Spondylolisthesis localized to the cervicothoracic junction, where one vertebra has translated anteriorly relative to the vertebra immediately below it at the C7-T1 transition zone.

Documentation tips

What should appear in the chart to support M43.13.

Source · Editorial brief grounded in 4 cited references ↓

• Specify the vertebral level(s) involved by name — C7-T1 or 'cervicothoracic junction' — so the coder can confirm M43.13 over adjacent-region codes M43.12 or M43.14.
• Record the type or grade of spondylolisthesis (e.g., degenerative, isthmic/spondylolytic, Meyerding Grade I-IV) to support medical necessity and surgical planning documentation.
• Cite the imaging modality and key finding: plain radiograph with measurable anterior slip, CT showing pars defect, or MRI with canal compromise — all strengthen the diagnosis and payer audit defense.
• Document whether the condition is symptomatic (radiculopathy, myelopathy, neck/upper back pain) to support additional diagnosis codes and justify the level of service.
• Explicitly exclude acute trauma and congenital etiology in the note; a single sentence ('no acute fracture identified; no congenital vertebral anomaly') protects against Excludes1 violations on audit.

Related CPT procedures

Procedure codes commonly billed with M43.13. 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 M43.13 and adjacent codes.

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

• Assigning M43.13 after acute cervicothoracic trauma violates the Excludes1 note — acute traumatic slippage at non-lumbosacral sites must be coded to the appropriate vertebral fracture code, not M43.1x.
• Defaulting to M43.10 (site unspecified) when imaging clearly identifies the cervicothoracic level is an undercoding error; specificity is available and required when documented.
• Confusing the cervicothoracic region (C7-T1) with the cervical region (M43.12) or thoracic region (M43.14) — the coder must confirm the apex level in the imaging report before selecting the 5th character.
• Using M43.13 for congenital spondylolisthesis — Q76.2 is the correct code when a congenital origin is established, per the Excludes1 instruction under M43.1.
• Omitting secondary diagnosis codes for associated neurological compromise (e.g., cervical myelopathy M47.12, radiculopathy M54.12) when documented — these support medical necessity for advanced imaging and surgical intervention.

Clinical context

Source · Editorial summary grounded in 4 cited references ↓

Sibling codes

Other billable codes under M43.1 (laterality / anatomic variants).