Myelomeningocele (spina bifida): Management and outcome

INTRODUCTION — Neural tube defects are the most common congenital central nervous system (CNS) anomalies and are the cause of chronic disability of between 70,000 and 100,000 individuals in the United States. Myelomeningocele (spina bifida) is the most common neural tube defect. It is characterized by a cleft in the vertebral column, with a corresponding defect in the skin so that the meninges and spinal cord are exposed. Patients with myelomeningocele may have weakness and absence of sensation affecting the lower extremities and bowel/bladder dysfunction, depending upon the level of the spinal lesion.

An overview of the management of myelomeningocele and its complications will be presented here. Occult spinal dysraphism is discussed separately. The pathophysiology, clinical manifestations, prenatal diagnosis, orthopedic management, and urologic management of myelomeningocele are also discussed separately:

●(See "Closed spinal dysraphism: Pathogenesis and types".)

●(See "Myelomeningocele (spina bifida): Anatomy, clinical manifestations, and complications".)

●(See "Neural tube defects: Overview of prenatal screening, evaluation, and pregnancy management".)

●(See "Myelomeningocele (spina bifida): Orthopedic issues".)

●(See "Myelomeningocele (spina bifida): Urinary tract complications".)

PRENATAL COUNSELING AND CHOICE OF MANAGEMENT — Most centers treat all viable newborns aggressively without selection. Historically, selective treatment was provided only for infants considered to have the best chance of neurologic outcome; however, nonselective treatment increases overall survival several-fold, and there is little difference in functionality as compared with individuals surviving selective treatment protocols. (See 'Outcome' below.)

At our institution, the management choice is dependent on parent preference after ensuring that parents understand the management options and expected outcomes. During prenatal counseling, discussion with the parents includes the natural history of myelomeningocele and the prenatal management decisions, including termination of the pregnancy, pursuit of additional prenatal testing, choice of delivery setting, and, when applicable, the possibility of fetal surgery. The postnatal management choices are also discussed, including surgical closure of the defect and possible need for ventriculoperitoneal shunt placement. Longitudinal follow-up after prenatal diagnosis of myelomeningocele suggests that approximately 60 to 70 percent of pregnancies end in termination or fetal demise [1,2].

Serial ultrasounds for fetal growth, head size, and ventricular size can provide useful information to inform prenatal counseling and delivery planning [1]. Additional prenatal evaluation is reviewed in detail separately. (See "Neural tube defects: Overview of prenatal screening, evaluation, and pregnancy management", section on 'Postdiagnostic fetal evaluation'.)

FETAL SURGERY — Fetal surgery for myelomeningocele can arrest leakage of spinal fluid from the back thereby preventing or reversing herniation of the hindbrain (Chiari II malformation) and reducing the development of hydrocephalus and need for cerebrospinal fluid (CSF) shunting [3]. Fetal surgery is performed at many specialized centers across North America and Europe.

Our approach — Because fetal surgery is associated with risks of fetal and maternal complications, we agree with recommendations of the American College of Obstetricians and Gynecologists (ACOG) that fetal surgery only be offered at facilities with the special expertise, multidisciplinary teams, and facilities to provide the intensive care required for these patients [4,5]. In our practice, the fetal team (consisting of a pediatric neurosurgeon, fetal surgeon, maternal fetal medicine specialist, and neonatologist) meets with the expectant family in three separate counseling sessions:

●At the first meeting, we discuss the disease, its long-term impact on the patient, and postnatal management of the open defect. We assess candidacy for fetal surgery, utilizing the inclusion and exclusion criteria from the Management of Myelomeningocele Study (MOMS) trial, which is discussed below (see 'Efficacy' below). Important criteria when assessing candidacy for fetal surgery include that the pregnancy is an otherwise uncomplicated singleton pregnancy and that the fetus has an isolated myelomeningocele with normal karyotype and no additional major structural anomalies. If the mother is a candidate for fetal surgery, we inform her of this option and provide a brief summary of the risks and benefits associated with prenatal surgery.

●If the family is interested in pursuing more in-depth knowledge of fetal surgery, they return for a second counseling session, during which the maternal and fetal risks and potential benefits of prenatal surgery are reviewed in greater detail.

●In the third session, the family meets with the entire fetal surgery team, including the surgical, medical, and anesthesia staff. The expectant family's questions are addressed, and consent is obtained for surgery.

These counseling sessions usually occur over several weeks, which allows the family time to process the information and make a decision that is best for them.

Additional details of the fetal evaluation are provided in a separate topic review. (See "Neural tube defects: Overview of prenatal screening, evaluation, and pregnancy management", section on 'Postdiagnostic fetal evaluation'.)

