Extracorporeal Irradiation: Biological Reconstruction Following Tumor Resection With A Large Bone Defect

Introduction: Reconstruction of massive segmental bone defects is a crucial point of limb salvage surgeries after malignant bone tumor resections. Megaendoprostheses implantation is a commonly used method for adult patients, but hardly usable for children below 12 years old, because of the small size of the host bone and multiple mechanic complications.Objective: Extracorporeal irradiation and allograft reimplantation (ECRT, ECI) are promising methods for these young children for limb salvage, reducing the number of prostheses revisions, reoperations.Method: In Hungary, we performed limb salvage surgery for malignant bone tumor in 12 cases in children under 12 years old, using extracorporeally irradiated autografts as biological reconstruction. All cases were primary bone tumors (Ewing's sarcoma: 7, osteosarcoma: 4, chondrosarcoma: 1). The average age of our patients was 9 (3-12) years, the average follow-up was 32.5 (2-73) months. At follow-up, we performed physical examination, X-ray, and other imaging methods if they were necessary. Our results were compared to international publications.Results: We observed no local recurrence, but in one case we had to perform above-knee amputation, due to a skip metastasis in the proximal tibia. The complication rates were similar to those reported in other papers. Septic complications were treated in two cases (16.7%). Total union of the resection lines was observed at 3-9 months in 60% of all cases. Reoperations were performed due to nonunion, or allograft fracture/partly desorganization in 3 cases, twice with new allograft, and with prostheses in one case. The subjective opinion of our patients is positive, they walk with full weightbearing, some of them do even light sporting activities.Conclusions: We found extracorporeal irradiation a useful and safe method for children under 12 years old for biological reconstruction after malignant bone tumor resection. Complication rate stays under the rate of growing prostheses complications, in optimal cases further radical, and extensive surgeries may be avoided. In the case of major complications, megaendoprostheses implantation later on is still an option as salvage procedure with limb salvage.