Treat the wound, not the weapon
Just as with any medical topic, surgeons must understand the pathophysiology of war wounds in order to best care for the patient.
Epidemiology of Injuries
Weapons of conventional war can be divided into explosive munitions and small arms.
- Explosive munitions: artillery, grenades, mortars, bombs, and hand grenades.
- Small arms: pistols, rifles, and machine guns.
Two major prospective epidemiological studies were conducted during the 20th century looking at the cause of injury as well as outcome.
- During the Bougainville campaign of World War II, a medical team was sent prospectively to gather data on the injured, including the cause of injury. This campaign involved primarily infantry soldiers and was conducted on the South Pacific island of Bougainville during 1944.
- US Army and Marine casualties from the Vietnam War collected by the Wound Data and Munitions Effectiveness Team (WDMET) in Vietnam.
The most common pattern of injury seen on a conventional battlefield is the patient with multiple small fragment wounds of the extremity.
Mechanism of Injury
For missile injuries
There are two areas of projectile-tissue interaction, permanent cavity and temporary cavity
- Permanent cavity. Localized area of cell necrosis, proportional to the size of the projectile as it passes through.
- Temporary cavity. Transient lateral displacement of tissue, which occurs after passage of the projectile. Elastic tissue, such as skeletal muscle, blood vessels and skin, may be pushed aside after passage of the projectile, but then rebound. Inelastic tissue, such as bone or liver, may fracture in this area.
The shock (or sonic) wave (commonly mistaken for the temporary cavity), though measurable, has not been shown to cause damage in tissue.
- Fragments from explosive munitions cause ballistic injuries.
- Fragments are most commonly produced by mortars, artillery, and grenades.
- Fragments produced by these weapons vary in size, shape, composition, and initial velocity. They may vary from a few milligrams to several grams in weight.
- Modern explosive devices are designed to spread more uniform fragments in a regular pattern over a given area.
- Fragments from exploding munitions are smaller and irregularly shaped when compared to bullets from small arms.
- Although initial fragment velocities of 5,900 ft/s (1,800 m/ s) have been reported for some of these devices, the wounds observed in survivors indicate that striking velocities were less than 1,900 ft/s (600 m/s). Unlike small arms, explosive munitions cause multiple wounds.
- The blast effects take place relatively close to the exploding munition relative to the ballistic injury.
- Blast overpressure waves, or sonic shock waves, are clinically important when a patient is close to the exploding munition, such as a land mine.
- The ears are most often affected by the overpressure, followed by lungs and the gastrointestinal (GI) tract hollow organs. GI injuries may present 24 hours later.
- Injury from blast overpressure is a pressure and time dependent function. By increasing the pressure or its duration, the severity of injury will also increase.
- Thermobaric devices work by increasing the duration of a blast wave to maximize this mechanism of injury. The device initially explodes and puts a volatile substance into the air (fuel vapor). A second explosion then ignites the aerosolized material producing an explosion of long duration. The effects from this weapon are magnified when detonated in an enclosed space such as a bunker.
- Air displaced on the site after the explosion creates a blast wind that can throw victims against solid objects, causing blunt trauma.
- Thermal effects occur as the product of combustion when the device explodes. Patients wounded near exploding munitions may have burns in addition to open wounds, which may complicate the management of soft tissue injuries.