Purpose: Selective laser sintering (SLS) is a rapid pro- totyping technique applied to produce tissue-engineer- ing scaffolds from powder materials. The standard scanning technique, however, often produces struts of extensive thickness, which means fabrication of high- ly porous scaffolds with small overall dimensions is quite difficult. Nevertheless, this study aims to overcome this shortfall. Design/methodology/approach: To this end, three scanning methods were evaluated in terms of minimum feature size and freedom of design, using a test polyamide (PA) material. Polycaprolactone (PCL) was then employed to create highly porous 3D scaffolds using the preferred scanning me- thod to produce thin struts. Findings: While in normal scanning mode some features were well above the laser spot diameter, strut thicknesses below the laser spot diameter were achieved when using the “outline scan” function for PA material. Those achieved for PCL were slightly higher and in the 500-800 ?m range, with an average pore size of 400 µm. Investigations on the properties of the scaffolds revealed an effective compression modulus of the PCL scaffold of 6.5 MPa. Furthermore, there was no change in physical or che- mical properties when the scaffolds were stored in a physiological environment for 7 weeks. Originality/ value: Though SLS is considered as a fabrication te- chnique for tissue engineering scaffolds, actually pro- duced scaffolds did not comply with porosity requirements and limitations of the SLS process in produ- cing features at the size of the laser beam spot have not been discussed. The present paper shows the capabilities of the SLS process based on two materials and presents a method to minimize feature size in scaffolds

Treating fractures of the spine is a major challenge for the medical community with an estimated 1.4 million fractures per annum worldwide. While a considerable volume of study exists on the biomechanical implications of balloon kyphoplasty, which is used to treat these fractures, the influence of the compacted bone-cement region properties on stress distribution within the vertebral body remains unknown. The following article describes a novel method for modelling this compacted bone-cement region using a geometry-based approach in conjunction with the knowledge of the bone volume fractions for the native and compacted bone regions. Three variables for the compacted region were examined, as follows: (1) compacted thickness, (2) compacted region Young's modulus and (3) friction coefficient. Results from the model indicate that the properties of the compacted bone-cement region can affect stresses in the cortical bone and cement by up to +28% and -40%, respectively. These findings demonstrate the need for further investigation into the effects of the compacted bone-cement interface using computational and experimental methods on multi-segment models.

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