision, usually in the shape of a Z (Z-plasty technique), as a means of altering and rearranging the lingual frenum tissue. The end result is the same as 41010, in which the patient should experience a greater range of motion within the tongue. Ultimately, the main distinction between these two procedures is the type of incision. If the provider performs a routine incision without rearranging the tissue, then you will apply code 41010. On the other hand, if the provider performs an incision, such as a Z-plasty, in addition to rearranging the tissue as a means for greater tongue mobility, then you will opt for code 41520.