Spina Bifida

Neural tube defects are the result of a teratogenic process that causes failed closure and abnormal differentiation of the embryonic neural tube. Neural tube defects occur between the 17th and 30th day of gestation, at a time when the mother may not be aware that she is pregnant and the fetus is estimated to be about the size of a grain of rice.

The most common neural tube defects are anencephaly and myelomeningocele. Anencephaly results from failed closure of the rostral end of the neural tube, resulting in incomplete formation of the brain and skull.

Myelomeningocele

Spina bifida cystica causes a problem when the meningeal cyst (meningocele) includes cord tissue extending into the cyst (in which case, it is a myelomeningocele). The condition is also of particular concern when the neural tube is completely open and the ependymal layer is exposed as a myelocele (or myeloschisis). A meningocele alone may cause no neurologic problems if the cord is confined to the vertebral canal.

Myelomeningocele results from failed closure of the caudal end of the neural tube, resulting in an open lesion or sac that contains dysplastic spinal cord, nerve roots, meninges, vertebral bodies, and skin (see the image below). The anatomic level of the myelomeningocele sac roughly correlates with the patient's neurologic, motor, and sensory deficits.[11]

Myelomeningocele is associated with abnormal development of the cranial neural tube, which results in several characteristic CNS anomalies. The Chiari type II malformation is characterized by cerebellar hypoplasia and varying degrees of caudal displacement of the lower brainstem into the upper cervical canal through the foramen magnum. This deformity impedes the flow and absorption of cerebrospinal fluid (CSF) and causes hydrocephalus, which occurs in more than 90% of infants with myelomeningocele. (See the image below.)

Cerebral cortex dysplasia, including heterotopias, polymicrogyria, abnormal lamination, fused thalami, and corpus callosum abnormalities, also occurs frequently. In addition, mesodermal structures surrounding the neural tube, such as the vertebra and ribs, may be malformed.

Unprotected neural elements are at severe risk during delivery. The sequelae of the neural tube defect follow directly from this lack of protection, occurring mechanically or resulting from desiccation, scarring with closure, and/or a lack of vascular support or from other insults to the delicate neural elements.

The neurologic damage generally results in a neurogenic bowel and bladder, which leads to incontinence. With a lack of neural input, a contracted bladder causes hydronephrosis, along with infections and renal failure, which may be the prime determinant of longevity in patients with spina bifida.

As a pattern, neurologic innervation is not symmetrical between lower-limb flexors and extensors; the corresponding levels are lower (caudal) for the extensors than for the flexors. Generally, muscular imbalance is present in patients with myelomeningocele, which results in joint contractures and developmental problems, such as hip dislocation and spinal deformities.

Normal intelligence can be expected with aggressive shunting for hydrocephalus, although seizure activity secondary to the neural tube defect may be noted. In addition, subtle defects in coordination may be associated with the cerebellar deficiency from the Arnold-Chiari malformation, which is a malformation of the cerebellum, with elongation of the cerebellar tonsils and with the cerebellum drawn into the fourth ventricle. The condition also is characterized by smallness of the medulla and pons and by internal hydrocephalus. In fact, all patients with spina bifida cystica (failure to close caudally) have some form of Arnold-Chiari malformation (failure to close cranially).

Myelomeningocele often occurs along with multiple system congenital anomalies. Commonly associated anomalies are facial clefts, heart malformations, and genitourinary tract anomalies. Urinary tract anomalies, such as solitary kidney or malformed ureters, may contribute to increased morbidity in the presence of neurogenic bladder dysfunction.

A study by Flores et al indicated that in children with myelomeningocele, greater movement quality and trunk control predict functional ambulation in the patient, with more optimal spatiotemporal gait parameters. The investigators found good correlation between the Pediatric Neuromuscular Recovery Scale (Peds NRS) summary score and the modified Hoffer Functional Ambulation Scale score. They also determined that sit-to-stand and three standing/walking items were strongly associated with cadence and with swing and stance time. In addition, two Peds NRS standing items and the modified Hoffer scale score correlated well with velocity.[12]

Embryology

During prenatal development, neuroectoderm thickens into the neural plate, which then folds into a neural groove by the time somites appear. The groove deepens to become the neural tube, and dorsal fusion begins centrally, extending cephalad and caudally, with the cephalad pole fusing at the 25th day. The ventricle becomes permeable at the 6th to 8th week of gestation but this apparently does not proceed normally in patients with myelomeningocele.

Some studies suggest that an increased amount of neural crest material in the defect prevents neural tube closure. Another hypothesis is that an already closed tube ruptures; increased permeability of the rhombic groove leads to greater CSF secretion and increased luminal pressure, with the tube then expanding and essentially splitting the neural element at its weakest areas (ie, the cephalic and caudal ends).

Research by McLone and Knepper supports the latter hypothesis and details the implications of this defect on the entire CNS.[13]

Obesity

Obesity is prevalent in children with myelomeningocele, especially those with high-lumbar and thoracic-level lesions, because of reduced capacity for caloric expenditure. The decreased muscle mass of the lower body musculature results in a lower basal metabolic rate. In addition, activity levels generally are lower than in unaffected children as a direct result of lesion-related mobility deficits and as an indirect result of decreased opportunities for disabled children to participate in physical play.

A report by Polfuss et al attributed obesity in patients with spina bifida to multiple factors, including individual ones (ie, body composition and measurement issues, energy needs, eating patterns, physical activity, sedentary activity), parenting/family, peers, community factors (ie, culture, built environment, and factors related to healthcare, healthcare providers, and school), and societal factors (ie, policy issues).[14]

Obesity can exert negative impact on self-image and further perpetuate a cycle of inactivity and overeating. Excessive weight impedes maximal independence and ambulation.

Bone involvement

Bone mineral density is decreased in patients with myelomeningocele.[15] Markers of bone reabsorption have been found more frequently in limited ambulators and nonambulators than in children who ambulate regularly.

Children with myelomeningocele are at higher risk of lower extremity fractures. Reduced muscle activity in the paralyzed limb and decreased weight-bearing forces result in decreased bone mass. In addition, many fractures occur after orthopedic interventions, especially after procedures associated with cast immobilization. Fractures in myelomeningocele tend to heal quickly, and excessive callus formation often is seen.

Urinary tract dysfunction

The main determinant of upper urinary tract deterioration is the intravesical pressure in storage and voiding situations. A high incidence of vesicoureteral reflux and ureteral dilation has been found in patients with myelomeningocele whose leak-point pressures are greater than 40 cm water.

High pressures may result from increased outlet resistance or decreased bladder wall compliance. Increased outlet resistance may be caused by sphincter dyssynergia or fibrosis of a denervated sphincter. Decreased bladder wall compliance is associated with areflexia of the detrusor. Any of these urologic dysfunctions can occur in myelomeningocele, but manifestations may vary over time because of the changing neurologic status in some of these patients.

Abnormalities in sexual development and function

Females with myelomeningocele go through puberty 1-2 years earlier than their unaffected peers. Sexual precocity is associated with hydrocephalus and obesity. Abnormal genital sensation is typical, but some female patients with myelomeningocele are able to achieve orgasm. Fertility is not affected in females with myelomeningocele; however, pregnancy carries increased risk of urinary tract infection, back pain, and perineal prolapse postpartum.

Young men with myelomeningocele have abnormal genital sensation, decreased ability to achieve and sustain erections, and decreased fertility. However, the potential for ejaculation and reproduction must be assessed for each individual patient. Implantable penile prosthetic devices, vacuum tumescence devices, and electrical stimulation have been used for some patients unable to achieve erections.

Latex sensitization

Latex sensitization is more common in patients with myelomeningocele, likely due to a genetic predisposition and a higher degree of exposure. The number of surgical interventions (particularly orthopedic and urologic procedures), the presence of a ventriculoperitoneal shunt, and total serum immunoglobulin E (IgE) levels have been associated with latex allergy in children with myelomeningocele. Establishment of a latex-free environment for surgery, however, has resulted in a decrease in sensitization of these patients to latex.

