Despite the relative success of internal fixation devices, most notably pedicle screw systems (which are fixed to the spine via screws placed through the bony pedicles of the vertebra), surgeons have long sought a less invasive method. The 1990’s saw the evolution of interbody devices that had previously only been used to span defects in the vertebra, as when entire vertebra needed to be removed for tumor (referred to as a corpectomy). Improvements in design offered the potential that these interbody devices, i.e.”cages”, could be used to fuse the spine. These cages resembled threaded screw devices that were packed with bone. The failure rate, and hence the need for revision surgery, was unfortunately unacceptable. Opinion has swung back to a combination of posterior fixation with pedicle screws and rods supplemented by interbody support. Circumferential fusions, utilizing both posterolateral (from the back and placed both left and right of the midline nerve structures) and interbody grafting, have gained in popularity. Mechanical and in vivo studies have shown the superiority of bonegrafts placed along the anterior (front) column of the spine, as in interbody fusion, especially when supplemented with pedicle screw fixation. Bonegraft heals more quickly and to a greater extent under compression. This is the case in interbody fusion, as opposed to bonegraft being placed under tension in traditional posterolateral techniques.