Spinal dysraphism represents a generic term for abnormalities in the formation of the neural tube or abnormal development of the structures immediately associated with the neural tube. It is often used interchangeably with the term neural tube defect. Specific dysraphisms discussed in this article include lipomeningocele, diastematomyelia, spina bifida occulta, caudal regression syndrome, myelocystocele, tight filum terminale, and sacral agenesis. While this is certainly not an all encompassing list, they are some of the more common. Spina bifida cystica, which traditionally includes myelomeningocele and meningocele, syringomyelia, and isolated tethered cord are discussed in separate KnowledgeNow topics.
Spinal dysraphisms occur when primary neurulation of the spinal cord is altered. This typically occurs on the caudal aspect around day 27-28 post-conception.1,2 In patients with spina bifida occulta and cystica, failure to close completely results in posterior spinal abnormalities of varying clinical significance.
In patients with caudal regression syndrome, the lower portion of the spine fails to develop, resulting in a myriad of developmental outcomes.
Epidemiology including risk factors and primary prevention
Risk factors for the development of neural tube defects include low maternal folate levels, low socioeconomic status, younger maternal age (more common in teenage mothers), race (highest in non-Hispanic whites and Hispanics), hyperthermia in early pregnancy, maternal caffeine intake, maternal medication usage (i.e., valproic acid, antiretroviral drugs, isotretinoin, methotrexate), maternal obesity and diabetes, and genetic influences.1-3
The worldwide incidence of neural tube defects is 1-10 per 1,000 live births.3 However, the incidence of affected pregnancies in the United States has decreased significantly since 1998, when the U.S. Food and Drug Administration mandated all cereals and grain products be fortified with folic acid. The current incidence in the United States is estimated at 5-7 per 10,000 live births. The American Academy of Pediatrics recommends supplementation with folic acid 400 mcg/day for women of child-bearing age.1,2,4
Spina bifida occulta has a predominance for the lumbosacral levels (i.e. L5 and S1), and some studies show an increased incidence in females compared to males.5
Spinal dysraphisms vary in their presentation and clinical description. There is not a single agreed upon nomenclature system that defines these entities, and there are various proposed classifications found throughout the literature.6 A few of the more common other dysraphisms are described below:
- Lipomeningocele/lipomyelomeningocele: These are often also referred to as lipomas with dural defect. Typically these terms refer to a meningocele or myelomeningocele that has a large amount of fat (i.e. a lipoma) associated with it.
- Lipoma: Also known as lipomas without dural defect, this term refers to a fatty tumor in the area of the spine and many authors propose various subtypes.
- Diastematomyelia: Splitting of the spinal cord in a longitudinal direction which often occurs in the upper lumbar spine. Many have associated bony spurs or fibrotic septums7.
- Spina bifida occulta: A mild form of spinal dysraphism in which the outer/bony portion of the spinal canal is not closed. No CNS components protrude through the bony defect. Most patients are diagnosed incidentally on radiograph.5
- Myelocystocele: A closed neural tube defect that consists of a mass containing fat, cerebrospinal fluid and neural elements.8,9
- Meningocele: Protrusion of the meninges through a bony defect without accompanying nervous tissue2
- Tight filum terminale: Subtype of tethered cord syndrome where the filum terminale is thick, short and inflexible.
- Sacral agenesis: Rare disorder where all or part of the sacrum fails to form. Highly associated with bowel and bladder dysfunction.10
- Caudal regression syndrome: Absence of the sacrum and/or portions of the lumbar spine with motor and sensory abnormalities.
Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)
Spinal dysraphism is often evident at birth, but it may not be symptomatic until later in childhood. Thus thorough neurologic history and exam should be performed for any change in bowel, bladder, strength or mobility
In lipomeningocele patients may initially exhibit a stable exam with varying degrees of neurologic abnormality. However, patients with these diagnoses may have increased neurologic issues if the spinal cord is tethered.
