Chapter 6. Open traumatic injuries

6.1. Wounds

A wound is called damage to the skin or mucous membrane of any area and depth. In such event, the integrity of the main mechanical and biological barriers of the body that separates it from the external environment is violated, and local (changes in tissues in the circumference of the wound), regional (reflex reactions, vascular and neuro-logical disorders within the damaged segment) and general (shock, endotoxicosis) disorders of life activity are developed.

Classification

Wounds are classified according to a number of characteristics:

• for reasons of occurrence - surgical (operating), accidental (traumatic) and combat (firearms, mine-explosives);
• quantity (single, multiple);
• anatomical localization (head, neck, chest, abdomen, pelvis, limbs);
• the type of damaged tissues (soft tissues, brain with damage to the brain substance, bone with open fractures, wounds with damage to blood vessels, nerves, tendons);
• the nature of the wound channel (blind, perforating, tangential, penetrating and not penetrating into the body cavity);
• morphological features - stabbed (usually with a deep canal), cut (with smooth edges), scalped (superficial with separation of the skin and subcutaneous tissue), chopped (with significant trauma to the skin edges), bruised (torn, crushed), bitten (contaminated specific microflora or poison - poisoned) and mixed (for example, stab-cut, torn-scalped).

Gunshot wounds

Gunshot wounds belong to a special type, characterized by the severity of damage due to the effect on the tissue of a significant kinetic energy of the injuring projectile and shock wave.

In this case, the effect of "interstitial explosion" occurs, when the bulk of the energy is transferred to tissues in a few milliseconds. A bullet with a steady motion that has passed through at a high speed will cause less tissue destruction than a fragment of the same mass and flying at the same speed, since it rotates in several planes and its jagged edges damage tissue more than a smooth bullet.

The shock wave accompanying the bullet or splinter, already at the stage of penetration, can cause concentric tears of tissues, forming a wound channel. During the passage of a projectile, the energy of a side impact produces temporary pulsating cavities in the tissues with a powerful dynamic effect on the surrounding tissues, which subsequently merge into one large cavity of the wound canal. Subsequently, due to tissue contraction, this cavity is somewhat reduced.

A wounding projectile can change the direction of movement in the tissues, either when it encounters an obstacle in the form of a denser tissue (bone), or due to its design features. The curvature of the wound canal formed for that reason is usually called the primary deviations of the wound canal. At the same time, due to the different contractility of the damaged tissues, their unequal displacement occurs after injury, which leads to a secondary deviation of the wound canal. In this case, the wound canal may be not only curved but even divided into separate blind closed cavities, which is especially dangerous due to the possibility of anaerobic infection. Bone fragments in gunshot fractures also acquire a translational movement and can inherently cause the formation of additional blind wound cavities in the soft tissues - secondary wound canals.

Thus, a gunshot wound has a special internal structure, and tissue destruction usually extends far beyond the wound canal.

Through the formed entrance hole, air, bacteria, foreign bodies (scraps of clothing, shoes, earth) are sucked into the wound canal, which is facilitated by a zone of low pressure formed behind the injuring projectile. This is how the primary contamination of the wound occurs. Thus, the lumen of the wound canal contains blood clots, fragments of necrotic tissues, foreign bodies, as well as microorganisms (their composition is identical to the microflora of the soil and skin).

In the gunshot wound, the presence of three specific affected areas was established:

• a wound canal (characterized by the length of the tissue defect, direction, penetration into the body cavity, the presence of lateral blind cavities and "pockets");
• injury, or primary traumatic necrosis (the tissues of this zone are not viable, since they are destroyed during injury; they are a favorable environment for the development of wound microflora);
• molecular concussion, or secondary necrosis (the vital activity of the tissues of this zone is significantly impaired, but there is no mechanical destruction; subsequently, the viability of these tissues may be restored; otherwise, necrosis will develop).

Wound process

It is necessary to distinguish microbially contaminated and infected wounds.

All wounds are microbially contaminated. Primary microbial contamination occurs at the time of injury, and secondary - during the treatment. Thus, the presence of microorganisms in the wound is a natural phenomenon.

A wound is considered infected when the body's defenses have failed to cope with the microflora that got into the wound, and the microorganisms begin to multiply. This should be regarded as a complication of the course of the wound process. In addition to microbial contamination, infection of the wound is facilitated by such factors as the presence of non-viable tissues or tissues with reduced viability, blood clots, foreign bodies in the wound; additional traumatization of tissues in the absence of immobilization; local and systemic microcirculation disorders; a decrease in the overall reactivity of the body (concomitant diseases, multiple injuries, hypothermia).