What is spina bifida?

Spina Bifida: Definition and Clinical Implications

Spina bifida is a birth defect caused by failure of the caudal neural tube to fuse normally in early development, resulting in an open vertebral column often with spinal cord involvement. 1 It is the most common nonchromosomal birth defect in the United States, with a birth prevalence of approximately 30 per 100,000 live births. 1

Types and Pathophysiology

• Myelomeningocele is the most common and clinically severe form of open spina bifida, where the spinal cord and neural elements are exposed, resulting in neurological deficits that vary with the level of the lesion. 1, 2
• The exposed neural tissue degenerates in utero, causing variable impact on somatic, parasympathetic, and sympathetic innervation affecting multiple organ systems. 1
• Less severe forms include meningocele, where only meninges protrude through the defect. 3

Epidemiology and Economic Impact

• Spina bifida affects approximately 3 of 10,000 live births worldwide. 4, 2
• The economic impact is significant, with estimated total lifetime medical expenses ranging from $236,000 to $319,000 per patient. 1
• The condition results in severe disability affecting multiple organ systems. 1, 5

Clinical Manifestations and Complications

• Neurological deficits vary depending on the severity of the fusion abnormality and location of the lesion. 1
• Urological complications are a major source of morbidity, including:
  • Poor bladder dynamics leading to chronic kidney disease 1
  • Urinary incontinence 1
  • Recurrent urinary tract infections 1
  • Urological issues are implicated in almost one-third of deaths in patients with open spina bifida followed long-term 1
• Other complications include:
  • Hydrocephalus requiring shunt placement (86% of patients) 6
  • Scoliosis (49% of patients) 6
  • Tethered cord syndrome requiring surgical release (32% of patients) 6
  • Fecal incontinence, which significantly impacts quality of life 7
  • Mobility limitations 6
  • Latex allergies (approximately 1/3 of patients) 6

Diagnosis

• Prenatal diagnosis is achieved through ultrasound screening, which can characterize the anatomical nature of the lesion and identify the level of involvement. 1
• Fetal MRI can differentiate unique anatomical features, though it is more expensive. 1
• Prenatal diagnosis allows consideration of pregnancy termination or prenatal closure of the defect. 1

Management Approaches

• Initial management focuses on neurosurgical closure of the defect, ideally within 24 hours of birth to improve bladder capacities and decrease detrusor leak point pressures. 1

• Treatment goals evolve with age: 1

  • Newborn: preserving renal function
  • School age: urine and fecal continence along with kidney preservation
  • Adolescence and adulthood: independence and sexual function

• Urological management is critical as bladder dysfunction can lead to chronic kidney disease: 1

  • Clean intermittent catheterization (CIC)
  • Pharmacotherapy
  • Surgical interventions including bladder augmentation and bladder neck procedures when necessary

• Bowel management options include: 7, 8

  • First-line: dietary modifications, laxatives, suppositories (50% success rate)
  • Second-line: retrograde enemas (75% success rate)
  • Third-line: Antegrade Continence Enema (MACE) procedure (77% success rate)
  • Final option: colostomy for definitive management of fecal incontinence

Long-term Outcomes and Survival

• With modern treatment, at least 75% of children born with myelomeningocele can be expected to reach early adulthood. 6
• Mortality (24%) continues to climb into young adulthood. 6
• Educational outcomes: 85% attend or graduate from high school and/or college. 6
• Continence: More than 80% of young adults achieve social bladder continence. 6
• Late deterioration is common, requiring ongoing multidisciplinary care. 6

Recent Advances

• Prenatal closure of the defect has shown decreased need for ventriculoperitoneal shunting and improved lower extremity motor outcomes, though benefits for bladder function remain unclear. 1
• The Management of Myelomeningocele Study (MOMS) demonstrated improved outcomes with prenatal versus postnatal closure, though with increased risks of preterm delivery and uterine dehiscence. 1

Transitional Care

• Transition from pediatric to adult care remains a major avenue for improvement in disease management. 1
• With improved survival, transitional care issues including health-related independence, sexual health needs, and development of support systems are increasingly important. 1