Many successful attempts to increase pullout strength of pedicle screws in osteoporotic bone have been accompanied with an increased risk of catastrophic damage to the patient. To avoid this, a single-armed expansive pedicle screw was designed to increase fixation strength while controlling postfailure damage away from the nerves surrounding the pedicle. The screw was then subsequently tested i...

The adhesion between a polymer melt and substrate is studied in the presence of chemically attached chains on the substrate surface. Extensive molecular dynamics simulations have been carried out to study the effect of temperature, tethered chain areal density (Σ), tethered chain length (Nt), chain bending energy (kθ) and tensile pull velocity (v) on the adhesive failure mechanisms of pullout a...

This study presents an innovative technique of executing soil nails called sectorized post grouting (SPG). The most utilized nail is gravity grouting, with the literature reporting advances in pressurized grouting. Although obtaining higher pullout resistance nails, mostly done single-stage does not compensate for exudation and its use lengths difficult. Thus, a has been developed that compensa...

BACKGROUND Pedicle screw loosening is a major safety concern in instrumented spinal surgery due to loosening with potential pseudarthrosis and possible loss of correction requiring revision surgery. Several cadaver studies have compared insertion torque of pedicle screws with resistance to pullout or cyclic loading. In most of these studies, a correlation has been found between these variables....

Ti6Al4V titanium alloy is applied extensively in the aviation, aerospace, jet engine, and marine industries owing to its strength-to-weight ratio, excellent high-temperature properties and corrosion resistance. In order to extend the application range, investigations on welding characteristics of Ti6Al4V alloy using more welding methods are required. In the present study, Ti6Al4V alloy sheets w...

Materials and methods Eighteen vertebrae were harvested from the lumbar section of six porcine spines ranged from L1 to L3. All vertebrae were instrumented on both pedicles using pedicle screws. Quantitative CT scans were used before instrumentation in order to assess the bone density of each vertebra. Cyclic bending (toggling) load of ± 1mm displacement at 3Hz for 5000 cycles were assigned in ...

Pressure-grouted helical pile (PGHP) is an innovative piling system that allows a significant increase in capacity with relatively low additional cost. The constructed by applying pressurized grout during the installation of conventional piles. injected into ground through two nozzles welded to hollow shaft. This paper presents comprehensive laboratory study investigate effect three different n...