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S22.5XXB ICD-10-CM Code: Flail chest, initial encounter for open fracture

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Inpatient Payment Groups (MS-DRG)

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0, Appendix B.

  • MS-DRG 183 — MAJOR CHEST TRAUMA WITH MCC (MDC 04)
  • MS-DRG 184 — MAJOR CHEST TRAUMA WITH CC (MDC 04)
  • MS-DRG 185 — MAJOR CHEST TRAUMA WITHOUT CC/MCC (MDC 04)
  • MS-DRG 963 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITH MCC (MDC 24)
  • MS-DRG 964 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITH CC (MDC 24)
  • MS-DRG 965 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITHOUT CC/MCC (MDC 24)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Official Registry Overview & Definition

Flail chest, initial encounter for open fracture is a billable ICD-10-CM diagnosis code (S22.5B).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for S22.5XXB in the official ICD-10-CM tabular list.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • fracture of thoracic neural arch
  • fracture of thoracic spinous process
  • fracture of thoracic transverse process
  • fracture of thoracic vertebra
  • fracture of thoracic vertebral arch
  • injuries of breast
  • injuries of chest (wall)
  • injuries of interscapular area

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Code First

Underlying conditions that must be sequenced before this code.

  • Code first, if applicable, spinal cord injury (S24.0-, S24.1-)

Code Also

Additional codes that may be required to fully describe the encounter.

  • Code also, if applicable, any associated condition such as:
  • injury of intrathoracic organ (S27.-)
  • traumatic hemopneumothorax (S27.2)
  • traumatic hemothorax (S27.1-)
  • traumatic pneumothorax (S27.0)

Frequently Compared Codes

The official Excludes notes on S22.5XXB name these codes. Each comparison page covers when the two can — or must not — be reported together.

Change history

  • FY2027 — 2026-10-01
    Code First note added
    , if applicable, spinal cord injury (S24.0-, S24.1-)
    FY2027 changes
  • FY2027 — 2026-10-01
    Code Also note removed
    spinal cord injury (S24.0-, S24.1-)
    FY2027 changes

Verify Before Coding

  • MCC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

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

Contextual Map

Every relationship of S22.5XXB 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.

Hierarchy

  • S00-T88 — Chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) (S00-T88) [Hierarchy]
  • S20-S29 — Injuries to the thorax [Hierarchy]

Referenced by Excludes1 notes

  • M48.5 — Collapsed vertebra, not elsewhere classified [Excludes1](via S22.-): “traumatic fracture of vertebra (S12.-, S22.-, S32.-)” · check together
  • M84.3 — Stress fracture [Excludes1](via S22.-): “traumatic fracture (S12.-, S22.-, S32.-, S42.-, S52.-, S62.-, S72.-, S82.-, S92.-)” · check together
  • M84.4 — Pathological fracture, not elsewhere classified [Excludes1](via S22.-): “traumatic fracture (S12.-, S22.-, S32.-, S42.-, S52.-, S62.-, S72.-, S82.-, S92.-)” · check together
  • S22.4 — Multiple fractures of ribs [Excludes1](via S22.5.-): “flail chest (S22.5-)” · check together

Clinical classification (CCSR)

  • INJ003 — Fracture of torso, initial encounter [CCSR]

Potential MS-DRG

  • MCC — Major Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (MCC). Not counted when the stay groups to DRGs 957-959 (Other O.R. Procedures for Multiple Significant Trauma); DRGs 963-965 (Other Multiple Significant Trauma).”
  • DRG 183 — MAJOR CHEST TRAUMA WITH MCC [MS-DRG]: “MAJOR CHEST TRAUMA WITH MCC (MDC 04)”
  • DRG 184 — MAJOR CHEST TRAUMA WITH CC [MS-DRG]: “MAJOR CHEST TRAUMA WITH CC (MDC 04)”
  • DRG 185 — MAJOR CHEST TRAUMA WITHOUT CC/MCC [MS-DRG]: “MAJOR CHEST TRAUMA WITHOUT CC/MCC (MDC 04)”
  • DRG 963 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITH MCC [MS-DRG]: “OTHER MULTIPLE SIGNIFICANT TRAUMA WITH MCC (MDC 24)”
  • DRG 964 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITH CC [MS-DRG]: “OTHER MULTIPLE SIGNIFICANT TRAUMA WITH CC (MDC 24)”
  • DRG 965 — OTHER MULTIPLE SIGNIFICANT TRAUMA WITHOUT CC/MCC [MS-DRG]: “OTHER MULTIPLE SIGNIFICANT TRAUMA WITHOUT CC/MCC (MDC 24)”

