Vertebral Pathology and Vertebrogenic Myelopathy in Patients with Mucopolysaccharoidosis Type IV A (Morquio Syndrome)

Abstract

Background: Upper cervical spine instability in patients with Morquio´s syndrome is of common occurrence. Dysplastic odontoid is one of the prominent aetiologies behind the development of atlanto-axial instability which eventually leads to morbid vertebrogenic myelopathy. Material and Methods: We describe 10 children (7 boys and 3 girls) with the phenotype/genotype of Morquio´s syndrome (MPS IVA). Lumbar kyphosis occurs at the age of six months, followed by apparent waddling gait at the age of 3 years. Clinical phenotype and genotype are the baseline tools to set up a crystal clear long term management. Firstly, we proceed via clinical assessment of C1-2 instability. The latter is carried out with full dynamic lateral cervical spine radiographs. Instability can be visualized through the precise interpretations of the anatomical structures around the atlanto-axial segments. 3D sagittal CT scan has been applied to further localize the exact pathology. In 7 cases, there was an initial myelopathy at the level of the cranio-vertebral junction. Results: The most threatening complication of MPS IVA is the vertebrogenic myelopathy. The latter emerged as a notorious complication in connection with atlanto-axial instability and progressive thickening of the spinal cord due to accumulation of Glycosaminoglycan (GAGs). Vertebrogenic myelopathy have been encountered in seven children. All underwent decompression and stabilization of the cervical spine Conclusion: Patients with MPS IV, in their first year of life usually manifest growth deficiency and lumbar kyphosis, but unfortunately passed unnoticed by most of the paediatricians. Progressive dysplasia of the acetabulae is the reason behind the waddling gait. The misconception of generalized ligamentous hyper laxity accompanied with waddling gait were the main incentives of confusion among most of the paediatricians and physicians. Thereby, the false diagnosis of Duchenne Muscular dystrophy has been falsely considered by some colleagues. The purpose of this paper is threefold. First, overlooking the early mal-development of the backbone (lumbar kyphosis) is not a simple mistake. Second, marked ligamentous hyperlaxity warrants the attention toward cervical ligaments, and as ligaments are the main supporters of the craniocervical junction and spine stability, such abnormality demands prompt clinical attention. Third, is to assess the vertebral pathology and vertebrogenic myelopathy from the standpoint of syndromic assessment and the efficiency of decompression and stabilization operations.