This article presents a clinical observation of the successful treatment of a 3-year-old child with severe combined fall-related trauma (fall from the 11th floor), complicated by an extensive (30 × 20 cm) contaminated trunk wound defect with damage to internal organs. The key factor that determined the success in treating such a large wound, with documented microbial contamination but without secondary infectious complications, was the combined use of low-temperature argon plasma, vacuum therapy. The use of these methods at all stages of treatment, from initial surgical debridement to preparation for plastic reconstruction, provided a pronounced bactericidal effect, including control of nosocomial bacteria, destruction of bacterial biofilms, and rapid wound cleansing, which created optimal conditions for plastic surgery within a short time frame. For objective infection control, microbiological and molecular-genetic monitoring (using polymerase chain reaction) of the wound surface was actively employed. Serum was also examined for microbial metabolites and sepsis biomarkers, which made it possible to dynamically assess the response to therapy and to perform plastic procedures at an early stage, without purulent-inflammatory complications and without excessive escalation of antibiotic therapy. Such a rapid transition of an extensive wound process to the regeneration phase demonstrates the high effectiveness of the combined use of modern physical methods of wound treatment and laboratory monitoring techniques. This approach made it possible to achieve a favorable outcome in a child in a life-threatening condition, to avoid septic complications, and to discharge the patient from the hospital in a short period with a good result.