RESUMEN
The essence of treating scar contractures lies in covering the skin deficit after releasing the contractures, typically using flaps or skin grafts. However, the specific characteristics of scar contractures, such as their location, shape, and size, vary among patients, which makes surgical planning challenging. To achieve excellent outcomes in the treatment of scar contractures, we have developed a dimensional classification system for these contractures. This system categorizes them into four types: type 1 (superficial linear), type 2-d (deep linear), type 2-s (planar scar contractures confined to the superficial layer), and type 3 (planar scar contractures that reach the deep layer, i.e., three-dimensional scar contractures). Additionally, three factors should be considered when determining surgical approaches: the size of the defect, the availability of healthy skin around the defect, and the blood circulation in the defect bed. Type 1 and type 2-d are linear scars; thus, the scar is excised and sutured in a straight line, and the contracture is released using z-plasty or its modified methods. For type 2-s, after releasing the scar contracture band, local flaps are indicated for small defects, pedicled perforator flaps for medium defects, and free flaps and distant flaps for large defects. Type 2-s has good blood circulation in the defect bed, so full-thickness skin grafting is also a suitable option regardless of the defect's size. In type 3, releasing the deep scar contracture will expose important structures with poor blood circulation, such as tendons, joints, and bones. Thus, a surgical plan using flaps, rather than skin grafts, is recommended. A severity classification and treatment strategy for scar contractures have not yet been established. By objectively classifying and quantifying scar contractures, we believe that better treatment outcomes can be achieved.
RESUMEN
This study examines a rare case of frostbite on the hands caused by liquid nitrogen, focusing on the scar maturation process. Frostbite is typically less prone to abnormal scarring compared to burns, and this report contrasts the differences in scar maturation between the two. A 31-year-old male hospital employee sustained first- to second-degree frostbite on his gloved hands from a 20-second exposure to liquid nitrogen while changing a cylinder. Conservative treatment was applied, and the patient was monitored for 9 months. The deeply affected area took 50 days to epithelialize but healed without hypertrophic scarring. A mild extension contracture was noted in the distal interphalangeal joint of the right index finger, but the skin remained supple and soft. Incidents of liquid nitrogen-induced frostbite are uncommon, with only 14 cases reported in PubMed® previously. In frostbite, the wound healing involves a slow replacement of damaged connective tissue, which acts as an internal splint, reducing wound contraction. This contrasts with burns, where rapid connective tissue replacement occurs, often leading to significant wound contraction due to the presence of myofibroblasts in granulation tissue. In the presented case, the slow healing process and minimal wound contraction led to mature scarring without abnormalities, underlining a distinctive healing trajectory in frostbite injuries compared to burns.