Histological characteristics of diffuse idiopathic skeletal hyperostosis

Abstract

Diffuse idiopathic skeletal hyperostosis (DISH) is a predominantly radiographic diagnosis and histological knowledge of DISH is limited. The aim of this study was to describe the histological characteristics of DISH in the spinal column and to study the relation between DISH and intervertebral disc (IVD) degeneration. Therefore, 10 human cadaveric spines with fluoroscopic evidence of DISH were compared with 10 controls. Plain radiographs and computed tomography (CT) scans were obtained and tissue blocks were resected from three predefined levels of all specimens. The microscopic sections were scored by two blinded observers using a newly developed scoring system specific for characteristics of DISH and a validated scoring system for IVD degeneration. Maximum IVD height was measured on the CT scans. Analyses were performed using Fisher's exact test and Student's t-test. When compared to controls, the right sided sections from DISH specimens showed partial or complete bone bridges, consisting of cortical woven bone, accompanied by morphological changes in the adjoining part of the IVD. Using the histological scoring system for DISH, all parameters were significantly different between the DISH and control group (p < 0.01). The contralateral location did not show differences between the groups. The overall degree of IVD degeneration and height of IVD was comparable for the two groups. The histopathological changes observed in spines with DISH corresponded to the fluoroscopic images and CT scans. The degree of IVD degeneration and IVD height was comparable for both groups, suggesting a limited role for IVD degeneration in the pathogenesis of DISH. Keywords: diffuse idiopathic skeletal hyperostosis (DISH); histology; classification; ossification; disc degeneration Diffuse idiopathic skeletal hyperostosis (DISH) is a condition characterized by flowing ossifications on the anterolateral side of the thoracic spine with relative preservation of the intervertebral disc (IVD). 1 The new bone formation is most frequently observed on the right side of the thoracic spine, and aortic pulsations have been suggested to prevent ossification on the left side. 2 The prevalence of DISH ranges from 2.9% to 42% in a general population over 50 years of age. [2][3][4] Several studies have shown a correlation between DISH and advanced age, the metabolic syndrome, and cardiovascular disease. [2][3][4] The prevalence of DISH can be expected to rise in Western societies due to increased exposure to endemic risk factors including sedentary lifestyle, obesity, and long life expectancy. 5 The clinical relevance of DISH is slowly being acknowledged as several symptoms, including stiffness of the back and joints, skeletal pain, reduced lung capacity, dysphagia, and airway obstruction have been shown to be related to DISH. 2,6,7 Furthermore, individuals with spinal ankylosis have a four-to-eight times higher risk of spinal fractures after low impact trauma compared to individuals with a non-ankylotic spine. 8,9 Although the pathogenesis ...

Diffuse idiopathic skeletal hyperostosis (DISH): where we are now and where to go next

“…[48][49][50][51][52][53][54][55][56][57][58] Previous examination of spinal entheses from cadavers showed findings similar to those observed on CT scans and concluded that the intervertebral disc degeneration has a limited role in the pathogenesis of DISH. 59 It has been reported that some animal breeds (ie, Boxer) have a high prevalence of DISH, 60 suggesting a genetic basis for this condition. A recently developed mouse model might be useful in future studies on DISH.…”

Dystrophic calcification and heterotopic ossification in fibrocartilaginous tissues of the spine in diffuse idiopathic skeletal hyperostosis (DISH)

“…30 A pilot study conducted with spinal tissues from ten cadavers with DISH established that the degree of histopathological IVD degeneration and measures of disc height were comparable between age-and sex-matched specimens without DISH, suggesting a limited role for IVD degeneration in the pathogenesis of DISH. 25 The histopathological evaluation in the current study demonstrated mild-to-moderate IVD degeneration in all specimens examined, which may have been insufficient to affect radiographic disc height. Note that loss of IVD height would preclude the diagnosis of DISH based on radiographic criteria.…”

“…Initial reports described histopathological features of endochondral ossification of the anterior longitudinal ligament 24 as well as changes in the gross features of the IVD. 21,25 In contrast, recent studies in cadaveric tissues demonstrated that the anterior longitudinal ligament was morphologically normal in appearance and was displaced by ectopic mineral, but did not itself undergo aberrant mineralization. 26 Taken together, these findings underscore the need to identify and characterize the composition of the ectopic mineral formed in DISH, as well as the tissue types affected and associated cellular changes.…”

New horizons in spine research: Intervertebral disc repair and regeneration

“…Adjacent segment intervertebral joint loads were calculated to be sensitive to sagittal alignment and degree of lordosis that is surgically imposed during fusion with a loss of lordosis increasing shear forces at the upper adjacent level . A human cadaveric study showed that degree of IVD degeneration and height were similar for Diffuse Idiopathic Skeletal Hyperostosis patients as for controls, suggesting a limited role for IVD degeneration in its pathogenesis …”

“…17 A human cadaveric study showed that degree of IVD degeneration and height were similar for Diffuse Idiopathic Skeletal Hyperostosis patients as for controls, suggesting a limited role for IVD degeneration in its pathogenesis. 18 Zhu et al developed a cell-activity-coupled mechano-electrochemical finite element model of the IVD with simulated degenerative changes and biological treatments. IVD spatial water content patterns were found to be very sensitive to degenerative state and to biological treatments that increased cell density, increased glycosaminoglycan synthesis rate, and decreased glycosaminoglycan degradation rate.…”