Bacterial or other microbial infection of the vertebral bone body within the cervical spine (C1–C7), classified under other inflammatory spondylopathies.

Documentation tips

What should appear in the chart to support M46.22.

Source · Editorial brief grounded in 5 cited references ↓

• Record the specific cervical level(s) involved (e.g., C4–C5) and the imaging modality that confirmed bone involvement — MRI with contrast is the gold standard.
• Document the causative organism and sensitivity results when culture data is available; this supports medical necessity for prolonged antibiotic therapy and may affect DRG assignment.
• Note whether osteomyelitis is hematogenous, contiguous spread, or post-procedural in origin, as etiology affects additional code assignment (e.g., postprocedural complication codes).
• Capture all relevant comorbidities — diabetes mellitus, immunosuppression, IV drug use, renal failure — to maximize accurate CC/MCC assignment alongside M46.22.
• If surgical debridement or fusion is performed, confirm the operative report specifies the cervical region to validate the diagnosis code against the procedure code.

Related CPT procedures

Procedure codes commonly billed with M46.22. Linking the right diagnosis to the right procedure is what establishes medical necessity.

Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis

Common coding pitfalls

The recurring mistakes coders make with M46.22 and adjacent codes.

Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓

• Using M46.20 (site unspecified) when the operative report, MRI, or provider note clearly names the cervical region — always code to the highest specificity documented.
• Confusing vertebral osteomyelitis (M46.22) with cervical disc space infection (M46.32); these are separate diagnoses with different MS-DRG implications and must not be used interchangeably.
• Missing the M46.21 vs. M46.22 distinction: occipito-atlanto-axial involvement at C1–C2 specifically documented as that articulation codes to M46.21, not M46.22.
• Failing to code the underlying infectious organism as an additional code when identified — the Tabular List includes a Use Additional Code note for the causative organism (B95–B97).
• Defaulting to an S-code (traumatic vertebral injury) when the presentation is infectious — osteomyelitis without a trauma mechanism belongs in the M-code range, not the injury chapter.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

Sibling codes

Other billable codes under M46.2 (laterality / anatomic variants).