Efficacy — The safety and efficacy of fetal surgery for repair of myelomeningocele were evaluated in the MOMS trial, which was a randomized controlled trial conducted from 2003 to 2010 at three institutions in the United States with extensive experience in fetal surgery [6-9]. Eligible women were randomized to undergo fetal surgery at 18 to 25 weeks gestation (n = 91) or standard postnatal repair (n = 92). The trial was stopped early because of efficacy [6]. Findings reported in the complete trial and in subsequent follow-up studies include the following [6-11]:

●Decreased need for CSF shunting – In the first year of life, 44 percent of infants in the fetal surgery group required CSF shunt placement for hydrocephalus compared with 84 percent in the postnatal repair group (relative risk [RR] 0.53, 95% CI 0.41-0.67) [8]. At age 6 to 10 years, children in the fetal surgery group had a lower rate of hindbrain herniation (60 versus 87 percent), less frequently required a shunt (49 versus 85 percent), and, among those with shunts, less frequently required shunt revision (47 versus 70 percent) [9].

●Improved motor development and function – At 30 months of age, more children in the fetal surgery group achieved independent ambulation compared with those in the postnatal repair group (45 versus 24 percent) [6,10]. Children in the fetal surgery group scored higher on standardized tests of motor development (mean psychomotor development index on the Bayley Scales of Infant Development II tool was 64±17 versus 59±15) [6,10]. Factors associated with independent ambulation included the presence of in utero ankle, knee, and hip movement; absence of a sac over the lesion; and a myelomeningocele lesion of ≤L3 [10]. At age 6 to 10 years, there were fewer children overall who maintained independent ambulation, though the difference between the two groups persisted (29 percent in the fetal surgery group versus 11 percent in the postnatal surgery group) [9]. Children in the fetal surgery group also scored higher on assessments of motor and self-care skills (mean composite score 92±9 versus 85±18) [9].

●Similar cognitive outcomes – Based on the available data, fetal surgery does not appear to improve cognitive and adaptive functioning. At 30 months of age, children in both groups had similar scores on standardized tests of mental development (mean mental development index on the BSID-II was 89±15 for the fetal surgery group versus 86±18 for the postnatal repair group) [10]. At age 6 to 10 years, scores on standardized developmental tests were similar in both groups within each domain of adaptive functioning (communication, daily living, and socialization) and for the overall composite score (89±10 versus 88±12) [9]. Additionally, there were no apparent differences on a variety of parent-rated assessments of attention, executive functions, and behavior.

●Possible improvement in bladder function – It is uncertain whether the rate of bladder dysfunction is lower in children who undergo fetal repair compared with those who undergo postnatal repair. If there is an improvement, it does not appear to be dramatic and therefore urologic outcomes alone should not be the sole impetus to perform fetal surgery. At 30 months of age, there was a nonsignificant reduction in the need for clean intermittent catheterization (CIC) (38 percent in the fetal surgery group versus 51 percent in the postnatal surgery group; RR 0.74, 95% CI 0.48-1.12) [7]. By school age, more children in the fetal surgery group reported voiding volitionally compared with the postnatal surgery group (24 versus 4 percent) and fewer children in the fetal surgery group required CIC (62 versus 87 percent) [11]. Rates of bladder augmentation, vesicostomy, and urethral dilation were similar in the two groups.

●Modest improvements in quality of life and impact on family – At age 6 to 10 years, parental assessments of health-related quality of life (HR-QOL) and impact of the child's health condition on the family were better in the fetal surgery group compared with the postnatal surgery group, though the differences were modest [9].

The participants of the MOMS trial are being followed into adolescence and adulthood to evaluate the long-term effect of fetal intervention on motor function, cognitive development, bowel and bladder function, and other important outcomes, including sexual function.

Risks — Risks of fetal surgery include preterm birth, chorioamnionitis, chorion-amnion separation, spontaneous membrane rupture, oligohydramnios, placental abruption, pulmonary edema, maternal bleeding, maternal transfusion, increased incidence of uterine thinning/dehiscence of the hysterotomy site, and need for cesarean delivery with future pregnancies [6,7,12,13]. Many centers perform the procedure via hysterotomy, which is associated with a risk of uterine rupture in the current and all subsequent pregnancies [14]. Fetoscopic repair is offered at some centers and may have a lower risk of uterine rupture. Fetoscopic repair is offered at some centers and may have a lower risk of uterine rupture. These issues are discussed in greater detail separately. (See "Neural tube defects: Overview of prenatal screening, evaluation, and pregnancy management", section on 'Consider fetal surgery for myelomeningocele repair'.)

In the MOMS trial, the incidence of preterm birth (ie, delivery at ≤34 weeks gestation) was 46 percent in the fetal surgery group versus 5 percent in the postnatal surgery group. Mortality was similar in the two groups (one fetal death and one neonatal death in the fetal surgery group; two neonatal deaths in the postnatal surgery group) [8]. However, in a review of the experience at one center after completion of MOMS, the reported perinatal mortality rate was higher than in the trial: Among 100 patients who underwent fetal surgery after 2011, perinatal mortality was 6 percent (two fetal and four neonatal deaths) [12].

