Surface analysis of retrieved pedicle screws by field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray (EDX) mapping.

<p>Following torsional screw extraction analysis, the surface of the threaded portion of removed pedicle screws (PSs) was evaluated by FE-SEM and EDX mapping. Little or no bony tissues were found on the surfaces of the control screws at 1-month (1M) <b>(A)</b> or 3-months post-surgery (3M) <b>(B)</b>. A number of bony tissues (white arrows in the magnified pictures) were observed on the surfaces of bioactive screws at 1M <b>(C)</b> and 3M <b>(D)</b> post-surgery. Scale bar: 10 μm.