General Child Neurology
Extracorporeal life support
Sep. 07, 2023
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Myelomeningocele is a devastating congenital disability that relatively spares cognitive function. It affects both the central and peripheral nervous systems and typically causes a spectrum of paralysis as well as bowel and bladder dysfunction. Myelomeningoceles may be associated with other anomalies, including hydrocephalus, tethered cord syndrome, and syringomyelia. New neurologic problems can present at any point throughout their lifespan. Patients require regular multidisciplinary follow-up to manage these conditions. A multicenter trial for prenatal myelomeningocele repair in 2011 showed that surgery performed before 26 weeks of gestation significantly reduced the need for cerebrospinal fluid shunting and improved motor function at 30 months. However, controversies still exist regarding the best timing for prenatal surgical intervention, the type of surgical approach, and the surgical risk to both the mother and fetus.
• Myelomeningocele is a devastating congenital disability that affects the complete neuroaxis and leads to multiple neurologic comorbidities, including hydrocephalus, Chiari II malformation, paralysis, sensory loss below the level of the lesion, and bowel and bladder dysfunction.
• Adequate folic acid intake and avoidance of medications in the periconceptual and early pregnancy periods significantly reduce the risk of myelomeningocele.
• Myelomeningocele level is the most important predictor of functional outcome.
• Myelomeningocele repair was traditionally done within 48 to 72 hours after birth to minimize the risk of infection.
• The pivotal MOMS trial, published in the New England Journal of Medicine in 2011, provided evidence that prenatal surgical closure improved outcomes as measured by ventriculoparietal shunt requirement and motor function at 30 months.
• The emergence of fetoscopic surgical techniques, available in a few academic centers, have further augmented the treatment landscape for myelomeningoceles.
• Worldwide, where surgical advancement is often limited, up to 90% of patients with a myelomeningocele will develop hydrocephalus.
• Patients with myelomeningocele require close multidisciplinary follow-up throughout life to promote maximum functional outcomes and to minimize further neurologic decline from associated anomalies.
Malformations involving the formation of the distal spinal cord and spinal column have been identified for centuries. The term "spina bifida" was used to describe these lesions, from the mildest to the most severe. The term "spinal dysraphism" is more suitable to describe myelomeningocele as "dysraphism" refers to the incomplete midline closure of osseous, mesenchymal, and nervous tissue (35). Most of these defects are thought to result from abnormal neurulation; therefore, they are also known as "neural tube defects." This section will discuss the most common clinically significant neural tube defect, myelomeningocele, a form of spina bifida associated with outpouching of the spinal cord and its coverings through an open defect in the vertebral arches. This form of spina bifida has effects on the entire neuroaxis, with a high association of hydrocephalus brainstem dysfunction, paralysis, sensory loss, and bladder and bowel dysfunction.
• Hydrocephalus is one of the most common comorbidities associated with myelomeningocele.
• Newborns with myelomeningocele may not show signs or symptoms of hydrocephalus until after 6 weeks of age. They are at a 10% risk of having clinically significant, life-threatening brainstem dysfunction.
• Postnatal closure has reduced the incidence of hydrocephalus to between 50% and 80%. Prenatal closure of the defect has further lowered the rate to 40% but not without risk.
• Renal function should be assessed with an ultrasound and should include outlet pressure measurement to determine if a neurogenic bladder is present.
• Almost 97% of the population has bowel and bladder dysfunction that progresses with age, regardless of the level of the lesion.
• Orthopedic assessments are necessary to evaluate the spine for scoliosis, contractures, and hip dislocations. Worsening scoliosis may indicate the presence of a tethered cord, shunt malfunction, or hydromyelia.
• Beyond the newborn period, the focus shifts to maximizing function and management of complications.
• The degree of motor impairment correlates directly with the level of the lesion. Patients also have coordination difficulties and sensory symptoms.
• After repair of the myelomeningocele, patients can develop symptomatic tethered cord syndrome later in life due to scar tissue.
• Cognitive and behavioral dysfunction are also observed, with impacts on spatial and executive functioning and decreased IQ scores.
• The incidence of seizures is about 2% to 8% in children without shunting and up to 15% to 20% in those with hydrocephalus requiring CSF diversion.
Newborn. The newborn should be assessed in the four following areas: (1) the degree of hydrocephalus; (2) the presence and severity of brainstem dysfunction; (3) the degree of motor and sensory dysfunction from the primary spinal cord and nerve root abnormalities; and (4) the presence and severity of associated malformations, such as renal, cardiac, and orthopedic deformities. Over 10% of newborns with myelomeningocele have clinically significant brainstem dysfunction that can be life-threatening (12). Hydrocephalus is seen in over 90% of patients with a lumbar lesion (21). After the introduction of CSF shunts in the 1950s, children with myelomeningoceles started living past the age of 2. After the implementation of postnatal surgical repair of myelomeningoceles, the rate of the need for CSF shunt to treat hydrocephalus ranged from 57% to 87%. The seminal study published in the New England Journal of Medicine in 2011 showed that prenatal closure of the defect significantly lowers the rate to 40%.