MDC crossing · procedures (26955)

  • MDC 04 — Diseases and Disorders of the Respiratory System [MDC crossing]: “Diseases and Disorders of the Respiratory System — 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.”
  • MDC 24 — Multiple Significant Trauma [MDC crossing]: “Multiple Significant Trauma — 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.”
  • 008Q0ZZ — Division of Vagus Nerve, Open Approach [Same-MDC procedure]: “Division of Vagus Nerve, Open Approach — grouped in MDC 04, the procedure side of this code's crossing.” · check together
  • 008Q3ZZ — Division of Vagus Nerve, Percutaneous Approach [Same-MDC procedure]: “Division of Vagus Nerve, Percutaneous Approach — grouped in MDC 04, the procedure side of this code's crossing.” · check together
  • 008Q4ZZ — Division of Vagus Nerve, Percutaneous Endoscopic Approach [Same-MDC procedure]: “Division of Vagus Nerve, Percutaneous Endoscopic Approach — grouped in MDC 04, the procedure side of this code's crossing.” · check together
  • 021P08A — Bypass Pulmonary Trunk from Innominate Artery with Zooplastic Tissue, Open Approach [Same-MDC procedure]: “Bypass Pulmonary Trunk from Innominate Artery with Zooplastic Tissue, Open Approach — grouped in MDC 04, the procedure side of this code's crossing.” · check together
  • 021P08B — Bypass Pulmonary Trunk from Subclavian with Zooplastic Tissue, Open Approach [Same-MDC procedure]: “Bypass Pulmonary Trunk from Subclavian with Zooplastic Tissue, Open Approach — grouped in MDC 04, the procedure side of this code's crossing.” · check together
  • and 26950 more

Nearest codes (40)

  • S22 — Fracture of rib(s), sternum and thoracic spine [Sibling]
  • S22.41XA — Multiple fractures of ribs, right side, initial encounter for closed fracture [Sibling]
  • S22.41XB — Multiple fractures of ribs, right side, initial encounter for open fracture [Sibling]
  • S22.41XD — Multiple fractures of ribs, right side, subsequent encounter for fracture with routine healing [Sibling]
  • S22.41XG — Multiple fractures of ribs, right side, subsequent encounter for fracture with delayed healing [Sibling]
  • S22.41XK — Multiple fractures of ribs, right side, subsequent encounter for fracture with nonunion [Sibling]
  • S22.41XS — Multiple fractures of ribs, right side, sequela [Sibling]
  • S22.42 — Multiple fractures of ribs, left side [Sibling]
  • and 32 more

Change history (2)

  • FY2027 — Code First note added [Change history]
  • and 1 more

Referenced by Other Codes

Clinical classification (AHRQ CCSR):INJ003 — Fracture of torso, initial encounter (default).

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

Potential MS-DRG Relationships (FY2026)

MCC — Major Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 54 clinically related codes on its CMS exclusion list. Does not count toward severity when the stay groups to DRGs 957-959 (Other O.R. Procedures for Multiple Significant Trauma); DRGs 963-965 (Other Multiple Significant Trauma).

Named in the grouper logic of 6 MS-DRGs: DRG 183 (MDC 04), DRG 184 (MDC 04), DRG 185 (MDC 04), DRG 963 (MDC 24), DRG 964 (MDC 24), DRG 965 (MDC 24).

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

Official ICD-10-CM tabular notes on other codes that name S22.5XXB or its code family.

4 Excludes1 notes across 2 chapters: M48.5 (via S22.-), M84.3 (via S22.-), M84.4 (via S22.-), S22.4 (via S22.5.-).

Frequently Asked Questions (FAQ) & Clinical Guidance

Does S22.5XXB require a 7th character?

Yes. The appropriate 7th character is to be added to each code from category S22.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to S22.5XXB in its code family, with their registry titles.

  • S22.49XG — Multiple fractures of ribs, unspecified side, subsequent encounter for fracture with delayed healing
  • S22.49XK — Multiple fractures of ribs, unspecified side, subsequent encounter for fracture with nonunion
  • S22.49XS — Multiple fractures of ribs, unspecified side, sequela
  • S22.5 — Flail chest
  • S22.5XXA — Flail chest, initial encounter for closed fracture
  • S22.5XXD — Flail chest, subsequent encounter for fracture with routine healing
  • S22.5XXG — Flail chest, subsequent encounter for fracture with delayed healing
  • S22.5XXK — Flail chest, subsequent encounter for fracture with nonunion
  • S22.5XXS — Flail chest, sequela
  • S22.9 — Fracture of bony thorax, part unspecified

View all codes in the S22 family