ICD-10-CM · Spine

M50.33

Degenerative change of the intervertebral disc at the C7-T1 junction (cervicothoracic region) that does not meet criteria for displacement, myelopathy, or radiculopathy — coded specifically to the lowest cervical level where the spine transitions into the thoracic segment.

Verified May 8, 2026 · 6 sources ↓

Status
Billable
Chapter
13
Related CPT
11
Region
Spine
Drawn from CDCICD10DataAAPCCMSOutsourcestrategies

Documentation tips

What should appear in the chart to support M50.33.

Source · Editorial brief grounded in 6 cited references ↓

  • Name the specific level: document 'C7-T1' or 'cervicothoracic junction' explicitly — 'lower cervical' alone is insufficient to support M50.33 over M50.30.
  • Record imaging findings that confirm degeneration at C7-T1: disc space narrowing, osteophyte formation, endplate changes, or T2 signal loss on MRI.
  • Distinguish the clinical picture clearly: if arm pain, numbness, or weakness is present, evaluate whether radiculopathy (M50.13) or myelopathy (M50.03) is the more accurate code.
  • Document chronicity — duration of symptoms and any prior conservative treatment (PT, NSAIDs, injections) supports medical necessity and reduces audit exposure.
  • If prior cervical spine surgery or trauma contributes to the degeneration, note that history; it contextualizes the diagnosis and may affect sequencing.

Related CPT procedures

Procedure codes commonly billed with M50.33. 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 M50.33 and adjacent codes.

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

  • Coding M50.33 when radiculopathy is documented: M50.13 is the correct combination code; do not stack M50.33 with a separate radiculopathy code.
  • Defaulting to M50.30 (unspecified) when the provider's note or imaging report clearly identifies C7-T1 — specificity is available and required when documented.
  • Confusing M50.33 (degeneration) with M50.23 (displacement/herniation) at the same level — these are distinct pathologies requiring different codes and different clinical criteria.
  • Applying M50.33 for disc disorders with myelopathy: use M50.03 instead; M50.33 is not appropriate when cord compression is documented.
  • Using an M51 lumbar/thoracic code for C7-T1 pathology — the cervicothoracic junction is classified under M50, not M51.

Clinical context

Source · Editorial summary grounded in 6 cited references ↓

M50.33 applies to disc degeneration documented at the cervicothoracic junction (C7-T1) when the clinical picture is degeneration alone — not herniation/displacement (M50.23), not myelopathy (M50.03), and not radiculopathy (M50.13). If the provider documents any of those associated neurological findings, step up to the appropriate combination code rather than stacking M50.33 with a symptom code.

Within the M50.3x family, the fifth character '3' locks the pathology to the cervicothoracic region. The sibling codes are M50.30 (unspecified region), M50.31 (high cervical, C2-C4), and M50.32 (mid-cervical, C4-C7). Use M50.33 only when documentation explicitly identifies C7-T1 or the cervicothoracic junction — not as a default for vague lower neck pain.

This code groups to MS-DRG 551 (Medical back problems with MCC) or 552 (without MCC) under v43.0. Payers scrutinize M50.3x codes for supporting imaging; MRI or CT findings of disc space narrowing, osteophyte formation, or signal change at C7-T1 are the documentation backbone. Conservative care history (physical therapy, medications) strengthens medical necessity for both non-operative management billing and pre-authorization for surgical intervention.

Inclusion & exclusion notes

Per the official ICD-10-CM Tabular List.

Source · CDC ICD-10-CM Official Tabular List · 2026

Includes

  • Other C7-T1 cervical disc degeneration

Sibling codes

Other billable codes under M50.3 (laterality / anatomic variants).

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01What spinal level does M50.33 cover?
M50.33 maps exclusively to C7-T1, the cervicothoracic junction. The ICD-10-CM Applicable To note states 'Other C7-T1 cervical disc degeneration.' Any other cervical level requires a different fifth-character code.
02Can I use M50.33 if the patient also has neck pain?
Cervicalgia is included in the M50 category per the Includes note ('cervicothoracic disc disorders with cervicalgia'), so do not add a separate neck pain code when M50.33 already captures it.
03What is the difference between M50.33 and M50.13?
M50.13 is a combination code for cervical disc disorder with radiculopathy at the cervicothoracic region. Use M50.13 when the provider documents arm pain, dermatomal numbness, or radicular symptoms. M50.33 applies when degeneration is present without documented radiculopathy.
04Does M50.33 require imaging confirmation?
ICD-10-CM does not mandate imaging as a coding rule, but payers routinely require MRI or CT evidence of degeneration at C7-T1 to approve claims. Document imaging findings in the medical record to support the diagnosis and withstand audit.
05Can M50.33 be the primary diagnosis for a surgical claim?
Yes. M50.33 can support surgical CPT codes such as 63075, 22551, or 22554 when the operative report and clinical documentation confirm degeneration at C7-T1 as the indication. Verify payer LCD/NCD criteria, as some require documented failure of conservative care before authorizing surgery.
06Is M50.33 valid for physical therapy claims?
Yes, M50.33 is billable and appropriate as a PT diagnosis code when the degeneration is at C7-T1. Ensure the plan of care documents functional deficits and goals tied to the cervicothoracic pathology. Some BCBS plans have flagged M50.3x codes for consistency audits, so confirm supporting documentation is complete.
07What MS-DRG does M50.33 map to for inpatient claims?
Under MS-DRG v43.0, M50.33 groups to DRG 551 (Medical back problems with MCC) or DRG 552 (Medical back problems without MCC), depending on the presence of a major complication or comorbidity.

Mira AI Scribe

Mira AI Scribe captures the documented spinal level (C7-T1 or cervicothoracic junction), imaging findings (MRI/CT disc space narrowing, osteophyte formation, signal change), symptom duration, and conservative care history — preventing a downcode to M50.30 (unspecified) or an upcoded mismatch to M50.13/M50.03 when neurological findings are absent.

See how Mira captures M50.33 documentation

Related ICD-10 codes

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