LABOR AND DELIVERY — For infants with a prenatal diagnosis of myelomeningocele who do not undergo fetal intervention, delivery should occur at a center with a level III neonatal intensive care unit, pediatric neurosurgery services, and other personnel experienced in the neonatal management of these infants. Latex-free gloves and equipment should be used during delivery and subsequent care of the infant because patients with myelomeningocele are at risk for developing a life-threatening latex allergy.

Term delivery is preferable, but increasing ventriculomegaly with macrocephaly on prenatal ultrasound may necessitate preterm delivery as determined by the obstetrical team.

Fetuses presenting in the breech position are typically delivered by cesarean section. The optimal route of delivery of a fetus presenting in the vertex position is uncertain. The route of delivery and other aspects of pregnancy management, labor, and delivery are discussed in greater detail separately. (See "Neural tube defects: Overview of prenatal screening, evaluation, and pregnancy management", section on 'Myelomeningocele'.)

MANAGEMENT OF THE NEONATE

Assessment — Immediately after birth, the lesion should be briefly assessed to note its location and size and whether it is leaking cerebrospinal fluid (CSF) [15]. Sterile, non-latex gloves should be used to minimize the risk of latex sensitization [16,17]. The defect should be covered with a sterile, saline-soaked dressing [18]. Large defects should also be covered by plastic wrap to prevent heat loss. In most cases, only the neurosurgeon should remove the dressing. The infant should be placed in a prone or lateral position to avoid prolonged pressure on the lesion.

A thorough neurologic examination should be performed. This should include (see "Neurologic examination of the newborn" and "Detailed neurologic assessment of infants and children", section on 'Neurologic examination'):

●Observation of spontaneous activity

●Extent of muscle weakness and paralysis

●Response to sensation

●Deep tendon reflexes

●Anocutaneous reflex (anal wink)

In many infants, the neurologic findings will improve during the first 72 hours of life. The examination should be interpreted to define the baseline neuropathology of the individual patient, as described separately (see "Myelomeningocele (spina bifida): Anatomy, clinical manifestations, and complications", section on 'Neurologic abnormalities'), with attention to the following features:

●Level of the spinal cord neurologic deficit

●Associated spinal cord anomalies, such as split cord malformation

●Signs of hydrocephalus

●Evidence of brainstem compression (from the Chiari II malformation)

The newborn should also be evaluated for associated abnormalities in order to make appropriate decisions regarding treatment, including:

●Clubfeet

●Flexion or extension contractures of hips, knees, and ankles

●Kyphosis

●Other congenital abnormalities, including structural anomalies of the heart, airway, gastrointestinal tract, ribs, and kidneys (eg, ultrasound evidence of hydronephrosis, absent kidney, or pelvic kidney), and developmental dysplasia of the hip

Antibiotics — Prophylaxis with broad-spectrum antibiotics should be given until the back is closed to reduce the risk of infection of the central nervous system (CNS). With this precaution and appropriate wound care, early CNS infection is rare. In a retrospective study of infants with back closure performed after 48 hours of age, ventriculitis occurred less often in infants given antibiotic prophylaxis as compared with those who were not (1 versus 19 percent) [19]. (See "Bacterial meningitis in the neonate: Treatment and outcome", section on 'Empiric therapy'.)

Surgical closure — The back lesion should be surgically closed within the first 72 hours after birth; this step further decreases the risk of CNS infection [20]. The recommended technique involves the approximation of the lateral edges of the open neural plate in the midline to form a neural tube [21]. This covers the caudal end of the spinal cord with a layer of pia mater. It is unclear whether this decreases the incidence of tethered cord, but it certainly facilitates untethering of the cord later in life, should this be necessary. Complications of closure include CSF leak, infection, and dermoid inclusion tumors [22].

Hydrocephalus — Following repair of the myelomeningocele, many infants develop some degree of hydrocephalus, which causes the head circumference to increase at a rate greater than the normal curve. We recommend active surveillance of head circumference and ventricular size in the weeks following repair to determine if the infant requires placement of a ventriculoperitoneal shunt.

Ventricular size should be evaluated soon after birth by ultrasound, computed tomography, or magnetic resonance imaging (MRI) (image 1) [20]. Serial neuroimaging using ultrasound is then performed to identify the development of hydrocephalus. The patient is reassessed every 3 to 10 days depending on the level of concern. Subsequent management varies with the clinical and radiologic findings:

●Stable or slowly progressive increases in ventricular size in a stable infant should be followed. If the infant is stable, without apnea, feeding normally, and responding normally, we suggest expectant management, measuring the head circumference and imaging of the ventricles with ultrasound every one to three weeks until the head growth has stabilized. In many of these infants, the head growth will slow and eventually follow a curve slightly above but parallel to the 95^th percentile line. This may take several weeks or up to three months.

