Ultrastructural change of ligamentum flavum in galactosialidosis

Abstract

Galactosialidosis is an autosomal recessive lysosomal storage disease caused by deficiency of both α-neuraminidase and β-galactosidase due to a defect of the protective protein/cathepsin A. Three clinical subtypes have been described, depending on the age of onset and severity of the symptoms: the early infantile, late infantile and juvenile/adult form. We report an adult-type patient who underwent surgery for galactosialidosis-related spinal deformity, and showed a favorable course thereafter. The patient was a 50-year-old male, and he consulted our hospital with pain of the bilateral anterior thigh. Lumbar radiograph showed applanation and horn-like deformity of the L2 vertebral body, which is characteristic of this disease, narrowing of the L1/2 intervertebral space, and topical kyphosis. Fenestration between the L1/2, decompression of the L2 nerve root, and posterolateral fusion involving the T12 to L3 were performed. Immediately after surgery, pain of the lower limbs disappeared. During the 2-year postoperative follow-up, bone assimilation was achieved, showing a favorable course. Histological examination of the ligamentum flavum (LF) collected during surgery showed that the elastic fibers were thin, whereas the collagen fibers were abundant and dense. The ligament cells were swollen, and there were a large number of vacuoles in the cytoplasm. This is the first report on spinal surgery for adult-type galactosialidosis and histological examination of spinal LF.