ICD-9-CM procedure code (retired)
01.21 — Incision and drainage of cranial sinus
ICD-9-CM was replaced by ICD-10 on October 1, 2015. These are the ICD-10-PCS equivalents from the CMS General Equivalence Mappings.
About ICD-9-CM 01.21
01.21 is an ICD-9-CM procedure code for incision and drainage of cranial sinus. ICD-9-CM was retired for U.S. claims on October 1, 2015, when ICD-10-PCS took over.
The CMS General Equivalence Mappings translate it to 4 ICD-10-PCS codes, such as 0N9000Z (Drainage of Skull with Drainage Device, Open Approach), 0N900ZZ (Drainage of Skull, Open Approach) and 0N9040Z (Drainage of Skull with Drainage Device, Percutaneous Endoscopic Approach). All of these are approximate matches, so review the record to pick the right one.
ICD-10-PCS equivalents
Common questions about 01.21
What is the ICD-10 code for ICD-9 01.21?
- The GEMs map 01.21 to ICD-10-PCS 0N9000Z, 0N900ZZ, 0N9040Z and 0N904ZZ.
GEMs are a translation aid, not a substitute for coding from the record. The 2027 ICD-10 code set has changed since the last GEMs release in 2018. Page updated September 29, 2026.