Upper Limb-Salvage Surgery in Pediatric Patients with Malignant Bone Tumors Using Microsurgical Free Flaps: Long-Term Follow-Up

<b>Background</b>: Primary malignant bone tumors among adolescent patients are most commonly associated with burdensome surgeries that can severely affect young patients' early life. To this day, despite available autologous tissue donor sites, cement spacers or endoprostheses are still most commonly used as a form of reconstruction of post-resection defects. <b>Methods</b>: The study group includes 20 adolescent patients diagnosed with Osteosarcoma or Ewing Sarcoma involving the upper limbs. The inclusion criteria were as follows: primary malignant bone tumors sensitive to neoadjuvant chemotherapy, tumors not infiltrating major blood vessels and nerves, and the appliance of the microsurgical free flap as a reconstructive method. Poor tumor response to neodajuvant chemotherapy or patients with incomplete follow-up were excluded from this study. To achieve the functional reconstruction of post-resection defects, fibula free flaps were applied. In cases of resection, including the metaphysis of a long bone, a modification of the flap harvest was applied in order to prevent arthrodesis. The MSTS (Musculoskeletal Tumor Society Scoring System) scale was used as a functional outcome measurement tool. <b>Results</b>: The reported outcomes of this study prove the efficiency of the treatment's approach of combining the resection of the tumor with subsequent microsurgical restoration with the use of autologous tissues. The average score on the MSTS scale, which assesses the functional outcome, was 26.8/30 points, which indicates great motor outcomes. There were no reports of local recurrence during follow-up. <b>Conclusions</b>: Patients with primary malignant bone tumors in the upper limbs can benefit from microsurgical techniques, which are highly customized; effective; and give sufficient functionality following extensive resection.