Takashi Tsuji

STUDY DESIGN: Prospective, multicenter, nationwide study. OBJECTIVE: To investigate perioperative complications and risk factors in surgery for thoracic ossification of the posterior longitudinal ligament (T-OPLL) using data from the registry of the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament. SUMMARY OF BACKGROUND DATA: There is no prospective multicenter study of surgical complications and risk factors for T-OPLL, and previous multicenter retrospective studies have lacked details. METHODS: Surgical methods, preoperative radiographic findings, pre- and postoperative thoracic myelopathy (Japanese Orthopaedic Association [JOA] score), prone and supine position test (PST), intraoperative ultrasonography, and intraoperative neurophysiological monitoring (IONM) were investigated prospectively in 115 cases (males: 55, females: 60, average age 53.1 y). Factors related to perioperative complications and risk factors for postoperative motor palsy were identified. RESULTS: Posterior decompression and fusion with instrumentation with or without dekyphosis was performed in 85 cases (74%). The JOA recovery rate at 1 year after surgery in all cases was 55%. Motor palsy occurred postoperatively in 37 cases (32.2%), with a mean recovery period of 2.7 months. A long recovery period for postoperative motor palsy was significantly associated with a high number of T-OPLL levels (P < 0.0001), lower preoperative JOA score (P < 0.05), and greater estimated blood loss (P < 0.05). Perioperative complications or postoperative motor palsy were significantly related to a higher number of T-OPLL levels, comorbid ossification of ligamentum flavum rate, lower preoperative JOA score, higher preoperative positive PST rate, more surgical invasiveness, a lower rate of intraoperative spinal cord floating in ultrasonography, and higher rate of deterioration of IONM. CONCLUSION: This study firstly demonstrated the perioperative complications with high postoperative motor palsy rate in a nationwide multicenter prospective study. Surgical outcomes for T-OPLL should be improved by identifying and preventing perioperative complications with significant risk factors. LEVEL OF EVIDENCE: 3.

BACKGROUND: Few studies have addressed in detail long-term degenerative changes in the cervical spine. In this study, we evaluated the progression of degenerative changes of the cervical spine that occurred over a 20-year period in an originally healthy cohort. We also sought to clarify the relationship between the progression of cervical degenerative changes and the development of clinical symptoms. METHODS: For this prospective follow-up investigation, we recruited 193 subjects from an original cohort of 497 participants who had undergone magnetic resonance imaging (MRI) of the cervical spine between 1993 and 1996. The subjects were asked about the presence or absence of cervical spine-related symptoms. Degenerative changes of the cervical spine were assessed on MRI using an original numerical grading system. The relationship between the progression of degenerative changes and the onset of clinical symptoms was evaluated by logistic regression analysis. RESULTS: Degeneration in the cervical spine was found to have progressed in 95% of the subjects during the 20-year period. The finding of a decrease in signal intensity of the intervertebral disc progressed in a relatively high proportion of the subjects in all age groups and occurred with similar frequency (around 60%) at all intervertebral disc levels. The rate of progression of other structural failures on MRI increased with age and was highest at C5-C6. The progression of foraminal stenosis was associated with the onset of upper-limb pain (odds ratio, 4.71 [95% confidence interval, 1.02 to 21.7]). CONCLUSIONS: A progression of degenerative changes in the cervical spine on MRI over the 20-year period was detected in nearly all subjects. There was no relationship between the progression of degeneration on MRI and the development of clinical symptoms, with the exception of an association found between foraminal stenosis and upper-limb pain. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.