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ICD-9-CM
Procedure Codes
20.21

20.21

Incision of mastoid

The ICD-9 procedure code for incision of mastoid is 20.21.

Legacy code — retired October 1, 2015

Source: final official CMS ICD-9-CM release (Version 32, FY2014), Volume 3 procedure codes. ICD-9-CM was retired for U.S. billing on October 1, 2015. Informational only.

Data current as of FY2026 CMS/NCHS release. Not affiliated with or endorsed by CMS, HHS, or NCHS.

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