🧬 ICD-10 CM S12.401A — Unspecified Nondisplaced Fracture of Fifth Cervical Vertebra, Initial Encounter for Closed Fracture
Billable Code Confirmed
ICD-10 CM S12.401A is a fully billable 8-character ICD-10-CM code valid for FY2026. The 7th character “A” specifies this is an initial encounter for a closed fracture, meaning the patient is receiving active treatment for the fracture (includes surgical treatment, ER visits, and evaluation visits while treatment is being decided). All codes in subcategories S12.0-S12.6 require the appropriate 7th character extension per ICD-10-CM tabular instruction.
Clinical Context
The fifth cervical vertebra (C5) is one of the most clinically significant levels in the cervical spine — C5 nerve root involvement produces deltoid and biceps weakness, and fracture at this level with cord injury can result in incomplete or complete tetraplegia. The designation “nondisplaced” means the fracture fragments have not shifted from their anatomic position, which generally carries a more favorable prognosis than displaced fractures but still requires urgent evaluation for cord injury. The “unspecified” qualifier means the fracture type has not been further clarified as a burst, compression, teardrop, or other specific morphology — a CDI query opportunity if imaging supports a more specific descriptor.
Code Classification
ICD-10 CM S12.401A is a diagnosis code (ICD-10-CM), not a procedure code. It classifies a traumatic injury to the cervical spine and belongs to Chapter 19 of ICD-10-CM (Injury, Poisoning and Certain Other Consequences of External Causes, S00-T88). An external cause code (V00-Y99) should always accompany this code to identify the mechanism of injury (e.g., V49.9XXA motor vehicle accident, W17.89XA fall).
🔍 Code Description
ICD-10 CM S12.401A describes an acute, closed, nondisplaced fracture of the fifth cervical vertebra (C5) at an initial encounter. The cervical spine includes seven vertebrae (C1-C7), and the fifth cervical vertebra is located in the mid-cervical region, forming part of the structural and neural pathway between the brainstem and thoracic spine**. A nondisplaced fracture means the bony cortex has been disrupted without significant translation or angulation of fragments, though the spinal canal and cord remain at risk depending on fracture morphology and associated ligamentous injury**. The ICD-10-CM category S12 broadly includes fractures of the cervical neural arch, cervical spine, cervical spinous process, cervical transverse process, cervical vertebral arch, and fracture of neck — all mapping to this same category header.
The 7th character system for S12 codes is critical to accurate billing and clinical documentation alignment. Character “A” (initial encounter) applies throughout the entire active treatment phase — not just the first visit. Once the fracture has received definitive treatment and the patient is in recovery/rehabilitation, the 7th character shifts to “D” (S12.401D — subsequent encounter) or “S” (S12.401S — sequela). Failure to advance the 7th character appropriately is a common audit flag and can affect claim adjudication, particularly for post-acute facilities and outpatient follow-up billing. For inpatient profee coding, verifying the encounter type against the documentation phase of treatment is a key compliance step.
