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ICD-10 Guide
ICD-10 CodesS21.20

S21.20

Billable

Unspecified open wound of back wall of thorax without penetration into thoracic cavity

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/23/2025

Code Description

ICD-10 S21.20 is a billable code used to indicate a diagnosis of unspecified open wound of back wall of thorax without penetration into thoracic cavity.

Key Diagnostic Point:

An unspecified open wound of the back wall of the thorax refers to a traumatic injury that results in a break in the skin and underlying tissues in the thoracic region, specifically the posterior aspect, without breaching the thoracic cavity. This type of injury can occur due to blunt or penetrating trauma, such as falls, motor vehicle accidents, or stab wounds. Clinically, these wounds may present with varying degrees of tissue damage, including lacerations, abrasions, or contusions. While the wound does not penetrate the thoracic cavity, it can still be associated with significant complications, such as rib fractures, pneumothorax, or hemothorax, depending on the mechanism of injury. The management of these wounds often involves thorough assessment for associated injuries, wound care, and possibly surgical intervention if there is significant tissue damage or risk of infection. Accurate coding is essential for proper treatment documentation and reimbursement, as well as for tracking injury patterns in trauma patients.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variability in documentation of wound specifics
  • Potential for associated injuries requiring additional codes
  • Differentiation from similar codes for rib fractures or pneumothorax
  • Need for precise clinical details to avoid misclassification

Audit Risk Factors

  • Inadequate documentation of the mechanism of injury
  • Failure to identify associated rib fractures or other thoracic injuries
  • Misclassification of wound type or severity
  • Inconsistent coding practices among different providers

Specialty Focus

Medical Specialties

Trauma Surgery

Documentation Requirements

Detailed descriptions of the wound, mechanism of injury, and any associated injuries.

Common Clinical Scenarios

Trauma patients presenting with open thoracic wounds from accidents or violence.

Billing Considerations

Ensure all associated injuries are documented to support comprehensive coding.

Emergency Medicine

Documentation Requirements

Immediate assessment findings, imaging results, and initial treatment provided.

Common Clinical Scenarios

Patients with acute chest trauma requiring urgent evaluation and management.

Billing Considerations

Accurate documentation of vital signs and any interventions performed in the emergency setting.

Coding Guidelines

Inclusion Criteria

Use S21.20 When
  • According to ICD
  • 10 guidelines, this code should be used when the wound is not specified further and does not involve penetration into the thoracic cavity
  • Coders should ensure that the documentation supports the diagnosis and that any associated injuries are coded separately

Exclusion Criteria

Do NOT use S21.20 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

12001CPT Code

Simple repair of superficial wounds

Clinical Scenario

Used for the repair of the open wound on the thoracic wall.

Documentation Requirements

Document the size of the wound and the method of repair.

Specialty Considerations

Trauma surgeons should ensure that all associated injuries are documented.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of injuries, improving the accuracy of data collection and reimbursement processes. S21.20 provides a clear designation for open wounds without thoracic cavity involvement, facilitating better patient management and tracking of trauma cases.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of injuries, improving the accuracy of data collection and reimbursement processes. S21.20 provides a clear designation for open wounds without thoracic cavity involvement, facilitating better patient management and tracking of trauma cases.

Reimbursement & Billing Impact

reimbursement processes. S21.20 provides a clear designation for open wounds without thoracic cavity involvement, facilitating better patient management and tracking of trauma cases.

Resources

Clinical References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Coding & Billing References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Frequently Asked Questions

What is the difference between S21.20 and S21.21?

S21.20 is used for open wounds of the back wall of the thorax without penetration into the thoracic cavity, while S21.21 is for wounds that do penetrate the thoracic cavity, which may involve more serious complications.