Newborns may not show signs of increased intracranial pressure, such as down setting eyes or limited upgaze, irritability, lethargy, and a rapidly growing head circumference, until after 6 weeks of age. Thus, neuroimaging is vital to identify the presence of hydrocephalus early. Placing a shunt while repairing the myelomeningocele may reduce additional complications, such as wound dehiscence and CSF leak (21).
Almost all patients with a myelomeningocele also have a Chiari II malformation. This malformation causes a downward pull of the cerebellar vermis through the foramen magnum, elongation and kinking of the medulla, caudal displacement of the cervical spinal cord and medulla, and obliteration of the cisterna magna. Compression of the hindbrain through the foramen magnum is the leading cause of mortality in this patient population (01).
Initial assessment with a bedside examination of the abdomen should be performed for evidence of bladder distention. This is followed by a renal ultrasound to assess for associated renal problems with myelomeningocele. Of particular importance is whether both kidneys are present, whether there is any hydronephrosis, and whether there is low outlet pressure. Low outlet pressure is likely to protect the urinary tract from the negative effects of a neurogenic bladder (ie, a situation of high bladder pressure from outlet dyssynergy that results in urinary reflux and hydronephrosis). Almost 97% of patients with myelomeningocele have bladder or bowel dysfunction.
Orthopedic assessment should focus on the spine (for the presence of any congenital scoliosis or kyphosis), hips (for dislocations), and ankles or feet (for club feet). Many newborns with myelomeningocele are born with club feet, which will require management, such as taping, casting, or surgery.
Beyond the newborn period. The clinical manifestations of myelomeningocele beyond the newborn period relate to two major areas: (1) the maximization of function and (2) the prevention and management of complications. The maximization of function requires an adequate assessment of the primary neurologic impairments and an understanding of how these impairments affect function.
The degree of motor impairment correlates directly with the level of the lesion. A low lumbar myelomeningocele may result only in foot drop, sensory loss in the feet, and bowel and bladder dysfunction. A high lumbar or thoracic level lesion, on the other hand, can result in complete paralysis of the legs, in addition to bowel and bladder dysfunction. This in general determines the potential for functional ambulation. However, individuals with similar muscle paresis can exhibit different ambulatory function for a variety of reasons (06).
There are four functional categories of ambulation (29):
(1) Community ambulators (L3 levels and lower) are able to walk indoors and outdoors for most activities, although a wheelchair may be used for longer trips outside their immediate vicinity.
(2) Household ambulators (L3 or mid lumbar) may be able to walk indoors and transfer to a wheelchair for community use and most outdoor activity.
(3) Nonfunctional ambulators (L1 to L3) may walk as part of a therapy session or in a gymnasium with orthotic devices but use a wheelchair for any useful mobility needs.
(4) Nonambulators use a wheelchair for indoor and outdoor activities.
Issues of bladder and bowel impairment do not correlate as well with the level of the neurologic spinal lesion in individuals with myelomeningocele as they do in spinal injury. Most individuals with myelomeningocele have some degree of neurogenic bladder and bowel with a lower motor neuron component. Clinical manifestations include incontinence, renal tract deteriorations from malfunction and infections, and fecal impactions or neurogenic constipation. Many patients can maintain a reasonably predictable bowel and bladder regimen with the use of medications and straight catheterization, although some also require surgical procedures to manage these functions.
In addition to bowel and bladder dysfunction, patients also develop sexual dysfunction. Seventy-five percent of patients can maintain an erection; however, other factors such as urinary incontinence, performance anxiety, and other physical limitations lead to a reflexive inability to maintain an erection. Sildenafil has significantly helped men with myelomeningoceles with erectile dysfunction (43).
Due to scarring that can develop around the spinal cord after myelomeningocele repair, 10% to 30% of patients can develop symptomatic tethered cord syndrome later in life, especially at times of significant growth (43). The manifestations of tethered cord syndrome include back pain, scoliosis, and worsening of bowel and bladder function. Significant scoliosis leads to respiratory issues due to compromised total lung capacity. Surgery to untether the spinal cord is needed if these symptoms develop. The function of the upper extremities can also be impaired in those with myelomeningocele. Weakness, incoordination, and sensory deficits may all be seen as consequences of syringomyelia.
Brainstem dysfunction can also be a feature of the condition beyond the newborn period, including adulthood. Dysfunction can be minimal to severe and can become symptomatic at any time. Symptoms of particular importance are sleep apnea (55; 34), dysphagia, vocal cord paresis, and gastroesophageal reflux. Signs and symptoms can present in a progressive fashion, but acute presentations are also seen.
