Clinical significance of laterality on diffuse idiopathic skeletal hyperostosis with unstable thoracolumbar vertebral...

This study was conducted to compare clinical characteristics and surgical outcomes based on the laterality of diffuse idiopathic skeletal hyperostosis (DISH) with vertebral fracture (VF).

We extracted 444 thoracolumbar VF patients in a single center, and 217 patients who underwent balloon kyphoplasty and 159 patients with conservative treatment were excluded. This retrospective study enrolled 68 adult patients who were diagnosed with thoracolumbar VFs that required posterior fusion surgery due to instability. We examined the distribution of DISH on the preoperative whole spine CT images. In particular, we researched the radiographic and clinical characteristics according to the laterality of DISH. We developed a simple grading system (grade 0, no DISH; grade 1, unilateral DISH; grade 2, bilateral DISH≧involving 4 vertebral bodies on both sides).

There were 23 DISH patients with VFs, consisting of seven bilateral DISH patients (grade 2) and 16 unilateral DISH patients (grade 1). The ratio of male and lumbar Young Adult Mean index were significantly higher in grade 2 (p < 0.05). The number of contiguous vertebrae was larger in grade 2 than in grade 1 (8.1 ± 3.1 vs. 16.3 ± 2.9, p < 0.001). Among all bilateral DISH patients, DISH extended to the lumbar and was accompanied by other ligamentous unions. The locations of fractured vertebrae in grade 2 were mainly between Th11-L1 (85.7%), and all of them were fractured within the contiguous vertebrae, accompanied by DISH.

The present study demonstrated that bilateral DISH was significantly more extensive than unilateral DISH, and the fractured levels of bilateral type were within the contiguous vertebral bodies, accompanied by DISH. On the other hand, there were no differences in surgical outcomes. Our grading system may reflect the radiographic features of DISH with unstable VFs. Further studies with a large number of patients are warranted to provide a better understanding of its validity and reliability. Level of Evidence 2b.