Reconstruction using a frozen autograft for a skull and humeral lesion of synchronous multicentric osteosarcoma after undergoing successful neoadjuvant chemotherapy: a case report and review of the literature.

BACKGROUND: Synchronous multicentric osteosarcoma (SMOS) is a rare disease characterized by simultaneous multicentricity of intraosseous osteosarcoma without visceral involvement. SMOS, including a skull lesion, which occurs relatively rarely, and reconstruction using a frozen autograft after the excision of a lesion of SMOS has been infrequently reported previously. CASE PRESENTATION: We report an 18-year-old girl with SMOS, with lesions located in the left distal femur, right proximal humerus, and left occipital bone. Her major complaint was pain and swelling around the left knee joint. Asymptomatic lesions of the humerus and skull bone were detected on a systemic bone scan. No visceral organ metastasis was observed. A biopsy of the distal femoral lesion revealed osteosarcoma. Based on the histological findings, multiple bone lesions, and absence of visceral lesion, the clinical diagnosis of SMOS was made. After five courses of neoadjuvant chemotherapy with a regimen of doxorubicin and cisplatin, reconstruction using a tumor prosthesis following wide excision of the left distal femur was performed, and total necrosis was histologically observed in the retracted specimen. Following three cycles of adjuvant chemotherapy, tumor excision and reconstruction with a frozen autograft treated with liquid nitrogen was conducted for both lesions of the humerus and skull, rather than tumor prosthesis or synthetics, in order to retain a normal shoulder function, and to obtain a good cosmetic and functional outcome after treatment of the skull lesion. Further adjuvant chemotherapy could not be administered after the completion of the surgical treatment for all lesions because the adverse events due to chemotherapy were observed. At over 5 years after the diagnosis, she remains clinically disease-free. CONCLUSIONS: An early correct diagnosis, the proper management of chemotherapy, and surgical treatment for all lesions are essential for achieving a good clinical outcome, even in SMOS including a skull lesion. By performing reconstruction using a frozen autograft for a proximal humeral lesion and a skull lesion after confirming the good histological efficacy of neoadjuvant chemotherapy for the primary lesion, the excellent function of the shoulder joint and a good cosmetic outcome at the site of the skull lesion was acquired without complications or recurrence.

Comparison between polyurethanes containing castor oil (soft segment) and cancellous bone autograft in the treatment of segmental bone defect induced in rabbits.

The aim of this study is to compare polyurethanes containing castor oil (soft segment) in granular form compared to cancellous bone autograft applied to a segmental bone defect. Norfolk adult female rabbits - approximately 13 months of age with a mean body weight of 4.5 kg - are used. In both radial diaphyses, 1 cm osteoperiosteal segmental defects are created. The defect in the left radius is filled with the castor-oil-based polyurethane, and the right one, filled with cancellous bone autograft, collected from the left proximal humerus. The rabbits are euthanazed at 15, 30, 60, and 120 days postsurgery (5 animals/ period), for histological analyses. By radiographic analyses, at these time points, the bone regeneration is more evident and accelerated in the bone defects treated with the cancellous bone autograft. At 120 days postsurgery, the segmental bone defects treated with the cancellous bone autograft are totally reconstituted and remodeled, while the bone defects treated with polyurethane polymer have bone formation of 79%. Histological study shows that the polyurethane acts as a space filler, minimizing the local production of fibrous tissue. No granule degradation, resorption or any inflammatory reaction is detected. Thus, it is possible to conclude that the castor-oil-plant-based polyurethane - in the granule presentation - is biocompatible and osteointegrated, but does not show the same bone regeneration capacity as the cancellous bone autograft.