●By contrast, rapidly progressive hydrocephalus that causes the infant to become unstable or to develop stridor, poor feeding, or emesis should be treated by insertion of a ventriculoperitoneal shunt. Shunt placement may also be triggered by cosmetic concerns if the infant's head circumference is markedly larger than that of a normal infant this age (eg, nearing the size of a three-year-old child).

Approximately 60 percent of infants require ventriculoperitoneal shunt placement when followed using the above protocol [23]. The remaining infants appear to do well without a shunt, and there is no evidence that the lack of a shunt impairs their development. Additional evidence that mild hydrocephalus is not necessarily associated with cognitive dysfunction comes from historical observations: Many of the adults who survived prior to the availability of shunting have large heads and very large ventricles but have normal intelligence and are living independently. Although shunt placement increases survival through childhood for infants with rapidly progressive hydrocephalus, there is some evidence that having a shunt may reduce survival during adulthood [24].

In a few infants with very early evidence of progressive hydrocephalus, simultaneous myelomeningocele repair and shunt placement may be appropriate. This approach does not appear to increase the complication rate. In a retrospective review, the frequency of CSF infection, shunt malfunction, and symptomatic Chiari II malformation was similar with simultaneous and sequential repair and shunting [25]. The rate of wound leak was lower and hospital length of stay was shorter in the group that underwent simultaneous repair and shunt placement.

SUBSEQUENT MANAGEMENT

Neurologic complications — Neurologic and physical function often deteriorate over time. Almost all deterioration has a treatable cause and, if not treated appropriately, can lead to severe disability by adulthood.

Deterioration in a patient with a ventriculoperitoneal shunt should prompt evaluation for possible shunt malfunction as the initial consideration. Other causes of progressive disability include tethered cord, progressive compression of the cervical canal from the Chiari II, and hydromyelia, as well as orthopedic and urologic complications. The most common cause of decline is a shunt malfunction; the second most common cause is a tethered cord [26]. Awareness of these complications and their management has resulted in a stable and much more functional population of young adults with myelomeningocele.

Routine surveillance — Deterioration can only be identified if baseline functional data exists. A baseline head computed tomography scan, spine magnetic resonance imaging (MRI), and manual muscle tests are essential.

Regular reevaluation is necessary to allow early detection of deterioration. Children should be followed by a multidisciplinary team, including pediatric, orthopedic, urologic, and neurosurgical specialists. Patients should be evaluated at least annually for function and clinical status, including manual muscle tests. The parents and/or patient should be charged with observing for changes in neurologic function and should report suspected changes promptly. (See "Detailed neurologic assessment of infants and children".)

Shunt malfunction — Any neurologic deterioration (new deficits, deterioration in lower extremity or urinary tract function, decrease in school performance) or other concerning signs or symptoms (eg, headache, vomiting, lethargy, papilledema, pain at myelomeningocele repair site) in a patient with a ventriculoperitoneal shunt should prompt evaluation for possible shunt malfunction. Identifying patients who may have a shunt malfunction in this population can be difficult as the classic signs and symptoms may be absent. The signs and symptoms tend to be consistent for a given patient but vary between individuals.

Shunt malfunction and infection are discussed in greater detail separately. (See "Infections of cerebrospinal fluid shunts" and "Hydrocephalus in children: Management and prognosis", section on 'Shunt malfunction'.)

Tethered cord — Progressive deterioration in lower extremity function, changes in urinary tract function, progressive scoliosis, or pain suggest the possibility of a tethered cord, which is a functional disorder caused by fixation and abnormal stretching of the spinal cord [27,28]. In patients with myelomeningocele, tethered cord is typically caused by scar tissue at the site of prior closure. Nearly all children who have undergone myelomeningocele repair have a low-lying spinal cord with adhesions to the surrounding dura; however, only 10 to 30 percent develop symptoms of neurologic deterioration that prompt surgical release [29,30]. The symptoms of tethered cord are nonspecific, and shunt malfunction must be excluded. (See 'Shunt malfunction' above.)

If a child demonstrates concerning neurologic, urologic, or orthopedic decline, a search for the cause should be undertaken, including imaging of the brain and spine. Neuroimaging is performed chiefly to exclude other potential causes (eg, shunt malfunction). Tethered cord is largely a clinical diagnosis in children with myelomeningocele since nearly all demonstrate radiographic evidence of tethering.

Treatment of tethered cord is surgical and consists of releasing the scar tissue around the prior placode closure. Untethering will be easier if the exposed neural tissue was closed into a tube during the primary closure. The symptoms will often stabilize or improve with untethering; however, symptomatic retethering may occur in some patients [26,30]. (See 'Surgical closure' above.)

