ICDcodes.org
FY2027

M51 vs S23.0

M51 and S23.0 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.

The official note, declared on S23.0
rupture or displacement (nontraumatic) of thoracic intervertebral disc NOS (M51.- with fifth character 4)
M51

Thoracic, thoracolumbar, and lumbosacral intervertebral disc disorders

Not billable
Chapter 13
Diseases of the musculoskeletal system and connective tissue
Section
M50-M54
S23.0

Traumatic rupture of thoracic intervertebral disc

Not billable
Chapter 19
Injury, poisoning and certain other consequences of external causes
Section
S20-S29
Indexed under
  • Rupture, ruptured › traumatic › intervertebral disc › thoracic

These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.

Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027