Thoracic Myelopathy Caused by Ossification of the Ligamentum Flavum

Abstract

Objectives : Ossification of the ligamentum flavum (OLF) is a rare cause of thoracic myelopathy. The aim of this study was to identify factors associated with the surgical outcome on the basis of preoperative clinical and radiological findings. Methods : Data obtained in 26 patients whot underwent posterior decompression for thoracic myelopathy, caused by thoracic OLF, were analyzed retrospectively. Patient age, duration of symptoms, OLF type, preoperative and postoperative neurological status using the Japanese Orthopedic Association (JOA) scoring system, surgical outcome, and other factors were reviewed. We compared the various factors and postoperative prognosis. All patients had undergone decompressive laminectomy and excision of the OLF. Results : Using the JOA score, the functional improvement was excellent in 8 patients, good in 14, fair in 2, and unchanged in 2. A mean preoperative JOA score of 6.65 improved to 8.17 after an average of 27.3 months. According to our analysis, age, gender, duration of symptoms, the involved spinal level, coexisting spinal disorders, associated trauma, intramedullary signal change, and dural adhesions were not related to the surgical outcome. However, the preoperative JOA score and type of OLF were the most important predictors of the surgical outcome. Conclusion : Early diagnosis and sufficient surgical decompression could improve the functional prognosis for thoracic OLF. The postoperative results were found to be significantly associated with the preoperative severity of myelopathy and type of OLF.

Thoracic myelopathy due to ossification of ligamentum flavum: a retrospective analysis of predictors of surgical outcome and factors affecting preoperative neurological status

“…Park et al [32] in a non-statistical survey found that recovery is less in this group of * Statistically significant at P \ 0.05 Table 9 Independent factors associated with preoperative neurological status (preoperative JOA score) with MRA patients. However, we agree with Hur et al [15] and Li et al [33] who reported that trauma has no influence on recovery in a statistical and nonstatistical survey, respectively. Compressive effects of hematoma and edema of spinal cord after traumatic event are likely to regress, resulting in good surgical outcome.…”

“…Two studies [10,15] reported same, but Miyakoshi et al [10] found that recovery at 1 month is significantly less in the presence of dural adhesions though final recovery remains unaffected.…”

Clinical characteristics and surgical outcome of thoracic myelopathy caused by ossification of the ligamentum flavum: a retrospective analysis of 85 cases

“…41,55,57 Compared with the middle thoracic spine, it seems to be more particularly easy to make degenerative processes on the lower thoracic spine owing to the high tensile force present on the posterior column. 22,55 Maigne et al 55 reported that OLF occurred most frequently at the lower thoracic spine especially at the thoracolumbar junction, and its appearance correlated with a unique orientation of the facet joints that generated increased rotatory instability and micromotion.…”

“…13,19,20,22,33,34,56 Preoperative severity of myelopathy was considered as the most important predictor of the postoperative outcome. 19,20,22,56 In accordance with this finding, our research confirmed that preoperative severity of myelopathy was the most important predictor of the highest postoperative JOA score and the lowest percentage RR in multiple linear regression analyses. In addition, the OLF level (middle thoracic), preoperative duration of symptoms and intramedullary signal change on T2WI were also confirmed and significantly correlated with the surgical outcome by multiple regression analysis.…”

“…Thus, when the ligamentum flavum is replaced by a mature bone, its osseous morphology should be V-shaped or a part of V shape on CT images. 12 Although thoracic OLF has been reported in several Asian countries, such as Japan, [11][12][13][14] China 3,4,[15][16][17][18][19] and South Korea, [20][21][22] and also in Caucasian and Caribbean ethnic groups, [23][24][25][26][27][28] extensive studies on thoracic OLF including a large number of patients have not yet been reported in the literature. This is partly due to the relatively low mean prevalence of thoracic OLF, which was reported as 3.8% in China and as 6.2% for Japanese men and 4.8% for Japanese women.…”