S12.64XK ICD-10-CM Code: Type III traumatic spondylolisthesis of seventh cervical vertebra, subsequent encounter for fracture with nonunion

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for S12.64XK in the official ICD-10-CM tabular list, quoted as published.

Notes without a marker are published on S12.64XK itself; “inherited from” names the category or block whose note applies here.

7th Character Guide

"The appropriate 7th character is to be added to all codes from subcategories S12.0-S12.6"

• A — initial encounter for closed fracture
• B — initial encounter for open fracture
• D — subsequent encounter for fracture with routine healing
• G — subsequent encounter for fracture with delayed healing
• K — subsequent encounter for fracture with nonunion (this page’s code)
• S — sequela

How the encounter character is assigned. “Initial encounter” means the patient is receiving active treatment for the condition — it is not limited to the first visit, and a different or new provider giving active treatment still assigns it. “Subsequent encounter” covers care during the healing or recovery phase after active treatment. “Sequela” is for complications or conditions that arise as a direct result of the original condition.

ICD-10-CM Official Guidelines for Coding and Reporting, Section I.C.19.a (paraphrased by MedCoder).

Variant codes in this family

S12.64XA, S12.64XB, S12.64XD, S12.64XG, S12.64XK, S12.64XS

Character meanings are CMS's official 7th-character extensions for this family, as carried in each variant code's official description; variant codes are registry rows. The explanation of how the encounter character is assigned is MedCoder editorial, distinct from the official content above it.

Coder workflow for S12.64XK

MedCoder structured workflow — derived from this code’s own official record

Before you code S12.64XK

1. A 7th character is required in this family. Confirm the documented encounter: initial (active treatment), subsequent (healing or recovery phase), or sequela. This page’s code carries “K”. “Initial” means active treatment, not the first visit (Guidelines I.C.19.a).

   See the 7th Character Guide · Guide: 7th characters: initial, subsequent, sequela →

2. S12.64XK’s title joins a condition with an associated condition or complication. Confirm each component is documented. Where the classification presumes the link through the “with” convention, only a provider statement that the conditions are unrelated defeats it. A combination code is assigned only when it fully identifies the documented conditions; a required second code for the stage, type or manifestation is still reported when the notes ask for it (Guidelines I.B.9, I.A.15).

   Guide: Combination codes →

3. Confirm the injury type, the anatomical site at the most specific level documented, laterality where the family codes it, and the encounter for the 7th character. Each injury is coded separately unless the classification provides a combination code, and a superficial injury is not coded when a more severe injury of the same site is documented. A fracture not documented as open or closed is coded as closed; one not documented as displaced or nondisplaced is coded as displaced. Injury chapter guidelines (Guidelines I.C.19.b, I.C.19.b.1, I.C.19.c).

   Guide: Traumatic vs pathological vs stress fracture →

Choose the right path

1. Is the underlying (etiologic) condition the Code First note names documented?
   Yes → Sequence the underlying condition first, then S12.64XK.
   No → Continue; do not add an underlying condition the record does not document.

   ReviewS14.0, S14.1

2. Is the encounter phase documented — active treatment, healing or recovery, or a sequela?
   Yes → Assign the matching 7th character; the variant codes are in the 7th Character Guide.
   No → The code is invalid without its 7th character — query for the missing element.

Consider S12.64XK. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement

Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

Anatomical site

At the most specific level the record states; a site the classification separates cannot be assumed from a procedure or a measurement.

Encounter type

Active treatment, healing or recovery phase, or sequela — the basis of the 7th character (Guidelines I.C.19.a).

The associated condition or complication

Whether the associated condition the title names is documented; the “with” convention presumes some links, and a provider statement that the conditions are unrelated defeats it (Guidelines I.A.15).

Open or closed; displaced or nondisplaced

Defaults apply when the record is silent: closed, and displaced (Guidelines I.C.19.c).

The underlying (etiologic) condition

Named in the Code First note; sequenced before this code when documented (Guidelines I.A.13).

External cause, place and activity

For the external cause codes reported with the injury or poisoning, where documented (Guidelines I.C.20.a).