Children with diastematomyelia typically exhibit varying degrees of neurologic dysfunction including pain, weakness, reflex asymmetry, bladder and bowel disturbance, paresis spasticity, and sensation disturbances. These symptoms are exacerbated and progressive when there are concerns for tethered spinal cord.7
Spina bifida occulta is typically discovered incidentally when imaging is obtained for other reasons.5
Caudal regression syndrome is a non-progressive neurologic condition; however, patients’ functional abilities may decline over the years. For example, those patients who initially have some ability to ambulate may develop contractures which make ambulation more difficult. This may prompt some to switch to using a wheelchair for their primary form of mobility.
For most patients with spinal dysraphisms, it is standard of care for regular follow-up to monitor for changes in symptoms and exams. Optimally this is done in a multidisciplinary spina bifida clinic (or spinal cord clinic) with access to care coordination services.11,12 Planned transition to adult care providers is recommended but remains challenging due to the need for care coordination and adult provider education regarding this category of diagnosis.13
Specific secondary or associated conditions and complications
In patients with spinal dysraphism, certain neurologic conditions can develop such as neurogenic bowel, neurogenic bladder, spasticity, weakness, altered sensation, scoliosis, and pain.1,12 Frequency of these issues is related to the underlying type of dysraphism present. Some specific associated complications for each type of spinal dysraphism are found below:
Lipmyelomeningoclee: Associated anomalies include genitourinary tract anomalies, split cord malformations, associated dermal sinuses, dermoid or epidermoid cysts, diastematomyelia, terminal hydromyelia, anal stenosis, and Down syndrome. 14
Diastematomyelia: There is large variability in associated conditions and anomalies. However, some more common are congenital scoliosis, clubfoot, and lower limb discrepancy. Children with this type of spinal dysraphism have often been found to have different skin manifestations such as hemangiomas, local hypertrichosis or skin dimples. 7Caudal regression syndrome: Typical associated abnormalities can include genital anomalies, gastrointestinal anomalies including anal imperforation, renal dysplasia/aplasia, pulmonary hypoplasia, and lower limb abnormalities.6
Myelocystocele: Often associated with significant abdominal wall and genitourinary abnormalities including the omphalocele, bladder exstrophy, imperforate anus, and spinal anomaly (OEIS) complex8,9
Essentials of Assessment
Spinal dysraphisms are often diagnosed prenatally on ultrasound. Adequate prenatal history regarding maternal health, drug exposure, nutritional history, and prior family/birth history facilitates evaluation of potential risk factors.1,12
As the child ages, it is important to question the family regarding movement patterns, perceived level of sensation, function, and changes over time. Symptoms of neurogenic bowel or bladder should be evaluated.1,12
In patients with spinal dysraphism, exam can be completely normal, as is often seen with spina bifida occulta5, to very involved, such as in patients with caudal regression syndrome or thoracic level lesions.
The most important aspects of the exam are evaluation and documentation of the level of motor and sensory involvement and the degree of functional impairment. This helps with prognosis and serves as a reference if there are concerns about neurologic decline. Range of motion should also be evaluated and monitored closely for any changes.2,12
Clinical functional assessment: mobility, self-care, cognition/behavior/affective state
Utilization of physical and occupational therapy greatly influence the ability to objectively evaluate function in the clinical setting. Review of mobility, self-care, and educational needs such as 504 or Individualized Educational Plans should be a routine part of a visit to assess functioning outside of the clinical setting.12 Cognitive deficits/concerns are of much lower frequency with the spinal dysraphisms discussed in this article, as compared to myelomeningocele; however, all children should be screened for cognitive and speech delay as part of routine visits to assess development.
Routine laboratory evaluation is not done in patients with spinal dysraphism; however, in pregnancy, mothers are generally checked for alpha-fetoprotein levels which are elevated in pregnancies with some open forms of spinal dysraphism, namely spina bifida cystica.1 While no formal protocols exist, many providers will follow vitamin D levels, especially in minimally or non-ambulatory patients, to optimize bone health.
Many times, routine prenatal ultrasound can detect spinal dysraphism before delivery; in some cases, magnetic resonance imaging can help to determine if there is protrusion of neural elements through a spinal opening and shed light on the specific type of spinal dysraphism that is present.