The etiology in most cases of myelomeningocele is multifactorial, involving genetic, racial, and environmental factors, in which nutrition, particularly folic acid intake, is key. Cytoplasmic factors, polygenic inheritance, chromosomal aberrations, and environmental influences (eg, teratogens) have all been considered as possible causes. A small number of cases are linked to specific etiologic factors.

Most infants born with myelomeningocele are born to mothers with no previously affected children. However, other offspring in a family with 1 affected child are at greater risk for neural tube defect than are children without affected siblings. The risk is 1 in 20-30 for subsequent pregnancies, and if 2 children are affected, the risk becomes 1 in 2. An increase in the risk of myelomeningocele has also been reported for second- and third-degree relatives of affected individuals.

Up to 10% of fetuses with a neural tube defect detected in early gestation have an associated chromosome abnormality. Associated chromosome abnormalities include trisomies 13 and 18, triploidy, and single-gene mutations.

In women with pregestational diabetes, the risk of having a child with a CNS malformation, including myelomeningocele, is 2-10 fold higher than the risk in the general population. The mechanism underlying this teratogenic effect is not well defined but is related to the degree of maternal metabolic control. The risk in women who develop gestational diabetes is lower than the risk in women with pregestational diabetes, but it might not be as low as in the general population.

Other risk factors for myelomeningocele include maternal obesity, hyperthermia (as a result of maternal fever or febrile illness or the use of saunas, hot tubs, or tanning beds), and maternal diarrhea. Identified risk factors also include intrauterine exposure to antiepileptic drugs, particularly valproate and carbamazepine, and to drugs used to induce ovulation.[16, 17, 18]

The risk of having a child with myelomeningocele has also possibly been associated with maternal exposures to fumonisins, electromagnetic fields, hazardous waste sites, disinfection by-products found in drinking water, and pesticides.

Folic acid deficiency

Research in the 1980s showed correction of folic acid deficiency as an effective means of primary and recurrent prevention.[19] At least half of cases of neural tube defects are related to a nutritional deficiency of folic acid or increased requirement and, thus, are potentially preventable. (An elevated risk of neural tube defects has also been linked to higher levels of folate receptor autoimmunity, in a dose-response manner.[20] )

In September 1992, the US Public Health Service (USPHS) recommended intake of folic acid at a dosage of 0.4 mg (400 mcg) per day for all women anticipating pregnancy. (Currently, the US Centers for Disease Control and Prevention [CDC] also recommends 400 mcg/day, while the US Preventive Services Task Force recommends 400-800 mcg/day.) In January 1998, the mandatory fortification of enriched cereal grain products with folic acid went into effect in the United States; this measure that was expected to increase the daily intake of folic acid in women of reproductive age by approximately 100 mcg/day.

According to the CDC, the prevalence of spina bifida from October 1995 to December 1996 (before mandatory fortification) was 2.62 per 10,000 live births, while the prevalence from October 1998 to December 1999 was 2.02 per 10,000 live births, a 22.9% reduction. Later declines were smaller, however, with the prevalence of spina bifida falling just 6.9% between the surveillance periods 1999-2000 and 2003-2005; for reasons that remain unclear, this included a significant decrease in prevalence within the black population but not within the white and Hispanic populations.[19, 21]

Occurrence in the United States

The incidence of spina bifida has been estimated at 1-2 cases per 1000 population, with certain populations having a significantly greater incidence based on genetic predilection. Folate fortification of enriched grain products has been mandatory in the United States since 1998; research indicates that folate can reduce the incidence of neural tube defects by about 70% and can also decrease the severity of these defects when they occur.[18, 22, 23, 24]

Neural tube defects are the second most common type of birth defect after congenital heart defects, and myelomeningocele is the most common form of neural tube defect. In the United States, approximately 1500 infants are born with myelomeningocele each year.

Birth incidence of the disease was reported to be 4.4-4.6 cases per 10,000 live births from 1983-1990. Rates varied by region, with the incidence being higher on the East Coast than on the West Coast and with the highest rates occurring in Appalachia. The rate of myelomeningocele and other neural tube defects has declined since the late 20th century. This is attributed to the widespread availability of prenatal diagnostic services and to improved nutrition among pregnant women.

International occurrence

The average worldwide incidence of spina bifida is 1 case per 1000 births, but marked geographic variations occur. Neural tube defects occur at frequencies (per 10,000 births) ranging from 0.9 in Canada and 0.7 in central France to 7.7 in the United Arab Emirates and 11.7 in South America.

The highest rates of spina bifida are found in parts of the British Isles, mainly Ireland and Wales, where 3-4 cases of myelomeningocele per 1000 population have been reported, along with more than 6 cases of anencephaly (both live births and stillbirths) per 1000 population. The reported overall incidence of myelomeningocele in the British Isles is 2-3.5 cases per 1000 births.

In France, Norway, Hungary, Czechoslovakia, Yugoslavia, and Japan, a low prevalence is reported, being just 0.1-0.6 cases per 1000 live births.

A study by Blencowe et al estimated that in 2015, there were 260,100 birth outcomes worldwide impacted by neural tube defects, with about half ending in elective pregnancy termination (owing to the presence of fetal anomalies) or in stillbirth.[25]

Low socioeconomic status is associated with higher risk of neural tube defects in many populations. Since approximately 1940, epidemics of myelomeningocele have occurred in Boston, Mass; Rochester, NY; Dublin, Ireland; The People's Republic of China; and Jamaica.[26]

Race-related demographics

According to the CDC, the prevalence of spina bifida in the United States is higher in the white and Hispanic populations (2 and 1.96, respectively, per 10,000 live births) than in the black population (1.74 per 10,000 live births).[27, 28, 29, 21]

Sex-related demographics

Data from state and national surveillance systems from 1983-1990 found the birth prevalence rate of myelomeningocele to be slightly higher in females than in males (1.2:1). A higher proportion of females than males exhibit thoracic-level malformations.

Studies of children with prenatally diagnosed myelomeningocele suggest that less severe ventriculomegaly and a lower anatomic level of lesion on prenatal ultrasonograms predict better developmental outcomes in childhood. Aggressive treatment with closure in the neonatal period leads to survival in most cases of spina bifida.

Cognitive function

As a group, patients with myelomeningocele have intelligence scores below the population average but within the normal range. Cognitive dysfunction is most strongly correlated with the presence of hydrocephalus, along with hydrocephalus-related illness parameters (ie, the necessity of shunting, number of shunt revisions, shunt infections, and additional structural abnormalities of the CNS).[30]

Aggressive shunting of hydrocephalus can permit the retention of near-normal intelligence in the majority of patients. Children who do not require shunt revisions are more likely to be employed, live independently, and drive as adults.[31]

Cognitive function has also been related to the level of the lesion. Upper-level lesions have been associated with a higher frequency of mental retardation and lower scores on measures of intelligence, academic skills, and adaptive behavior.

Children with myelomeningocele tend to demonstrate generalized deficits in visual memory and auditory/verbal memory. Verbal subtest scores usually exceed performance subtest scores, with visual-spatial organizational deficits that may be explained in part by upper limb discoordination and/or memory deficits.

The term "cocktail personality" has been applied to a subgroup of patients with hydrocephalus who appear to have advanced expressive language skills. The speech of these individuals typically is verbose, but it tends to lack content and contains jargon and many clichés. This pattern often is associated with poor comprehension skills and reflects significant cognitive impairments and functional deficits.

Approximately 75% of children with myelomeningocele have an IQ higher than 80. Among those whose intelligence is normal, 60% are learning disabled, with the most common feature being a nonverbal learning disability. Particular deficits are seen in mathematics, sequencing, visual perceptual skills, and problem solving. Prevalence of attention problems has been estimated to be 30-40%.

