Carvable calcium phosphate bone substitute material.

This study investigated the use of partially set hydroxyapatite forming calcium phosphate cement as a carvable and mechanically stable bone substitute material. Hydroxyapatite-forming cements were made of either mechanically activated alpha-tricalcium phosphate or a mixture of tetracalcium phosphate and dicalcium phosphate anhydrous and setting was arrested up to 4 h post setting. The study showed that these partially set rigid samples of defined geometry could be carved into a desired shape when the degree of reaction was 30-40% and the relative porosity between 40 and 50%; samples are then expected to set completely after implantation in the presence of water or serum, having the same compressive strength as a continuously set calcium phosphate cement (up to 36 MPa). The development of compressive strength, phase composition, and crystallinity when varying production parameters of these partially "preset" bone substitute materials are presented for both cement systems.

Cortical bone screw fixation in ionically modified apatite cements.

Hydroxyapatite cements are used in reconstruction of the face; usually in well-defined cavities where the cement can be stabilized without the need for internal fixation. A hydroxyapatite cement that could enable screw fixation and some loading therefore has considerable potential in maxillofacial reconstruction. It has been demonstrated recently that water demand of calcium phosphate cements can be reduced by ionically modifying the liquid component. This study investigated the capacity of an ionically modified precompacted apatite cement to retain self-tapping cortical bone screws. Screw pullout forces were determined in the direction of the screw long axis and perpendicular to it, using cortical bone and polymethylmethacrylate cement as a control. In bending pullout tests, measured forces to remove screws from ionically modified precompacted cement were insignificantly different from cortical bone. However, pullout forces of bone screws from hydroxyapatite cement decreased with aging time in vitro.

Demographics and macroeconomic effects in aesthetic surgery in the UK.

Media interest in aesthetic surgery is substantial and suggestions of demographic changes such as reductions in age or an increase in the number of male patients are common. In spite of this, there is no peer reviewed literature reporting demographics of a contemporary large patient cohort or of the effect of macroeconomic indicators on aesthetic surgery in the UK. In this study, computer records 13006 patients presenting between 1998 and the first quarter of 2003 at a significant aesthetic surgery centre were analysed for procedures undergone, patient age and sex. Male to female ratios for each procedure were calculated and a comparison was made between unit activity and macroeconomic indicators. The results showed that there has been no significant demographic change in the procedures studied with patient age and male to female ratio remaining constant throughout the period studied for each procedure. Comparison with macroeconomic indicators suggested increasing demand for aesthetic surgery in spite of a global recession. In conclusion, media reports of large scale demographic shifts in aesthetic surgery patients are exaggerated. The stability of unit activity in spite of falling national economic indicators suggested that some units in the UK might be relatively immune to economic vagaries. The implications for training are discussed.

Enterocutaneous fistula: a reconstructive dilemma.

Surgical repair of enterocutaneous fistulae in Crohn's disease may result in large skin defects of the anterior abdominal wall. We present a case in which a large defect was managed with reconstruction using a pedicled rectus abdominis myocutaneous flap in a single procedure. The case highlights the technical challenge of such a case and the value of a joint surgical approach between plastic and colorectal services.