A preliminary study in osteoinduction by a nano-crystalline hydroxyapatite in the mini pig.

To test the probable osteoinductive properties of NanoBone, a new highly non-sintered porous nano-crystalline hydroxylapatite bone substitute embedded into a silica gel matrix, granules were implanted subcutaneously and intramuscularly into the back region of 18 mini pigs. After periods of 5 and 10 weeks as well as 4 and 8 months, implantation sites were investigated using histological and histomorphometric procedures. Signs of early osteogenesis could already be detected after 5 weeks. The later periods were characterized by increasing membranous osteogenesis in and around the granules leading to the formation of bone-like structures showing periosteal and tendon-like structures with bone marrow and focal chondrogenesis. Bone formation was better in the subcutaneous than in the intramuscular implantation sites. This ectopic osteogenesis is discussed with regard to the nanoporosity and microporosity of the material, physico-chemical interactions at its surface, the differentiation of osteoblasts, the role of angiogenesis and the probable involvement of growth factors. The results of this preliminary study indicate that this biomaterial has osteoinductive potential and induces the formation of bone structures, mainly in subcutaneous adipose tissue in the pig

Rare femoral metastasis in late recurrent squamous cell carcinoma of the oral cavity

Background/Aim: Squamous cell carcinoma (SCC) is the most frequent carcinoma when dealing with malignant tumors of the oral cavity. SCC of the head and neck show cervical lymphatic metastasis, which is the most important prognostic factor for the long-term outcome of these patients. Hematogenous spread of this entity is rare, especially distant osseous metastasis. Therefore, the therapy for SCC typically consists of surgical tumor resection, neck dissection and plastic reconstruction. Most recurrences occur within the first two years postoperatively. This results in the need for close tumor follow-up. Case report: The present case report describes a 79-year-old female suffering from a recurrent SCC of the oral cavity 19 years postoperatively firstly noticed through symptomatic osseous metastasis of the right femur. Trial excision of the right femur revealed the finding of a metastatic squamous cell carcinoma. The patient received palliative radiation therapy. Conclusion: Osseous metastasis of SCC to the femur is rare. What is remarkable about this case report is the time span of 19 years between primary curative treatment, unremarkable follow up and the presence of metastatic late recurrence. Therefore long-term close follow-up in the treatment of oral cavity SCC in an interdisciplinary context is crucial

A preliminary study in osteoinduction by a nano-crystalline hydroxyapatite in the mini pig.

To test the probable osteoinductive properties of NanoBone, a new highly non-sintered porous nano-crystalline hydroxylapatite bone substitute embedded into a silica gel matrix, granules were implanted subcutaneously and intramuscularly into the back region of 18 mini pigs. After periods of 5 and 10 weeks as well as 4 and 8 months, implantation sites were investigated using histological and histomorphometric procedures. Signs of early osteogenesis could already be detected after 5 weeks. The later periods were characterized by increasing membranous osteogenesis in and around the granules leading to the formation of bone-like structures showing periosteal and tendon-like structures with bone marrow and focal chondrogenesis. Bone formation was better in the subcutaneous than in the intramuscular implantation sites. This ectopic osteogenesis is discussed with regard to the nanoporosity and microporosity of the material, physico-chemical interactions at its surface, the differentiation of osteoblasts, the role of angiogenesis and the probable involvement of growth factors. The results of this preliminary study indicate that this biomaterial has osteoinductive potential and induces the formation of bone structures, mainly in subcutaneous adipose tissue in the pig