Chiari II — The Chiari II malformation (also known as Arnold-Chiari malformation type II, a misnomer) is characterized by herniation of the developing fetal cerebellum and medulla downward into the spinal canal and upward into the middle fossa, in association with myelomeningocele (figure 1 and image 2A-B). Abnormalities of the forebrain are also commonly associated with the Chiari II malformation [31]. (See "Chiari malformations", section on 'Chiari II anatomy' and "Myelomeningocele (spina bifida): Anatomy, clinical manifestations, and complications", section on 'Chiari II malformation'.)

The Chiari II malformation is present on baseline MRI in almost all patients with myelomeningocele; however, a minority of patients develop symptoms related to brainstem compression and only 5 to 10 percent of patients require surgical decompression [29,32]. Interestingly, the radiographic appearance of hindbrain herniation is improved in infants who have undergone prenatal closure of their nervous system [6]. Whether this has any long-term impact on outcome is yet to be determined. (See 'Fetal surgery' above.)

In some patients, the brainstem or spinal cord becomes progressively compressed within the spinal canal, causing swallowing difficulties, vocal cord paresis, stridor, and/or apneic episodes. Neck pain is also common. Other symptoms may include new onset of strabismus, facial weakness, progressive weakness in the lower extremities, or worsening incontinence. When present, brainstem compression caused by the Chiari II malformation is associated with a high mortality rate [33,34].

Many of these symptoms are nonspecific, and in our experience, they are more likely to be due to a shunt malfunction causing increased pressure on the lower brainstem located in the upper spinal canal. Shunt revision usually relieves the symptoms. Shunt malfunction must be definitively excluded before considering an alternative diagnosis and intervention: Surgical decompression of the cervical or lumbar cerebrospinal fluid (CSF) spaces in the face of a shunt malfunction may cause herniation of the hindbrain because of the sudden reduction of CSF pressure. (See 'Shunt malfunction' above.)

When surgical decompression of Chiari II is indicated and shunt malfunction has been definitively excluded, a variety of approaches are used, including cervical bone-only decompression, dural opening (with or without a graft to increase the size of the canal), resection of the cerebellar tonsils, stent placement into the fourth ventricle, or a combination of these.

Hydromyelia — Hydromyelia describes the accumulation of fluid within the central canal of the spinal cord. This occurs in individuals with myelomeningocele because of a shunt malfunction or untreated hydrocephalus acting through the persistent embryonic connection between the neurocele, central canal, and the ventricular system of the brain. Fluid outside of the central canal has a different pathophysiology and is known as syringomyelia. (See "Disorders affecting the spinal cord", section on 'Syringomyelia'.)

It is unclear what role hydromyelia plays in the deterioration of an individual with myelomeningocele. MRI of the spinal cord reveals that 50 percent of the patients who appear to be stable have some degree of hydromyelia; some have severe holocord hydromyelia or segmental hydromyelia [35]. Hydromyelia has some association with shunt malfunction: It is rare in the newborn and usually develops with the first shunt malfunction. Shunt revision often diminishes or reverses the asymptomatic hydromyelia.

For patients with hydromyelia and nonspecific symptoms such as progressive scoliosis, urologic problems, pain, and motor or sensory defects, we first exclude shunt malfunction or empirically revise the shunt. If this is not successful, we suggest untethering the cord before considering specific treatment for hydromyelia. In many cases, untethering leads to improvement in the neurologic deficits. It is unclear why untethering of the spinal cord is also effective in reducing the radiologic findings of hydromyelia. (See 'Shunt malfunction' above and 'Tethered cord' above.)

Interventions for hydromyelia include fenestration and shunting (either to the subarachnoid space or peritoneal cavity), but these approaches can paradoxically increase the defect, cause tethering, or create an imbalance with the ventricular shunt.

Seizures — Seizures occur in 10 to 25 percent of children with myelomeningocele and correlate with poor cognitive outcome [29,36]. Patients presenting with new onset of seizures should undergo evaluation for shunt malfunction. (See 'Shunt malfunction' above.)

The management of seizures and epilepsy in children is discussed in detail separately. (See "Seizures and epilepsy in children: Initial treatment and monitoring".)

Learning disabilities — Most patients with myelomeningocele have normal intelligence, but almost all experience learning disabilities. The Chiari II malformation is the major factor that distinguishes myelomeningocele from other disorders that are limited to the spinal cord (eg, traumatic paraplegia, spinal cord lipomas) and hence are not associated with cognitive impairment. The Chiari II malformation alters cognitive function by affecting brain development. Cognitive function may be further affected by the common complications of hydrocephalus and infection [37-41].