Official instructions as workflow

• Excludes2 — not part of S12.64XK(7 notes)

  Coding workflow: The conditions named in this note are not included in S12.64XK. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareT18.1, T17.3, T17.2, T17.4, T63.4

  See the official tabular notes · Guidelines I.A.12.b

• Code First — sequencing check(1 note)

  Coding workflow: Check whether the underlying or etiologic condition the note names is documented. When it is, sequence it before S12.64XK. Do not add an underlying condition the record does not document.

  ReviewS14.0, S14.1

  See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Official Coding Guidelines

Verbatim excerpts from the ICD-10-CM Official Guidelines for Coding and Reporting (CMS/NCHS) that govern this code.

Don’t confuse S12.64XK with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of S12.64XK — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• S12.64XA— Encounter relationship (Review)

  Same underlying diagnosis, different encounter phase.

  The same diagnosis at a different phase of care; one encounter takes one 7th character.

  What moves you there: Documentation of a initial encounter for closed fracture moves the case to S12.64XA.

  Full comparison: S12.64XK vs S12.64XA →

• S12.64XB— Encounter relationship (Review)

  Same underlying diagnosis, different encounter phase.

  The same diagnosis at a different phase of care; one encounter takes one 7th character.

  What moves you there: Documentation of a initial encounter for open fracture moves the case to S12.64XB.

  Full comparison: S12.64XK vs S12.64XB →

• T20— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of burns and corrosions adds T20; it is not part of this code and both may be reported when both are documented.

  Full comparison: S12.64XK vs T20 →

• T32— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of burns and corrosions adds T32; it is not part of this code and both may be reported when both are documented.

  Full comparison: S12.64XK vs T32 →

• T18.1— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of effects of foreign body in esophagus adds T18.1; it is not part of this code and both may be reported when both are documented.

  Full comparison: S12.64XK vs T18.1 →

• T17.3— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of effects of foreign body in larynx adds T17.3; it is not part of this code and both may be reported when both are documented.

  Full comparison: S12.64XK vs T17.3 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

1. A 7th character applies in this family. Confirm the documented encounter matches the character assigned. See the official 7th-character definitions and this code’s variants
2. Sequencing: 1 Code First instruction — the underlying condition is sequenced before this code when present. See the Code First notes
3. 7 Excludes2 entries — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

• No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

Other codes that name S12.64XK or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 4 Excludes1 notes: M48.4 — Fatigue fracture of vertebra (via S12.-), M48.5 — Collapsed vertebra, not elsewhere classified (via S12.-), M84.3 — Stress fracture (via S12.-), M84.4 — Pathological fracture, not elsewhere classified (via S12.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 3 Excludes2 notes: S11 — Open wound of neck (via S12.-), S13.1 — Subluxation and dislocation of cervical vertebrae (via S12.-), S27 — Injury of other and unspecified intrathoracic organs (via S12.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Referenced by 1 Use Additional Code instruction: T71.16 — Asphyxiation due to hanging (via S12.-).

These codes instruct coders to additionally report this code when it applies.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

Not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity.

Named in the grouper logic of 3 MS-DRGs: DRG 564 (MDC 08), DRG 565 (MDC 08), DRG 566 (MDC 08).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):INJ039 — Fracture of the spine and back, subsequent encounter (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same injury, other encounter phase

Same injury, coded at a different phase of treatment via the 7th character.

S12.64XA — Type III traumatic spondylolisthesis of seventh cervical vertebra, initial encounter for closed fractureCompare S12.64XK vs S12.64XA →, S12.64XB — Type III traumatic spondylolisthesis of seventh cervical vertebra, initial encounter for open fracture, S12.64XD — Type III traumatic spondylolisthesis of seventh cervical vertebra, subsequent encounter for fracture with routine healing, S12.64XG — Type III traumatic spondylolisthesis of seventh cervical vertebra, subsequent encounter for fracture with delayed healing, S12.64XS — Type III traumatic spondylolisthesis of seventh cervical vertebra, sequela

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Fracture of the spine and back, subsequent encounter).

