Objective It is difficult to treat chronic osteomyel itis due to the formation of the Staphylococcus aureus biofilms. Liposomal gentamicin-impregnated allogeneic cortical bone can inhibit the formation of the Staphylococcus aureusbiofilms. To explore the treatment of chronic osteomyel itis of rabbit by l iposomal gentamicin-impregnated allogeneic cortical bone. Methods The l iposomal gentamicin, l iposomal gentamicin-impregnated allogeneic cortical bone and gentamicinimpregnated allogeneic cortical bone were produced. Then the chronic Staphylococcus aureus osteomyel itis models of rabbit were made in left lower l imbs of 40 6-month-old rabbits and the right lower l imbs were used as controls. After 2 weeks, the observations of gross and X-ray were done. Four rabbits died within 10 days after the models were made and other 36 rabbits were devided into 6 groups: group A (no antibiotics), group B (intravenous injection of gentamicin), group C (intravenous injection of l i posomal gentamicin), group D (implantation of gentamicin-impregnated allogeneic cortical bone), group E (implantation of l i posomal gentamicin-impregnated allogeneic cortical bone), and group F (implantation of allogeneic cortical bone). After 2 weeks of treatment, the bacterial culture, X-ray and HE staining were done. Results The chronic Staphylococcus aureus osteomyel itis model of rabbit was made successfully. The X-ray showed dissolution of bone and periosteal reaction in groups A, B, C, and F, and no obvious dissolution of bone and periosteal reaction in groups D and E. The Norden scores were (2.5 ± 0.3), (2.1 ± 0.2), (1.5 ± 0.3), (1.5 ± 0.2), (0.9 ± 0.3), and (2.7 ± 0.3) points in groups A-F, respectively; showing significant differences between group A and groups B-E (P lt; 0.05), between groups B, E, F and other groups (P lt; 0.05). The results of blood and marrow cultures for Staphylococcus aureus were positive in groups A and F, and negative in other 4 groups; the results of bone marrow culture for Staphylococcus aureus were positive in 6 rabbits of group B, 4 rabbits of group C and 3 rabitts of group D; and the results were negative in group E. HE staining showed: in groups A and F, abscess and dead bone formed, and no new bone formation were observed; in groups B and C, different degrees of neutrophil accumulation was seen; in group D, some neutrophil accumulation occurred, and osteoprogenitor cells and osteoclasts were seen around implanted bone; and in group E, no neutrophil accumulation was observed, a lot of granulation tissues formed, and osteoprogenitor cells and osteoclasts were seen around implanted bone. Conclusion Implantation of l iposomal gentamicin-impregnated allogeneic cortical bone has remarkly better effect in treating chronic osteomyel itis than intravenous injection of l iposomal gentamicin and implantation of gentamicin-impregnated allogeneic cortical bone.
Objective To explore a surgical method for chronic osteomyel itis of sternum after thoracotomy. Methods From January 2006 to February 2009, 11 cases of chronic osteomyelitis after thoracotomy (2 cases of coronary bypass, 6 cases of mitral valve replacement, and 3 cases of ventricular defect repair) were admitted. Of them, there were 6 males and 5females, aged from 6 to 62 years (median 34 years), including 6 cases of simple osteomyelitis of sternum, 2 cases of osteomyelitis of sternum with suppurative infection of mediastinum, and 3 cases osteomyel itis of sternum with costal chondritis. Necrotic sternum were excised and defect was from 4 cm × 3 cm to 7 cm × 4 cm. Greater pectoral muscle flap was designed from 8 cm × 5 cm to 10 cm × 6 cm on one side and was transferred to defect. Negative drainage and sensitive antibiotics were administered after operation. Results Healing by first intention was achieved in 10 patients except 1 patient who had a few discharge at the drainage outlet and whose incision healed 1 week later. The follow up was from 3 to 10 months with an average of 6 months. The formed scars were flat with soft texture in 8 patients and moderately hypertrophy in 3 patients. The wounds healed without pain, relapse or abnormal function of donor upper limb. Conclusion Transplantation of greater pectoral muscle flap is an effective way to repair chronic osteomyelitis of sternum after thoracotomy.