Signs and symptoms of increased intracranial pressure, including headache, nausea, vomiting, lethargy, irritability, and personality change, can occur at any time in the life of an individual with myelomeningocele. It is important to note that this is true in those with ventricular shunts in place. Those without a shunt usually present in the first few months of life with increased intracranial pressure causing a rapidly enlarging head circumference with bulging fontanelle. However, there are older individuals without shunts (including adults) with myelomeningocele who develop the need for a shunt to relieve intracranial pressure. Individuals with shunts can present with elevated intracranial pressure related to shunt malfunction at any time.
Finally, function of the cerebrum is often affected to some degree in myelomeningocele Myelomeningocele rarely isolates to just the lower spinal cord alone. Cognitive and behavioral functions are often also altered. Dysfunction impacts spatial and executive functioning and decreased IQ scores (02). Memory deficits are becoming an increasingly recognized problem, and a debate has emerged regarding its association with the number of shunt revisions required by an individual (18).
Moreover, seizures may also coexist. The incidence of seizures is about 2% to 8% in children without shunting and up to 15% to 20% in those with hydrocephalus requiring CSF diversion (32).
Currently, most individuals born with myelomeningoceles are treated aggressively in the newborn period. Mortality rates in the newborn period were extremely high (approximately 90%) in the 1950s. However, the mortality rate has significantly decreased with the introduction of ventriculoparietal shunts, earlier timing of surgical shunt intervention, and the technique and early timing of myelomeningocele repair, which has reduced the risk for infection; more patients are now living into adulthood. The overall quality-of-life ratings for these patients remains good. Cope’s team examined the long-term quality-of-life outcomes for patients between 25 and 85 years of age, and myelomeningoceles did not affect overall life satisfaction scores in this group (13). Many patients lived independently, had partner relationships, and had children, although the presence of hydrocephalus decreased the likelihood of these outcomes.
However, despite aggressive interventions, nearly 14% of all spina bifida neonates do not survive past 5 years of age, and the mortality rises to 35% in those with symptoms of brainstem dysfunction (01). Some authors have proposed poor prognostic factors that lead to early deaths, including the presence of symptoms within the first 3 months of age, with low Apgar scores; large myelomeningocele defects; early central apnea; and large head circumference at birth. Patients with higher lesions (ie, high lumbar and thoracic levels) are also at a greater risk for mortality, hydrocephalus, scoliosis, lower intelligence (measured by IQ), and other complications (39).
The patient, an 18-year-old Caucasian male, was followed in a spina bifida clinic since birth. His myelomeningocele was closed just after birth, and he received a ventriculoperitoneal shunt. He did not have brainstem signs or symptoms. He had a lumbar 3 neurologic lesion as well as a low-pressure outlet bladder. He did not have an anal wink.
His motor development progressed along slightly slower than normal, particularly for gross motor milestones. With the aid of ankle-foot orthoses, he began to ambulate with a waddling (Trendelenburg) gait. He remained incontinent of urine and stool. Clean intermittent catheterization and anticholinergic medication were started, allowing him to have up to 4-hour periods of dryness.
He had one shunt revision before starting school. School performance was somewhat irregular, as he exhibited difficulty completing multistep assignments. Psychological testing revealed a verbal IQ of 85 and a performance IQ of 70. With some assistance with homework and adaptations in the classroom, he continued to make academic progress throughout his school career.
In his junior year of high school, he developed headaches and subjective increased hand clumsiness. His examination remained stable regarding his neurologic findings. There was upbeat and end gaze nystagmus. Funduscopic examination did not reveal papilledema. His tongue was normal, and there was no atrophy of his hand muscles. He had mild dysmetria, left greater than right. His gait continued to be Trendelenburg with some crouch. His upper extremity reflexes were hyperactive, and his lower extremity reflexes were absent. MRI revealed a Chiari II malformation with tonsillar descent down to C2. A concomitant cervical syrinx was also present.
The patient underwent a suboccipital craniectomy as well as C1-C2 laminectomy and dural decompression. He did well post-operatively with resolution of his headaches and hand clumsiness.
His clinical status has remained good for 4 years. He has only had occasional headaches, and there has been no increase in the size of his syrinx. Ambulation and hand function have remained stable. He has been able to maintain a job as a cashier in a grocery store and is in a committed relationship. He did, however, develop changes in erectile function. After a follow-up visit with his urologist, he was placed on sildenafil with clinical improvement.
• Multifactorial components, such as genetics and environmental factors, cause the development of a myelomeningocele.
• Siblings have an increased risk of up to 5% for developing a neural tube defect.
• There is a strong association between folic acid intake and neural tube defects.
• Valproic acid, carbamazepine, and methotrexate have also been observed to increase the risk for neural tube defects.
• The pathogenesis and pathophysiology of neural tube defects remain unclear.