+493 more

Contextual Map

Every relationship of S12.64XK in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run S12.64XK with these 8 related codes in Claim Check

Hierarchy

• S00-T88 — Chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) (S00-T88)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S10-S19 — Injuries to the neck[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes1 notes

• M48.4 — Fatigue fracture of vertebra[Excludes1](via S12.-): “traumatic fracture of vertebrae (S12.0-S12.3-, S22.0-, S32.0-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• M48.5 — Collapsed vertebra, not elsewhere classified[Excludes1](via S12.-): “traumatic fracture of vertebra (S12.-, S22.-, S32.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• M84.3 — Stress fracture[Excludes1](via S12.-): “traumatic fracture (S12.-, S22.-, S32.-, S42.-, S52.-, S62.-, S72.-, S82.-, S92.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• M84.4 — Pathological fracture, not elsewhere classified[Excludes1](via S12.-): “traumatic fracture (S12.-, S22.-, S32.-, S42.-, S52.-, S62.-, S72.-, S82.-, S92.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes2 notes

• S11 — Open wound of neck[Excludes2](via S12.-): “open fracture of vertebra (S12.- with 7th character B)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S13.1 — Subluxation and dislocation of cervical vertebrae[Excludes2](via S12.-): “fracture of cervical vertebrae (S12.0-S12.3-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S27 — Injury of other and unspecified intrathoracic organs[Excludes2](via S12.-): “injury of cervical esophagus (S10-S19)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Use Additional Code instructions

• T71.16 — Asphyxiation due to hanging[Use Additional Code](via S12.-): “fracture of cervical vertebrae (S12.0-S12.2-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• INJ039 — Fracture of the spine and back, subsequent encounter[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• DRG 564 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH MCC[MS-DRG]: “OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH MCC (MDC 08)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 565 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH CC[MS-DRG]: “OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH CC (MDC 08)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 566 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITHOUT CC/MCC[MS-DRG]: “OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITHOUT CC/MCC (MDC 08)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 08 — Diseases and Disorders of the Musculoskeletal System and Connective Tissue[MDC crossing]: “Diseases and Disorders of the Musculoskeletal System and Connective Tissue — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 18,508 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Nearest codes (40)

• S12 — Fracture of cervical vertebra and other parts of neck[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S12.63 — Unspecified traumatic spondylolisthesis of seventh cervical vertebra[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S12.630 — Unspecified traumatic displaced spondylolisthesis of seventh cervical vertebra[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S12.630A — Unspecified traumatic displaced spondylolisthesis of seventh cervical vertebra, initial encounter for closed fracture[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S12.630B — Unspecified traumatic displaced spondylolisthesis of seventh cervical vertebra, initial encounter for open fracture[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S12.630D — Unspecified traumatic displaced spondylolisthesis of seventh cervical vertebra, subsequent encounter for fracture with routine healing[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S12.630G — Unspecified traumatic displaced spondylolisthesis of seventh cervical vertebra, subsequent encounter for fracture with delayed healing[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S12.630K — Unspecified traumatic displaced spondylolisthesis of seventh cervical vertebra, subsequent encounter for fracture with nonunion[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 32 more

Change history

• FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Coding guidelines Official source data

ICD-10-CM Official Guidelines for Coding and Reporting (FY2026), quoted by section Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Inpatient payment groups Official source data

CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to S12.64XK in its code family, with their registry titles.

• S12.64 — Type III traumatic spondylolisthesis of seventh cervical vertebra
• S12.64XA — Type III traumatic spondylolisthesis of seventh cervical vertebra, initial encounter for closed fracture
• S12.64XB — Type III traumatic spondylolisthesis of seventh cervical vertebra, initial encounter for open fracture
• S12.64XD — Type III traumatic spondylolisthesis of seventh cervical vertebra, subsequent encounter for fracture with routine healing
• S12.64XG — Type III traumatic spondylolisthesis of seventh cervical vertebra, subsequent encounter for fracture with delayed healing
• S12.64XS — Type III traumatic spondylolisthesis of seventh cervical vertebra, sequela
• S12.65 — Other traumatic spondylolisthesis of seventh cervical vertebra
• S12.650 — Other traumatic displaced spondylolisthesis of seventh cervical vertebra
• S12.650A — Other traumatic displaced spondylolisthesis of seventh cervical vertebra, initial encounter for closed fracture
• S12.650B — Other traumatic displaced spondylolisthesis of seventh cervical vertebra, initial encounter for open fracture

View all codes in the S12 family