1. The location of the target is estimated based on palpation of anatomical landmarks and marked on the skin.

2. The localizer’s bombsight is centered on the skin mark.

3. The two sagittal beams are aligned with the midline of the spine (placing the two axial beams prependicular to the spine).

4. The two radio-opaque cables are aligned with the two axial beams.

5. the crosshairs on the x-ray source (machine) are aligned with one axial laser beam.

6. The x-ray film is centered on the opposite axial laser beam.

7. An x-ray is obtained. The two cables are nearly superimposed on the x-ray, traversing through a disc space. If this is not the desired disc space, the localization can be repeated or the correct disc space can be counted above or below the localized segment.

To view an animation of the localization steps and intraoperative photos, watch Narrated Slideshow #3.

Illustrated and copyrighted by Delilah Cohn; reproduced by permission here.