Fractures in Spinal Ankylosing Disorders: A Narrative Review of Disease and Injury Types, Treatment Techniques, and Outcomes.

INTRODUCTION: Spinal ankylosing disorders encompass ankylosing spondylitis (AS), disseminated hyperostosis of the spine, and end-stage spondylosis. All these result in a stiffened and frequently deformed spinal column. This makes the spinal column highly susceptible to severe injuries that are commonly associated with unfavorable outcomes. Improved understanding of the underlying disease processes and clinical comorbidities may alter the poor injury related morbidity and mortality outcomes.

METHODS: A systematic review of the MEDLINE and PubMed databases was performed using the following key words to identify articles published between 2001 and 2016: "ankylosing spondylitis," "epidemiology," "DISH," "treatment," "outcome," and/or "fracture." Articles were read for data on methodology (retrospective vs. prospective), type of treatment, number of patients, mean patient age, and mean follow-up.

RESULTS: Twenty-one identified articles were analyzed. Average age was 63.4 years. Most patients were men. Ground level fall or low energy trauma caused most injuries. Diagnosis was delayed in 15%-41% cases. Hyperextension fracture patterns were most common. Cervical spine fractures were more common than thoracolumbar fractures, with the highest prevalence between C5 and C7. Neurologic deficits were encountered in 21%-100% of patients. Operative fixation and fusion were performed in 40%-100% of patients. Mortality was reported between 0% and 32% at 1 year postinjury. Complications were encountered in 84% of patients, mostly in the form of pneumonia, respiratory failure, and pseudoarthrosis. Neurologic deterioration has been reported in 16% of patients. Fusion was successful in 87%-100% of patients. Neurologic deficits improved in function in 6%-66% at the final follow-up.

CONCLUSIONS: Because of the stiffening of the spinal column, patients with spinal ankylosing disorders are preferably evaluated for spinal fractures and ligamentous injuries after even trivial trauma. Spinal injuries in patients with AS are difficult to diagnose on plain radiographs; computed tomography and magnetic resonance imaging are recommended instead. The entire spine should be scanned for multilevel involvement. Although osteoporosis makes fixation of spine implants a significant concern, the literature has reported that most patients with AS treated surgically had good outcomes. Numerous studies have reported risks associated with conservative management.