Learning disabilities may include poor executive skills, attention deficits, and retrospective and prospective memory problems [42-44]. These intellectual disabilities may also delay maturation and impede the patient's ability to acquire the skills needed to live independently, which in turn affects family members [45]. Early recognition of these problems and intervention to optimize learning and independence are critical to allowing these young people to participate in society [20]. (See "Intellectual disability (ID) in children: Clinical features, evaluation, and diagnosis" and "Intellectual disability (ID) in children: Management, outcomes, and prevention".)

Urinary tract complications — Nearly all patients with myelomeningocele have bladder dysfunction (neurogenic bladder), and some may develop progressive deterioration of the upper urinary tract and chronic renal disease [20,46]. Treatment to reduce bladder pressures and minimize urine stasis usually prevents or attenuates this important complication. Close attention to urinary tract function is also important because changes in bladder function may be the only indication of a change in neurologic function and should prompt an evaluation for shunt malfunction or tethered cord, as previously discussed. (See 'Shunt malfunction' above and 'Tethered cord' above.)

Management of the urinary tract includes early initiation of clean intermittent catheterization and close monitoring for changes in bladder function. Most patients also benefit from anticholinergic medication. These and other interventions can also improve urinary continence, which has important social benefits, allowing children with myelomeningocele to participate in mainstream educational settings. Management of neurogenic bladder and other urinary tract complications associated with myelomeningocele is discussed in detail in a separate topic review. (See "Myelomeningocele (spina bifida): Urinary tract complications".)

Bowel management — In almost all individuals with myelomeningocele, innervation of the bowel and anus are affected, leading to dysmotility and poor sphincter control and, often, to fecal incontinence [20]. Bowel incontinence occurs in 60 to 70 percent of patients and is an important concern for individuals with myelomeningocele and their families [47]. Fecal incontinence can impair social relations and self-esteem, and management of this problem is time-consuming and limits independence [46].

Decreased bowel motility frequently leads to constipation and fecal impaction, which causes an elevation in intra-abdominal pressure and can lead to shunt malfunction. Impaction may also cause liquid encopresis, which is sometimes mistaken by the family as an episode of diarrhea.

The goals of a bowel management program are to achieve continence by prompting regular elimination of stool and to avoid fecal impaction:

●First-line options – Adequate bowel management is often achievable through the use of oral laxatives, suppositories, and enemas, singly or in combination. At the initiation of the bowel program or at intervals later, a bowel clean-out may be necessary. Some individuals are able to prompt evacuation of the bowel by using a suppository once daily, shortly after a meal, to take advantage of the gastrocolic reflex.

●Advanced bowel management options – For individuals who do not respond to first-line interventions, additional options include transanal irrigation and antegrade continence enema (ACE):

•Transanal irrigation – A system of transanal irrigation is successful in the majority of patients but is time-consuming and sometimes requires assistance [48-51]. Devices have been developed for this purpose (Peristeen [Coloplast, Denmark] or the Enema Continence Catheter [CardioMed, Canada]). (See "Chronic functional constipation and fecal incontinence in infants, children, and adolescents: Treatment".)

•ACE – Patients with severe refractory constipation and incontinence may benefit from surgical intervention [52-54]. In the ACE procedure (also called Malone antegrade continence enema), the appendix and cecum are used to create a catheterizable stoma. The patient is then able to clean out the colon by irrigating the colon through the stoma. The irrigation is usually performed every other day but can take as long as two hours to complete. ACE achieves continence in approximately 85 percent of patients with myelomeningocele [54]. One report suggests that use of a glycerin-based irrigant achieves high levels of continence (95 percent) with lower irrigant volume and relatively short evacuation time (mean 47 minutes) as compared with other irrigants [55].

Pressure ulcers — Pressure ulcers can negatively impact the overall health and quality of life in patients with myelomeningocele and contribute to the cost of their medical care [56]. In a cross-sectional study of 1763 patients with myelomeningocele, 15.6 percent reported having one or more pressure ulcers in the previous 12 months [46]. Prevention and management of pressure ulcers are discussed separately. (See "Prevention of pressure-induced skin and soft tissue injury" and "Clinical staging and general management of pressure-induced skin and soft tissue injury".)

Orthopedic problems — Orthopedic management should be directed at correcting deformities, maintaining posture, and promoting ambulation to maximize function and independence, if possible. Individuals with myelomeningocele often have congenital skeletal deformities involving the feet, knees, hips, and spine. Unbalanced muscle action around joints contributes to the orthopedic dysfunction. These issues are discussed in detail in a separate topic review. (See "Myelomeningocele (spina bifida): Orthopedic issues".)

Scoliosis occurs in most children with lesions above the second lumbar vertebra (L2). New or rapidly progressive scoliosis in an individual with myelomeningocele may be caused by a reversible neurologic complication such as shunt malfunction, tethered cord, and/or hydromyelia and should prompt a thorough neurologic evaluation. (See 'Shunt malfunction' above and 'Tethered cord' above.)

