M46.91 Unspecified inflammatory spondylopathy, occipito-atlanto-axial region

Billable ICD-10-CM code, FY2026.

Risk adjustment (HCC)

• CMS-HCC V22: HCC 40 — Rheumatoid Arthritis and Inflammatory Connective Tissue Disease
• ESRD V24: HCC 40

MS-DRG index

Defines the logic of DRG(s) 551-552 in MDC 08.

Approximate ICD-9-CM (GEMs)

• 720.9 Unspecified inflammatory spondylopathy (approximate)

Code annotations containing back-references to M46.91

Back-references to M46

• Type 1 Excludes: G55 Nerve root and plexus compressions in diseases classified elsewhere ("nerve root compression (due to) (in) spondylopathies (M46.-, M48.-)")

Diagnosis Index entries for M46.91

• Spondylopathy › inflammatory › occipito-atlanto-axial region

Nearby codes

• M46.87 Other specified inflammatory spondylopathies, lumbosacral region
• M46.88 Other specified inflammatory spondylopathies, sacral and sacrococcygeal region
• M46.89 Other specified inflammatory spondylopathies, multiple sites in spine
• M46.9 Unspecified inflammatory spondylopathy
• M46.90 Unspecified inflammatory spondylopathy, site unspecified
• M46.91 Unspecified inflammatory spondylopathy, occipito-atlanto-axial region (this code)
• M46.92 Unspecified inflammatory spondylopathy, cervical region
• M46.93 Unspecified inflammatory spondylopathy, cervicothoracic region
• M46.94 Unspecified inflammatory spondylopathy, thoracic region
• M46.95 Unspecified inflammatory spondylopathy, thoracolumbar region
• M46.96 Unspecified inflammatory spondylopathy, lumbar region