1. Determine the location and extent of the nerve tube, which can be determined through the use of medical imaging techniques, including CT scans or MRIs.
2. After locating the nerve tube, the surgeon will use a special marker to draw the outline of the nerve tube on the skin. This helps the surgeon more accurately identify the location of the nerve tube during the procedure.
3. Once the drawing is complete, the surgeon will use a special marking method to further mark the nerve tube, including the use of special stains, metal markers, or radioactive tracers.