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Biomedical subjects

G Daculsi

Publications and source records attributed to G Daculsi.

167 records · Page 10Linked to original sources
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[Calcium phosphate ceramics in orthopedic surgery].

Calcium phosphate ceramics might replace bone grafts in orthopaedic surgery. The chemical determination of these materials is now well known, and world-wide animal experiments as well as our own experience have proven that these products are both biocompatible and bioactive. The early chemical and physico-chemical mechanisms of interaction between calcium phosphate ceramics and bone tissue and biological fluids at the site of implantation are numerous (degradation, dissolution, crystal precipitation). These processes precede the cellular mechanisms of osteogenesis which take place during contact with the materials and define osteoconduction. When implanted in a bony environment, the ceramic ensures the formation of a genuine bone which within a few months will acquire all the characteristics of a normal lamellated bone with areas of apposition and resorption during remodeling. However, the mechanical characteristics of calcium phosphate ceramics do not permit an early loading, and they should only be used to fill bone cavities. In vertebral arthrodesis they must be implanted in stress-free areas and combined with strong and stable appliances. To benefit from the special bioactivity of calcium phosphate ceramics, research workers are now turning towards the treatment of metal alloys or composite fibres surfaces as well as of calcium phosphate complexes and extracellular matrix constituents (collagen, proteoglycans, etc.).

Biocompatible Materials↗
PubMedDate not supplied

[The sheep: an animal model for ligament prostheses?].

Ruptures of the anterior cruciform ligament is difficult to repair. Ligament prostheses are sometimes useful. We tested a ligament prosthesis which had the original property of combining a polyester braid with a matrix favouring collagen ingrowth. We implanted this prosthesis in the knee joint of 10 sheep after sectioning the anterior cruciform ligament at it origin. The ligaments were recovered after 6 months. We studied the functional and radiographic results. Tolerance was studied in samples of the articular fluid and synovial tissue. We evaluated bone attachment and fibrous growth using micro-radiography and specific coloration techniques. Samples were examined under electron microscope. No rupture was encountered. We observed a satisfactory functional and radiographic result. No intolerance was observed. The neoligament had a bony or mixed attachment in 60% of the cases and was comprised of oriented tissue in 90% of the cases. Vascular invasion was important. These findings are promising and suggest that long-term studies should be undertaken.

Animals↗
PubMedDate not supplied

[Air pouch model in the rat for evaluating articular phlogogenic capacity of ceramics].

We used the joint air pouch model in rats to study the inflammation induced by three types of calcium phosphate biomaterial: 10 mg of synthetic hydroxyapatite (HA), a sintered ceramic made of hydrooxyapatite and phosphate tricalcium (BCP), and calcium phosphate in the form of a fibre extracted from a vitro-ceramic material (VPC). Histological examination was made after 48 hours. The most intense inflammatory reaction was observed with BCP: the thickness of the superficial stratified layer of synoviocyte-like cells doubled, interstitial fibrosis occurred and neovascularization with polymorphous inflammatory infiltration was seen. HA led to the same, though less intense, type of reaction. Discrete, variable, localized inflammation was seen with VPC and was limited to the areas where the calcium phosphate fibres rolled. Despite good bone tissue tolerance, intraarticularly, these biomaterials can lead to synovial inflammation. This phlogogenic action varies greatly depending on the microcrystals injected. The factors which might affect the joint inflammatory reaction, including the size and surface of the microcrystals, the crystallinity, pH and physical treatments (heat, compaction) should be further evaluated with precision.

Animals↗