🌳 Code Tree / Hierarchy
S12 Fracture of cervical vertebra and other parts of neck ❌ Non-billable
│
├── S12.0 Fracture of first cervical vertebra ❌ Non-billable
├── S12.1 Fracture of second cervical vertebra ❌ Non-billable
├── S12.2 Fracture of third cervical vertebra ❌ Non-billable
├── S12.3 Fracture of fourth cervical vertebra ❌ Non-billable
│
├── S12.4 Fracture of fifth cervical vertebra ❌ Non-billable
│ │
│ ├── S12.40 Unspecified fracture of fifth cervical vertebra ❌ Non-billable
│ │ │
│ │ ├── S12.400_ Unspecified displaced fracture of fifth cervical vertebra
│ │ │ ├── S12.400A ✅ Billable — initial encounter, closed
│ │ │ ├── S12.400B ✅ Billable — initial encounter, open
│ │ │ └── S12.400D / S12.400S ✅ Billable — subsequent / sequela
│ │ │
│ │ └── S12.401_ Unspecified nondisplaced fracture of fifth cervical vertebra ❌ Non-billable (no 7th char)
│ │ ├── S12.401A ✅ Billable — initial encounter, closed ◀ THIS CODE
│ │ ├── S12.401B ✅ Billable — initial encounter, open
│ │ └── S12.401D / S12.401S ✅ Billable — subsequent / sequela
│ │
│ └── S12.49 Other fracture of fifth cervical vertebra ❌ Non-billable
│ ├── S12.490A / S12.491A ✅ Billable — displaced/nondisplaced, initial closed
│
├── S12.5 Fracture of sixth cervical vertebra ❌ Non-billable
└── S12.6 Fracture of seventh cervical vertebra ❌ Non-billable
Why "Unspecified" Fracture Type Matters for Inpatient Coding
When imaging (CT/MRI) describes a specific fracture morphology — burst, compression, teardrop, or lateral mass — a more specific code under S12.49_ may be appropriate and should be queried with the provider. Assigning “unspecified” when the chart supports a specific type is a documentation deficiency that can affect DRG optimization and medical necessity review.
7th Character Discipline
The 7th character must reflect the current phase of treatment, not just the date of injury. An inpatient admission for surgical stabilization of a C5 fracture first diagnosed in the ER still uses “A” — because definitive surgical treatment is being rendered. The encounter type advances to “D” only when active treatment is complete and the patient is receiving routine care or healing checks.
✅ Includes
The following terms and fracture sites map to the S12 category and are included under this code family:
- Fracture of cervical neural arch — includes posterior arch fractures at C5
- Fracture of cervical spine — general term mapping to S12
- Fracture of cervical spinous process — isolated process fractures at C5
- Fracture of cervical transverse process — lateral process fractures at C5
- Fracture of cervical vertebral arch — arch integrity disruption
- Fracture of neck — colloquial or general documentation term mapping to S12
❌ Excludes
Excludes 1
These codes represent mutually exclusive conditions that cannot be coded simultaneously with S12.401A:
- S12.400A — Unspecified displaced fracture of fifth cervical vertebra, initial encounter for closed fracture. A fracture cannot be simultaneously displaced and nondisplaced; documentation must clearly support one designation. If displacement status is not documented, ICD-10-CM default rules instruct coders to code to displaced (S12.400A), not S12.401A.
- S12.401B — Unspecified nondisplaced fracture of fifth cervical vertebra, initial encounter for open fracture. S12.401A is specifically for closed fractures; open fractures (skin/mucosa communication with fracture site) require the “B” 7th character.
Most Common Excludes 1 Error
The most frequent error is assigning S12.401A (nondisplaced) when the operative or radiology report documents displacement or when the provider documentation is silent on displacement status. Per ICD-10-CM coding guidelines, a fracture not indicated as displaced or nondisplaced defaults to displaced — coders should never assume nondisplaced without explicit documentation.
Excludes 2
These conditions can be coded in addition to S12.401A when separately documented:
- S14.0XXA / S14.1_XA — Concussion and edema of cervical spinal cord / Other and unspecified injuries of cervical spinal cord. These are actually “Code First” instructions (not purely Excludes 2) — the tabular instructs coders to code any associated cervical spinal cord injury first if it drives the admission, or as an additional code if the fracture is the principal diagnosis. These are separately identifiable and critical for DRG optimization.
