Narrowing of the neural canal in the lower extremity caused by a subluxation — a partial dislocation or biomechanical displacement — that mechanically compresses the neural passageway in that region.

Documentation tips

What should appear in the chart to support M99.26.

Source · Editorial brief grounded in 4 cited references ↓

• Document that the neural canal narrowing is caused by subluxation specifically — distinguish from osseous, disc, or soft-tissue stenosis mechanisms, each of which maps to a different M99.x6 sibling code.
• Record the clinical rationale for placing the subluxation at the lower extremity; vague references to 'leg pain' or 'radiculopathy' without a biomechanical etiology will not support this code on audit.
• Include any imaging findings (MRI, CT, X-ray) that corroborate neural canal compromise in the lower extremity, noting joint alignment, foraminal narrowing, or subluxation position.
• Note that M99 category codes should only be used when the condition cannot be classified under a more specific musculoskeletal or neurological code — document why a more definitive code does not apply.
• If treating with manipulation or OMT, link the M99.26 diagnosis explicitly to the treated region in the visit note to support medical necessity for procedure codes.

Related CPT procedures

Procedure codes commonly billed with M99.26. 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 M99.26 and adjacent codes.

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

• Using M99.26 when a more specific spinal stenosis code (e.g., M48.06 for lumbar spinal stenosis) is supported by documentation — M99 codes are explicitly 'not elsewhere classified' and must yield to more definitive diagnoses.
• Confusing M99.26 (subluxation stenosis) with M99.36 (osseous stenosis of neural canal, lower extremity) or M99.46 (connective tissue stenosis, lower extremity) — the mechanism documented by the provider determines the correct subcategory.
• Coding M99.06 (segmental and somatic dysfunction of lower extremity) instead of M99.26 when the provider specifically documents neural canal stenosis secondary to subluxation — these are distinct concepts within the M99 block.
• Failing to check payer-specific coverage policies for M99-range biomechanical lesion codes, which some Medicare and commercial payers scrutinize heavily for medical necessity, particularly in chiropractic billing contexts.

Clinical context

Source · Editorial summary grounded in 4 cited references ↓

Sibling codes

Other billable codes under M99.2 (laterality / anatomic variants).