Segmental Spinal Dysgenesis–“Redefined”

STUDY DESIGN: Retrospective single institutional observational study. PURPOSE: Segmental spinal dysgenesis (SSD), a complex spinal dysraphic state caused by notochord malformation disorders, is named after its morphological presentation where a spine segment is dysgenetic, malformed or absent. This study’s objective was to examine and reassess SSD imaging findings and correlate them with an embryological explanation. OVERVIEW OF LITERATURE: Scott and his colleagues defined SSD as segmental agenesis or dysgenesis of the lumbar or thoracolumbar vertebrae and underlying spinal cord. Tortori-Donati and his colleagues defined it as a morphologic continuum ranging from hypoplasia to an absent spinal cord segment. METHODS: Fifteen children, whose imaging findings and clinical features were consistent with SSD, were included in the study. Magnetic resonance imaging (MRI) was performed per institutional spine protocol. RESULTS: Five children (33.3%) presented with a high-ending bulbous cord with no caudal segment, six (40%) presented with a dorsal or lumbar segmental dysgenetic cord with a low-lying, bulky caudal cord but without significant spinal canal narrowing, and four (26.6%) presented with segmental caudal dysgenesis with severe kyphoscoliosis, gibbus deformity, and spinal canal narrowing with a normal distal segment (normal or low-lying). CONCLUSIONS: SSD is a complex spinal anomaly in children requiring clinical-radiological assessment followed by multidisciplinary management based on the extent and severity of the dysgenetic cord and the type of SSD. MRI plays a crucial role in both diagnosing and classifying SSD prior to surgical treatment to prevent further impairment.

Segmental Spinal Dysgenesis: Case report

Segmental spinal dysgenesis (SSD) is a rare congenital abnormality in which a segment of the spine and spinal cord fails to develop properly. Segmental vertebral anomalies involve the thoracolumbar, lumbar, or lumbosacral spine. We report two cases of SSD associated with other spinal dysraphism. Radiologic investigations revealed segmental dysgenesis of thoracic spinal cord without an associated vertebral bony anomaly in one case and segmental dysgenesisof the cervico-thoracic cord with diastematomyelia in the other case. The neurologic picture depends on the severity of the malformation and on its segmental level along the longitudinal embryonic axis. The pathogenesis of SSD syndrome is not clear but its cause is probably related to a segmental maldevelopment of the neural tube.