A Rare Case of Ossification of Ligamentum Flavum presenting as Dorsal Myelopathy in Achondroplasia

Abstract

Ossification of the ligamentum flavum (OLF) was discovered by Polgar and further described by Yamaguchi and Isuruni [1]. Among the thoracic myelopathies, its incidence is less than that of ossification of the posterior longitudinal ligament (OPLL) and higher than that of herniated nucleus pulposus (HNP) [1]. It is mostly prevalent in Japan and other East Asian countries such as Korea and China [2]. Achondroplasia is a genetic disorder of bone growth with congenital spinal stenosis being a well known complication [3]. Degenerative changes of the spine, such as disc herniation, degenerative spondylosis and arthrosis result in worsening of stenosis [4]. However, symptomatic spinal stenosis due by ossification of the ligamentum flavum (OLF) in achondroplasia is extremely rare [5,6]. We present a rare case of spinal stenosis due to ossified ligamentum flavum in a 30 year old Indian female of achondroplasia presenting as dorsal myelopathy.