Craniovertebral instability with spinal cord compression in a 17-month-old boy with Sly syndrome (mucopolysaccharidosis type VII) - A surgical dilemma

Study Design. A case study with review of surgical technique in craniovertebral stabilization for young children with mucopolysaccharidosis. Objectives. To describe an interesting patient with a rare metabolic disorder and review surgical technique for craniovertebral instability in this rare patient population. Summary of Background Data. Craniovertebral instability has been reported in patients with mucopolysaccharidosis and poses a problem for spinal surgery because of the inherent metabolic disorder and age at presentation. We present the first case of craniovertebral instability and spinal cord compression occurring in Sly syndrome (mucopolysaccharidosis type VII) who is the youngest patient afflicted with this metabolic disorder to undergo craniovertebral stabilization. Methods. A 17-month-old boy presented with inability to support his head, decreasing muscle strength in all extremities, distended abdomen, and shortness of breath. The patient was found to have a dilated cardiomyopathy, hepatosplenomegaly, abnormal hepatobiliary function, corneal clouding, and a questionable tracheal anomaly. Genetic testing provided a diagnosis of Sly syndrome, mucopolysaccharidosis type VII. Magnetic resonance imaging revealed focal stenosis with significant spinal cord compression at the craniovertebral junction. Neurologic examination revealed normal muscle volume with strength 3/5 in all extremities and significant weakness in the neck muscles with instability at the craniovertebral junction. Results. On a concerted preoperative medical clearance by pediatric intensive care, pediatric neuroanesthesia, pediatric cardiology, pediatric gastroenterology, and pediatric neurosurgery, the patient underwent occipital to C3 decompression and fusion with autogenous rib grafts. The patient was placed in a prefitted halo-vest after surgery and was neurologically intact. Conclusions. This case demonstrates the heterogeneity of cervical spine deformities among the mucopolysaccharidosis syndromes and confirms the propensity for deposition of glycosaminoglycans at the craniovertebral junction. Further studies should investigate the etiology for this propensity of glycosaminoglycan deposition at the craniovertebral junction. We think that this case demonstrates that, with appropriate preoperative planning, these patients can undergo successful posterior cervical arthrodesis despite their age or metabolic defects.