Rigid spine injuries - A comprehensive review on diagnostic and therapeutic challenges

Abstract

Injuries to the rigid spine have a distinguished position in the broad spectrum of spinal injuries due to altered biomechanical properties. The rigid spine is more prone to fractures. Two ossification bone disorders that are of particular interest are Ankylosing Spondylitis (AS) and Diffuse Idiopathic Skeletal Hyperostosis (DISH). DISH is a non-inflammatory condition that leads to an anterolateral ossification of the spine. AS on the other hand is a chronic inflammatory disease that leads to cortical bone erosions and spinal ossifications. Both diseases gradually induce stiffening of the spine. The prevalence of DISH is age-related and is therefore higher in the older population. Although the prevalence of AS is not age-related the occurrence of spinal ossification is higher with increasing age. This association with age and the aging demographics in industrialized nations illustrate the need for medical professionals to be adequately informed and prepared. The aim of this narrating review is to give an overview on the diagnostic and therapeutic measures of the ankylosed spine. Because of highly unstable fracture configurations, injuries to the rigid spine are highly susceptible to neurological deficits. Diagnosing a fracture of the ankylosed spine on plain radiographs can be challenging. Moreover, since 8% of patients with ankylosing spine disorders (ASD) have multiple non-contagious fractures, a CT scan of the entire spine is highly recommended as the primary diagnostic tool. There are no consensus-based guidelines for the treatment of spinal fractures in ASD. The presence of neurological deficit or unstable fractures are absolute indications for surgical intervention. If conservative therapy is chosen, patients should be monitored closely to ensure that secondary neurologic deterioration does not occur. For the fractures that have to be treated surgically, stabilization of at least three segments above and below the fracture zone is recommended. These fractures mostly are treated via the posterior approach. Patients with AS or DISH share a significant risk for complications after a traumatic spine injury. The most frequent complications for patients with thoracolumbar burst fractures are respiratory failure, pseudoarthrosis, pneumonia, and implant failure.

Keywords: Ankylosing spondylitis; DISH; Spine surgery; Spine trauma; Stiff spine; Surgical complications.

Fig. 1

Diagnostic algorithm. The primary diagnostic tool for evaluating spinal fractures in patients with ankylosing spine disorders is the whole spine CT. In patients with neurological deficits, an additional MRI is recommended. After identification of a fracture in the CT, DISH patients may benefit from a standing plain X-ray to determine spinal stability because this has relevant implications on indication for a surgical treatment strategy. In patients with AS, the whole spine CT is usually sufficient, as fracture severity in these patients excludes a non-surgical approach. In case of a negative CT, a total spine MRI is recommended (Ren et al., 2021; Vazan et al., 2019; Tavolaro et al., 2019).