For those with concern for occult lesions that are not diagnosed prenatally, ultrasound is typically utilized as a screening tool, however for those patients for whom there is a high suspicion of spinal dysraphism, MRI is likely more cost effective in the long run.15
All children with spinal dysraphism should be clinically monitored on physical exams for scoliosis and kyphosis. Should deformity be suspected based on clinical exam, it is recommended to obtain anteroposterior and lateral spinal radiographs. In patients who are at risk for hip dysplasia, hip radiographs to evaluate for dysplasia or dislocation should be obtained. 12
Supplemental assessment tools
In patients with neurogenic bladder, a renal ultrasound, voiding cystourethrogram, and urodynamic assessment can help to evaluate the structure and physiology of the urologic system and guide in management.1,12
Early prediction of outcomes
Better functional outcomes are seen in those who meet developmental milestones on time with peers. Patients with spinal bifida occulta typically have a normal exam and normal function; however, patients with caudal regression syndrome frequently have difficulties with ambulation. This occurs due to a combination of underdevelopment of lower extremities, decreased range of motion, and decreased strength.
Evaluation of school and social environment is paramount to allow for socialization and optimization of learning.12 Accessibility can be a factor in patients with caudal regression syndrome, especially if they are primarily wheelchair users for mobility.
Social role and social support system
Urologic issues may significantly impact social interactions. Patients with poor bowel and bladder control tend to have worse self-esteem.1 Parents and caregivers provide the initial support for children with spinal dysraphisms; however, peers impact decision making especially from early adolescence and onward.
The primary aim of each healthcare professional remains to impact children with spinal defects in a manner that allows them to progress through their developmental milestones at an age-appropriate level. Physical, social, cognitive, and psychological outcomes are equally important. Ongoing guidance regarding functional and cognitive outcomes aids in parental decision-making and the pursuit of optimal supports and realistic goals.1,12
Rehabilitation Management and Treatments
Available or current treatment guidelines
Patients with spina bifida occulta typically do not have any rehabilitation needs. Patients with lipomeningocele and diastematomyelia have more variable needs and are individualized to the patient’s functional status and physical exam. While cognitive deficits are not prominent, screening should occur, and neuropsychological testing may benefit cognitive development, if needed.
In caudal regression syndrome, the risk of cognitive deficits is also minimal and rehabilitation providers should seek to facilitate mobility to allow experiential learning. Minimization of contractures is of the utmost importance and allows for improved mobility and positioning. Education about wound prevention should also be started at an early age.
By using equipment, therapies, and bracing, the functional level of patients with spinal dysraphisms can be optimized.12
Various orthopedic interventions for scoliosis and hip dysplasia may be undertaken based on clinical context. Surgical intervention for hip dysplasia is not performed as often as in previous years and typically is limited to those with significant pain or functional limitations thought to be a direct result of the dislocated hip.12
At different disease stages
Children with spina bifida occulta typically meet development milestones on time. Attainment of developmental milestones during childhood for children with lipomeningocele, diastematomyelia, caudal regression,and sacral agenesis is variable and typically is correlated with the neurologic exam. Often, from birth to the first six months of life, these children are on-target or close to on-target with milestones.
From 6 months to 1 year of age, those children with lower extremity and truncal weakness may display delays with sitting, pulling to stand, and ambulating. Degree of contractures, when present, can also result in further limitations.
