Soraya Nishimura1,2, Narihito Nagoshi2, Akio Iwanami2, Ayano Takeuchi3, Takashi Hirai4, Toshitaka Yoshii4, Kazuhiro Takeuchi5, Kanji Mori6, Tsuyoshi Yamada4, Shoji Seki7, Takashi Tsuji8, Kanehiro Fujiyoshi9, Mitsuru Furukawa10, Kanichiro Wada11, Masao Koda12, Takeo Furuya13, Yukihiro Matsuyama14, Tomohiko Hasegawa14, Katsushi Takeshita15, Atsushi Kimura15, Masahiko Abematsu16, Hirotaka Haro17, Tetsuro Ohba17, Masahiko Watanabe18, Hiroyuki Katoh18, Kei Watanabe19, Hiroshi Ozawa20, Haruo Kanno21, Shiro Imagama22, Kei Ando22, Shunsuke Fujibayashi23, Masashi Yamazaki24, Kota Watanabe2, Morio Matsumoto2, Masaya Nakamura2, Atsushi Okawa4, Yoshiharu Kawaguchi7. 1. Department of Orthopedic Surgery, Kawasaki Municipal Hospital, Kawasaki. 2. Departments of Orthopedic Surgery. 3. Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo. 4. Department of Orthopedic Surgery, Tokyo Medical and Dental University, Tokyo. 5. Department of Orthopedic Surgery, National Hospital Organization Okayama Medical Center, Okayama. 6. Department of Orthopedic Surgery, Shiga University of Medical Science, Shiga. 7. Department of Orthopedic Surgery, Faculty of Medicine, University of Toyama, Toyama. 8. Department of Orthopedic Surgery, Fujita Health University, Toyoake. 9. Department of Orthopedic Surgery, National Hospital Organization Murayama Medical Center, Tokyo. 10. Department of Orthopedic Surgery, Shizuoka City Shimizu Hospital, Shizuoka. 11. Department of Orthopedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki. 12. Department of Orthopedic Surgery, University of Tsukuba, Tsukuba. 13. Department of Orthopedic Surgery, Chiba University Graduate School of Medicine, Chiba. 14. Department of Orthopedic Surgery, Hamamatsu University School of Medicine, Hamamatsu. 15. Department of Orthopedics, Jichi Medical University, Shimostuke. 16. Department of Orthopedic Surgery, Graduate School of Medicine and Dental Science, Kagoshima University, Kagoshima. 17. Department of Orthopedic Surgery, University of Yamanashi, Yamanashi. 18. Department of Orthopedic Surgery, Surgical Science, Tokai University School of Medicine, Tokyo. 19. Department of Orthopedic Surgery, Niigata University Medical and Dental General Hospital, Niigata. 20. Department of Orthopaedic Surgery, Tohoku Medical and Pharmaceutical University. 21. Department of Orthopedic Surgery, Tohoku University School of Medicine, Tohoku. 22. Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya. 23. Department of Orthopedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto. 24. Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
Abstract
STUDY DESIGN: This was a retrospective multicenter study. OBJECTIVE: To clarify the progression of diffuse idiopathic skeletal hyperostosis (DISH) using whole-spine computed tomography in patients with cervical ossification of the posterior longitudinal ligament (OPLL). SUMMARY OF BACKGROUND DATA: DISH and cervical OPLL frequently coexist, and can cause ankylosing spinal fractures due to biomechanical changes and fragility of the affected vertebrae. The epidemiology and pathophysiology of DISH occurring with cervical OPLL are unclear. MATERIALS AND METHODS: We used whole-spine computed tomography to determine the prevalence of DISH in 234 patients with a diagnosis of cervical OPLL based on plain cervical radiographs. We established a novel system for grading the progression of DISH based on a cluster analysis of the DISH distribution along the spine. We calculated the correlation coefficient between this grading system and patient age. RESULTS: The prevalence of DISH in patients with cervical OPLL was 48.7%. Patients with DISH were significantly older than those who did not have DISH (67.3 vs. 63.4 y; P=0.005). Cluster analysis classified the DISH distribution into 6 regions, based on the levels affected: C2-C5, C3-T1, C6-T5, T3-10, T8-L2, and T12-S1. DISH was observed most frequently at T3-T10. We defined a system for grading DISH progression based on the number of regions involved, from grade 0 to 6. DISH was distributed at T3-T10 in >60% of the grade 1 patients, whereas most patients with DISH at the cervical or lumbar spine were grade 4 or 5. There was a weak but significant correlation between the DISH grade and patient age. CONCLUSIONS: DISH was present in nearly half of the patients with cervical OPLL. DISH was more common in older patients. DISH developed at the thoracic level and progressed into the cervical and/or lumbar spine with age. LEVEL OF EVIDENCE: Level III.
STUDY DESIGN: This was a retrospective multicenter study. OBJECTIVE: To clarify the progression of diffuse idiopathic skeletal hyperostosis (DISH) using whole-spine computed tomography in patients with cervical ossification of the posterior longitudinal ligament (OPLL). SUMMARY OF BACKGROUND DATA: DISH and cervical OPLL frequently coexist, and can cause ankylosing spinal fractures due to biomechanical changes and fragility of the affected vertebrae. The epidemiology and pathophysiology of DISH occurring with cervical OPLL are unclear. MATERIALS AND METHODS: We used whole-spine computed tomography to determine the prevalence of DISH in 234 patients with a diagnosis of cervical OPLL based on plain cervical radiographs. We established a novel system for grading the progression of DISH based on a cluster analysis of the DISH distribution along the spine. We calculated the correlation coefficient between this grading system and patient age. RESULTS: The prevalence of DISH in patients with cervical OPLL was 48.7%. Patients with DISH were significantly older than those who did not have DISH (67.3 vs. 63.4 y; P=0.005). Cluster analysis classified the DISH distribution into 6 regions, based on the levels affected: C2-C5, C3-T1, C6-T5, T3-10, T8-L2, and T12-S1. DISH was observed most frequently at T3-T10. We defined a system for grading DISH progression based on the number of regions involved, from grade 0 to 6. DISH was distributed at T3-T10 in >60% of the grade 1 patients, whereas most patients with DISH at the cervical or lumbar spine were grade 4 or 5. There was a weak but significant correlation between the DISH grade and patient age. CONCLUSIONS: DISH was present in nearly half of the patients with cervical OPLL. DISH was more common in older patients. DISH developed at the thoracic level and progressed into the cervical and/or lumbar spine with age. LEVEL OF EVIDENCE: Level III.