Ambulation

The ability to ambulate depends on, and directly correlates with, the functional sensorimotor level. The patient’s motor level is difficult to assess in the neonate, but the sensory level in infancy is easier to evaluate. Children with sensory levels below L3 are more likely to ambulate as adults and are less likely to have pressure sores or need daily care.[31, 32, 33, 34]

Studies have shown that approximately 50-60% of young adult patients ambulate household or community distances, with about 20% of these patients using some orthotic or assistive device. The other 50% of patients use wheelchairs as their primary form of mobility. Approximately 20% of these individuals ambulate with orthotics and assistive devices as a form of therapeutic exercise.[35]

Several studies have shown that ambulation in patients with myelomeningocele is related to the strength of certain key muscles, including the iliopsoas, gluteus medius, hamstrings, and/or quadriceps. Specifically, a motor neurologic level of L5 or quadriceps strength graded as good (4 out of 5) in the first 3 years of life is predictive of a good prognosis for community ambulation. Gluteus medius strength was the best predictor of a need for gait aids and orthoses. In a 25-year follow-up study of young adults with myelomeningocele, no patient with a lesion at L3 or above ambulated a majority of the time.[36]

Maximal ability to ambulate usually is achieved by the time the child reaches age 8-9 years. Studies have shown that a majority of preadolescent patients, even those with higher-level lesions, are community ambulators when they receive aggressive multidisciplinary interventions. After adolescence, however, community ambulation decreases to approximately 50%.

The ability to ambulate tends to decline in the second decade of life because of increased body dimensions and higher energy requirements. Lower-extremity muscle deterioration also may play a role. Functional decline with aging in patients with myelomeningocele also can be exacerbated by obesity, decubitus ulcers, and psychological issues.

For example, a retrospective study by Dicianno et al found that depressive symptoms in adult patients with spina bifida were significantly associated with lower mobility scores on the Craig Handicap Assessment and Reporting Technique-Short Form (CHART-SF). The study, of 190 adults with spina bifida, also suggested that depressive symptomatology was common in this cohort, determining that 49 of the patients (25.8%) had Beck Depression Inventory-II (BDI-II) scores of over 14 and that 69 patients (36.3%) were taking antidepressants for the treatment of depressive symptoms.[37]

Activities of daily living

Except for sphincter control, independence in activities of daily living (ADL) is likely for children born with myelomeningocele without hydrocephalus. Similarly, for children born with myelomeningocele and hydrocephalus, those with a level of lesion of L4/5 (quadriceps grade of good) or below are likely to be independent for almost all ADL except sphincter control. Those with higher-level lesions are at significant risk for dependence in ADL.

Continence

The data on continence from the literature is variable, which in part reflects inconsistencies in the definition of social continence. Studies report 40-85% achievement of bladder continence and 50-85% achievement of bowel continence. Approximately 25% of patients are continent of both bowel and bladder. The likelihood of social continence improves when training is instituted before age 7 years. The psychosocial consequence of bowel and bladder incontinence can have a dramatic impact on children with myelomeningocele, especially in adolescence.

Employment, independence, and quality of life

Studies of adults with myelomeningocele have shown that about 20-30% secure gainful employment. In one study, employment status was related to lesion level and motor independence. However, motor independence was not found to be related to self-reported quality of life or range of life experiences.[38]

Several studies have shown a greater number of shunt revisions to be associated with reduced independence and achievement in adulthood.[39] This suggests that close medical management in order to minimize episodes of increased intracranial pressure may improve adult employment and quality of life.

Perceived family environment may explain different levels of participation of patients with myelomeningocele in employment, community mobility, and social activity as an adult, even beyond what can be explained by lesion level and intelligence. A positive correlation exists between perceived family encouragement of independence and outcomes in young adults with myelomeningocele.

A study by Davis et al indicated that in adults with spina bifida, those with a higher level of education and no stool incontinence are less likely to experience permanent disability.[40]

Complications

Neurologic complications

Neurologic complications in patients with myelomeningocele are related to a variety of CNS and spinal cord pathologies. Approximately 25-35% or more of children with myelomeningocele are born with hydrocephalus, and an additional 60-70% of patients with myelomeningocele develop hydrocephalus after closure of the myelomeningocele lesion. Hydrocephalus can cause expansion of the ventricles and loss of cerebral cortex and is associated with an increased risk of cognitive impairment.

Seizures occur in 10-30% of affected children and adolescents. These can be related to brain malformation, or they may be a sign of shunt malfunction or infection.

The Chiari type II malformation is present anatomically in almost all patients with myelomeningocele and can result in hindbrain and/or upper cervical spinal cord dysfunction. Clinical manifestations of the Chiari II malformation are more common during infancy and, overall, are seen in 20-30% of affected children. However, symptoms can develop at any age and can manifest acutely or chronically.

Urologic complications

Myelomeningocele is the most common cause of neurogenic bladder dysfunction in children. The nature of the urinary tract dysfunction in myelomeningocele depends on the level and extent of the spinal cord lesion.

Disruption of the neural axis between the pons and the sacral spinal cord by the myelomeningocele may cause uninhibited detrusor contractions or dyssynergia, a lack of coordination of the external bladder sphincter that causes involuntary sphincter activity during detrusor contraction. Myelomeningocele in the sacral area can produce a lower motor neuron lesion, resulting in detrusor areflexia.

These abnormalities may occur singly or in combination and typically result in incontinence and impaired bladder emptying that can lead to vesicoureteral reflux and high voiding pressures.[41] If untreated, such dysfunction can lead to potentially more serious complications, including frequent infections, upper urinary tract deterioration, and, ultimately, renal failure.

Skin breakdown

Skin breakdown occurs in 85-95% of children with myelomeningocele before young adulthood, and recurrent decubitus ulcers can lead to prolonged morbidity and functional disability. Healing can occur if the precipitating mechanical factors are eliminated. Plastic surgical correction may be necessary in severe cases and may involve orthopedic correction of underlying postural abnormalities.

The sites and causes of skin breakdown vary by age and lesion level. Skin breakdown on the lower limb occurs in 30-50% of cases in all lesion-level groups.

The most common areas of breakdown in the thoracic-level group are the perineum and above the apex of the kyphotic curve. Overall, tissue ischemia from pressure necrosis is the most common etiology.

Older children may have higher risk of skin breakdown, because of increased pressure of a larger body habitus, asymmetrical weight-bearing from acquired musculoskeletal deformities, and lower limb vascular insufficiency or venous stasis.

Frequent causes of skin breakdown that are more prevalent in younger children include casts or orthotic devices, skin maceration from urine and stool soiling, friction, shear, and burns.

Ulcers from bracing are prominent in the lower extremities, in the pelvis, and, particularly, over the bony prominences as a result of sitting. Carefully inspecting the skin on a routine basis is important because the area may be subjected to pressure for a couple of hours. The skin subsequently may be reddened, and although the patient may have no pain, the skin can develop significant full-thickness problems after only a brief period of neglect.

Mortality

In general, survival and degree of neurologic impairment depend on the level of the spinal segment involved, the severity of the lesion, and the extent of associated abnormalities.[42]

The mortality rate for infants with myelomeningocele is increased over the general population risk in the first year of the life. Mortality rates reported for untreated infants range from 90-100%, based on several studies dating from the turn of the century through recent years. Most untreated infants die within the first year of life. Death in the first 2 years of life for those untreated usually results from hydrocephalus or intracranial infection. An infant aged 2 months with untreated myelomeningocele has only a 28% likelihood of living 7 years.[43]

Survival rates for infants born with myelomeningocele have improved dramatically with the introduction of antibiotics and developments in the neurosurgical treatment of hydrocephalus. Early death in treated and untreated patients is associated with advanced hydrocephalus and multiple system congenital anomalies.

Renal compromise occurs because of problems related to neurogenic bladder. Despite advances in the management of neurogenic bladder, renal failure is still the leading cause of death in patients with myelomeningocele after the first year of life.