The etiology of myelomeningocele is multifactorial and includes genetic and environmental factors (11). There is a familial tendency, with a 5% increased risk of recurrence of neural tube defects after the first affected child. The risk increases to 10% after two affected children (41). A strong association between folic acid intake and neural tube defects has been demonstrated. A study by Daly and colleagues has shown a continuous dose response relationship between a woman's risk of having a child with a neural tube defect and her red blood cell folate levels in early pregnancy (15). The multicenter Medical Research Council Vitamin Study confirmed a protective effect of periconceptual folic acid intake in preventing neural tube defects in over 70% of at-risk pregnancies (44). A prospective study proved that the protective effects of folic acid extend to all pregnancies, not just those at risk (14).
Aside from nutritional folic acid deficiency, certain medications contain folic acid antagonistic properties that can increase the risk of neural tube defects, such as valproic acid, carbamazepine, methotrexate, and certain antibiotics. In addition, external factors such as maternal hyperthermia, diabetes mellitus, obesity, Meckel-Gruber syndrome, Dandy-Walker syndrome, and trisomy 13, are all associated with an increased risk for neural tube defects.
The pathogenesis behind neural tube defects is still not clearly understood. The spinal cord is formed during embryogenesis by two processes: (1) neurulation and (2) canalization. Errors in either process can lead to a neural tube defect. The fusion starts at the level of the hindbrain (medulla and pons) and progresses rostrally and caudally. Neurulation occurs at approximately the fourth week post-fertilization (26 days) when the flat neural plate forms the cylindrical neural tube. Neurulation is complete with the closure of the posterior neuropore of the distal spinal cord. Caudal to this point of closure (which is believed to be at the lower thoracic spinal cord level), the lumbosacral spinal cord forms by the clustering and cavitation of a group of cells. Thus, neural tube defects can be classified into two groups: (1) neurulation defects (upper neural tube defects) and (2) canalization defects (lower neural tube defects).
• Myelomeningocele is the most common disorder of neurulation, with an incidence in the U.S. of approximately 0.2 to 0.4 per 1000 live births and higher rates in the Latino population.
• The highest prevalences of neural tube defects have been recorded in Ireland (4 per 1000 live births) and China (up to 10 per 1000 live births).
• Globally, the prevalence is about 1 per 1000 births (02).
• Improvements in folic acid intake have likely played a major role in the declining incidence.
There are geographic and temporal variations in the birth prevalence rates of neural tube defects. The highest prevalences of neural tube defects have been recorded in Ireland (4 per 1000 live births) and China (up to 10 per 1000 live births) (03; 56). The lowest prevalences occur in the United States (0.5 per 1000 live births), continental Europe (1 per 1000 live births), and Japan (1 per 1000 live births) (03; 04; 28).
A decrease in the birth prevalence of neural tube defects has been recorded in many, but not all, countries over the past 20 years. This decrease is not fully explained by the known increase in prenatal diagnosis of neural tube defects and subsequent termination of many of these pregnancies (53). Improvements in folic acid intake have likely played an important role in the declining incidence of this condition.
• Serum alpha-fetoprotein, which has a higher sensitivity for detecting defects than ultrasound, is a standardized biomarker used during prenatal screening for the presence of open neural tube defects.
• In 1992, the Centers for Disease Control and Prevention published folic acid recommendations to reduce the number of neural tube defects.
Prenatal screening programs based on detection of a raised serum alpha-fetoprotein level as a marker for an open neural tube defect are now common (48). Ultrasonic demonstration of a spinal defect, hydrocephalus, or evidence of Chiari malformation is also used in prenatal detection programs. Without the use of alpha-fetoprotein screening, however, ultrasound is believed to be unreliable as a screening tool. These programs report a significant decrease of spina bifida births (48). The serum alpha-fetoprotein levels are screened in maternal serum at 16 weeks' gestation. Those pregnancies with significantly elevated levels are investigated with ultrasonography. Amniocentesis is performed to determine amniotic alpha-fetoprotein and acetylcholinesterase levels. This approach can detect 95% to 98% of cases of open myelomeningocele (26). Early termination rates have increased in certain states with these diagnostic capabilities. However, as each state legislation evolves with varied abortion rights, the number of births with neural tube defects may fluctuate in the coming years.
Folic acid prevention. In 1992 the Centers for Disease Control and Prevention published recommendations for use of folic acid to reduce the number of spina bifida cases and other neural tube defects (05). According to these recommendations, evidence indicates that women can reduce the chance of neural tube defects by consuming 0.4 mg of folic acid per day. Because the effects of high intakes are not well known but include complicating the diagnosis of B12 deficiency, the recommendations call for keeping total folate consumption at less than 1 mg per day, except under the supervision of a physician.