📋 Clinical Overview
Cervical Fracture Displacement & Encounter Type Coding Distinctions
The most consequential code selection decisions for S12.4_ codes hinge on two axes: (1) displacement status and (2) encounter type. Inpatient coders must verify both against operative and radiology reports before finalizing the principal diagnosis code. The table below maps the most commonly confused sibling codes:
| Feature | S12.401A | S12.400A | S12.491A |
|---|---|---|---|
| Fracture Type | Unspecified nondisplaced | Unspecified displaced | Other nondisplaced (specific type) |
| Displacement | Nondisplaced — explicitly documented | Displaced — documented or default if unspecified | Nondisplaced — specific morphology documented (e.g., burst) |
| 7th Character | A — initial, closed | A — initial, closed | A — initial, closed |
| Default if Silent | ❌ Not the default — displaced is the default | ✅ Default when displacement not specified | Requires specific documentation |
| DRG Impact | DRG 052/053 — no surgical shift | DRG 052/053 — may be higher severity | DRG 052/053 — same MDC grouping |
| CDI Opportunity | Query for morphology specificity | Query for displacement clarification | None — already specific |
CDI Query Trigger
Manifestations & Symptom Burden
Cervical spine fractures at C5 may present with a range of neurologic manifestations that should be captured as additional diagnoses to ensure accurate DRG assignment and severity documentation:
- S14.105A / S14.1_XA — Cervical spinal cord injury (incomplete or complete) — MCC; drives DRG 052 grouping
- G89.11 — Acute pain due to trauma — separately codeable when pain management is addressed
- R29.5_ — Transient paralysis — if neurologic deficits are transient and documented
- M54.12 — Radiculopathy, cervical region — for radicular symptoms without cord injury
- Z79.01 — Long-term use of anticoagulants — critical to capture for surgical planning and complication risk
💰 HCC Risk Adjustment
| Attribute | Detail |
|---|---|
| CMS-HCC V28 Mapping | No direct HCC mapping for S12.401A as a standalone traumatic fracture |
| Associated HCC Opportunity | S14.0/S14.1- (spinal cord injury) → HCC 71 (Paraplegia / Quadriplegia) if chronic cord injury results |
| RAF Impact | Low for acute fracture alone; significant RAF uplift if cord injury or neurologic sequela is coded |
| Annual Capture | Sequela codes (S12.401S) do not carry RAF value; capture any chronic neurologic effects under specific myelopathy or deficit codes (e.g., G82.50) |
| Payer Note | Commercial HHS-HCC models may apply differently; verify per contract |
Acute traumatic fracture codes in the S12 series do not themselves map to CMS-HCC V28 risk adjustment categories. However, when C5 fracture results in documented cervical myelopathy, radiculopathy, or cord injury, those associated codes may carry meaningful RAF weight. CDI teams should monitor discharge summaries for any documentation of ongoing neurologic deficits that can be coded with greater specificity for risk adjustment capture in subsequent encounters.
🏥 MS-DRG Assignment
| Scenario | DRG | Title | FY2026 Relative Weight |
|---|---|---|---|
| S12.401A + CC or MCC (e.g., S14.1-) | 052 | Spinal Disorders and Injuries with CC/MCC | Higher weight |
| S12.401A alone, no CC/MCC | 053 | Spinal Disorders and Injuries without CC/MCC | Lower weight |
| S12.401A + cervical fusion (22600) | 028-030 | Anterior/Posterior Cervical Fusion DRGs | Significantly higher weight |
ICD-10 CM S12.401A is classified under MDC 01 (Diseases and Disorders of the Nervous System), which is the correct MDC for cervical spine fractures — not MDC 08 (Musculoskeletal), a common confusion point for newer coders. The DRG 052/053 split is driven entirely by the presence or absence of a qualifying CC or MCC; the most impactful MCC for this fracture is an associated cervical spinal cord injury coded from the S14.0-S14.1 range. If a surgical procedure is performed (e.g., anterior cervical discectomy and fusion), the case will shift from the medical DRG 052/053 into a surgical DRG with a substantially higher relative weight, underscoring the importance of accurate procedure coding on the UB-04.