Longevity may depend on the careful use of clean intermittent catheterization and compliance with a bowel and bladder regimen. Long-term survival into adulthood and advanced age is now common with aggressive treatment and an interdisciplinary clinical approach. With proper urologic management, more than 95% of children with myelomeningocele continue to have normal renal function. In addition, bladder augmentation has been reported to have a positive impact on urologic infections and mortality in spina bifida.[44]

Institute measures to avoid development of soft tissue contractures in the neonatal period. Physical and/or occupational therapists provide caregivers with instruction in handling and positioning techniques. In the first several years of life, recommend incorporation of stretching and strengthening exercises into a home program performed by the caregivers and later into play and physical education activities at school.

Instruct preschool and school-aged children with myelomeningocele in the use of adaptive equipment and alternative methods for self-care and performance of ADL. To become independent by school age, young children with myelomeningocele need to become active participants in skin care, bowel and bladder management, and donning and doffing of orthotics, in addition to traditional ADL tasks such as feeding and dressing.

Acquisition of ADL skills often is influenced by attitudes and expectations, so the multidisciplinary team members need to emphasize carryover of ADL skills in the home and school environments by providing anticipatory guidance to parents and caregivers.

Strategies for prevention of skin breakdown first are directed at parents and caregivers, but children with myelomeningocele should be encouraged from an early age to take responsibility for their own skin care. Parents must first be made aware of the areas of abnormal sensation. Necessary precautions include daily skin inspections, pressure relief, avoidance of exposure to extreme temperatures and harmful surfaces, and frequent monitoring of shoes and orthotics.

Self-catheterization techniques should be introduced during the later preschool years to promote normal progress toward independence. Mastery of self-catheterization in patients with myelomeningocele usually is achieved by age 6-8 years, depending on the severity of cognitive and motor involvement.

A functional environment should be created for the patient at home and school to facilitate efficient independent functioning.

A study by Vaccha and Adams indicated that family environment can influence language skills in children with myelomeningocele.[45] The investigators studied 75 children with myelomeningocele, aged 7-16 years, along with 35 age-matched controls, and found a positive association between language performance in children with myelomeningocele and a focus on intellectually and culturally enhancing activities by their families.

Sex education

Sex education and counseling should begin early to help adolescents with myelomeningocele make a positive adjustment to adolescence and to help them avoid misinformation. Sex education, including accurate information about safe sex, should be included in the routine health-care maintenance of the older child and adolescent with myelomeningocele.

Studies of young people with myelomeningocele have shown that, although many are involved in intimate relationships, most had inadequate knowledge about sexuality and reproductive health issues related to their condition. A report indicated that young people with spina bifida face difficulties in obtaining answers to questions concerning romantic relationships, fertility, and sexuality and encouraged medical providers to educate these patients with regard to sexual health.[46, 47]

For patient education information, see the Brain and Nervous System Center, as well as Spina Bifida and Bladder Control Problems.

Myelomeningocele is diagnosed at birth or in utero. At birth, a midline defect in the posterior elements of the vertebrae is noted with protrusion of the meninges and neural elements through an external dural sac.

Although spina bifida occulta is common and almost always without consequence, some developmental abnormalities may occur—such as a spinal cord lipoma or a fibrous cord—that can cause subtle or rare neurologic signs.

A fibrous cord may extend from an interdural component of one of these developmental abnormalities to the skin, producing a dimple, an area of pigmentation, or a hairy patch at the base of the spine; such symptoms can be noted on physical examination.

Patients with a fibrous cord may have problems with micturition, or they may have subtle neurologic signs, such as a foot deformity (most commonly, a cavus foot). A prompt and thorough investigation is mandatory for any progressive neurologic signs. When a lipoma is present, there may be a lipomeningocele, a lipomyelomeningocele, or a lipomyelocele. These may be associated with areas of fluid in the cord, which may be a syringomyelia.

In general, infants with spina bifida cystica present with the following:

• Lethargy

• Poor feeding

• Irritability

• Stridor

• Ocular motor incoordination

• Development delay

Older children may present with the following:

• Cognitive or behavioral changes

• Decreased strength

• Increased spasticity

• Changes in bowel or bladder function

• Lower cranial nerve dysfunction

• Back pain

• Worsening spinal or lower extremity orthopedic deformities

Some patients, however, may present with only papilledema. In any patient with myelomeningocele who presents with deterioration in neurologic, orthopedic, or urologic function, uncontrolled hydrocephalus should be excluded as a cause before any other treatment is pursued.

Chiari type II malformation

The Chiari type II malformation may cause acute or subacute signs and symptoms of lower brainstem and/or upper cervical spinal cord compression, including the following:

• Laryngeal and pharyngeal paralysis

• Apnea

• Swallowing difficulty

• Respiratory stridor

• Nystagmus

• Upper extremity weakness

These problems rarely are severe. A varying degree of interference with cerebellar function seems to occur, particularly with balance and coordination, which has a significant influence on ambulation, the results of physical therapy, and overall orthopedic care.

Coordination and cognitive function

Failure to control a seizure disorder, recurrence of hydrocephalus, or even low pressure hydrocephalus can cause subtle coordination defects and interruption of some cognitive functions.

Tethered spinal cord

The tethered spinal cord may be signaled by foot deformities that previously braced easily, new onset of hip dislocation, or worsening of a spinal deformity, particularly scoliosis. Progressive neurologic defects in growing children may suggest a lack of extensibility of the spine or indicate that the spine is tethered and low-lying in the lumbar canal, with the potential for progressive, irreversible neurologic damage that requires surgical release.

The most obvious finding on physical examination is some degree of motor and sensory loss.[1] Neurologic impairment is classified by traditional neurosegmental levels based on the clinically determined strength of specific muscle groups. The functional motor level does not always correspond to the anatomic level of the lesion.

In addition, it is important to realize that the motor paresis may be asymmetrical, that it may not correspond to the sensory level, and that it may result from a combination of upper and lower motor neuron lesions. Serial measurements and accurate documentation of the functional level of the lesion allow for early detection of progressive neurologic deterioration related to a variety of associated CNS problems.

In addition to determining the functional neurosegmental level, it is important to distinguish the type of paralysis, either spastic or flaccid. Most patients with myelomeningocele have a flaccid paraparesis below the spinal cord lesion.

An estimated 10-25% of patients have been reported to have a spastic paraparesis. This presentation is presumably related to an intact, but isolated, segment of cord distal to the lesion. Spastic paraparesis has been associated with a poorer prognosis for walking and higher rates of orthopedic procedures.

Neurosegmental levels and musculoskeletal complications

For the sake of general functional prognosis and anticipation of specific musculoskeletal complications, myelomeningocele patients frequently are classified as belonging to one of the following groups, based on the neurosegmental level of the lesion:

• Thoracic

• High lumbar

• Low lumbar

• Sacral

Thoracic

In the thoracic group, innervation of the upper limb and neck musculature and variable function of trunk musculature are present, with no volitional lower limb movements. Patients with thoracic malformations tend to have more involvement of the CNS and associated cognitive deficits.

High lumbar

In the high-lumbar group, variable hip flexor and hip adductor strength is characteristic. Absence of hip extension, hip abduction, and all knee and ankle movements is noted.

Low lumbar

In the low-lumbar group, hip flexor, adductor, medial hamstring, and quadriceps strength is present. The strength of the lateral hamstrings, hip abductors, and ankle dorsiflexors is variable; the strength of the ankle plantar flexors is absent.

Sacral

In the sacral-level group, strength of all hip and knee groups is present. Ankle plantar flexor strength is variable.

Complications of hydrocephalus

Involvement of the upper extremities is also common. Spasticity in the upper extremities occurs in approximately 20% of patients with myelomeningocele. It has been related to the number of shunts required to control hydrocephalus and has been shown to adversely affect independence in activities of daily living (ADL).

In patients with hydrocephalus, lack of upper extremity coordination is also seen. This lack of coordination also may be related to Chiari II malformation, motor-learning deficits, and/or delayed development of hand dominance. Affected children have problems with fine motor tasks, particularly when timed. New-onset weakness or spasticity in the upper extremities may be a hallmark of progressive neurologic dysfunction.

