John W. Brock III, M.D.
Monroe Carell Jr. Chair and Surgeon-In-Chief, Monroe Carell Jr. Children's Hospital at Vanderbilt; Professor of Urologic Surgery; Professor of Pediatrics; Director, Division of Pediatric Urology
VKC Member
Overview of Interests
John Brock is the Principal Investigator for the Management of Myelomeningocele Study (MOMS) at Vanderbilt, an NICHD-assisted randomized study comparing the outcomes of children undergoing prenatal vs. postnatal closure of their congenital neural tube defect. The MOMS study currently evaluates the children during 12- and 30-month follow-up, which includes neurocognitive, psychological, behavioral, and physical examinations. Brock and colleagues are working to apply for funding for a third follow-up evaluation at 7-8 years of age.
Infant death related to open spina bifida in the United States is estimated at 10 percent and remains about 1 percent per year. Those who survive are likely to experience significant life-long disabilities that can include paralysis, hydrocephalus, Arnold-Chiari type II malformation, endocrine abnormalities, tethered cord, syringomyelia, syringobulbia, deformations of the limbs and spine, bladder, bowel, and sexual dysfunction, and learning disabilities. The first year of life for a child with spina bifida is dominated by neurosurgical interventions, in particular, ventricular peritoneal shunting to control the effects of hydrocephalus, itself a result of hindbrain herniation. Untreated, severe hydrocephalus can lead to brain damage and death.
Nearly 90 percent of infants with spina bifida also have some type of foot deformity such as clubfoot, vertical talus deformity, or calcaneovalgus, which requires splinting and/or casting followed by surgical repair once weight-bearing activities are achieved. Hip surgery in the form of muscle-tendon releases, open reduction of the hip, and proximal femoral osteotomy with or without acetabuloplasty and muscle balancing, is often necessary if the “verticalization” process of the child is inhibited.
A mere 2 to 3 percent of children with spina bifida achieve urinary continence and spontaneous voiding without urologic intervention. However, 70 percent of patients can achieve urinary continence with conservative medical therapy.
Numerous studies have documented that children with spina bifida are at increased risk for a variety of neuropsychological and behavioral problems. These include impairments in cognitive, perceptual-motor, memory, fine and gross motor, language, and attention skills, as well as academic achievement and psychosocial functioning. Intelligence quotients (IQ) of children who have myelomeningocele and the common complication of hydrocephalus vary widely but tend to cluster in the borderline to low average range, i.e., IQ's of 70-90. Difficulties with memory and attention are also frequently reported, particularly in children with hydrocephalus.
Children with spina bifida are also at risk for poorer psychosocial adjustment in relation to the general population. Children with spina bifida have been found to have higher rates of internalizing and externalizing behavior problems than unaffected children based on parental reports.
The MOMS participants are a historically unique cohort that documents a multitude of data points for longitudinal clinical investigation. An unprecedented 98 percent of participants return for follow-up. It is therefore critical to capture additional data and insight into not only the world of a child born with spina bifida but whether fetal intervention has improved their quality of life.
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