Epidemiological survey of ossification of the ligamentum flavum in thoracic spine: CT imaging observation of 993 cases

Abstract

Objective To investigate the characteristics of epidemiological distribution of the ossification of the ligamentum flavum (OLF) in the thoracic spine including the incidence, segmental distribution, and shape. Methods Chest spiral computed tomography scans of 993 cases (male 506, female 487, mean age 60 years, range 5-102 years) who presented due to chest symptoms were analyzed with axial slices combined with sagittal slices. The conditions of OLF in the thoracic spine, including segments, thickness, location, and dural sac compression, were recorded. Prevalence was standardized according to the ''Age Structure of Population in Beijing 2008''. Results Among the population investigated, the standardized prevalence rate was 63.9 %. The standardized prevalence rate for males (68.5 %) was higher than that for females (59.0 %). The highest prevalence rate of OLF was in the 50-59 years age group (79.2 %); however, high density originated it can be found in individuals aged 10-19 years. The comparison of different thoracic segments showed that T10-11 (44.0 %) and T11-12 (41.6 %) had the highest prevalence rates. ConclusionThe prevalence of ossification of the ligamentum flavum was highest in the 50-59 years group, but also occurred in early years. OLF occurs more frequently in the lower than in the upper and middle thoracic regions and its prevalence increases with aging.

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

“…15,18,34,54,55 In our study, we also found similar results. In addition, it has been reported Clinical characteristics and surgical outcome of TM caused by OLF Z Li et al that the location of OLF is less vulnerable in mobile segments such as the cervical and lumbar vertebra than in the thoracic vertebrae.…”

“…Analysis of previously published epidemiological data revealed that the mean age of thoracic OLF patients ranged from 50 to 60 years and most required surgical treatment. 17,18,21 Another large-scale epidemiological study on OLF in patients who presented with chest symptoms and underwent multidetector CT examination showed that the prevalence rate of OLF was much higher, at 63.9%, than in previous reports. 18 The process of OLF occurred earlier than was previously thought and was even found in 10-19-year-old individuals.…”

“…17,18,21 Another large-scale epidemiological study on OLF in patients who presented with chest symptoms and underwent multidetector CT examination showed that the prevalence rate of OLF was much higher, at 63.9%, than in previous reports. 18 The process of OLF occurred earlier than was previously thought and was even found in 10-19-year-old individuals. The prevalence peaked in the 50-60 years age group, and tended increase with increasing age.…”

“…We also found that the prevalence of OLF in men was higher than in women at most segments, which was in line with most of the literature. 12,15,18,36 This finding may be due to heavier physical activity in men, which causes heavier stress on the ligamentum flavum. However, in some studies, the prevalence rates were reported to be higher in women than in men.…”

“…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.…”