Spinal and lower extremity deformities

Spinal and lower extremity deformities and joint contractures are prevalent in children with myelomeningocele. Multiple factors may be involved, including intrauterine positioning, other congenital malformations, muscle imbalances, progressive neurologic dysfunction, poor postural habits, and reduced or absent joint motion.

Spinal deformities may be congenital or acquired. Vertebrae and rib anomalies are associated with congenital or early development of severe kyphotic and scoliotic deformities. Acquired scoliosis is neuromuscular in origin and is related to muscle imbalances.[48] Increased lumbar lordosis and kyphosis of the entire spine or localized to the lumbar region are also observed. All of the spinal deformities occur more frequently in groups with higher spinal lesions.

Thoracic and high-lumbar lesions

The lower extremity deformities that occur are related to the functional level of the lesion. Thoracic and high-lumbar groups tend to have increased prevalences of the following:

• Lumbar lordosis

• Hip abduction and external rotation contractures

• Knee flexion

• Equinus contractures of the ankles

Unopposed hip flexion and adduction contractures in the high-lumbar group frequently result in dislocated hips.

Mid- and low-lumbar lesions

The mid- and low-lumbar groups often have the following deformities:

• Hip and knee flexion contractures

• Increased lumbar lordosis

• Genu valgus and calcaneal valgus malalignment

• Overpronated feet

Sacral lesions

Patients in the sacral group often exhibit mild hip and knee flexion contractures and increased lumbar lordosis with various ankle and foot positions.

Stature

Children with myelomeningocele are often short in stature. This has been related to multiple factors, including the following:

• Structural issues (eg, abnormalities of the spinal column and lower limb contractures)

• Functional spinal level: This influences the amount of neurotrophic input from the lower extremities on appendicular skeletal growth

• Alteration in the hypothalamic-pituitary axis, with associated growth hormone deficiency

Weight

Weight should be assessed in patients with spina bifida. Because of their decreased linear limb growth and spine growth, patients should be monitored for weight using arm-span measurements, as opposed to ratios of height versus weight. During growth spurts, patients require close monitoring for the development of any deformities, from scoliosis to deformities of the lower extremities.

Cranial nerve dysfunction

Symptoms of cranial nerve dysfunction include the following:

• Ocular muscle palsies

• Swallowing and eating problems

• Abnormal phonation

These symptoms may be related to the Chiari II malformation, hydrocephalus, and/or brainstem dysplasia.

Lower brainstem dysfunction

While symptoms are often mild, lower brainstem dysfunction is the leading cause of death in infants with myelomeningocele because of associated stridor, apnea, and aspiration pneumonitis. Common symptoms of lower brainstem dysfunction in infants include the following:

• Abnormal cry

• Swallowing or feeding difficulties

• Frequent vomiting or gastroesophageal reflux

Older children and adults may present with the following:

• Weakness or spasticity of the upper extremities

• Headache or neck pain

• Cerebellar dysfunction

• Oculomotor changes

• Scoliosis

Tethered spinal cord

A tethered spinal cord is caused by the tendency for the spinal cord to adhere to the meningocele repair and can prevent the normal cephalad migration of the cord during growth. A tethered cord is present anatomically in most children with myelomeningocele; the diagnosis of tethered cord syndrome is confirmed on the basis of clinical signs and symptoms, which can include pain, sensory changes, spasticity, and progressive scoliosis.

However, uncontrolled hydrocephalus and Chiari II malformation must be excluded as causes of these symptoms. Moreover, symptoms similar to those of tethered cord syndrome can also be caused by other intraspinal pathologies (eg, mass lesions of the cord, diastematomyelia, cord cavitation and narrowing, adhesions, dural bands).

Syringomyelia

Syringomyelia is caused by uncontrolled hydrocephalus that results in entry of cerebrospinal fluid (CSF) into the central canal of the spinal cord, causing dilatation and pressure. While this is a common MRI finding in patients with myelomeningocele, this condition is symptomatic in only 2-5% of cases. Symptoms described include the following:

• Progressive scoliosis

• Spasticity

• Increasing weakness of the extremities

Laboratory screening tests for neural tube defects can be performed through blood tests, amniocentesis, or both. These typically are used in combination with fetal ultrasonography. Prenatal diagnosis and ultrasonographic confirmation allow for preparation and parental referral to appropriate care services.

The fetal presence of an open neural tube defect is marked by an elevated alpha-fetoprotein (AFP) level in the amniotic fluid. Peak concentrations of AFP in the 13th to 15th weeks of pregnancy permit diagnosis, and ultrasonographic confirmation with amniocentesis generally is possible at 15-18 weeks. Encephaloceles or skin-covered myeloceles are unlikely to be detected by AFP measurement.

In children with spina bifida, in addition to routine laboratory screening examination, testing would include levels of anticonvulsants, urine cultures, and perhaps cystometrograms and skin testing for latex sensitivity. The last can be performed by enzyme-linked immunosorbent assay (ELISA) or skin prick.

Perform urinalysis, urine culture, and a serum urea nitrogen creatinine test at birth to evaluate renal function in neonates with spina bifida. Recommend regular bacterial urinary cultures for children who have vesicoureteral reflux or signs and symptoms of urinary tract infection.

Early accurate assessment and subsequent frequent reassessments of neurologic status are necessary with anatomic and physiologic evaluation techniques. Obtain the anatomic information with a voiding cystogram that assesses the lower urinary tract, including bladder capacity and the presence of vesicoureteral reflux. Urodynamics help in physiologic evaluation of urologic function by characterizing abnormalities of detrusor control and sphincter function.

Estimation of maternal serum AFP has been used since the late 1970s. Blood samples are taken early in the second trimester. The AFP level is elevated in 70-75% of cases in which the fetus has an open spina bifida.

Since many possible reasons exist for false-positive results, a presumptive diagnosis based on maternal serum AFP is confirmed with amniocentesis and assay of the amniotic fluid for AFP, as well as for the presence of acetylcholinesterase, a nerve-specific enzyme. Myelomeningocele can be detected in 99% of affected fetuses through combined use of these tests.

Siblings of patients with spina bifida have an increased incidence of neural tube defects. Consequently, following the birth of a child with spina bifida, amniocentesis is suggested during subsequent pregnancies to monitor AFP.

As previously discussed, cognitive dysfunction is most strongly correlated with the presence of hydrocephalus, along with hydrocephalus-related illness parameters (ie, the necessity of shunting, number of shunt revisions, shunt infections, and additional structural abnormalities of the CNS).[30] Cognitive function has also been related to the level of the patient’s lesion.

Psychometric assessments of intelligence and cognitive function are indicated for patients with hydrocephalus and for patients who display deficits in speech and language functions and/or cognitive or academic skills. Repeated, prolonged ventriculoperitoneal shunt dysfunction, as well as CNS infections, are associated with an increased risk of functional and cognitive deficits.

Gait analysis has been introduced to evaluate patients functionally. It is also used to study muscle innervation, strength, and coordination patterns, which may interfere with ambulation or with a patient's ability to live independently.

Gait analysis may serve as a useful preoperative diagnostic tool. It can be helpful in evaluating patients for reduction of a dislocated hip and transfer of muscles for imbalances (which lead to progressive deformities, difficulty bracing, and problems with ambulating).

Some centers use fetal ultrasonography as the primary screening tool for neural tube defects, usually at approximately 18 weeks’ gestational age. This trend reflects the increasing sophistication of fetal ultrasonographic technology. The procedure avoids the roughly 1% risk of abortion following amniocentesis, but accurate diagnosis depends on the skill and experience of the operator and the quality of the equipment.

The combination of maternal serum AFP screening with second-trimester ultrasonographic screening detects over 90% of neural tube defects from 20 weeks' gestation.