Women with a prior pregnancy that was affected by neural tube defects are at high risk of having a subsequent affected pregnancy. When these women are planning to become pregnant, they should consult their physician for advice. A 1991 guideline from the Centers for Disease Control and Prevention called for 4 mg of folic acid per day (from at least 1 month before conception through the third month of pregnancy) for women with a prior affected pregnancy who are planning a new pregnancy. Although such a high dose may have associated risks, and a lower dose may have an equally beneficial effect, women may choose to follow this guideline because it is based on data from the most rigorous study directly pertaining to neural tube defects and because their risk of a pregnancy affected by neural tube defects probably outweighs the risk of consuming 4 mg of folic acid per day.
The following are occasionally confused with myelomeningocele: sacral teratoma, caudal regression syndrome (sacral agenesis), spine segmental dysgenesis, and VACTERL (vertebral anomalies, anal atresia, cardiac abnormalities, tracheoesophageal atresia/esophageal atresia, renal anomalies, and limb defects).
The related condition of terminal myelocystocele is sometimes seen. This lesion is skin-covered, and no bony lesions are found. However, a sacral fluid sac and a tethered spinal cord are shared features. A simple meningocele can also be seen where the dural outpouching contains cerebrospinal fluid but does not contain the spinal cord or other neural elements.
• Maternal serum alpha-fetoprotein is a highly used biomarker that screens for neural tube defects, and levels are measured between 15 and 20 weeks of gestation.
• MRI provides the best detail of the brain and spinal cord to assess for hydrocephalus, Chiari malformation, and syringomyelia.
Prenatal. Maternal serum alpha-fetoprotein levels are measured between 15 and 20 weeks of gestation. This protein is made in the baby’s liver, and increased levels may signify a neural tube defect. However, this protein production is not specific. Thus, ultrasounds or amniocentesis are required for secondary confirmation.
Newborn. Imaging of the head and spine is usually performed prior to the repair. MRI provides the best detail of both the spinal cord and brain. This can assess for the presence of hydrocephalus, Chiari I malformation, and syringomyelia. Cranial ultrasonography can also demonstrate hydrocephalus, and serial ultrasounds are a convenient way to monitor for the possible development or progression of hydrocephalus.
Beyond the newborn period. Evaluation is, for the most part, the same as in the newborn period. MRI or CT of the brain can be used to assess ventricular caliber when symptoms of hydrocephalus are present. MRI of the cervical spine can be used to monitor for Chiari malformation and syrinx. MRI of the repaired spinal lesion is required to evaluate an individual with symptoms or signs of tethered spinal cord.
• Closure of myelomeningocele defects have been performed in utero at several centers. The rationale is that this may protect the neural elements from the damaging effects of exposure to amniotic fluid and help restore cerebrospinal fluid dynamics.
• Studies have investigated the developmental outcomes of prenatal closure.
• Prenatal closure is not without risks to the mother and child, including infection and preterm labor.
• Prenatal closure is also associated with a higher rate of surgeries for tethered cord release later in life.
Fetus. The closure of the myelomeningocele defect in utero has been performed at several centers. The rationale behind this approach is that in utero closure may protect the neural elements (placode) from the damaging effects of exposure to amniotic fluid and may help restore more normal cerebrospinal fluid dynamics to decrease the development of hydrocephalus and subsequent shunt dependency. However, some evidence now exists that the neural placode shows evidence of developmental abnormalities, problems that would not be prevented by surgery (22). Early studies unfortunately did not yield convincing results with regards to improvement in motor and sensory level outcomes. However, they did suggest less hindbrain herniation (due to Chiari) and possibly a decreased requirement for ventriculoperitoneal shunt placement with this approach (09; 54). Further, midgestation repair of myelomeningocele appeared to improve fetal head growth (16).
In 2011, a multicenter, randomized prospective trial comparing prenatal to postnatal myelomeningocele repair was published (01). One hundred and eighty-three patients were randomized to prenatal (19-26 weeks gestation) or postnatal closure of the defect. Primary outcomes were mortality and rate of shunt placement by 12 months. Mortality was similar, with two perinatal deaths in each group. However, shunts were placed for hydrocephalus in 40% of the prenatal group and 82% of the postnatal group. Due to this clear difference between the groups, the trial was ended prior to full patient accrual. In addition, prenatal repair was associated with a lower rate of Chiari malformation and syrinx development. However, prenatal closure was also associated with a higher rate of later surgeries for tethered cord release.
A second set of primary outcomes included scores on the Bayley Mental Development Index and the difference between functional and anatomical level. Again, there was a significantly better outcome for those in the prenatal surgery group. Despite a higher anatomic level on average, the prenatal group also had higher motor scores at this point in follow-up. Furthermore, prenatal myelomeningocele repair may provide better outcomes for sacral function. In a preliminary review of patients at the Children’s Hospital of Philadelphia, children who underwent prenatal repair had higher rates of both bowel and bladder continence than those who underwent postnatal repair (10).
