Figure 7 | Scientific Reports

Figure 7

From: Improved fixation stability for repairing pedicle screw loosening using a modified cement filling technique in porcine vertebrae

Figure 7

Salvage screws and tapping screw. Two salvage screw designs were employed in the present study: cylindrical and conical shaped (A and B, middle and right). The outer geometry of the conical and cylindrical screws differed mainly in the taper of their major and minor diameters from the hub to the screw tip. The cylindrical screws maintained a constant diameter from hub to tip (A and B, middle); in contrast, the conical screws tapered 10%, from 5.0 mm at the hub to 4.5 mm at the tip (A and B, right). The tapping screw was cylindrical and maintained a diameter of 4.5 mm from hub to tip (A and B, left). For all screw designs, the thread pitch was 2 mm and the thread depth was 0.8 mm.

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