Clinical analysis and prognostic study of ossified ligamentum flavum of the thoracic spine

Object. A variety of factors may affect surgery-related outcome in patients with ossification of the ligamentum flavum (OLF) of the thoracic spine. Th e aim of this study was to determine these factors on the basis of preopera tive clinical and radiological findings. Methods. The authors treated 31 cases of symptomatic thoracic OLF between 1 988 and 1999. The following factors were retrospectively studied: patient a ge, sex, morbidity level, initial symptoms, chief complaint, duration of sy mptoms, patellar reflex, Achilles reflex, computerized tomography (CT) find ing, presence of intramedullary change determined by magnetic resonance ima ging, coexistent spinal lesions, preoperative grade, and postoperative grad e. A decompressive laminectomy was performed in all cases. In 29 patients (94% ) improved symptoms were demonstrated postoperatively. In terms of function al prognosis, the preoperative duration of symptoms was significantly short er in the group of patients with excellent outcomes than in those with fair outcomes (p < 0.05). No significant difference was observed in the correlation between other fac tors. To evaluate the degree of preoperative thoracic stenosis and the seve rity/extent of OLF-induced spinal compression, we used an original OLF CT s coring system. A score of excellent on the CT scale tended to indicate an e xcellent prognosis (p < 0.01). Conclusions. Thoracic OLF frequently develops in the lower-thoracic spine i n middle-aged men, and it is complicated by various spinal lesions in many cases. Early diagnosis and treatment are important for understanding the cl inical symptoms and imaging diagnosis because the present findings suggest that a delay in diagnosis and treatment correlates with the functional prog nosis postoperatively.