OUTCOME — Approximately 75 percent of patients who undergo myelomeningocele repair in infancy survive into early adulthood [29,57]. Long-term prognosis is largely dependent upon the following factors:

●Myelomeningocele level (thoracic and high lumbar defects are associated with greater disability and higher risk of mortality compared with sacral and lower lumbar defects)

●Severity of the Chiari II malformation (greater degree of hindbrain herniation is associated with worse prognosis)

●Presence or absence of hydrocephalus (hydrocephalus is associated with greater disability and higher risk of mortality)

In addition, many of the complications discussed above (eg, shunt malfunction, tethered cord, scoliosis) may negatively impact long-term prognosis. (See 'Shunt malfunction' above and 'Tethered cord' above and 'Orthopedic problems' above.)

The long-term outcome following postnatal closure of myelomeningocele is described in a single institution's report of 118 children with myelomeningocele born between 1975 and 1979 and followed for 20 to 25 years after initial back closure [29]. The following findings were noted:

●The overall mortality for the cohort was 24 percent and continued to increase into young adulthood.

●Among the 71 patients available at follow-up, 52 (73 percent) had a level of motor impairment that was stable compared with the level in infancy, 8 (11 percent) had improvement, and 11 (16 percent) had worsened level of motor function.

●The proportion of patients who reported ambulating a majority of the time declined from approximately 75 percent in early childhood to approximately 50 percent in young adulthood. Approximately 40 percent of young adults relied solely on their wheelchairs for locomotion. The ambulatory status was determined largely by the myelomeningocele level. Nearly all patients with a sacral level reported ambulating all of the time; >90 percent of those with L5 motor level ambulated a majority of the time as compared with 57 percent of those with an L4 level. None of the patients with a thoracic, L1, L2, or L3 level relied on ambulation for a majority of their locomotion.

●Of the 118 patients in the original cohort, 94 (80 percent) required cerebrospinal fluid (CSF) shunt placement. Of the 71 patients available at follow-up, 68 (96 percent) had undergone at least one shunt revision and 61 (86 percent) had undergone two or more shunt revisions. Approximately one-third of patients had undergone release of a tethered cord.

●Most patients (85 percent) were maintained on clean intermittent catheterization of their bladder. The majority of patients reported bowel control most of the time; however, only one-half reported social bowel continence all of the time.

●Of the 118 patients in the original cohort, 7 percent underwent a posterior cervical decompression, 10 percent underwent tracheostomy, and 8 percent had a gastrostomy tube placed.

●Most of the children in this cohort attended regular classes; 37 percent required assistance in school or special education. At the time of follow-up, one-half of the patients were attending college or had graduated; 45 percent were employed.

●At the time of follow-up, most of the young adults in this cohort were still living with their parents; 13 (18 percent) were living independently (two were married and living with their spouses) and 3 patients were in residential homes. None of the patients in the cohort had children.

In another report of a cohort of 117 patients who were born between 1963 and 1971 and underwent nonselective surgery after birth, only one-third of the patients were still alive at follow-up 40 to 50 years after the initial surgery [58]. Median survival was 28.5 years; approximately one-half of the deaths occurred before the age of five years. Causes of death were cardiorespiratory (33 percent), neurologic (31 percent), urologic (28 percent), or other (8 percent). Of the 57 patients with a neurologic level of L1 or above, only 12 percent survived compared with 55 percent of those with lower level defects.

Similar long-term mortality estimates were given in a population-based study from the United Kingdom [57]. For infants born with spina bifida between 1985 and 2003, 71 percent survived until one year of age (56 percent of those with hydrocephalus and 88 percent of those without hydrocephalus). Survival rates decreased slightly with advancing age among those with hydrocephalus, falling to 50 percent by 20 years.

Outcomes will probably be better in subsequent cohorts of patients due to improvements in management of the neurologic and urinary tract complications.

Limited data are available on long-term outcomes after fetal surgery [9,59,60]. The available data suggest that children who undergo fetal surgery have improved motor function, but cognitive outcomes appear to be similar (see 'Efficacy' above). In a follow-up study of 78 children who underwent fetal repair of myelomeningocele as part of the Management of Myelomeningocele Study (MOMS) trial and who were evaluated at age 6 to 10 years, 29 percent could walk independently, 42 percent could walk with orthotics only, 22 percent could walk with an assistive device, and 7 percent required the use of a wheelchair [9]. Scores on standardized tests of cognitive function and behavior were similar to those of children who underwent postnatal repair. Parent-rated assessments of attention and executive function were also similar. Both groups demonstrated better reading than math skills, higher verbal than nonverbal scores, below-average verbal memory performance, and impaired visuomotor integration. These findings are similar to other reports in children with postnatally managed myelomeningocele. (See 'Learning disabilities' above.)