With ultrasonography, myelomeningocele may be detected during scanning of the fetal head for subtle changes in the cranial and cerebellar configurations. The diagnosis of myelomeningocele is certain when the following 3 classic central findings are present:

• Concavity of the frontal bones

• Ventriculomegaly

• Chiari II malformation

Currently, ultrasonography is not sensitive enough to provide reliable and accurate detection of the level of the defect. Preliminary experience indicates that the use of 3- and 4-dimensional ultrasonography improves the accuracy in determining the upper level of the myelomeningocele lesion.

After confirmation of fetal myelomeningocele, clinicians at most tertiary care centers perform weekly ultrasonographic examinations to observe the growth and development of the fetus.

Hydrocephalus can be tracked with serial cranial ultrasonograms (in infants) or computed tomography (CT) scans. A CT scan of the head is appropriate to evaluate for possible recurrent hydrocephalus or a change in the size or function of the ventricles, which may be affected even with normal pressure hydrocephalus.

Magnetic resonance imaging (MRI) of the spine and brain is helpful in neurologic assessment and provides a baseline for comparison in future investigations, especially in the context of progressive neurologic deterioration. MRI provides considerable detailed information regarding the spinal cord and its malformations, including low-lying or tethered cords. (See the images below.)

By definition, all children with a myelomeningocele have a tethered cord on MRI, but only about 20% of children require an operation to untether the spinal cord during their first decade of life, during rapid growth spurts. Thus, the MRI scan must be placed in the context of a history and examination consistent with mechanical tethering and the resultant neurologic deterioration.

Radiographs of the vertebrae provide information for early evaluation when an infant is born with myelomeningocele. After delivery, the criterion standard for determining the level of the lesion is a plain film radiograph.

Congenital spinal deformities need to be tracked closely. Acquired or neuromuscular spinal deformities require imaging based on clinical examination; these deformities should be followed routinely during growth and more frequently during times of rapid growth.

Plain radiographs are important for clinical evaluation of the patient for scoliosis, dysplasia, and dislocation of the hip. Radiographs, along with ultrasonographic evaluation, should be used to assess any area of pain because of the high risk of pathologic fractures.

In the United States, antibiotics, sac closure, and ventriculoperitoneal shunt placement are the standard of care for spina bifida and are implemented in the perinatal period in 93-95% of patients. Supportive care alone may be recommended in cases associated with an irreparable sac, active gross CNS infection or bleeding, and/or other gross congenital organ anomalies causing life-threatening problems.

Patients with spina bifida require extensive, active, interdisciplinary treatment by a trained and coordinated team. Neonatal neurosurgery is followed by monitoring of head size and condition for potential hydrocephalus, evaluation of sphincters, and progression toward an appropriate bowel and bladder regimen.[49, 50]

Early monitoring of motor function in the lower extremities also is necessary. Such monitoring should later consist of serial orthopedic examination, including muscle strength and joint range of motion (ROM) assessment, to detect any early changes that may require intervention. In addition, patients should be monitored for appropriate development and be provided with prolonged physical therapy, gym resources, and adaptive training while in school. Subsequent efforts are necessary to encourage, develop, and maintain independence.

Considerable attention may be needed to prevent the "outhouse syndrome," in which the patient's physical problems give rise to social consequences because of a failure to comply with an appropriate bowel regimen. Clean intermittent catheterization has been a very helpful adjunct to the preservation of urinary function.

Rehabilitative therapies

In addition to physical therapy, rehabilitation for spina bifida includes occupational and recreational therapy; speech therapy may be indicated for patients with speech and/or swallowing difficulties.[7, 8, 9, 10]

Physical therapy programs are designed to parallel the normal achievement of gross motor milestones. Occupational therapy should be initiated early to compensate for motor skill deficits and should progress along the normal developmental sequence. Recreational therapy is helpful for promoting independence by enhancing play and recreational opportunities.

Treatment strategies are designed to prevent deterioration of renal function and to establish infection-free social continence. These goals can be accomplished by several different methods of bladder drainage, including intermittent catheterization, vesicostomy, and placement of indwelling catheters.

Clean intermittent catheterization on a regular schedule is preferred to the use of long-term indwelling catheters, as it keeps children drier, less prone to infection, and in better control of urinary function. This technique is used from birth, if indicated, for reduction of bladder pressures or may be initiated to establish social continence at a developmentally appropriate time.[51]

However, intermittent catheterization may not be feasible for, or accepted by, the caregivers of infants and young children. In these cases, a temporary vesicostomy, in which an opening in the bladder is brought out to the level of the skin, may be a useful alternative. Vesicostomies can drain spontaneously and/or be catheterized.

Intravesical transurethral bladder stimulation has been shown to improve bladder compliance through increased functional bladder capacity and to improve sensation; however, this type of stimulation has been less successful in achieving volitional voiding and total urinary control.

Long-term maintenance of low bladder pressures may require the adjunctive use of medications to reduce bladder pressures and/or decrease spastic or hypotonic sphincter function. The success rate of intermittent catheterization and/or anticholinergic medications in achieving continence is estimated to reach 70-80%.

Children whose high bladder pressures are refractory to intermittent catheterization and/or medications (approximately 15-30% of patients with myelomeningocele) are candidates for surgical intervention. Various surgical techniques for augmentation cystoplasty and urinary diversion have been described in the literature.

When infection occurs, antibiotics are used in combination with the usual techniques of bladder management. In general, high fluid intake is recommended to assist the flow of urine, as residual urine in the bladder fosters bacterial growth and infection.

Abnormal anal sphincter function and anorectal sensation are associated with myelomeningocele involving spinal segments S2-S4. Many individuals with myelomeningocele, therefore, do not have the sensation and control needed to defecate volitionally. The result is bowel incontinence, often with related problems of constipation and impaction. Fecal incontinence can become a serious barrier to attending school, obtaining employment, or sustaining an intimate relationship.

Assisted bowel programs designed to empty the bowels regularly can establish social continence and prevent constipation. Patients are guided to develop a regimen for bowel movements, usually on a daily or every-other-day basis. These programs typically attempt to take advantage of the gastrocolic reflex by timing the bowel movement after a meal, typically breakfast or dinner.

Some patients are able to use the Valsalva maneuver to defecate, but some may need the assistance of digital stimulation, a stimulant suppository, and/or an expansion enema. Use of these techniques can help the patient to achieve proper timing of the bowel movement and complete evacuation. A high-fiber diet, sometimes in combination with use of stool softeners, may help to optimize stool size and consistency.

Individualized programs are necessary for proper bowel management, given the different manifestations of defecation dysfunction seen in patients with myelomeningocele. Consistency of the routine is extremely important for avoidance of accidents. Behavior modification and biofeedback techniques have increased success in achieving bowel continence in some children with myelomeningocele.

The goal of bracing is to allow patients to function at the maximum level permitted by their neurologic lesion and intelligence. Bracing also ensures a normal developmental progression, its aim being to enable patients to ambulate and to participate in appropriate age-related activities. Finally, orthotics should aid in minimizing the energy needed for the patient to maintain mobility levels.

In infants aged 9 months and younger, sitting balance and support may be provided with a standard car seat, elevated 45-60°. A car seat may be appropriate to maintain mobility with head and trunk control and to increase upper-extremity strength in children as old as 18 months. A standing frame may be used for those aged 1-2 years to diminish the degree of osteoporosis and to limit the contracture of the hip, knee, and ankle.

A parapodium may be helpful for children aged 3-12 years, allowing them to gain greater experience in standing and in manipulating work with their upper extremities at a table or desk. Because parapodiums are cumbersome, however, their use is limited as patients get older.

Subsequently, a wheelchair can provide mobility and often is used with a molded ankle-foot orthosis (MAFO). As the child has less neurologic input, a knee-ankle-foot orthosis (KAFO) may be helpful in allowing ambulation. Hip-knee-ankle-foot orthoses (HKAFOs) generally are useful in therapy but are not practical for long-term use.

