Presentation of two cases of pelvic periacetabular sarcoma, which were treated with wide resection of the tumor, pelvic reconstruction and lower limb salvage. Two patients, one male 23 y.o. with chondrosarcoma and one female 75 y.o. with chondroblastic osteosarcoma, were treated in our clinic. Both tumors were stage II according to Enneking’s classification. Both tumors were treated with Enneking type II internal hemipelvectomy due to their periacetabular localization. After wide resection of tumors, pelvic deficit was reconstructed with allograft, which was internally fixated, and total hip replacement with constrained prosthesis. Clinical evaluation showed absence of pain and satisfactory function of the limb. Imaging evaluation with x-ray, 3D-scan kai MRI showed satisfactory position and condition of allograft and internal fixation without evidence of loosening. Non weight bearing mobilization commenced 3 weeks postoperatively. Internal hemipelvectomy requires precise preoperative planning and surgical knowledge because it is technically demanding due to complex structure of the pelvis, the great number of muscular attachments and the presence of important vessels, nerves and pelvic viscera. Wide pelvic resection and reconstruction with allograft for periacetabular sarcomas is a challenging procedure, which offers the opportunity of limb salvage associated with functional outcome.
This study aimed to investigate the ability of vascularized periosteum to induce bone formation under functional loading in vivo. To achieve this, a gap was created in the ribs of mini pigs while functional loading was provided by the respiratory movements. Sixteen juvenile mini pigs were used, assigned in 4 different groups. In group A, a 1,4 cm rib gap was internally fixated (KLS Martin LP 2,0 mm mini plates and screws) and the periosteum flap was entirely preserved and sutured in situ. In group B the same method was followed, but the periosteum adjacent to the gap was completely excised. In group C, the periosteum was preserved; fixation was used and in addition to these, a biologically inert cement was used to obliterate the marrow cavities at the osteotomy sites. Finally, group D (control) included animals in which the gap was left without fixation and periosteum was completely removed. Specimens were harvested at 8 weeks and were evaluated macroscopically, radiologically and histopathologically. Data was analyzed using Fisher’s exact test and non-parametric statistics. Results of this study showed that all gaps created in group A and 10 in 11 in group C demonstrated complete bone formation, bridging the entire defect. No traces of bone formation were observed in groups B and D. These results indicate that rib periosteum has extremely high osteogenic capacity and can bridge large defects in vivo under the following conditions: a) its vascular supply is preserved and b) rigid fixation and functional loading is applied.
