2026 ICD-10-CM Diagnosis Code M46.81Other specified inflammatory spondylopathies, occipito-atlanto-axial region

ICD-10-CM Codes›M00–M99›M45-M49›M46

ICD-10-CM M46.81
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M46.81 is a billable ICD-10-CM diagnosis code for other specified inflammatory spondylopathies, occipito-atlanto-axial region. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 551 through 552. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Spondylopathies/spondyloarthropathy (including infective).

Code Identity

ICD-10-CM Code
M46.81
Billable Status
Yes — Valid for Submission
Code Describes
Other specified inflammatory spondylopathies, occipito-atlanto-axial region
Short Description
Oth inflammatory spondylopathies, occipt-atlan-ax region
Parent Code
M46.8
Other specified inflammatory spondylopathies

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM45-M49Spondylopathies
CategoryM46Other inflammatory spondylopathies
This CodeM46.81Other specified inflammatory spondylopathies, occipito-atlanto-axial region

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Spondylopathy
      • inflammatory
        • specified type NEC
          • occipito-atlanto-axial region

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MUS011
Spondylopathies/spondyloarthropathy (including infective)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Neck Injuries and Disorders

Any part of your neck - muscles, bones, joints, tendons, ligaments, or nerves - can cause neck problems. Neck pain is very common. Pain may also come from your shoulder, jaw, head, or upper arms.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert M46.81 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
720.89 Inflam spondylopathy NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About M46.81Overview

Is M46.81 (Other specified inflammatory spondylopathies) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other specified inflammatory spondylopathies, occipito-atlanto-axial region on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M46.81 group to?

When other specified inflammatory spondylopathies, occipito-atlanto-axial region is the principal diagnosis on an inpatient stay, it groups to MS-DRG 551, 552, with relative weights from 0.9613 to 1.6761 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M46.81?

Under the General Equivalence Mappings, other specified inflammatory spondylopathies, occipito-atlanto-axial region converts to ICD-9-CM 720.89 (inflam spondylopathy NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.