The addition of a reciprocating gait orthosis (RGO) may help in reducing the energy expenditure required for mobility. Success with the RGO requires proper selection, strong motivation, and realistic goals and expectations. The patient and caregivers also must be able to participate in a training program and make frequent visits for orthotic repairs.

General functional expectations have been developed for patients in each lesion-level group to help direct physical therapy goals within an appropriate developmental context from infancy through adulthood.[52] The therapy programs should be designed to parallel the normal achievement of gross motor milestones.

In treating newborns with myelomeningocele, the physical therapist establishes a baseline of muscle function. As the child develops, the therapist monitors joint alignment, muscle imbalances, contractures, posture, and signs of progressive neurologic dysfunction. The physical therapist also provides caregivers with instruction in handling and positioning techniques and recommends orthotic positioning devices to prevent soft tissue contractures.

Provide the infant with sitting opportunities to facilitate the development of head and trunk control. Near the end of the first year of life, provide the child with an effective means of independent mobility in conjunction with therapeutic exercises that promote trunk control and balance.

For patients who are not likely to become ambulatory, place emphasis on developing proficiency in wheelchair skills. For patients who are predicted to ambulate, pregait training should begin with use of a parapodium or swivel walker. Exercise or household-distance ambulation may be pursued with the use of traditional long leg braces (eg, KAFOs, HKAFOs) or RGOs.

Teach the school-aged child community-level wheelchair mobility skills, emphasizing efficiency and safety. The physical therapist assists with assessment of the community, home, and school environments to determine whether architectural barriers exist that may interfere with the child's daily activities.

Children with spina bifida often have impairment in fine motor skills and in conducting activities of daily living (ADL). Initiate training early to compensate for these deficits and to progress along the developmental sequence as closely as possible.

Upper extremity stabilization and dexterous hand use require adequate postural control of the head and trunk. In the first year of life, encourage development of these postural mechanisms or substitute passive support, if necessary, to promote eye-hand coordination and manipulatory skills. When adequate fine motor skills have been achieved, the occupational therapist provides instructions for the use of adaptive equipment and alternative methods for self care and other ADL for preschool- and school-aged children.

Children with myelomeningocele often experience restricted play and recreational opportunities because of limited mobility and physical limitations.[53] This inactivity decreases the potential for normal development in all spheres and can exert a negative impact on self-esteem.

For the infant and toddler with myelomeningocele, recreational therapy enhances opportunities for environmental exploration and interaction with other children. For the school-aged child, recreational therapy provides opportunities for participation in adapted sports and exercise programs, which can result in long-term interest in personal fitness and health.

Recreational and physical fitness goals include socialization, weight control, and improved fitness (eg, flexibility, strength, aerobic capacity, cardiovascular fitness, coordination). Recreational therapy is useful for promoting independence with adult living skills and often is employed to help the patient shop for and purchase personal items, use public transportation, and develop appropriate leisure activities.[52, 53]

Closure of the myelomeningocele is performed immediately after birth if external cerebrospinal fluid (CSF) leakage is present. In the absence of CSF leakage, closure typically occurs within the first 24-48 hours. The surgery can be delayed for several days without additional morbidity or mortality, giving families more time to deal with the emotional impact of their child’s condition. This delay also gives parents more time to learn about myelomeningocele and to therefore better participate in the decision-making process regarding their child’s treatment.

Steps in the closure procedure include extensive undermining of the skin, dissection of the neural plaque that is replaced into the spinal canal, and meticulous watertight closure of the dura, fascia, subcutaneous tissues, and skin. (See the images below.)

Neurosurgical follow-up is required to recognize the complications of hydrocephalus or a possible tethered cord and to monitor any potential causes of seizure activity. In addition, urologic evaluation is necessary to establish a bladder regimen to prevent frequent urologic infections and to recognize and treat early, potential hydronephrosis or other causes of renal damage that can limit life expectancy.

Perioperative complications include wound infection, CNS infection, delayed wound healing, CSF leakage, additional neurologic damage to the cauda equina, and acute hydrocephalus. Long-term complications include cord tethering and progressive hydrocephalus.

Although in a few cases hydrocephalus arrests spontaneously, 80-90% of children with myelomeningocele ultimately require shunting. Ventriculoperitoneal shunting is the preferred modality. Alternatives include ventriculoatrial and ventriculopleural shunting.

Perioperative complications include intracerebral and/or intraventricular hemorrhage, bowel perforation, and infection. Long-term complications include infection, overdrainage or underdrainage, and obstruction of the shunt system.

Shunt dysfunction, which may result in an acute or chronic rise in intracranial pressure, occurs more commonly in the first 2 years of life. Diagnosis may be difficult, as early signs and symptoms are extremely variable and often nonspecific.

Symptomatic syringomyelia may resolve after shunt insertion or revision. If symptoms persist in the absence of a shunt malfunction, surgical intervention may involve a Chiari decompression or direct shunting of the syrinx.

The Chiari II malformation results in problems severe enough to warrant surgical intervention in approximately 15-35% of patients with myelomeningocele. Potential surgical candidates include patients with the following:

• Vocal cord weakness or paralysis

• Significant stridor

• Apnea

• Aspiration

• Sensorimotor deterioration

Treatment initially involves control of hydrocephalus. If this does not improve symptoms, surgical repair of the Chiari II malformation is pursued. This involves an occipital craniotomy and upper cervical laminectomy for decompression of the medulla and upper cervical spinal cord.

Musculoskeletal problems in myelomeningocele can be congenital or acquired and often require orthopedic intervention. Orthopedic surgeries are directed toward functional improvement as opposed to correction of radiologic findings.

Kyphosis and scoliosis

Spinal deformities are common in myelomeningocele, and progressive kyphosis or scoliosis may lead to a decline in functional status and to an increased risk for the development of decubitus ulcers and cardiopulmonary compromise.

Spinal stabilization is necessary to correct kyphosis, which may be related to congenital vertebral malformation or may be a result of the collapsing spine in high-thoracic paraplegia. The development of techniques such as decancellation and longer fusions, along with earlier intervention (around age 3 y), has improved outcomes.

Scoliosis affects 30-50% of children with myelomeningocele and may be the result of asymmetrical muscle forces, unilateral hip dislocation and pelvic obliquity, or an underlying, progressive neurologic process such as tethered cord syndrome. Spinal orthotic devices may serve as a temporizing measure, but growing children with spinal curves greater than 30-35° typically require surgical fusion. Lumbosacral fusions are avoided in order to preserve pelvic motion.

Hip relocation surgery

Paralytic muscle imbalance around the hip joints may lead to progressive hip dislocation. This typically occurs in early childhood in patients with high- and mid-lumbar lesions and in late childhood or adolescence in children with low-lumbar lesions.

The literature evaluating the benefits of surgical relocation of the hips reflects the ongoing controversy surrounding the topic.[54] No good evidence supports the functional benefits of hip relocation surgery in patients with high-lumbar lesions. Surgery to release contractures limiting motion at the hip and causing an asymmetrical gait is recommended in patients with low-lumbar myelomeningocele and hip dislocation.

Surgery for relocation of the hips is indicated for patients who ambulate without support and have a strong quadriceps, a good ROM for the hip, and a level pelvis or sacral-level lesions. Gait analysis has been proposed to better understand these complex systems and may refine future indication, but long-term follow up is critical.

Correction of knee contractures

Common knee deformities in myelomeningocele include flexion and extension contractures, usually related to a capsular contracture. Surgery is indicated when the contracture causes a functional problem. Types of procedures include a simple tenotomy of the knee flexor tendons in the child with a high-level lesion, and lengthening of the tendons in the child with a low-lumbar or sacral-level lesion, for whom preservation of hamstring function is important.

Extension contractures are less common, but they interfere with sitting and are associated with hip dislocation and clubfoot. If the contracture is not amenable to conservative measures (eg, serial casting), an extensor tendon release is performed.

