Instrumented posterior interbody fusion in degenerative and multioperated lumbar spine

Lumbar interbody fusion is a valid technique for the treatment of disc diseases. We report a series of 37 patients who underwent posterior lumbar interbody fusion with titanium cylindric screwing-expansion cages. Clinical outcomes and radiological results were evaluated years after surgery. After surgery, the majority of patients returned to their normal activities. Follow-up plain roentgenograms showed no loss of disc height and no signs of implant looseness. Computed tomography (CT) showed the presence of mineralized autologous bone grafts inside the interbody cages. Expandable interbody cages allow the restoration of disc space height, giving support to the anterior column, opening the neuroforaminal area and providing increased stability. The interpretation of fusion on the basis of roentgenograms is difficult; CT offers more information than radiography about the fusion process, but a bony arthrodesis cannot be demonstrated with certainty.