Children enrolled in the MOMS trial are being followed longitudinally to better understand long-term outcomes. (See 'Fetal surgery' above.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Congenital malformations of the central nervous system".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or email these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword[s] of interest.)

●Basics topic (see "Patient education: Spina bifida (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Myelomeningocele (spina bifida) is the most common neural tube defect and is characterized by a cleft in the vertebral column, with a corresponding defect in the skin so that the meninges and spinal cord are exposed. Patients with myelomeningocele usually have complete paralysis and absence of sensation affecting the lower extremities and trunk, depending upon the level of the spinal lesion. (See 'Introduction' above and "Myelomeningocele (spina bifida): Anatomy, clinical manifestations, and complications".)

●Prenatal counseling includes discussion of the natural history of myelomeningocele and the prenatal management decisions including termination of the pregnancy, pursuit of additional prenatal testing, choice of delivery setting, and, when applicable, the possibility of fetal surgery. The postnatal management choices are also discussed, including surgical closure of the defect and possible need for ventriculoperitoneal shunt placement. (See 'Prenatal counseling and choice of management' above and "Neural tube defects: Overview of prenatal screening, evaluation, and pregnancy management", section on 'Postdiagnostic fetal evaluation'.)

●Fetal surgery is offered at a few select facilities with the required special expertise, multidisciplinary teams, and facilities to provide intensive care. (See 'Fetal surgery' above.)

●For infants with a prenatal diagnosis of myelomeningocele who do not undergo fetal intervention, delivery should occur at a center with a level III neonatal intensive care unit, pediatric neurosurgery services, and other personnel experienced in the neonatal management of these infants. Latex-free gloves and equipment should be used during delivery and subsequent care of the infant because patients with myelomeningocele are at risk for developing a life-threatening latex allergy. (See 'Labor and delivery' above.)

●Following delivery, initial management of the neonate includes covering and dressing the lesion and initiating prophylactic antibiotics. The infant should be evaluated for the possibility of associated congenital anomalies. (See 'Assessment' above and 'Antibiotics' above.)

●The back lesion should be surgically closed, preferably within the first 72 hours after birth if the infant is stable. For the next few weeks, the infant should be monitored closely for the development of hydrocephalus, using serial head circumference measures and head ultrasounds. (See 'Surgical closure' above and 'Hydrocephalus' above.)

•For patients who have rapidly increasing ventricular size, we recommend ventriculoperitoneal shunt placement (Grade 1B).

•Patients who have stable or slowly increasing ventricular size can be followed with serial head circumference measurements and ventricular ultrasounds every one to three weeks, depending on the level of concern, until the head growth has stabilized.

●Throughout life, patients with myelomeningocele should have serial evaluations of their neurologic function, including signs and symptoms of spinal cord or brainstem compression. Any changes should prompt evaluation for shunt malfunction. If this possibility is excluded, then tethered cord and brainstem compression from the Chiari II malformation should be considered. (See 'Neurologic complications' above.)

●Nearly all patients with myelomeningocele have neurogenic bladder. Treatment with early initiation of clean intermittent catheterization reduces the risk of progressive renal disease. Changes in bladder function may be a sign of an acute neurologic complication (eg, shunt malfunction or tethered cord). (See 'Urinary tract complications' above and "Myelomeningocele (spina bifida): Urinary tract complications".)

●In almost all individuals with myelomeningocele, innervation of the bowel and anus are affected, leading to decreased bowel motility and poor sphincter control and, often, to fecal incontinence. The goals of a bowel management program are to achieve continence by prompting regular elimination of stool and to avoid fecal impaction. This is often achievable through the use of oral laxatives, suppositories, and enemas, singly or in combination. Advanced bowel management options include transanal irrigation and the antegrade continence enema (ACE) procedure. (See 'Bowel management' above.)

●Orthopedic management is directed at correcting deformities, maintaining posture, and promoting ambulation to maximize function and independence. Scoliosis occurs in most children with lesions above the second lumbar vertebra. New or rapidly progressive scoliosis in an individual with myelomeningocele may be caused by a reversible neurologic complication such as shunt malfunction, tethered cord, and/or hydromyelia and should prompt a thorough neurologic evaluation. (See "Myelomeningocele (spina bifida): Orthopedic issues" and 'Shunt malfunction' above and 'Tethered cord' above.)

●Approximately 75 percent of patients with myelomeningocele survive to early adulthood. Long-term outcomes vary considerably depending on the myelomeningocele level, presence of hydrocephalus, and severity of the Chiari II malformation. (See 'Outcome' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges David G McLone, MD, PhD, who contributed to an earlier version of this topic review.