Pedicle screw fixation is performed in conjunction with spinal fusion surgery to secure the vertebrae of the treated area in a fixed position. These devices provide stability and support to the spine after surgery and keep bone grafts in position while the spine heals. SPINE stands for strep–protein interaction experiment. SPINE may be a powerful tool to detect protein-protein interactions in vivo. The bait protein has got to be expressed with a Strep-tag under the conditions when the potential interaction partners are presumably present within the cells. The addition of formaldehyde links the bait protein to its potential interaction partners. The bait protein alongside its potential interaction partners can then be isolated employing a Streptactin sepharose column. The cross-links between the bait protein and therefore the potential interaction partner are often cleaved by heating the samples in Laemmli buffer. Finally, the co-purified interaction partner can be separated by SDS PAGE and identified by mass spectrometry. The spine also helps us to stand straight. The spine has 26 vertebrae.