Figure 1
Set for four-segmental stabilization of scoliosis in children SOCORE GGS by NovaSpine: (a) diagram of installation of elements in the Th12-L6 spine segment with transverse connector (green colour); and (b) typical fixed pedicle screw with locking cap (orange colour) and sliding cap of pedicle screw with a gap for the movement of the rod (blue colour) with set (or cap) screw without coatings (NC) and with DLC coatings.
Figure 2
Schematic cross-sectional view of the coated sliding cap (sliding nut) showing the Ti-6Al-4V substrate, CrN interlayer (20 nm), and outer a-C-H(Si) DLC coating (1,000 nm). The layer thicknesses are not shown to scale.
Figure 3
Schematic diagram of: (a) measurement system for high-cycle compression tests; (b) placement of markers in the Th12–L6 vertebral bodies, based on which changes in the angular position of the vertebrae were determined in the sagittal and horizontal planes; and (c) measurement system using digital image correlation with a speckle pattern applied to the implant surfaces.
Figure 4
Characteristics: (a) a change in the height value (H); and (b) value of the stiffness coefficient (k) in subsequent cycles for the groups C, NC, and WC. *– Statistical significance (p < 0.05).
Figure 5
Graph of angular range of motion, in the sagittal plane, of the Th12–L6 vertebrae during axial spine compression for the groups C, NC, and WC: (a) scheme of the arrangement of markers (red points) and stabilizer elements – screws with a sliding nut (blue), standard non-sliding screws (orange), connector (green); (b) initial value of angular displacement after 100 cycles; and (c) final value of angular displacement after 100,000 cycles. *– Statistical significance (p < 0.05).
Figure 6
Mechanical parameters of sliding pedicle screw (L5 vertebra) in NC and WC. The value were obtained using the DIC method after 100 and 100,000 cycles: (a) engineering principal strain X (%); (b) exemplary distribution engineering principal strain X (%) of NC stabilization; (c) engineering principal strain Y (%); and (d) value of the total displacement in groups NC and WC.