Bone-driven narrowing of the neural canal in the upper extremity — shoulder girdle, arm, elbow, or forearm region — caused by osseous (bony) encroachment rather than soft-tissue or disc pathology.

Documentation tips

What should appear in the chart to support M99.37.

Source · Editorial brief grounded in 4 cited references ↓

• Specify 'osseous' or 'bony' as the cause of neural canal narrowing — vague 'stenosis' without etiology may cause a query or down-code to an unspecified category.
• Document the imaging findings that confirm osseous stenosis: osteophyte size, degree of foraminal narrowing (mild/moderate/severe), and affected level (e.g., C5-C6 bony foraminal stenosis with upper extremity radiation).
• Record the upper extremity neurological findings that tie the bony stenosis to clinical presentation — dermatomal numbness, motor weakness, diminished reflexes — to support medical necessity.
• If radiculopathy is present, code it as an additional diagnosis (e.g., M54.12) alongside M99.37; the stenosis code alone does not capture the neurological symptom.
• Document prior conservative treatment history (physical therapy, chiropractic, injections) when supporting surgical or advanced imaging authorization — payers often require failure of conservative care tied to this diagnosis.

Related CPT procedures

Procedure codes commonly billed with M99.37. 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 M99.37 and adjacent codes.

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

• Using M99.31 (osseous stenosis, cervical region) when the clinical focus is upper extremity neurological symptoms — if the stenosis manifests as upper limb radiculopathy/canal compromise affecting the extremity, M99.37 is the correct regional pick.
• Defaulting to M99.37 when the stenosis is disc or ligamentous in origin — osseous stenosis requires documented bony etiology; soft-tissue or disc-driven narrowing belongs under M99.4x or M50/M51 categories respectively.
• Omitting a radiculopathy or neurological symptom code — M99.37 describes the structural finding, not the neurological consequence; most claims require the symptom code to establish medical necessity.
• Assuming M99.37 carries laterality — it does not; document both sides in the note if bilateral, and use additional codes if side-specific clarification is clinically required.

Clinical context

Source · Editorial summary grounded in 4 cited references ↓

Sibling codes

Other billable codes under M99.3 (laterality / anatomic variants).