Bone Abstracts

Introduction: Most reports focused on clinical advantages of intervertebral cages; only a few studies reviewed the complications. As one of the major complications, cage migrating into vertebral body or spinal canal may result in disastrous consequence. Multiple risk factors may result in cage migration, such as geometric design of cage, surgical technique, the bone quality and post-operative protection. The following is a presentation of nine patients with migrated cage.

Materials and methods: From 2010 to 2015, there were total nine cases of cage migrations in our institution. Posterior migration in seven cases with dura compression, anterior migration in one case, and subsidence of inferior endplate in one case. Seven cases treated with anterior approach, and two cases treated with posterior approach.

Results: Successfully removal of cage was performed in eight cases, and acceptable image outcomes in seven patients. Repeated cage subsidence occurred in one case due to new cage over sizing and limited distraction of previous posterior instrumentation. Failed in cage removal through anterior approach in one case due to great vessel adhesion. After revision or removal surgery, residual numbness or sciatica was noted in three patients. Six cases were with satisfactory or acceptable outcome.

Discussion: Spine fusion is not always an effective treatment for chronic low back pain. Complications such as cage migration may result in severe sequelae, and revision surgery is technically demanding. The anterior approach is a reliable technique for removal of migrated cages.