BACKGROUND:
Iatrogenic chemical burns caused by skin preparation solutions and pneumatic tourniquets have rarely reported in the literatures. To date, no such cases have been documented in the context of free flap harvesting.

MATERIALS AND METHODS:
We present a case of a suspicious chemical burn injury at posterior thigh of the donor leg during fibular flap harvesting in a 65-year-old man. The patient was diagnosed with right buccal squamous cell carcinoma and underwent tumor wide excision and segmental mandibulectomy by oncologic surgeon first. Free fibular osteocutaneous flap was planned for restoring both mandible and intraoral mucosal defects. The operation preparation was performed standardly by povidone-iodine alcoholic solution (10% povidone-iodine and 95% alcohol). Pneumatic tourniquet on the thigh of donor leg was then inflated to 250 mmHg (100 mmHg above systolic blood pressure) for bleeding control while flap harvesting as usual. The whole procedure was about 3 hours, and the tourniquet was deflated. Unfortunately, full-thickness skin necrosis was observed postoperatively at the depending side of thigh, where the tourniquet had just been applied.

RESULTS:
In addition to the skin-depth injury, rhabdomyolysis also developed shortly after the incident. The biochemistry profile revealed elevated levels of CK and myoglobin, reaching 13,222 U/L and 11,846 ng/mL, respectively. Despite aggressive fluid hydration and urine alkalinization, acute kidney injury ensued. The patient progressed to pulmonary edema and acute respiratory distress syndrome within approximately one week, necessitating the initiation of continuous venovenous hemofiltration and, ultimately, extracorporeal membrane oxygenation. Following intensive treatment, the general condition stabilized. Approximately one month later, the burn wound was successfully resurfaced with skin grafting. The wound healed well, and the patient was discharged home in a stable condition.

DISCUSSION:
Significant mechanisms contributing to this chemical burn included skin irritation from the preparation solution, as well as maceration, friction, and pressure. These factors collectively led to skin burn or ulceration. Failure to allow the skin preparation solution to dry, leading to its entrapment under the patient's body, particularly beneath a tourniquet, may result in skin irritation and subsequent burns.

CONCLUSIONS:
This report aims to heighten awareness among plastic surgeons regarding iatrogenic burn injuries and underscores the critical importance of preventive measures in the region where the tourniquet is applied.

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