Occult Spinal Dysraphism

Spinal dysraphism is an incomplete fusion of the spine during embryologic development and encompasses a spectrum of congenital anomalies that can affect the spinal cord, nerve roots, and vertebral column. These anomalies can be categorized into open and closed spinal dysraphism. Open spinal dysraphism is also known as spina bifida aperta. The neural tissue in these lesions is exposed, and examples include meningoceles and myelomeningoceles. Closed spinal dysraphism is also referred to as occult spinal dysraphism (OSD). In these lesions, the neural tissue is covered with skin, making the diagnosis less apparent. Isolated vertebral defects are the most common and least severe form of OSD. Other examples of OSD include neurenteric cysts, split notochord syndrome, split spinal cord malformation, sacral meningeal cysts, spinal lipomas, caudal regression syndrome, dorsal dermal sinus tracts and cysts, and tethered cord syndrome. Among these diagnoses for OSD, evaluations for potential tethered cord syndrome and dermal sinus tracts are the most common reasons for referrals to pediatric neurosurgeons. Because the scope of this In Brief cannot go into detail with all of these diagnoses, we describe tethered cord syndrome and dorsal dermal sinus tracts in more detail and then focus on the epidemiology, associated morbidity, physical findings, challenges with diagnosis, and management of all types of OSD.

Tethered cord syndrome can result from several types of spinal dysraphism. A tethered cord arises when the spinal dysraphic malformation creates a situation where the spinal cord is anchored in some way, thereby causing the spinal cord to stretch as the child grows. This leads to ischemic changes in the neurons. Findings on imaging depend on the type of …