Vertebral Body Reconstruction Using Expandable Cages
Spinal tumors, infections, myelopathic and traumatic spinal conditions may require vertebral body reconstruction following surgical treatment. Sometimes these conditions require the surgeon to perform a corpectomy or vertebrectomy. A corpectomy involves surgically removing a portion of one or more vertebrae and the adjacent discs. A vertebrectomy is the surgical removal of one or more vertebral bodies and discs.
Vertebral body reconstruction following corpectomy or vertebrectomy can present the surgeon with a technical challenge. The surgeon has several choices for spinal reconstruction. Generally, good results can be obtained by combining techniques.
Autologous (Autograft) and Allograft Struts:
Struts are bone from the fibula, one of the bones in the leg. Struts are placed into the space around or between vertebral bodies. Autologous means the patient's own bone is use and allograft refers to donor bone. Sometimes autologous and allograft are combined.
Struts may be used for vertebral body defects. Human fibular (calf bone) and femoral (thigh bone) ring grafts are common types of allograft used. Potential long-term problems include poor sagittal reconstruction, graft fracture and disease transmission. Autograft may be used as well, but carries donor site morbidity and may not be enough or suitable for vertebral body defects (such as two or more spinal levels).
Mesh cages are interbody devices usually made of titanium. Interbody means the cage is implanted between two vertebral bodies. The cage is filled with bone graft to facilitate spinal fusion.
Medical grade cement is injected into the defective vertebral body. The cement hardens adding strength to the bone.
With each of these treatment options are potential complications. Complications include poor sagittal alignment (kyphosis, rounded back) and bone strut and graft problems such as settling, extrusion, fracture, and fusion failure (pseudoarthrosis).
Expandable Cages: A Better Option
Expandable cages offer surgeons a vertebral body reconstruction solution. These cages combine rigid anterior (front) spinal column support, excellent fixation into the vertebral endplate, adequate room within the cage for bone graft, and generally unmatched ability for distraction (surgically create space) and sagittal (lordosis, standing upright) alignment.
Many expandable cages are available that offer different expansion mechanisms, endplate fixation options, and sizes of the bone graft chamber.
Three case studies are presented below and on the pages that follow. Each presentation features the patient's preoperative and postoperative radiographs (x-rays, CT scans, MRI).
A 31-year-old female trauma patient with a spinal cord injury at C4 and C5; compressive flexion injury.
Preoperative lateral (side) CT scan
Preoperative lateral MRI
Postoperative cervical lateral (side) x-ray
6 months after surgical reconstruction