Association between diffuse idiopathic skeletal hyperostosis and thoracic kyphosis in patients with cervical myelopathy: a retrospective observational study

Abstract

Background Diffuse idiopathic skeletal hyperostosis (DISH) is a structural abnormality of the thoracic spine that is known to impair posture. However, the relationship between DISH and sagittal balance in the whole spine is unclear. The aims of this study were to investigate the prevalence of DISH in patients with cervical myelopathy caused by cervical ossification of the posterior longitudinal ligament (OPLL) or cervical spondylosis and to compare sagittal alignment of the spine between patients with and without DISH. Methods A total of 103 consecutive patients with a diagnosis of cervical myelopathy due to cervical OPLL or spondylosis were retrospectively enrolled in this single-center study. DISH was defined as an ossified lesion that was seen to be completely bridging at least four contiguous adjacent vertebral bodies in the thoracic spine on computed tomography scans. Cervical and spinopelvic sagittal parameters were measured in whole spine radiographs. Results The study population included 28 cases with DISH [DISH (+) group] and 75 without DISH [DISH (−) group]. OPLL was more prevalent in the DISH (+) group than in the DISH (−) group; however, there were no significant differences in other clinical findings. Propensity score matching produced 26 pairs. C7 slope, C2-7 sagittal vertical axis (C-SVA), whole thoracic kyphotic angles, upper thoracic kyphosis, and T5-T12 thoracic kyphosis values were significant higher in the DISH (+) group than in the DISH (−) group. There was no significant between-group difference in the other sagittal spinopelvic parameters. Conclusions This study is the first to compare sagittal alignment in patients with cervical myelopathy according to whether or not they have DISH. Patients with DISH are more likely to have excessive kyphosis in the thoracic spine, a high C7 slope, and a high C2-7 SVA.

Evidence for a genetic contribution to the ossification of spinal ligaments in Ossification of Posterior Longitudinal Ligament and Diffuse idiopathic skeletal hyperostosis: A narrative review

“…DCM can be secondary to osteoarthritic degeneration or to ligamentous ossifications such as the Ossification of the Posterior Longitudinal Ligament (OPLL) or the ossification of the Ligament Flavum (OLF) (Nouri et al, 2015). OPLL, frequently in association with DISH, can result in various degrees of neurological complications that can range from a slowly progressive painless myelopathy to a rapid progression of a neurological deficit even after minor injury (Takayuki et al, 2021;Prabhu et al, 2022). The physical and socioeconomic burden of disability associated with DCM is expected to grow evenly, due to the ageing population (Badhiwala et al, 2020).…”

“…A short outline of DISH, OPLL and OLF can be seen in Table 1. These conditions may co-occur in some patients suggesting possible common etiopathogenic factors (Nouri et al, 2015;Takayuki et al, 2021). The objective was to collect and present evidences that supports a genetic foundation, based on the following observations: 1) familial aggregation reports, 2) animal models, 3) associated genetic variants and 4) genetics of associated disorders.…”

Is spinal sagittal alignment of diffuse idiopathic skeletal hyperostosis relevant to thoracolumbar pain? A controlled study

“…Many people with this DISH may be completely asymptomatic, while the hyperostotic ossification is discovered incidentally in their spine images. In addition, DISH usually starts from the lower thoracic spine and then spreads to the upper thoracic and especially the lumbar spine over time [ 5 , 7 ], resulting in decreased mobility and even complete ankylosis of the affected spine [ 5 , 8 ]. However, the currently used criteria do not consider the progressive nature of DISH [ 6 ].…”

“…The sagittal alignment of the spine is an interesting area to understand the correlation between DISH symptoms and radiological findings [ 8 , 11 ] . In patients with lumbar spinal stenosis, DISH leads to kyphotic changes in the lumbar and thoracic spine [ 14 ].…”

“…In addition, DISH patients with lower fused vertebral ends at the lumbar level had significantly decreased lumbar lordosis (LL) [ 14 ]. In patients with cervical myelopathy due to cervical ossification of the posterior longitudinal ligament (OPLL) or spondylosis, DISH was related to excessive thoracic spine kyphosis [ 8 ]. Moreover, sagittal alignment chance in DISH individuals tends to cause the abnormal posture [ 11 ].…”