Foramen magnum decompression for cervicomedullary encroachment in craniometaphyseal dysplasia: case report

Foramen magnum encroachment has been cited as a potential cause for the premature demise of patients afflicted with craniometaphyseal dysplasia (CMD). To our knowledge, the association of Chiari malformation and syringomyelia with CMD has not been previously reported. We describe our evaluation and surgical treatment of a patient presenting with CMD, foramen magnum stenosis, Chiari I malformation, and syringomyelia.

A 15-year-old female patient with CMD presented with severe headaches and progressive myelopathy. Evaluation by computed tomography and magnetic resonance imaging revealed mild ventriculomegaly, cervicomedullary compression secondary to Chiari I malformation and foramen magnum stenosis, and C3-T10 syringomyelia.

Foramen magnum decompression was performed via suboccipital craniectomy, C1-C2 laminectomy, and dural augmentation. Dysplastic bone was revealed to be extremely thick and mineralized. Removal required lengthy and extensive drilling. The postoperative course was complicated by prolonged intubation secondary to airway obstruction and a perforated duodenal ulcer. Airway obstruction was attributed to severe nasopharyngeal bony dysplasia and soft tissue edema. The use of steroids in the treatment of airway edema and delayed enteral feeding was thought to contribute to ulcer development. Nevertheless, neurological symptoms improved dramatically.

Foramen magnum decompression can be used to treat life-threatening cervicomedullary compression in patients with CMD. However, caution should be used because surgical intervention may be associated with a higher incidence of complications because of lengthy procedures and the spectrum of craniofacial impairments in patients with CMD.