Kei Ando1,2, Shiro Imagama1,2, Takashi Kaito3,2, Shota Takenaka3,2, Kenichiro Sakai4,2, Satoru Egawa5,2, Shigeo Shindo6,2, Kota Watanabe7,2, Nobuyuki Fujita7,2, Morio Matsumoto7,2, Hideaki Nakashima8,2, Kanichiro Wada9,2, Atsushi Kimura10,2, Katsushi Takeshita10,2, Satoshi Kato11,2, Hideki Murakami11,2, Kazuhiro Takeuchi12,2, Masahiko Takahata13,2, Masao Koda14,2, Masashi Yamazaki14,2, Masahiko Watanabe15,2, Shunsuke Fujibayashi16,2, Takeo Furuya17,2, Yoshiharu Kawaguchi18,2, Yukihiro Matsuyama19,2, Toshitaka Yoshii5,2, Atsushi Okawa5,2. 1. Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan. 2. Japanese organization of the Study for Ossification of Spinal Ligament (JOSL), Tokyo, Japan. 3. Department of Orthopedic Surgery, Osaka University Graduate School of Medicine Osaka, Japan. 4. Department of Orthopedic Surgery, Saiseikai Kawaguchi Hospital, Kawaguchi, Saitama, Japan. 5. Department of Orthopedic Surgery, Tokyo Medical and Dental University, Tokyo, Japan. 6. Department of Orthopedic Surgery, Kudanzaka Hospital, Tokyo, Japan. 7. Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo, Japan. 8. Department of Orthopedic Surgery, Fukui University, Fukui, Japan. 9. Department of Orthopedic Surgery, Hirosaki University Graduate School of Medicine, Aomori, Japan. 10. Department of Orthopedics, Jichi Medical University, Tochigi, Japan. 11. Department of Orthopedic Surgery, Kanazawa University, Ishikawa, Japan. 12. Department of Orthopedic Surgery, National Hospital Organization Okayama Medical Center, Okayama, Japan. 13. Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Hokkaido, Japan. 14. Department of Orthopedic Surgery, University of Tsukuba, Ibaraki, Japan. 15. Department of Orthopedic Surgery, Surgical Science, Tokai University School of Medicine, Tokyo, Japan. 16. Department of Orthopedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan. 17. Department of Orthopedic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan. 18. Department of Orthopedic Surgery, Faculty of Medicine, University of Toyama, Toyama, Japan. 19. Department of Orthopedic Surgery, Hamamatsu University School of Medicine, Shizouka, Japan.
Abstract
STUDY DESIGN: Prospectively collected, multicenter, nationwide study. OBJECTIVE: The aim of this study was to investigate recent surgical methods and trends, outcomes, and perioperative complications in surgery for thoracic ossification of the ligamentum flavum (T-OLF). SUMMARY OF BACKGROUND DATA: A prospective multicenter study of surgical complications and risk factors for T-OLF has not been performed, and previous multicenter retrospective studies have lacked details for these items. METHODS: Surgical methods, pre- and postoperative thoracic myelopathy (Japanese Orthopedic Association [JOA] score), symptoms, and intraoperative neurophysiological monitoring were investigated prospectively in 223 cases. Differences in these factors between fusion and nonfusion procedures for T-OLF were examined. The minimum follow-up period was 2 years after surgery RESULTS.: The mean JOA score was 6.2 points preoperatively, and 7.9, 8.2, and 8.2 points at 6 months, 1, and 2 year postoperatively, giving mean recovery rates of 35.0%, 40.9%, and 41.4% respectively. Posterior decompression and fusion with instrumentation was performed in 109 cases (48.9%). There were 45 perioperative complications in 30 cases (13.5%), with aggravation of motor disturbance in the lower extremities being most common (4.0%, n = 9). Patients treated with fusion had a significantly higher BMI, rate of gait disturbance, ossification occupation rate of OLF at computed tomography, and intramedullary high intensity area at magnetic resonance imaging (P < 0.01). The preoperative JOA score was lower (P < 0.05) and the JOA recovery rate at 1 year after surgery was significantly higher in cases treated without fusion (44.9% vs. 37.1%, P < 0.05). CONCLUSION: The high rate of surgery with instrumentation of 48.9% reflects the current major trend toward posterior instrumented fusion surgery for T-OLF. Fusion surgery with instrumentation may be appropriate for patients with severe OLF and preoperative myelopathy. A further prospective study of long-term outcomes is required with a focus on optimal surgical timing and the surgical procedure for T-OPLL. LEVEL OF EVIDENCE: 3.
STUDY DESIGN: Prospectively collected, multicenter, nationwide study. OBJECTIVE: The aim of this study was to investigate recent surgical methods and trends, outcomes, and perioperative complications in surgery for thoracic ossification of the ligamentum flavum (T-OLF). SUMMARY OF BACKGROUND DATA: A prospective multicenter study of surgical complications and risk factors for T-OLF has not been performed, and previous multicenter retrospective studies have lacked details for these items. METHODS: Surgical methods, pre- and postoperative thoracic myelopathy (Japanese Orthopedic Association [JOA] score), symptoms, and intraoperative neurophysiological monitoring were investigated prospectively in 223 cases. Differences in these factors between fusion and nonfusion procedures for T-OLF were examined. The minimum follow-up period was 2 years after surgery RESULTS.: The mean JOA score was 6.2 points preoperatively, and 7.9, 8.2, and 8.2 points at 6 months, 1, and 2 year postoperatively, giving mean recovery rates of 35.0%, 40.9%, and 41.4% respectively. Posterior decompression and fusion with instrumentation was performed in 109 cases (48.9%). There were 45 perioperative complications in 30 cases (13.5%), with aggravation of motor disturbance in the lower extremities being most common (4.0%, n = 9). Patients treated with fusion had a significantly higher BMI, rate of gait disturbance, ossification occupation rate of OLF at computed tomography, and intramedullary high intensity area at magnetic resonance imaging (P < 0.01). The preoperative JOA score was lower (P < 0.05) and the JOA recovery rate at 1 year after surgery was significantly higher in cases treated without fusion (44.9% vs. 37.1%, P < 0.05). CONCLUSION: The high rate of surgery with instrumentation of 48.9% reflects the current major trend toward posterior instrumented fusion surgery for T-OLF. Fusion surgery with instrumentation may be appropriate for patients with severe OLF and preoperative myelopathy. A further prospective study of long-term outcomes is required with a focus on optimal surgical timing and the surgical procedure for T-OPLL. LEVEL OF EVIDENCE: 3.