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M48.51XA vs M84.4

M48.51XA (Collapsed vertebra, not elsewhere classified, occipito-atlanto-axial region, initial encounter for fracture) compared with M84.4 (Pathological fracture, not elsewhere classified), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.

Relationship

Conflict

Excludes1 conflict

M48.51XA
Collapsed vertebra, not elsewhere classified, occipito-atlanto-axial region, initial encounter for fracture
↔
M84.4
Pathological fracture, not elsewhere classified

Not coded here — these two are mutually exclusive.

“pathological fracture NOS (M84.4-)”

An Excludes1 note means the two conditions cannot occur together, so the pair should not be reported for the same encounter. The sole exception is when the conditions are documented as unrelated to each other.

Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a

Conflict

Excludes1 conflict

M84.4
Pathological fracture, not elsewhere classified
↔
M48.51XA
Collapsed vertebra, not elsewhere classified, occipito-atlanto-axial region, initial encounter for fracture

Not coded here — these two are mutually exclusive.

“collapsed vertebra NEC (M48.5)”

An Excludes1 note means the two conditions cannot occur together, so the pair should not be reported for the same encounter. The sole exception is when the conditions are documented as unrelated to each other.

Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a

Can these codes be reported together?

No — do not report together. M48.51XA carries an Excludes1 note covering M84.4: “pathological fracture NOS (M84.4-)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

No — do not report together. M84.4 carries an Excludes1 note covering M48.51XA: “collapsed vertebra NEC (M48.5)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Side by side

M48.51XACollapsed vertebra, not elsewhere classified, occipito-atlanto-axial region, initial encounter for fractureM84.4Pathological fracture, not elsewhere classified
Billing statusBillableNon-billable header
ClassificationM00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)
DefinitionCollapsed vertebra, not elsewhere classified, occipito-atlanto-axial region, initial encounter for fracture is a billable ICD-10-CM diagnosis code (M48.51A).Pathological fracture, not elsewhere classified is a non-billable ICD-10-CM category code (M84.4).
7th characterThe appropriate 7th character is to be added to each code from subcategory M48.5:The appropriate 7th character is to be added to each code from subcategory M84.4:
Includes—
Chronic fracture
Pathological fracture NOS
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Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources