Abbreviated Injury Scale


The Abbreviated Injury Scale is an anatomical-based coding system created by the Association for the Advancement of Automotive Medicine to classify and describe the severity of injuries. It represents the threat to life associated with the injury rather than the comprehensive assessment of the severity of the injury. AIS is one of the most common anatomic scales for traumatic injuries.

History

The first version of the scale was published in 1969 with major updates in 1976, 1980, 1985, 1990, 1998, 2005, 2008 and 2015.

Scale

The score describes three aspects of the injury using seven numbers written as 12.7
  • Type
  • Location
  • Severity
Each number signifies
  • 1- body region
  • 2- type of anatomical structure
  • 3,4- specific anatomical structure
  • 5,6- level
  • 7- Severity of score
AIS CodeRegion
1Head
2Face
3Neck
4Thorax
5Abdomen
6Spine
7Upper Extremity
8Lower Extremity
9Unspecified

AIS CodeRegion
1Whole Area
2Vessels
3Nerves
4Organs
5Skeletal
6Loss of Consciousness

Whole Area-
AIS CodeRegion
02Skin Abrasion
04Contusion
06Laceration
08Avulsion
10Amputation
20Burn
30Crush
40Degloving
50Injury - NFS
60Penetrating
Head - Loss of Consciousness -
02Length of loss of consciousness
04-08Level of consciousness
10Concussion
Spine-
02Cervical
04Thoracic
06Lumbar
Vessels, Nerves, Organs, Bones, Joints-
02Vessels
04Nerves
06Organs
08Bones
10Joints

Specific Injuries are assigned consecutive two-digit numbers beginning with 02
Fractures, rupture, laceration, etc.

Severity

Abbreviated Injury Score-Code is on a scale of one to six, one being a minor injury and six being maximal. An AIS-Code of 6 is not the arbitrary code for a deceased patient or fatal injury, but the code for injuries specifically assigned an AIS 6 severity. An AIS-Code of 9 is used to describe injuries for which not enough information is available for more detailed coding, e.g. crush injury to the head.
The AIS scale is a measurement tool for single injuries. A universally accepted injury aggregation function has not yet been proposed, though the injury severity score and its derivatives are better aggregators for use in clinical settings. In other settings such as automotive design and occupant protection, MAIS is a useful tool for the comparison of specific injuries and their relative severity and the changes in those frequencies that may result from evolving motor vehicle design.
AIS-CodeInjuryExampleAIS % prob. of death
1Minorsuperficial laceration0.1-1
2Moderatefractured sternum1-2
3Seriousopen fracture of humerus2-16
4Severeperforated trachea16-30
5Criticalruptured liver with tissue loss30-99
6Fataltotal severance of aorta100
9Not further specified

Usage in the European Union

The European Union defined the MAIS3+ as the maximum abbreviated injury scale with a score of 3 or more. The definition was used to harmonize count of serious injuries or serious road injury in different member States. Since 2017 Valletta Council conclusions on road safety, States started collecting those numbers. This need use of hospital data rather than police data.
Those data can be computed in three different ways:
  1. with a link between police and hospital data;
  2. reporting injuries from hospitals;
  3. using police data with a corrective coefficient computed from samples
Previously each State had a different definition of a serious injury.
It has been estimated that 110,000 people were seriously injured in traffic collisions on the roads of European Union member States in 2019, based on MAIS3+ definition. In 2018, some Eastern European countries do not provide data. When data is available, the breakdown attributes 19 thousandths to Italy, 16 to France, 15 to Germany, 7 to the Netherlands, 5 to Spain, 3 to Belgium, 3 to Czechia, 2 to Portugal, 1 to Austria, and less than one thousands for each other countries. However, these data are computed with different methods in each country. One reason is that medical diagnoses are often coded with the WHO’s International Classification of Diseases. Also, Italy uses ICD-9 and other countries use ICD-10.