Expandable Cages and Minimal Invasive Approaches to the Thoracolumbar Spine for Anterior Column Reconstruction

Expandable cages placed through minimal invasive approaches represent the last frontier for the anterior column reconstruction in the thoracolumbar spine. A minimal invasive approach is desirable whenever it provides the same effectiveness as the traditional one as it may consistently reduce intraoperative bleeding and postoperative pain decreasing the hospital stay. Expandable cages offer adequate anterior support; they can be filled with bone graft to promote fusion and provide a superior primary stability compared to old style titanium mesh. Actually, adding preloading forces during the implant expansion, they increase the contact between vertebral body and cage end-plates, reducing the risk for delayed hardware subsidence. Appositely designed instrumentation, including retractors, may help the surgeon during the different steps of surgery, and their relatively high costs can be rewarded by a shorter hospitalization. Nevertheless, full understanding of spine biomechanics and sagittal balance rules as well as accurate preoperative workup is necessary to plan an effective anterior column reconstruction that should always be patient tailored. Therefore, as in traditional procedures, the surgeon must always consider different aspects of the patient such as diagnosis, previous surgery, osteoporosis, posterior ligament complex state, and so on.