Closed spinal dysraphism

Closed spinal dysraphism (also known as occult spinal dysraphism or spina bifida occulta complex) is a group of congenital malformations of the spine and spinal cord in which the neural tissue is not exposed to the environment, meaning the skin overlying the defect remains intact. Unlike open spinal dysraphisms (such as myelomeningocele), the defect is covered by skin, which may show cutaneous markers such as a hairy patch (hypertrichosis), dimple, dermal sinus tract, subcutaneous lipoma, hemangioma, or skin appendage over the lower back. The condition results from abnormal development of the neural tube, vertebral column, and surrounding structures during embryogenesis. Closed spinal dysraphism encompasses several subtypes, including lipomyelomeningocele, lipomyelocele, tight filum terminale (tethered cord), split cord malformation (diastematomyelia), dermal sinus tract, and dorsal enteric fistula. These malformations primarily affect the nervous system and musculoskeletal system. Clinical manifestations vary widely depending on the specific subtype and severity, ranging from asymptomatic cases discovered incidentally to progressive neurological deterioration. Symptoms may include lower limb weakness or asymmetry, gait abnormalities, foot deformities (such as clubfoot or cavus foot), bowel and bladder dysfunction (including urinary incontinence or recurrent urinary tract infections), back pain, and scoliosis. Tethered spinal cord is a common underlying mechanism, where the spinal cord is abnormally attached, leading to progressive neurological damage with growth. Diagnosis is typically made through spinal ultrasound in neonates or MRI in older children and adults. Early identification is important because surgical intervention—primarily neurosurgical untethering of the spinal cord or excision of associated masses—can prevent or stabilize neurological deterioration. Management is multidisciplinary, involving neurosurgery, urology, orthopedics, and rehabilitation. Outcomes depend on the specific subtype, timing of diagnosis, and whether surgical correction is performed before irreversible neurological damage occurs. Folic acid supplementation before and during early pregnancy has been associated with reduced risk of neural tube defects overall, though its specific impact on closed dysraphisms is less well established.

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