Segmental spinal dysgenesis: report of four cases and proposed management strategy.

Introduction: Segmental spinal dysgenesis, a rare developmental malformation, usually manifests during pregnancy or at birth. The resulting gross spinal instability necessitates spinal stabilization, which is inherently challenging in neonates.
Methods: We report four cases of segmental dysgenesis: three in the thoracolumbar region and one at the cervicothoracic junction. The latter was maintained in a custom orthosis that restricted all craniospinal motion while allowing routine care. Two neonates underwent surgical stabilization. The fourth patient will remain in a brace until 12-14 months old when fusion is planned.
Results: Fusion with rib autografts failed in the two neonates. One patient has been followed for 13 years and is paraplegic. The second patient was lost to follow up. The patient with the cervicothoracic dysgenesis maintained normal neurologic function until his death at 8 months of cardiac failure. The fourth patient is 12 months old and has been maintained in a thoracolumbar orthosis with stable neurologic function.
Conclusion: Several factors contribute to the challenge of creating a stable fusion in neonates. Incomplete ossification of the vertebral bodies and poor results with allograft materials restrict fusion options. Neurologic deficits often prevent ambulation and decrease the axial-loading forces that enhance fusion. To allow children to grow and develop, we advocate rigid spinal immobilization for 12-18 months before spinal fusion (preferably, rib or fibular autograft). Given the already narrow spinal canal, the use of instrumentation is controversial. We advocate the use of instrumentation in infants only when a sound construct cannot be obtained with the graft alone.