[Aesthetic reconstruction of the scar contracture deformity in chin and neck with expanded flaps based on the "MRIS" principle].

Objective: The surgical reconstruction strategy for scar contracture deformity in chin and neck was explored, aiming to obtain better aesthetic outcome. Methods: A retrospective observational study was conducted. From December 2017 to April 2021, 34 patients with scar contracture deformity in chin and neck after burns were hospitalized in the Department of Plastic Surgery of the First Affiliated Hospital of Army Medical University (the Third Military Medical University), aged 12-54 years, including 13 males and 21 females, 4 cases with chin affected only, 7 cases with neck affected only, and 23 cases with both chin and neck affected. The scar areas were 48-252 cm². All the patients were treated by operation with expanded flaps, following the "MRIS" principle of matching of the color and thickness of the repair flaps (match), reconstructing of the aesthetic features of subunits (reconstruction), design of incision according to the plastic principle (incision), and prevention of the surgical incision scar (scar). The rectangular or kidney shaped skin and soft tissue expander (hereinafter referred to as the expander) with rated capacity of 80-400 mL was embedded in the first stage, which was routinely expanded to 3-5 times of the rated capacity of the expander. In the second stage, scar resection and expanded flap excision were performed to repair the secondary wound, and the flap donor site was sutured directly. The expansion ratio of the expander (with average value being calculated), the type of flaps used, the reconstruction of local aesthetic morphology, the appearance of postoperative incision, the survival of flap, and the situation of donor and recipient sites observed during follow-up were recorded. Results: Among the 34 patients, the average expansion ratio of the implanted expander was 3.82 times of the rated capacity of the expander. Three cases were repaired by the expanded local pedicled flap only, 19 cases by the expanded shoulder and/or chest perforator pedicled flap only, 10 cases by the expanded local pedicled flap combined with the expanded shoulder and/or chest perforator pedicled flap, and 2 cases by the expanded local pedicled flap combined with the expanded free flap of the second intercostal perforator of internal thoracic artery. After scar resection, the shapes of lower lip and chin-lip groove were reconstructed in 10 cases, chin process reconstruction and chin lengthening were performed in 16 cases, and the cervico-mental angle and mandibular margin contour were reconstructed in 28 cases. The surgical incision was concealed, most of which were located at the natural junction or turning point of the chin and neck subunits. The vertical incision of neck was Z-shaped or fishtail-shaped. All the expanded flaps in 34 patients survived after operation, of which 8 patients had minor necrosis at the edge or tip of the expanded flaps 1-3 days after operation and healed after dressing change. During the follow-up of 3-18 months, little difference in color and thickness between the expanded flap and the skin of chin and neck was observed, and the aesthetic shape of chin and neck was significantly improved, with mild scar hyperplasia of surgical incision. Conclusions: Reconstruction of scar contracture deformity in chin and neck by using expanded flaps based on the "MRIS" principle is beneficial to improve the quality of surgery and achieve better aesthetic outcome.