Trauma: general information

Proper treatment of traumatic wounds promotes accelerated healing, minimizes the risk of infectious complications and optimizes the cosmetic result.

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Physiology of injuries

The healing process begins immediately after injury with blood clotting and the initiation of white blood cell function; neutrophils and monocytes remove foreign material (including nonviable tissue) and bacteria. Monocytes also stimulate fibroblast replication and revascularization. Fibroblasts deposit collagen, usually beginning 48 hours after injury and peaking at 7 days. Collagen deposition is essentially complete by the end of the first month, but collagen fibers gain strength more slowly because cross-linking between fibers is necessary. The tensile strength of a postoperative scar is only 20% by the third week, 60% by the fourth month, and peaks by the end of the year; scar strength will never be the same as before the injury.

Shortly after injury, epithelial cells migrate from the edges of the wound to its center. After surgical treatment of the wound (primary healing), epithelial cells create an effective protective barrier for water and bacteria in the first 24-48 hours after injury and form normal epidermis within 5 days. In wounds that have not been surgically treated (healing by secondary intention), epithelialization slows down proportionally to the size of the defect.

Static forces are present in the skin, generated by the natural elasticity of the skin itself and the underlying muscles. Because the scar tissue is weaker than the surrounding intact skin, these forces stretch the scar, which sometimes becomes unacceptable from a cosmetic point of view, even after an apparently adequate wound closure. Scar widening is especially likely when the stretching forces are perpendicular to the wound edges. This tendency (which determines the strength of the scar) is especially easy to observe in a fresh wound: gaping of the wound edges under perpendicular tension and correspondingly good adaptation under parallel forces.

During the first 8 weeks after injury, the scar is red. After gradual collagen remodeling, the scar shrinks and becomes whitish.

Some patients, despite everything, develop a hypertrophic, unsightly scar that protrudes above the surrounding skin. A keloid is a hypertrophic scar that extends beyond the edges of the original wound.

The main factors that negatively affect the healing process include tissue ischemia, infection, or a combination of both. They can occur for a variety of reasons. Circulatory disorders in a number of diseases (e.g., diabetes mellitus, arterial insufficiency), the nature of the injury (e.g., crush syndrome, which damages microcirculation), and factors that arise during wound correction, such as too tight sutures and, possibly, the use of vasoconstrictors together with local anesthetics. The risk of circulatory disorders in the lower extremities is usually higher. Hematoma in the wound area, the presence of foreign bodies (including suture material), late treatment (more than 6 hours for a lower extremity, more than 12-18 hours for the face and scalp), and significant microbial contamination predispose to bacterial proliferation. Contused wounds are usually heavily contaminated with microorganisms.

Inspection

The clinician must first identify and stabilize the most serious injuries before concentrating on skin lesions, despite their sometimes gruesome appearance. Active bleeding from a wound must be stopped before proceeding with the examination. This is best accomplished by applying direct pressure to the bleeding area, and if possible by elevating it; clamping of bleeding vessels with instruments should be avoided because of the risk of compressing adjacent nerves.

The wound is then examined to detect damage to adjacent structures, including nerves, tendons, blood vessels, and bones, as well as foreign bodies or penetration into body cavities (e.g., the abdominal and thoracic cavities). Failure to detect these complications is the most serious error in wound care.

Sensory loss distal to the wound suggests possible nerve damage; the likelihood is increased by skin damage along the major nerve trunks. Examination should include testing for sensitivity and motor function. Determining the two-point threshold is useful for hand and finger injuries; the examiner touches the skin at two points, using, for example, an unfolded paper clip, gradually decreasing the distance between the points and thus determining the minimum distance the patient can discern without looking at the injury. The norm varies with the individual patient and the location on the hand; the best control is an identical zone on the uninjured limb.

Any injury along the course of the tendon suggests injury. Complete tendon ruptures usually result in resting deformity (e.g. foot drop with Achilles tendon rupture, loss of normal flexion with toe flexor injury) due to imbalance of muscle between the antagonist muscles. Partial tendon ruptures will not result in resting deformity; they may manifest only as pain or loss of function on stress testing or be discovered on wound exploration. Pale skin, diminished pulses, and possibly decreased capillary refill distal to the injury (all compared to the uninjured side) suggest the possibility of serious injury to vascular structures.

Sometimes bone damage is possible, especially with penetrating trauma (e.g., knife wound, bite), as well as in areas where it is located in close proximity to the skin. If the mechanism of damage or the location of the wound raises doubts, a survey radiography is performed to exclude a fracture.

Depending on the mechanism of injury, there may be foreign bodies in the wound. In the case of a glass wound, fragments are very likely to be present, while in the case of a sharp metal wound, the presence of its particles is rare; the risk of injury with other objects is intermediate. Patient complaints about the sensation of a foreign body should not be ignored; these symptoms are quite specific, although not very sensitive. Visual examination methods are recommended for all wounds associated with glass, as well as other foreign bodies, if the mechanism of injury gives reason to suspect them, and it is impossible to examine the wound to its full depth for some reason. In the case of glass or inorganic materials (stones, metal fragments), an overview radiograph is performed; glass fragments less than 1 mm may be visible. Organic materials (e.g., wood chips, plastic) are rarely detected on radiographs (although the contours of large objects can be seen by their displacement of the surrounding normal tissues). Other techniques used include electroradiography, ultrasound, CT, and MRI. None of these methods are 100% sensitive, but CT has the best balance between accuracy and practicality. In all cases, a high index of suspicion and careful examination of all wounds are advisable.

Penetration of the wound into the abdominal or thoracic cavity should be considered in any wounds whose bottom is not accessible for inspection and in their location in the projection of the above cavities. In no case should one try to determine the depth of the wound with a blind probe - probing is not diagnostically reliable and can cause additional trauma. A patient with suspected penetrating chest wound should first undergo radiography and repeat it after 6 hours of observation. Any pneumothorax, even slowly developing, will become visualized during this time. In patients with abdominal wounds, wound inspection is facilitated by local anesthesia (the wound can be expanded horizontally if necessary). Patients with wounds penetrating the fascia are subject to hospitalization for dynamic observation and treatment; in some cases, CT will help to identify hemoperitoneum.