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Introduction: Mucopolysaccharidosis type IVA (MPS IVA, Morquio A syndrome, MIM #253000) is an autosomal recessive lysosomal storage disorder, characterized by inability to break down keratin-sulfate and chondroitin-6-sulfatase. Skeletal changes may result in disabling neurological complications. Atlantoaxial instability and cervical spinal cord compression are common; posterior occipitocervical fusion with (or without) spinal decompression is recommended.

Method: Case description. This report describes a patient who required occipitocervical fusion and suffered an irreversible thoracic paraplegia in the immediate postoperative period.

Case description: A 17 year-old boy diagnosed with MPS IVA at the age of 5, had slowly developed progressive signs of spinal cord compression. Prior to surgery, his neurological examination showed MRC grade 3 in the upper limbs, and 2 in the lower limbs, hyperactive deep tendom reflexes, without clonus or Babinski sign, no sensorial impairment. His spinal MRI showed atlantoaxial subluxation and signs of myelomalacia at C1-C2 levels (fig.1). Postoperatively, after occipitocervical fixation in the prone position, he developed acute paraplegia, sensory losses below T3 and striking MRI abnormalities (fig.2).

Discussion: MPS patients may develop remote spinal cord injuries from maximum compression sites after general anesthesia in the prone position due to impaired cardiac output. The role of intraoperative monitoring with motor and/or somatosensory evoked potentials remains controversial in literature; although evoked potentials may indicate early signs of spinal infarct, they cannot prevent this unexpected complication. This outcome is unusual, but healthcare professionals, patients and their parents should be aware to this devastating complication after spinal cord decompression.

Mucopolysaccharidosis type IVA; Posterior Occipitocervical Fusion; thoracic paraplegia; remote; spinal cord injury