Iatrogenic fractures in ankylosing spondylitis—a report of two cases

Study design: Two cases of intraoperative, iatrogenic cervical spine fractures in patients with ankylosing spondylitis are reported. Objective: To describe the uncommon complication of iatrogenic cervical spine fractures occurring during spine surgery in patients with ankylosing spondylitis. Summary of background data: To our knowledge, this is the first report on this rare complication. Methods: A 39-year-old patient (1) with ankylosing spondylitis was operated on for cervical stenosis due to C1/2 anterolisthesis. Fifteen hours postoperatively, he developed acute quadriplegia. MRI revealed a fracture/dislocation of C6 on C7 and compression of the spinal cord at this level. Revision was performed with decompression and instrumentation from the occiput to T3. A 55-year-old patient (2) with ankylosing spondylitis and thoracic hyperkyphosis underwent a correction procedure consisting of costotransversectomy, anterior cage implantation at T8/9, and posterior instrumentation from T4 to L1. Halo traction was temporarily applied for correction. At the end of the operation, with the patient still under anesthesia, increased mobility of the cervical spine was noticed. Emergent MRI revealed a fracture of the anterior structures of C6/7. Posterior instrumentation from C5 to T1 was then performed. Results: Quadriplegia persisted in patient 1 until his death secondary to further complications. Patient 2 was mobilized without any neurologic deficits. The fracture healed in good alignment. Conclusions: Iatrogenic fractures of the cervical spine during surgery in ankylosing spondylitis patients are a rare but potentially severe complication. Early diagnosis and therapy are necessary before dislocation, cord compression, and subsequent neurologic impairment occur.