c l i n i c a l f o l i o s : d i s c u s s i o n




Related narrative: Myelomeningocele, Myelomeningocele (Video)

Spinal dysraphism is the most common central nervous system birth defect with an incidence of 0.1% (varying with population, lower in blacks, higher in Ireland, India for example). The defects range from asymptomatic occult to severe protrusion of meninges and nerve tissue. The diagnosis is usually made by prenatal ultrasound. Unless the defect is very large or the head is markedly enlarged by hydrocephalus, vaginal delivery is considered safe.

Etiology is unclear and thought to be multifactorial, with genetic and environmental components. The lower lumbar and upper sacral regions are the most common sites. Arnold-Chiari malformation of the occipitocervical area is associated with virtually all patients with myelomeningocele. The resulting restriction of CSF circulation causes hydrocephalus in 15% of these infants at birth and up to 80% by early infancy, requiring ventriculoperitoneal shunting.

The severity of vertebral deformity is proportional to the neurologic malformation. In addition to motor and sensory problems distal to the malformation, associated changes have been found throughout the central nervous system. Neurogenic bladder is found in 90% of these patients. The commonly associated anomalies are skeletal, cardiovascular and genitourinary. Other serious conditions must be ruled out immediately postnatally in preparation for prompt surgical treatment of the neural defect. Infection of the exposed neural tissue is a threat to potentially normal intelligence and can worsen the neurological defecit.

Prompt closure of the neural tissue with five layers (arachnoid, dura, fascia, sub-Q, and skin) is the goal of treatment. With modern surgical care, the prognosis for these patients has improved dramatically with negligible operative mortality, 95% survival at 2 years, 85% urinary continence and 80% ambulatory rate.


Larsen, WJ, Human embryology, Churchill Livingstone, NY, 1993, pp. 58, 59, 85-88.

Reigel, DH, Rotenstein, Spina Bifida, in Pediatric Neurosurgery, Cheek, WR (Ed.), 3rd ed, WB Saunders, Phila, 1994, pp. 51-64.

This page was last modified on 17-Oct-2000.