Acquired defect or stress fracture of the pars interarticularis in one or more cervical vertebrae, classified as a deforming dorsopathy of the cervical spine region.
Verified May 8, 2026 · 5 sources ↓
- Status
- Billable
- Chapter
- 13
- Related CPT
- 13
- Region
- Spine
Documentation tips
What should appear in the chart to support M43.02.
Source · Editorial brief grounded in 5 cited references ↓
- Specify 'cervical' as the spinal region affected — M43.02 requires region-level specificity; a note that says only 'spondylolysis' will drop to the non-billable parent M43.0.
- Document that the defect is acquired, not congenital — congenital spondylolysis routes to Q76.2 and is an Excludes1 exclusion at the M43.0 level.
- Record the imaging modality and findings that confirm the pars defect: CT is preferred; document Hounsfield density, fracture line location, or sclerosis at the pars interarticularis if available.
- If a vertebral slip is also present, document whether the clinical diagnosis is spondylolysis (pars defect only) or spondylolisthesis (slip confirmed), because they cannot be coded together under the Excludes1 rule.
- Capture any neurological findings (radiculopathy, myelopathy, sensory or motor deficits) as separate secondary diagnoses to reflect full clinical complexity and support DRG MCC/CC capture.
- Document history of conservative care (collar immobilization, physical therapy, NSAIDs) when surgical or interventional management is planned — this establishes medical necessity.
Related CPT procedures
Procedure codes commonly billed with M43.02. 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 M43.02 and adjacent codes.
Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓
- Assigning M43.02 alongside M43.12 (cervical spondylolisthesis) violates the Excludes1 note at M43.0 — if the vertebra has slipped, use M43.12 only.
- Using M43.02 for congenital cervical pars defects — congenital spondylolysis is Q76.2; M43.02 is reserved for acquired defects.
- Defaulting to lumbar spondylolysis codes (M43.06) when the operative or radiology report documents a cervical-level finding — always verify the spinal level against imaging.
- Leaving the diagnosis at the non-billable parent M43.0 when the region is clearly documented as cervical — M43.02 is the billable, region-specific code and must be used.
- Failing to code associated radiculopathy or myelopathy separately, which understates clinical complexity and can suppress MCC/CC DRG assignment.
Clinical context
Source · Editorial summary grounded in 5 cited references ↓
M43.02 captures acquired spondylolysis confined to the cervical region (C1–C7). The lesion represents a defect in the pars interarticularis — the bony bridge connecting the superior and inferior articular processes of a cervical vertebra. It is distinct from the far more common lumbar spondylolysis and must be supported by imaging (CT is the gold standard; plain radiographs and MRI may also identify the defect or associated edema). Use this code only when the defect is documented as acquired; congenital spondylolysis maps to Q76.2, not M43.02.
The critical Excludes1 note at M43.0 bars simultaneous use of M43.02 with spondylolisthesis codes (M43.1x). If imaging confirms the vertebra has already slipped forward, the diagnosis is cervical spondylolisthesis (M43.12), not spondylolysis. Spondylolysis is the pars defect alone; spondylolisthesis is the resultant displacement. When both pathologies are mentioned in the record, query the provider for the primary diagnosis before assigning codes.
MS-DRG grouping places M43.02 in DRG 551 (Medical back problems with MCC) or 552 (without MCC), so documented comorbidities and complications directly affect reimbursement weight. Code any associated cervical radiculopathy, myelopathy, or instability as secondary diagnoses to fully reflect complexity and support medical necessity for advanced imaging, bracing, or surgical intervention.
Sibling codes
Other billable codes under M43.0 (laterality / anatomic variants).
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 5 cited references ↓
01What is the difference between M43.02 and M43.12?
02Can I use M43.02 for a congenital cervical pars defect?
03Which imaging supports M43.02, and should I document the modality?
04Does M43.02 require a 7th character?
05How does M43.02 affect DRG assignment?
06Should I code cervical radiculopathy separately when it accompanies M43.02?
07What approximate synonyms are accepted for M43.02 in the ICD-10-CM index?
Sources & references
Editorial content was developed using the following public sources. Last verified May 8, 2026.
- 01CDC ICD-10-CM Tabular List 2026 (FY2026, effective Oct 1, 2025)
- 02icd10data.comhttps://www.icd10data.com/ICD10CM/Codes/M00-M99/M40-M43/M43-/M43.02
- 03aapc.comhttps://www.aapc.com/codes/icd-10-codes/M43.02
- 04cdek.pharmacy.purdue.eduhttps://cdek.pharmacy.purdue.edu/icd10/M43.0/
- 05CMS MS-DRG v43.0 Grouper — DRG 551/552
Mira AI Scribe
Mira AI Scribe captures the documented spinal level (cervical), confirmation that the defect is acquired rather than congenital, imaging modality and findings (CT/MRI pars defect, fracture line, sclerosis), presence or absence of vertebral slip, and any neurological symptoms (radiculopathy, myelopathy). Complete capture prevents downcoding to the non-billable M43.0, blocks an erroneous Q76.2 congenital assignment, and ensures associated neurological diagnoses are coded to support DRG MCC/CC grouping.
See how Mira captures M43.02 documentation