High grade osteosarcoma of the extremities metastatic to the lung: long-term results in 323 patients treated combining surgery and chemotherapy, 1985-2005.

BACKGROUND: Approximately one-third of patients with localized osteosarcoma at presentation relapse as well as about three-fourths of the patients with metastases at diagnosis, about 90% of relapses are lung metastases. The role of lung metastasectomy remains to be determined. PATIENTS: and methods: Three hundred and twenty three patients, 88 with resectable lung metastases at diagnosis and 235 with localized disease at presentation who relapsed with lung metastases were treated. RESULTS: A total of 498 lung surgeries and 607 thoracotomies were performed. The 5 year overall survival was 37%. Final outcome was significantly related to presence or absence of metastasis, time of first relapse and presence of local recurrences. According to stage of the disease, the rate of a 5 year event-free survival (EFS) was 36% for patients with localized disease who later relapsed and 9% for patients with resectable lung metastases at presentation (p<0.0001). However, there were no differences in EFS between patients who underwent two or three thoracotomies and patients who had four or five thoracotomies (7.5 vs 18.7%, p=0.29). CONCLUSIONS: In patients with recurrent resectable pulmonary metastases from high grade osteosarcoma treated with adjuvant or neoadjuvant chemotherapy, thoracotomy should always be considered regardless the number of previous lung relapses and the number of secondary pulmonary lesions.

Stromal stem cells and platelet-rich plasma improve bone allograft integration.

Early vascular invasion is a key factor in bone allograft incorporation. It may reduce the complications related to slow and incomplete bone integration. Bone-marrow-derived stromal stem cells associated with platelet-rich plasma are potent angiogenic inducers proven to release vascular endothelial growth factor. Our goal was to test whether the combination of stromal stem cells and platelet-rich plasma is able to increase massive allograft integration in a large animal model with sacrifice at 4 months. A critical defect was made in the mid-diaphysis of the metatarsal bone of 10 sheep; the study group received an allograft plus stromal stem cells, platelet-rich plasma, and collagen (six animals) and the control group received only the allograft (four animals). Investigation was done with radiographs, mechanical tests and histomorphometric analysis, including new vascularization. Results showed substantial new bone formation in the allograft of the study group. Bone formation is correlated with better vascular invasion and remodeling of the graft in the study group. These results confirm the key role played by stromal stem cells and platelet-rich plasma in bone repair. Further studies are needed to better define the role stromal stem cells play when implanted alone.

In vivo experimental study on bone regeneration in critical bone defects using an injectable biodegradable PLA/PGA copolymer.

OBJECTIVES: An assessment was done of the bone-healing rate after implantation of a polylactide/polyglycolide copolymer (PLA-PGA) 50/50 dispersed in aqueous solution of PGA and dextran, used as bone substitutes in an animal model. STUDY DESIGN: Two groups of 5 rabbits each were used. In both the femoral condyles, a critical size defect of 6x10 mm was made. On the right side PLA/PGA was inserted; the left side remained empty. Thirty and 90 days after surgery the animals were killed. RESULTS: Defects left unfilled showed no spontaneous healing after 30 and 90 days. Sites filled with experimental materials showed new bone ranging between 11.46% and 76.82% after 30 days, and 75.98% and 95.34% after 90 days. Histomorphometry showed an increase in bone maturation between day 30 and 90 in experimental sites. At day 90, no statistical difference was seen as compared to normal bone. CONCLUSION: PLA/PGA copolymer dispersed in hydrosoluble matrix seems to be suitable as osteoconductive material in critical size defects.

Osseointegration of endosseous ceramic implants after postoperative low-power laser stimulation: an in vivo comparative study.

Stimulation with low-power laser (LPL) can enhance bone repair as reported in experimental studies on bone defects and fracture healing. Little data exist concerning the use of LPL postoperative stimulation to improve osseointegration of endosseous implants in orthopaedic and dental surgery. An in vivo model was used for the present study to evaluate whether Ga-Al-As (780 nm) LPL stimulation can improve biomaterial osseointegration. After drilling holes, cylindrical implants of hydroxyapatite (HA) were placed into both distal femurs of 12 rabbits. From postoperative day 1 and for 5 consecutive days, the left femurs of all rabbits were submitted to LPL treatment (LPL group) with the following parameters: 300 J/cm2, 1 W, 300 Hz, pulsating emission, 10 min. The right femurs were sham-treated (control group). Three and 6 weeks after implantation, histomorphometric and microhardness measurements were taken. A higher affinity index was observed at the HA-bone interface in the LPL group at 3 (P<0.0005) and 6 weeks (P<0.001); a significant difference in bone microhardness was seen in the LPL group vs. the control group (P<0.01). These results suggest that LPL postoperative treatment enhances the bone-implant interface.

The role of different chemical modifications of superoxide dismutase in preventing a prolonged muscular ischemia/ reperfusion injury.

It is well know that a long period of ischemia followed by reperfusion can create an irreversible tissue damage, also due to the excessive generation of oxygen-derived free radicals. A possibility for avoiding this syndrome is represented by the use of free radical scavengers, such as the superoxide dismutase (SOD). The current authors compared the results achieved through different modifications of this enzyme in an experimental rat hind limb model of ischemia/reperfusion. 60 rats that had a 4 hour and 30 minute ischemia of the left hind limb were divided into four groups of 15 each and treated using a physiological solution (control group), native SOD, monomethoxypolyethylene-glycol-SOD (mPEG-SOD) or poly(acryloilmorpholine)-SOD (PAcM-SOD). The outcomes obtained in terms of limb survival (p < 0.05), as well as histomorphologic studies (p < 0.0005), revealed a superior capacity of mPEG-SOD when compared with the other three substances.