There were, however, increased risks to the mothers and the pregnancy when in utero surgery was performed. These included higher rates of chorioamniotic membrane separation, pulmonary edema, oligohydramnios, placental abruption, spontaneous membrane rupture, spontaneous delivery, and the need for maternal blood transfusion. A significant number of hysterotomy sites were thin or dehisced at the time of caesarean section delivery.
Furthermore, there was an increased risk of preterm birth in the prenatal surgery group. This led to an increased risk of apnea and respiratory distress syndrome in these children.
For these reasons, there continues to be a debate as to whether prenatal myelomeningocele repair carries enough benefit to warrant the risks. New techniques for prenatal repair, however, may tip the balance. Sanz Cortez and colleagues published data on 300 cases of prenatal fetoscopic open spina bifida repair (51). The study compared outcomes of prenatal repair via hysterotomy versus fetoscopic repair. The comparison revealed that outcomes of hysterotomy and fetoscopic repair are similar up to 12 months of age after repair. Importantly, fetoscopic repair allows for having a vaginal delivery and eliminates the risk of uterine scar dehiscence, which would protect future pregnancies and maternal risks.
Newborn. Early closure of the myelomeningocele is usually advocated to prevent further spinal cord damage and infection. After 72 hours, the risk of meningitis rises significantly, making this the usual upper limit for surgical timing. Commonly, the back lesion is closed by recreating a thecal sac from the open dura and then closing the skin. Sometimes a surgically created skin or skin and muscle flap is necessary to cover a particularly large defect. Parents should be informed that this initial surgery will not cure their child’s neurologic deficits.
Beyond the newborn period. Most authors agree that to achieve the goals of high-quality care for individuals with myelomeningocele, a system of comprehensive and coordinated care is required. A multidisciplinary spina bifida clinic or program can be the hub of such a system. Such a clinic should provide a number of important services, which include the following: (1) routine comprehensive medical evaluations that include ongoing communication with the family and the patient; (2) preventative health care and anticipatory guidance; (3) nursing services, especially to evaluate, plan, and coordinate the child's health needs within the home and school; and (4) psychosocial support, including evaluation and therapeutic and informational services.
The following important areas are addressed in the medical assessment:
(1) Serial assessment of the neurologic level of impairment (motor and sensory) to detect deterioration from such potentially reversible problems as ventricular shunt malfunction, tethered spinal cord, syringomyelia, and spinal cord compression from lumbar stenosis or arachnoid cysts. Other neurologic changes of potential importance include decrease of muscle strength or a change in tone.
(2) Assessment of upper extremity function (in particular, decreases in hand grip strength, changes in reflexes, evidence of hand atrophy, pain or paresthesia in the hands or arms, or onset of upper extremity weakness) should raise the suspicion of a symptomatic Chiari malformation or syringomyelia. Sometimes evidence of carpal tunnel syndrome is identified.
(3) Examination of coordination, as coordination problems may signify changes in the status of hydrocephalus or a Chiari malformation.
(4) Monitoring for symptoms and signs of increased intracranial pressure including headache, nausea, vomiting, lethargy, irritability, and personality change.
(5) Monitoring for changes in school performance or other functions. This may be a nonspecific indicator of a new problem arising, such as uncompensated hydrocephalus or depression. Medical disturbances such as electrolyte imbalance or renal failure may also present this way. Complex psychological adjustment reactions may come to the forefront as educational disturbances. However, medical causes need to be investigated and ruled out at the same time as the psychosocial issues are pursued. In some cases, the use of methylphenidate with careful monitoring of effect and side effects may be helpful (17).
(6) Management of such neurologic issues as seizures, which may occur in up to 15% of individuals with myelomeningocele by adolescence (07). Reports have identified a subgroup with mental deterioration from continuous spike-waves during slow sleep (08).
(7) A group of infants with spina bifida will develop early difficulties from Chiari malformation. Most of these problems have been described as the "infant brainstem syndrome" (12). Prominent symptoms include apnea, stridor, and dysphagia. Most authorities recommend that such cases have surgical decompression of the Chiari malformation.
Neuromuscular electrical stimulation is a technological treatment intervention that uses electrical stimulation to specific muscles to improve strength and function. This treatment has primarily been studied in children with cerebral palsy, the most common childhood motor disability (57). Neuromuscular electrical stimulation has been found to increase muscle fiber diameter, muscle size, and muscle strength. It also reduces spasticity by decreasing stretch reflex sensitivity.
Motavalli and colleagues managed an infant with spina bifida with an exploratory electrical stimulation protocol involving functional electrical stimulation and transcutaneous spinal cord stimulation (42). The most dramatic changes were observed in improvement of sensation and improved anal closure with less smearing. Circulation also improved over 12 months of therapy. Interestingly, spontaneous lower extremity movement developed after back extensors were targeted. The movements, however, are not purposeful for function. Abdominal muscles were targeted and showed improvement of truncal posture in sitting and standing positions. There were no adverse events observed. Based on this case report and previous studies, this noninvasive technique may be applied in conjunction with current physical and occupational therapies to help maximize function.
