Free Composite Osteotomized Serratus Anterior Chondroosteomusculocutaneous Flap for Dynamic Reconstruction of a Pediatric Combined Maxillectomy and Hemimandibulectomy Defect: A Case Report.

Pediatric mandibular reconstruction is challenging due to the need to restore mandibular continuity, temporomandibular joint (TMJ) function, and long-term craniofacial growth. Conventional osseous free flaps may not adequately reproduce the ramus-condyle unit or provide a growth-capable cartilaginous component. The serratus anterior-rib composite flap offers vascularized bone and costochondral tissue but remains rarely used in children. We presented a 12-year-old pediatric patient with rhabdomyosarcoma who underwent en bloc resection including hemimandibulectomy and maxillectomy. Reconstruction was achieved using a free composite multi-segment osteotomized serratus anterior chondroosteomusculocutaneous flap incorporating the vascularized 6th rib, its costochondral junction, serratus anterior muscle, and a skin paddle. The rib was osteotomized to recreate mandibular contour, and the costochondral junction was shaped to form a neocondyle. The flap tolerated adjuvant radiotherapy and chemotherapy without complications over a 19-month follow-up period. No mandibular asymmetry was observed. Although larger series with longer follow-up periods are needed, this technique may offer a single-flap, growth-preserving solution for complex defects involving the ramus-condyle unit in pediatric patients.