🔗 Related ICD-10-CM Codes
Same Fracture Level — Different Attributes
- S12.400A — Unspecified displaced fracture of C5, initial encounter, closed
- S12.401B — Unspecified nondisplaced fracture of C5, initial encounter, open
- S12.401D — Unspecified nondisplaced fracture of C5, subsequent encounter
- S12.401S — Unspecified nondisplaced fracture of C5, sequela
- S12.491A — Other nondisplaced fracture of C5, initial encounter, closed
Cervical Spine Fractures — Adjacent Levels & Associated Injuries
- S12.301A — Unspecified nondisplaced fracture of C4, initial encounter, closed
- S12.501A — Unspecified nondisplaced fracture of C6, initial encounter, closed
- S14.105A — Unspecified injury at C5 level of cervical spinal cord, initial encounter
- S14.155A — Other incomplete lesion at C5 level of cervical spinal cord, initial encounter
- S13.4XXA — Sprain of ligaments of cervical spine, initial encounter
- W17.89XA — Other fall from one level to another, initial encounter (external cause)
🛠️ Commonly Associated CPT Codes
Conservative / Non-Operative Management
- 99233 — Subsequent hospital inpatient care, high complexity (E/M for ongoing inpatient management of cervical fracture with neuro monitoring)
- 99232 — Subsequent hospital inpatient care, moderate complexity (routine inpatient monitoring days)
Operative / Interventional
- 22600 — Arthrodesis, posterior or posterolateral technique, single interspace; cervical below C2 segment. Reported when posterior cervical fusion is performed for stabilization of the C5 fracture; inpatient-only procedure.
- 22554 — Arthrodesis, anterior interbody technique, including minimal discectomy to prepare interspace (other than for decompression), cervical below C2. Used for anterior cervical fusion approach to C4-C5 or C5-C6 instability.
- +22840 — Posterior non-segmental instrumentation (add-on); reported in addition to the primary fusion code when posterior hardware is placed. Never reported alone.
- +22845 — Anterior instrumentation, 2-3 vertebral segments (add-on); reported with anterior fusion codes when anterior plating is used.
- 63081 — Vertebral corpectomy, partial or complete, anterior approach, cervical, single segment; used if the C5 body requires resection due to fracture.
NCCI Bundling Considerations
CPT add-on codes 22840 and 22845 are never reported as standalone codes — they must accompany a primary arthrodesis or corpectomy code or the claim will deny. Fluoroscopy guidance (77003) is generally bundled into spinal procedure codes for inpatient cases and should not be separately reported. E/M codes on the same day as a surgical procedure are bundled unless a separately identifiable, significant service is documented and modifier -25 is appended (outpatient only — not applicable for global inpatient surgical cases).
🔬 ICD-10-PCS Crosswalk
When S12.401A drives an inpatient admission resulting in a procedure, the following ICD-10-PCS codes may be applicable for facility coding:
- 0RG10Z0 / 0RG10ZJ — Fusion of cervical vertebral joint(s), posterior approach — used for posterior cervical fusion procedures at C4-C5 or C5-C6 level; character 4 specifies the joint, character 5 specifies approach, character 6 specifies device.
- 0RG00ZJ — Fusion of occipital-cervical joint with synthetic substitute, posterior approach — if fusion extends to upper cervical levels.
- 0PS300Z — Reposition of cervical vertebra with internal fixation device, open approach — for open reduction and internal fixation of the C5 fracture fragment.
- 0PS33ZZ — Reposition of cervical vertebra, percutaneous approach — for minimally invasive stabilization or percutaneous screw placement.
ICD-10-PCS procedure codes must be assigned for all significant inpatient procedures on the UB-04. The root operation selection (Fusion vs. Reposition) depends on the operative intent documented by the surgeon — Fusion implies the goal is creating bony union across a joint, while Reposition implies restoring normal anatomic position of a displaced fragment.
💊 Coding Scenarios and Examples
Scenario 1: Inpatient Admission — Nondisplaced C5 Fracture, Conservative Management
A 34-year-old male is admitted following a motor vehicle accident. CT cervical spine confirms a nondisplaced fracture of the C5 vertebral body. MRI shows no cord signal change. Neurosurgery manages conservatively with halo vest immobilization and pain control. Discharged after 3 days.