Treatment of urologic abnormalities ensures health and is a high management priority. Individuals who are at high risk for renal deterioration need to be identified. They include individuals with high-pressure bladder systems, vesicoureteral abnormalities leading to reflux and hydronephrosis, or recurrent urinary tract infections (20). It is important to emphasize that urologic status is rarely static in people with spinal dysraphism; individuals can convert from the low- to the high-risk group. Frequent monitoring and aggressive management centered around clean intermittent catheterization are needed to prevent such complications as hypertension and renal failure (47).
Another major aspect of urologic care is the management of urinary incontinence. The management of incontinence has advanced considerably over the last 2 decades, particularly with the acceptance of clean intermittent catheterization and advances in bladder augmentation surgery. A rational management plan must be based on adequate information about voiding function. This usually requires a cystometrogram to determine bladder tone and pressure, outlet function, and the coordination or degree of synergy or dyssynergy between the two. Management of urinary continence often includes the use of medications such as oxybutynin for bladder relaxation, sympathomimetics such as ephedrine to promote bladder outlet contraction, and imipramine to do both. Doses must be titrated, and side effects monitored. Some authors recommend intravesical infusion of oxybutynin when side effects like flushing become prohibitive in those on oral administration (25).
Finally, issues of sexual function need to be considered as the patients approach adolescence (31). The proper management of sexuality in this group goes beyond medical management and needs to involve disability-specific education as well as supportive home, community, and medical environments. It also involves parents and professionals working together to help patients overcome barriers and meet their needs of intimacy and sexuality.
The management of orthopedic deformities in individuals with states of dysraphism has been the subject of much discussion, and management philosophies often differ. The key issue is whether to pursue aggressive interventions to maintain ambulation as long as possible. Orthopedic interventions, often required to maintain an upright posture and adequate hip-knee-ankle alignment, include release of hip or knee contractures and procedures designed to manage dislocated hips. Proponents of aggressive maintenance of an ambulatory state maintain that this is a critical component of child development (30; 24). Other factors stated to support this approach include less skin breakdown, better renal health, and improved bowel function and continence. On the other hand, others argue that the repeated surgical procedures required to maintain ambulation are too high a price to pay (52). Risks and complications of these procedures can have lasting consequences (19). Furthermore, many individuals with myelomeningocele do not remain ambulatory, with this usually becoming evident in the second decade of life. There are also data suggesting that the ones who maintain ambulation have as many problems with skin breakdown as the ones who forgo ambulation in favor of wheeled mobility, just in a different distribution (feet or ankles vs. sacrum buttocks) (38).
The first orthopedic problem to be confronted in a newborn with myelomeningocele is the management of clubfoot, usually talipes equinovarus. Serial casting is the first line of treatment, with surgery being reserved until later (if it is even necessary).
The proper alignment of the spine is indisputably an important area for the orthopedist. It is recommended that scoliosis of greater than 40 degrees and kyphosis of greater than 60 degrees undergo orthopedic correction by some method of vertebral fusion with instrumentation (45). Lesser degrees of scoliosis that appear to be progressing are usually managed with a body brace.
Lesions of the fifth lumbar nerve root and below (ie, sacral lesions) are often associated with inversion eversion and calcaneal deformities of the foot and may require tendon releases, transfers, and sometimes joint fusions.
Orthopedic management also includes the appropriate introduction of orthoses such as hip-knee-foot, knee-ankle-foot, and ankle-foot orthoses. Parapodium and reciprocating gait orthoses may be considered for young patients with thoracic level lesions who are candidates for ambulation. Canes or crutches should also be offered. The evaluations for and prescriptions of these devices are best done by a cooperative team that includes the orthopedist, orthotist, and physical therapist.
Bowel continence. The management plan of fecal incontinence is based on an individual assessment of the child. The history should determine stool frequency and consistency, frequency and timing of toileting, level of functional independence, sensation for stool in the rectum, diet, and family attitudes and schedules. Physical examination should note external and internal sphincter tone, the ability for any voluntary sphincter contractions, presence or absence of an anal wink, and amount and consistency of stool in the rectal vault. A management plan should be step-wise in approach, including a large amount of education, feedback, and support. The major steps include the following:
(1) Regular toileting 10 to 15 minutes after meals to take advantage of the gastrocolic reflex. Behavioral therapy or biofeedback can be of use to reinforce positive toileting behaviors.
(2) Increase the stool bulk and consistency with a high-fiber diet or products.
(3) Use of suppositories or cathartics.
(4) Enemas such as standard or retention. There is danger in using repeated hypertonic phosphate enemas. Many patients have low anal sphincter tone and require a cuffed-balloon enema tube for effective enema use (37).
Most important is the need to approach each family and child as individuals, recognizing their resources and abilities to carry out the recommendations of a particular program designed to achieve fecal continence.
