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ICD-10-PCS 2027 procedure code

0N850ZZDivision of Right Temporal Bone, Open Approach

✓ Valid for 2027O.R. procedure

Code unchanged since ICD-10-PCS took effect on October 1, 2015. Source: official FY2027 ICD-10-PCS release from CMS. Page updated September 29, 2026. About our data

About 0N850ZZ

0N850ZZ is the ICD-10-PCS code for a division procedure on the right temporal bone using an open approach. In ICD-10-PCS, division means cutting into a body part, without draining fluids and/or gases from the body part, in order to separate or transect a body part.

In plain terms, this corresponds to other craniotomy, the ICD-9-CM procedure title it maps to (01.24).

For a different body part, codes include 0N800ZZ (skull), 0N810ZZ (frontal bone), 0N830ZZ (right parietal bone), 0N840ZZ (left parietal bone), 0N860ZZ (left temporal bone), 0N870ZZ (occipital bone) and 16 more.

The same procedure with a different approach is coded 0N853ZZ (percutaneous) and 0N854ZZ (percutaneous endoscopic).

It is an operating-room procedure in the MS-DRG logic for DRG 023 (Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis with MCC or Antineoplastic Implant or Epilepsy with Neurostimulator), DRG 024 (Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis without MCC), DRG 025 (Craniotomy and Endovascular Intracranial Procedures with MCC), DRG 026 (Craniotomy and Endovascular Intracranial Procedures with CC) and DRG 027 (Craniotomy and Endovascular Intracranial Procedures without CC/MCC), under the surgical categories “Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis” and “Craniotomy and endovascular intracranial procedures”.

It has been valid since ICD-10-PCS took effect on October 1, 2015.

What each character means

1. Section
0Medical and Surgical
2. Body System
NHead and Facial Bones
3. Operation
8Division

Cutting into a body part, without draining fluids and/or gases from the body part, in order to separate or transect a body part

All or a portion of the body part is separated into two or more portions

Includes: Spinal cordotomy, osteotomy

4. Body Part
5Temporal Bone, Right
5. Approach
0Open

Cutting through the skin or mucous membrane and any other body layers necessary to expose the site of the procedure

6. Device
ZNo Device
7. Qualifier
ZNo Qualifier

Other versions of this procedure

MS-DRG v44.0 grouping

All DRGs →

Surgical MS-DRGs this procedure can group to, depending on the principal diagnosis's MDC.

ICD-9-CM equivalent

Converter →
  • 01.24Other craniotomyapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about 0N850ZZ

Is 0N850ZZ a valid ICD-10-PCS code for 2027?

Yes. 0N850ZZ is valid for inpatient procedures from October 1, 2026 through September 30, 2027.

Is 0N850ZZ an O.R. procedure?

Yes. 0N850ZZ is an O.R. procedure in MS-DRG v44.0.

What DRG does 0N850ZZ group to?

Depending on the principal diagnosis, 0N850ZZ can group to MS-DRG 023, MS-DRG 024, MS-DRG 025, MS-DRG 026 and MS-DRG 027.

What is the ICD-9 procedure code for 0N850ZZ?

The CMS GEMs map 0N850ZZ to ICD-9-CM 01.24 (Other craniotomy).