Abbreviated Injury Scale

The Abbreviated Injury Scale (AIS) 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(34)(56).7 Each number signifies
 * Type
 * Location
 * Severity
 * 1- body region
 * 2- type of anatomical structure
 * 3,4- specific anatomical structure
 * 5,6- level
 * 7- Severity of score

Severity
Abbreviated Injury Score-Code is on a scale of one to six, one being a minor injury and six being maximal (currently untreatable). 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.

Usage in the European Union
The European Union defined the MAIS3+ as the maximum abbreviated injury scale (MAIS) 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 (see Killed or Seriously Injured). Since 2017 Valletta Council conclusions on road safety, States started collecting those numbers. This need use of hospital data rather than police data.

"Patients often have more than one injury. The Maximum Abbreviated Injury Score (MAIS) is the highest AIS score of all injuries of a person. A road casualty with a MAIS score of 3 or more is referred to as MAIS3+"

- European Road Safety Observatory.

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.