Injury: general information
Last reviewed: 23.04.2024
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Physiology of injuries
The healing process begins immediately after the wound is wounded with blood coagulation and the leukocyte function begins; neutrophils and monocytes remove foreign substances (including non-viable tissues) and bacteria. Monocytes also stimulate fibroblast replication and revascularization. Fibroblasts lay collagen, usually starting 48 hours after injury and reaching a maximum by the 7th day. Accumulation of collagen is essentially complete by the end of the first month, but the strength of collagen fibers is slower, since it is necessary to form cross-links between the fibers. The tensile strength of postoperative cicatrix by the third week is only 20%, 60% by the 4th month, and the maximum reaches by the end of the year; the strength of the scar will never be the same as before the injury.
Soon after injury, the epithelial cells from the edges of the wound migrate 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 trauma and form a normal epidermis for 5 days. In wounds that have not undergone surgical treatment (healing by secondary tension), epithelialization slows in proportion to the size of the defect.
The skin contains static forces, formed by the natural elasticity of the skin itself and underlying muscles. Because the scar tissue is weaker than the surrounding intact skin, these forces stretch the scar, which sometimes becomes unacceptable in cosmetic terms, even after externally adequately suturing the wound. Extension of the scar is especially likely when the tensile forces are perpendicular to the edges of the wound. This tendency (determining the strength of the scar) is especially easy to observe on a fresh wound: gaping of the edges of the wound at a perpendicular tension and accordingly a good adaptation in the parallel direction of forces.
During the first 8 weeks after the injury, the scar has a red color. After a gradual remodeling of the collagen, the scar is shortened and becomes whitish.
In some patients, in spite of everything, a hypertrophic unsightly scar is formed, protruding above the surrounding skin. A hypertrophic scar is called a keloid, which extends beyond the edges of the initial wound.
The main factors that negatively affect the healing process include tissue ischemia, infection, or a combination of these. Their occurrence can be caused by various reasons. Blood circulation disorders in a number of diseases (for example, diabetes mellitus, arterial insufficiency), the nature of the trauma (for example, the syndrome of prolonged crushing, damaging microcirculation) and the factors that have arisen in wound correction, such as overly tight seams and, possibly, the use of vasoconstrictors together with local anesthetics. The risk of circulatory disorders in the lower limbs is usually higher. Hematomas in the wound area, the presence of foreign bodies (including suture material), later treatment (more than 6 hours for the lower limb, more than 12-18 hours for the face and scalp) and significant microbial contamination predispose to bacterial proliferation. The bruised wounds are, as a rule, contaminated by microorganisms to a large extent.
Inspection
The clinician is obliged, first of all, to identify and stabilize the most serious lesions before concentrating on skin lesions, despite the sometimes terrible form. Active bleeding from the wound must be stopped before proceeding to the examination. It is better to do this by directly pressing the bleeding zone, and if possible, giving it an elevated position; clamping of blood vessels with instruments should be avoided because of the threat of compression of adjacent nerves.
Next, the wound is inspected for damage to adjacent structures, including nerves, tendons, vessels and bones, as well as foreign bodies or penetration into the body cavities (eg, abdominal and thoracic cavities). The failure to identify these complications is the most serious error in the treatment of wounds.
Distal sensation distal to the wound indicates a possible nerve damage; The probability increases with the presence of skin lesions along the main nerve trunks. During the examination, sensitivity and motor function should be checked. The definition of a two-point threshold is useful for damage to the hand and fingers; the doctor touches the skin at two points, using, for example, a deployed clerical clip, gradually reducing the distance between the points and thus determining the minimum distance that the patient can distinguish, without looking at the site of damage. The norm varies depending on the individual characteristics of the patient and the location on the hand; the best control will be an identical zone on the intact limb.
Any injury along the tendon gives reason to believe about its damage. A complete rupture of the tendon usually leads to deformity at rest (for example, a dangling foot when the calcaneal tendon ruptures, the loss of normal flexion when the flexor flexor is damaged) due to a violation of muscle balance between the antagonist muscles. With partial damage to the tendon, there will be no deformation in rest; It can be manifested only by pain or weakening of functions with a loading test, or it will be found during revision of the wound. Skin pallor, weakening of the pulse and, possibly, a slowing of the capillary filling distal to the damage (all in comparison with the undamaged side) indicate the likelihood of serious damage to vascular structures.
Sometimes bone damage is possible, especially with penetrating trauma (for example, knife wound, bite), as well as in areas where it is located in close proximity to the skin. If the mechanism of injury or wound localization leads to doubt, an overview radiograph is used to exclude a fracture.
Depending on the mechanism of injury in the wound, there may be foreign bodies, if a glass is injured, debris in the wound is very likely, when wounded with a sharp metal, the presence of its particles, on the contrary, is rare; risk of injury by other objects in between. Do not ignore the patient's complaints about the sensation of a foreign body, these symptoms are quite specific, although not very sensitive. Visualizing methods of investigation are recommended for all injuries associated with glass, as well as for other foreign bodies, if the mechanism of injury gives grounds for suspecting them, and it is impossible to investigate the wound to the full depth for some reason. In the case of glass or inorganic materials (stones, metal fragments), an overview X-ray diffraction pattern is performed; glass fragments of less than 1 mm can be seen. Organic materials (for example, wood chips, plastic) are rarely detected on radiographs (although the contours of large objects can be seen by the displacement of surrounding normal tissues by them). Other methods are used, including electro-radiography, ultrasound, CT and MRI. None of these methods have 100% sensitivity, but CT has the best correlation between accuracy and usability. In all cases, high alertness and thorough examination of all wounds are appropriate.
The penetration of the wound into the abdominal or thoracic cavity should be considered for any wounds, the bottom of which is not available for inspection and if they are located in the projection of these cavities. In no case can you try to determine the depth of the wound with a probe blindly - probing is not reliably diagnosed and can cause additional trauma. A patient with suspected penetrating chest injury should first perform radiography, and repeat it after 6 hours of follow-up. Any, even slowly developing pneumothorax during this time will become visualizable. In patients with wounds of the abdominal region, local anesthesia facilitates the examination of the wound (the wound can be widened horizontally if necessary). Patients with wounds penetrating the fascia are hospitalized for dynamic observation and treatment; in some cases, detect hemoperitoneum will help CT.