Skin integrity. This is the most important cause of morbidity in the population. Prevention and early detection are the best approach to this problem. Methods of prevention include teaching self–skin checks and recognizing such signs of an early pressure ulcer as persistent redness. Early detection must be followed by relief of such inciting factors as pressure and wetness, as well as appropriate wound care when needed.
Obesity. Like obesity in the general population, this is an extremely difficult problem to treat once it occurs. Excessive weight gain is best identified in the preschool age group when a child first begins to cross higher percentile curves for age. At this point, nutritional and fitness or activity level counseling should be initiated. Weight should also be monitored carefully after surgery, as this is a common period of weight gain from decreased activity level or increased caloric intake.
Endocrinopathies. The most common endocrine problem identified in patients with myelomeningocele is precocious puberty (40). Another problem is short stature (27). There is some concern that the short stature seen in these children has lasting psychological consequences over and above those resulting from other impairments associated with the condition. Treatment with growth hormone has been advocated by at least one group (49). However, growth hormone treatment is not without potential side effects, and the effectiveness of this therapy, either on ultimate height or for combating the psychological consequences of short stature, is not yet scientifically proven.
Latex allergy. This is now recognized as an important health issue for individuals with myelomeningocele. An incidence rate of at least 20% has been cited (36). Individuals allergic to latex can have life-threatening reactions to products containing latex. Exposure to latex during surgery represents a particular risk, with anaphylactic shock and death occurring. Screening for latex allergy prior to surgery is now carried out in many centers by direct inquiry about previous latex reactions and determining latex titers by immunologic testing. Individuals with high antibody titer to latex are counseled about risk, exposure, and avoidance of latex products during and after surgery. Also, surgical teams should be alerted to the risk so that appropriate precautions (latex-safe operating room, nonlatex gloves, etc.) can be taken. Many centers use only latex-free equipment in the operating room for all patients with myelomeningoceles to fully avoid this risk.
Genetic counseling. It is important to have professional genetic counseling services available to families of children born with spina bifida. Particular attention should now also be paid to folic acid education. It is now believed that over one half of cases of neural tube defects may be preventable with the use of folate supplementation before conception. This includes cases with a family history of previous neural tube defects. Finally, it has become increasingly clear that adolescents and young adults with spina bifida are often not given sufficient personal information regarding the genetic aspects of their condition. These individuals also deserve and would benefit from genetic counseling.
Role of the multispecialty clinic or program in the care of individuals with myelomeningocele. It would not be appropriate to complete a review of the care of individuals with myelomeningocele without further commenting on the methods used to deliver services to this population. Almost from the beginning of providing serious services to this group, the advantages of using a multispecialty or multidisciplinary group to deliver care have been emphasized (52). A key feature of this approach is the greater potential for communication among providers, thus, increasing coordination, comprehensiveness, and access. All of these elements of care are deemed important aspects of high-quality care. Their absence has been documented to lead to increased health problems for this population (33). The Spina Bifida Association of America produced the "Guidelines for Spina Bifida Health Care Services Throughout Life" in 1990 and updated in 1995, in which they emphasize the importance of the multispecialty spina bifida team for providing adequate levels of service. (The guidelines can be obtained from the Spina Bifida Association of America at 4509 MacArthur Blvd, NW, Suite 250, Washington, DC, 20007-4226.) The guidelines also focus on expected outcomes, with the goals of maintaining health status and preventing secondary disabilities, maximizing potential to participate in society, and fostering independence according to individual abilities. The guidelines further stress a developmental approach that adds an anticipatory element to the care. In this age of health care reform, the guidelines form the basis for a rational, coordinated, and comprehensive plan of care for individuals with spina bifida.
Patients with myelomeningoceles have a mortality rate of about 1% per year between the ages of 5 and 30. The higher the lesion, the greater the morbidity and mortality.
Psychosocial issues are a significant comorbidity in this patient population. Many suffer from anxiety and depression and have difficulties maintaining relationships, employment, and financial independence.
At least one adult series noted three cases of symptoms of tethered cord syndrome in individuals with spinal dysraphism precipitated after childbirth in the lithotomy position (46). Care needs to be taken in obstetrical situations with a patient with known spinal dysraphism.
Saitoh and colleagues suggest that proper management includes avoidance of increased intracranial pressure and respiratory dysfunction (50). These patients can also have autonomic dysfunction. Concerns about latex avoidance to minimize the risk of intraoperative anaphylaxis are indicated and need to be counseled during surgery and delivery situations (23).
All contributors' financial relationships have been reviewed and mitigated to ensure that this and every other article is free from commercial bias.
Nagma Dalvi MD
Dr. Dalvi of Albert Einstein College of Medicine Montefiore Medical Center has no relevant financial relationships to disclose.See Profile
Solomon L Moshé MD
Dr. Moshé of Albert Einstein College of Medicine has no relevant financial relationships to disclose.See Profile
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