G55 vs M51
G55 and M51 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.
Nerve root and plexus compressions in diseases classified elsewhere
- Chapter 6
- Diseases of the nervous system
- Section
- G50-G59
- Neuritis › due to › herniation, nucleus pulposus (rheumatoid)
- Compression › nerve › root or plexus NOS › neoplastic disease
Thoracic, thoracolumbar, and lumbosacral intervertebral disc disorders
- Chapter 13
- Diseases of the musculoskeletal system and connective tissue
- Section
- M50-M54
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