Correct Coding:
- Principal Dx: S12.401A — Unspecified nondisplaced fracture of C5, initial encounter, closed
- Secondary: S13.4XXA — Sprain of ligaments of cervical spine, initial encounter (if ligamentous injury documented)
- External Cause: V49.9XXA — Unspecified car occupant injured in traffic accident, initial encounter
Sequencing: S12.401A is principal because the fracture is the condition chiefly responsible for the admission after study. No CC/MCC present → DRG 053. CDI Note: Query provider for any documented upper extremity weakness, paresthesias, or Lhermitte sign — these findings may support an S14 code, which would drive DRG 052.
Scenario 2: Surgical Stabilization — C5 Nondisplaced Fracture with Cord Injury
A 58-year-old female with osteoporosis suffers a ground-level fall. CT shows nondisplaced C5 fracture; MRI demonstrates cord edema at C5 with incomplete motor deficit. She undergoes anterior cervical discectomy and fusion (ACDF) at C4-C5 with anterior plate placement.
Correct Coding:
- Principal Dx: S12.401A — Unspecified nondisplaced fracture of C5, initial encounter, closed
- Secondary: S14.155A — Other incomplete lesion at C5 level, initial encounter (MCC)
- Secondary: M81.0 — Age-related osteoporosis without pathological fracture
- External Cause: W19.XXXA — Unspecified fall, initial encounter
- ICD-10-PCS: 0RG10AJ — Fusion of cervical vertebral joint, anterior approach, interbody fusion device
- ICD-10-PCS: 0RG10J4 — add device character for anterior plate instrumentation per PCS table
Sequencing: S12.401A as principal; S14.155A as MCC secondary → shifts to surgical DRG with significantly higher relative weight than DRG 052. CDI Note: The incomplete cord injury must be clearly documented by the attending physician — radiology findings alone are insufficient per ICD-10-CM guidelines.
Scenario 3: Outpatient Follow-Up / Wrong 7th Character
A patient is seen 6 weeks post-discharge in the spine clinic for a follow-up visit. The fracture is healing per CT. Coder assigns S12.401A (initial encounter).
Error: The 7th character should be D (S12.401D — subsequent encounter) because the fracture is in the healing phase and active treatment is complete. Using “A” at a follow-up healing visit is a compliance risk and a common audit finding for profee outpatient spine claims.
Corrected Code: S12.401D — Unspecified nondisplaced fracture of C5, subsequent encounter.
⚠️ Coding Pitfalls and Tips
- Default to displaced, not nondisplaced. Per ICD-10-CM guidelines, when displacement status is not documented, code to displaced (S12.400A). Never assume nondisplaced without explicit provider documentation or radiology confirmation that is attested in the clinical note.
- 7th character advancement is mandatory. Using “A” (initial encounter) for outpatient follow-up visits during the healing phase is incorrect and a frequent CPC audit flag. Advance to S12.401D once active treatment is complete.
- Always query for cord injury documentation. If the operative report, MRI, or nursing neuro checks document any cervical cord findings, an S14 code must be added — this is a “Code First” instruction in the tabular and is also the most impactful MCC for DRG 052 grouping.
- Open vs. closed is determined by fracture type, not surgical approach. A fracture is “open” when there is communication between the fracture and the external environment (skin/mucosa breach), not simply because surgery was performed. A surgically treated closed fracture retains the “A” closed designation.
- External cause codes are not optional. ICD-10-CM guidelines require external cause codes (V/W/X/Y range) to identify mechanism, place of occurrence, and activity when treating traumatic injuries. Inpatient facility claims that omit external cause codes may face denials from payers with mandatory reporting requirements.
- MDC 01, not MDC 08. Cervical spine fracture codes group to MDC 01 (Nervous System), not MDC 08 (Musculoskeletal). This is a classic grouper trap — if you see the case landing in a musculoskeletal DRG, verify your principal diagnosis code is correct.