Spinal dysraphism

Spinal dysraphism designates a heterogenous group of spinal anomalies with the common feature of imperfect fusion of midline mesenchymal, bony and neural structures. There are two major types: spina bifida aperta and occult spinal dysraphism. The most common form is the spina bifida aperta, that signifies posterior protrusion of all or part of the spinal content through a posterior spina bifida to form: 1) a meningocele, 2) a myelocele, or 3) a myelomeningocele. Occult spinal dysraphism designates the group of skin-covered spinal dysraphisms which have no exposed neural tissue and no obvious cystic mass: diastematomelia, the 'split notochord' syndrome, dorsal dermal sinus, spinal lipoma and the 'tight filum terminale' syndrome. Evaluation by ultrasound, myelography, computed tomographic myelography, magnetic resonance imaging, as well as some surgical approaches, will be discussed.