CAISS Extremity Injuries 5 — Questions and Answers
Question 1: Which of the following best describes the use of the AIS severity score of 3 for extremity injuries?
- Minor, no hospitalization needed
- Serious but not life-threatening, hospitalization required (Correct answer)
- Critical with immediate life threat
- Fatal injury
Correct answer: Serious but not life-threatening, hospitalization required
AIS 3 (serious) indicates significant injury requiring hospitalization but without an immediate threat to life.
Question 2: A closed distal radius fracture (Colles' fracture) in an adult is typically assigned which AIS severity?
- AIS 1
- AIS 2 (Correct answer)
- AIS 3
- AIS 4
Correct answer: AIS 2
A closed distal radius fracture is a moderate injury coded AIS 2, reflecting need for treatment without serious morbidity.
Question 3: In AIS coding, compartment syndrome developing after a tibial fracture is treated as:
- A separate AIS code added to the fracture code
- Ignored if the fracture is already coded
- A complication that elevates the fracture's AIS severity (Correct answer)
- Coded under the skin/soft tissue chapter
Correct answer: A complication that elevates the fracture's AIS severity
Compartment syndrome is considered when selecting the appropriate AIS descriptor, generally elevating the overall severity of the associated fracture.
Question 4: What is the primary purpose of including extremity injuries in the ISS calculation?
- To document mechanism of injury
- To quantify overall trauma burden across body regions (Correct answer)
- To determine surgical approach
- To classify injury for billing
Correct answer: To quantify overall trauma burden across body regions
ISS uses AIS scores across body regions to provide a numeric summary of total injury burden that correlates with mortality and morbidity.
Question 5: A patient has an AIS 4 lower extremity injury and an AIS 3 upper extremity injury. These two scores contribute to ISS as:
- 4 + 3 = 7
- 4² + 3² = 25 (Correct answer)
- 4² = 16 only (same region rule)
- Max(4,3)² = 16
Correct answer: 4² + 3² = 25
Upper and lower extremity are separate AIS body regions, so both scores contribute: 4² + 3² = 16 + 9 = 25.
Question 6: Which of these extremity injury descriptions would be coded using a vascular qualifier in AIS?
- Closed femur fracture, nondisplaced
- Knee contusion
- Brachial artery laceration with upper extremity ischemia (Correct answer)
- Ankle fracture-dislocation without neurovascular compromise
Correct answer: Brachial artery laceration with upper extremity ischemia
Brachial artery laceration causing ischemia specifically involves a major vessel and requires the appropriate vascular AIS descriptor for upper extremity.
Question 7: According to AIS principles, which factor most directly determines whether a closed long-bone fracture is coded AIS 3 versus AIS 4?
- Patient age
- Presence of associated neurovascular injury (Correct answer)
- Number of fracture fragments
- Time to surgical treatment
Correct answer: Presence of associated neurovascular injury
Associated neurovascular injury is the primary anatomic factor that elevates a closed long-bone fracture from AIS 3 to AIS 4.
CAISS Extremity Injuries 5
Which of the following best describes the use of the AIS severity score of 3 for extremity injuries?