Extensive cervicothoracic posterior arch defects from C1 to T6 leading to myelopathy due to thoracic kyphosis in an adolescent boy.

Purpose: Limited dorsal myeloschisis, a form of cervical spinal dysraphism, is a rare anomaly and is typically associated with spinal cord tethering. The objective is to illustrate a rare dysraphic anomaly in the cervicothoracic spine causing myelopathy, not due to tethering but secondary to progressive kyphosis. To our knowledge, such an anomaly has not been described in the literature.

Study Design: Case report METHODS: A 16-year-old boy presented with lower extremity spastic paraparesis due to progressive cervicothoracic deformity. The imaging studies revealed extensive posterior arch defects from C1 to T6. The cervical spinal cord and meninges had herniated out of the spinal canal in the hyperlordotic cervical spine, and the thoracic spinal cord was stretched and compressed over the T4/5 kyphotic apex. Free-floating spinous processes were found compressing the cord at the T4-5 level. Tethering was not detected.

Results: The patient underwent a posterior vertebral column resection at T5 and excision of the free-floating spinous processes. The patient made a complete neurological recovery. At 8 year follow-up, he was asymptomatic and his deformity was stable.

Conclusion: We present a rare congenital cervical dystrophic anomaly causing myelopathy secondary to progressive kyphosis. We speculate that this anomaly was due to the sclerotomal cells' failure to migrate dorsally to the neural tube and fuse in the midline.