Abstract

AIM: To find out the prevalence, segmental distribution and morphological characteristics of ossification of ligamentum flavum in thoracic spine. MATERIALS AND METHOD: We examined 1786 numbers of dried thoracic vertebrae preserved in the osteology sections of our institutes for the presence of ossification of ligamentum flavum along the upper margin and inner surface of their laminae. We found out vertebral segments commonly affected by this pathology and compared with that of other studies. We also classified them into different morphological types according to Sato classification and found out the frequency of occurrence of each type. OBSERVATION: Out of 1786 thoracic vertebrae examined 261 number of vertebrae (14.6%) showed ossification of ligamentum flavum. A lower thoracic vertebra (T9-T12) was most frequently affected and was highest in T11. CONCLUSION: Ossification of ligamentum flavum is one of the most important contributing factor for acquired thoracic spinal stenosis leading to thoracic myelopathy and radiculopathy. It has been suggested by various authors that hypermobility of the thoracic spine could be responsible for this. As it develops more frequently in East Asians, most of the researches were done on populations of China, Japan and Korea. All the earlier studies are based on CT or MRI scans. Our study is an anatomical study in dried vertebrae. The prevalence and distribution of ossification was found to be consistent with most of the reports from other studies.

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