A retrospective review of long anterior fusions to the sacrum

Background contextIn the setting of tumor, infection, or trauma, a corpectomy of the L5 vertebral body may be necessary. However, the space has an irregular trapezoidal shape, and the failure to account for this may lead to improper fitting of the titanium cages or the allograft struts when performing a reconstruction.PurposeThe purpose of this study was to evaluate the failure rate of implants used to reconstruct the anterior lumbar spine when an L5 corpectomy has been performed.MethodsA retrospective review of the medical records and radiographs of 19 consecutive patients undergoing an L5 corpectomy and anterior spinal fusion was performed. The radiographs were reviewed for implant failure and successful fusions.ResultsCases included osteomyelitis (13), fractures (4), and tumor (2). Anterior reconstruction was performed with a straight cylindrical titanium cage in six cases, allograft in six cases, iliac crest bone graft (ICBG) in two cases, and cages with lordosis built into the cage or end plates in five cases. In the six straight cylindrical titanium cages, four cases had displaced anteriorly, necessitating revision surgery. In the other two cases, both had poor fixation to the sacrum and developed nonunions. In the six reconstructed with allograft, all three fibular struts developed nonunions. In the three reconstructed with humeral or femoral allograft, all patients formed a solid fusion. In the patients reconstructed with ICBG, one formed a nonunion, whereas the other one formed a solid fusion. In the cages with lordosis built into the cage or end plates, all five developed solid fusions.ConclusionsA corpectomy of L5 resulting in an irregular trapezoidal shape must be accounted for when performing the reconstruction. Use of straight cylindrical cages or allograft with small footprints may lead to an increased rate of failure. When performing the reconstruction, adding approximately 20° to 30° of lordosis to the construct may create a better fit and increase stability and result in an improved fusion rate. If using allograft, using a larger graft with greater end plate contact may also improve fusion rates.