Correction of rotational deformities

The most common rotational deformities seen in myelomeningocele are internal and external tibial torsion. These may result in significant gait deviations that affect functional mobility. The combination of femoral anteversion and excessive external tibial torsion, which is often seen in patients with low-lumbar and sacral-level lesions, can lead to abnormal valgus stress at the knee and can cause knee pain and arthritis in adult life.

Some rotational malformations improve with growth and/or the use of bracing. If improvement is not noted by age 6 years, surgical correction is indicated.

Correction of foot and ankle deformities

Foot and ankle deformities may cause skin breakdown and prevent the patient from wearing shoes and/or orthotics. Since almost all patients with myelomeningocele require orthoses, the goal of orthopedic treatment is achievement of a supple and flexible foot.

In the case of clubfoot, most patients need surgical correction in the first year of life, usually involving multiple soft tissue release procedures with tendon excisions. In older children, other types of deformities (eg, equinovalgus, cavus, calcaneovarus, calcaneovalgus) may require extra-articular bony procedures and tenotomies in order to correct the muscle imbalances and achieve a supple plantigrade foot that can tolerate a brace. Arthrodesis is rarely indicated but may be necessary in cases of severe ankle instability.

Patients who are born with a sac containing neural elements of the spine require neurosurgical closure of the defect in the neonatal period. They should be referred to an interdisciplinary clinic that includes the services of an orthopedic surgeon. Manifestations of myelomeningocele change as the infant develops, and multidisciplinary interventions are required to prevent the progressive deterioration of the multiple body systems affected.

The treatment team usually consists of pediatric specialists in physical medicine and rehabilitation, neurosurgery, urology, and orthopedics along with pediatric nursing, physical therapy, occupational and recreational therapy, psychology, and medical social work. A multidisciplinary clinic setting facilitates the coordination of comprehensive care for the patients.

Children with myelomeningocele should be scheduled for regular follow-up visits in the multidisciplinary clinic every 6 months throughout childhood and annually thereafter. More frequent visits with certain specialists may be necessary, depending on the outstanding medical and surgical issues that present at different times during the child's development.

Pediatric evaluation is appropriate for any child and, specifically, should include efforts to help the patient maintain a reasonable weight, because children without ambulation tend to gain excessive weight and develop associated morbidity. Endocrinologically, a growth hormone deficiency may be present, which could cause patients to be about 1 foot shorter than their peers. Consultations with an orthotist, a physical therapist, and a dietitian are appropriate to maintain optimal development and to maximize accessibility and independence.

Because muscle imbalance causes progressive, resistant deformities, the patient with spina bifida must be evaluated frequently by members of his or her support team. In this way, they can assess muscle groups, emphasize the need for balance to prevent deformities, and serially document changes that may result from a tethered cord, hydrocephalus, or other associated complications (eg, seizure disorder).

Frequent review of spina bifida support systems, aggressive shunting of hydrocephalus, the cooperation and success of patients in physical therapy, and assessment of the status of patients' braces, crutches, or wheelchairs are necessary for maximizing function in a multidisciplinary setting. With supplementary physical and occupational therapy, many children who were born with spina bifida can participate in mainstream society, gaining independence and success.

After childhood, group homes may be used to train patients with spina bifida to live independently. Clearly, these individuals have substantial problems. A supportive clinic and extensive interdisciplinary program are necessary to meet the affected individual's needs.

Because treatment and intervention for spina bifida involve the patient's entire family, parents can suffer significant stress, an area of concern for the pediatrician. It is necessary for the physician to counsel parents and family, informing them of the ramifications of the condition and of the surgical and medical care needed to maximize function.

While no cure for the patient is possible, pessimistic attitudes of or unrealistic expectations by the family, as well as parental feelings of guilt, anxiety, and inadequacy, must be addressed.

Since the late 20th century, the incidence of myelomeningocele has undergone a significant reduction in the United States and worldwide. This decline is related to the increasing availability and accuracy of prenatal diagnosis, along with the option for early pregnancy termination and the introduction of primary prevention in the form of folic acid therapy in the periconceptual phase.[19]

Studies demonstrating a reduction in the frequency of spina bifida with folic acid supplementation during pregnancy are accumulating, with reduction reported on the order of 50%.[55, 56, 57, 58, 59]

Bell and Oakley reported that current worldwide programs of folic fortification of wheat and maize flour have resulted in an annual worldwide decrease of about 6600 folic acid-preventable spina bifida and anencephaly cases since 2006. They noted that the pace of preventing these serious birth defects could be accelerated if more countries were to require fortification of both wheat and maize flour and if regulators were to set fortification levels high enough to increase a woman's daily average consumption of folic acid to 400 mcg.[60, 61] The US Preventive Services Task Force Recommendation remains 400-800 mcg of folic acid daily.

However, the metabolism of folic acid appears to be abnormal in affected patients, suggesting that spina bifida may result from an inherited defect rather than strictly from a deficiency.

High intake of folic acid may mask the anemia of vitamin B-12 deficiency and allow neurologic damage to progress untreated, so widespread folic acid supplementation has been recommended with caution, but in pregnancy it has had gratifying benefits. Improved understanding of the genetic factors involved in spina bifida could better allow its prevention.

The medications used most frequently in myelomeningocele are for treatment of neurogenic bladder dysfunction. These medications are used in conjunction with some form of bladder emptying technique to prevent upper urinary tract complications and to facilitate social continence. Among the drugs used are the following:

• Anticholinergics (oxybutynin chloride, hyoscyamine sulfate)

• Tricyclic antidepressants (imipramine hydrochloride; may act through anticholinergic effects)

• Alpha-adrenergic antagonists (terazosin)

Class Summary

These drugs competitively inhibit the binding of acetylcholine to the muscarinic cholinergic receptor, thereby suppressing involuntary bladder contraction of any etiology. In addition, they increase the volume at the first involuntary bladder contraction, decrease the amplitude of the involuntary bladder contraction, and, possibly, increase bladder capacity.

Oxybutynin chloride (Ditropan, XL, Gelnique, Oxytrol)

Oxybutynin chloride (Ditropan, XL, Gelnique, Oxytrol)

Oxybutynin exerts a direct antispasmodic effect on smooth muscle and inhibits muscarinic action of acetylcholine on smooth muscle. It is used to decrease bladder contractility and reduce detrusor-sphincter dyssynergia. Intravesical instillation of oxybutynin is associated with fewer side effects. A long-acting oral form is also available, for once-daily dosing.

Class Summary

Anticholinergics are used to suppress detrusor overactivity.

Hyoscyamine sulfate (Levsin, Levbid, Symax, Anaspaz, HyoMax)

Through parasympatholytic action, hyoscyamine relaxes smooth muscle spasms. It is indicated in the management of lower urinary tract disorders associated with hypermotility.

Class Summary

Tricyclic antidepressants may act through anticholinergic effects.

Imipramine hydrochloride (Tofranil)

Imipramine has significant anticholinergic activity, as well as some alpha-adrenergic activity. These combined effects may improve bladder-urethral storage function.

Class Summary

Alpha-adrenergic receptors are found in the bladder neck and urethra. Alpha-adrenergic antagonists decrease bladder outlet resistance, increase urinary flow rate, and improve bladder emptying.

Terazosin

Terazosin is an alpha 1-adrenergic blocking agent that decreases smooth muscle tone in the bladder neck, leading to reduction of bladder outlet obstruction without affecting bladder contractility. Its major side effects are postural hypotension and syncope, which can be avoided by starting at the lowest dose and increasing slowly. If terazosin therapy is discontinued for several days, restart using the initial dosing regimen.

Doxazosin mesylate (Cardura, Cardura XL)

Doxazosin is a selective inhibitor of alpha1-adrenergic receptors. Blockade of these receptors in the bladder neck decreases outflow resistance.

Alfuzosin (Uroxatral)

Doxazosin is a selective inhibitor of alpha1-adrenergic receptors. Blockade of adrenoreceptors relaxes smooth muscle in the in the bladder neck, which, in turn, decreases outflow resistance.