Should a child with spinal dysraphism attain ambulation, they may choose to use wheelchairs (either for long distances or primary form of mobility) for energy conservation as they age.12
The role of the rehabilitation physician is to facilitate optimization of function across developmental stages. Progression through the natural developmental stages influences treatment and guides therapies, bracing, and other interventions.12
Coordination of care
Team-based approaches with a multidisciplinary clinic involving rehabilitation medicine, orthopedics, neurosurgery, urology, physical therapy, occupational therapy, nutrition, social work, and nursing allow for improvement of care coordination and are recommended when at all possible for those with spinal dysraphisms.11-13
In early adolescence, discussions regarding transitions of care should begin to encourage more independence and ownership by the patient of health-related problems before moving to an adult provider.12,13
Patient & family education
Families who have children with spinal dysraphisms should have education regarding expectations related to motor function, risks of decreased sensation, and possibility of bowel or bladder dysfunction. Families are responsible for this care at early ages, but this responsibility should optimally be transferred, as appropriate, to the patient as they age. Counseling regarding potential for any orthopedic and neurosurgical problems helps educate family about potential warning signs such as skin ulcers, abnormal orthopedic growth, bowel/bladder changes, or neurologic complications such as tethered cord.12
Measurement of Treatment Outcomes including those that are impairment-based, activity participation-based and environmentally-based
Although there is no commonly used treatment outcome measure for the spinal dysraphisms listed in this article, the primary goal is to approximate age-appropriate development across affected domains of function. Because some children with spinal dysraphisms never present during the childhood period, treatments are not always necessary. In patients with caudal regression, lipomeningocele, or diastematomyelia, continued maximization of mobility into adulthood, social integration, and cognitive development are the main targeted outcomes.13
Translation into Practice: practice “pearls”/performance improvement in practice (PIPs)/changes in clinical practice behaviors and skills
Cutting Edge/ Emerging and Unique Concepts and Practice
Timing of surgical intervention for many of the other spinal dysraphisms has been controversial. Typical teaching was to operate when symptomatic for tethered cord or neuromotor changes,16 however many studies have reported minimal functional improvement with later surgical intervention. Thus, many surgeons are currently recommending early surgical/prophylactic intervention in attempt to minimize long term complications.7,17A hot topic for research in spina bifida relates to genetic etiology. A multitude of studies for various types of spinal dysraphism have attempted to find associations between genetic mutations and spinal dysraphisms. The associations are assumed to be multifactorial and complex and are beyond the scope of discussion for this article.3
With routine maternal ultrasound imaging, open neural tube defects are often diagnosed prenatally. Traditionally, closed neural tube defects are more difficult to diagnose prior to birth. Current research is focused on utilizing 3D ultrasound to more accurately characterize lesions prenatally.18,19
In regards to spina bifida occulta, there is controversy whether children/adults found to have spina bifida occulta should undergo full neuroaxis imaging. In one cohort of patients with symptomatic spina bifida occulta, a large percentage were found to have additional spine abnormalities with only a few having additional cranial findings. 20
Gaps in the Evidence- Based Knowledge
Evidenced-based, prediction of ambulation potential for the other spinal dysraphisms is limited. In addition, little is known about progression towards non-ambulation as these individuals age. Both of these would be of benefit when counseling families on prognosis.
Currently there is no consensus on optimization/management of bone health for those with spinal dysraphism, and clinical practice regarding calcium/vitamin D supplementation, bone densiometry screening, and use of bisphosphonates in the setting of fragility fractures is variable.
- Phillips LA, Burton JM, Evans SH. Spina bifida management. Current Problems in Pediatric and Adolescent Health Care 2017;47(7):173-177.
- Alexander MA, Matthews DJ, Murphy KP. Pediatric rehabilitation: principles and practice: Demos Medical Publishing, 2015.
- Au KS, Ashley‐Koch A, Northrup H. Epidemiologic and genetic aspects of spina bifida and other neural tube defects. Developmental disabilities research reviews 2010;16(1):6-15.
- Williams J, Mai CT, Mulinare J, et al. Updated estimates of neural tube defects prevented by mandatory folic acid fortification—United States, 1995–2011. MMWR Morbidity and mortality weekly report 2015;64(1):1.
- Tamas-Csaba S, Lorand D, Klara B, Sebastian SR, Gergo R, Zsuzsanna P. Study of Spina Bifida Occulta Based on Age, Sex and Localization. ARS Medica Tomitana 2019;25(3):95-99.
- Balani A, Chatur C, Biswas A, Oztekin O, Mankad K. Spinal dysraphisms: highlighting discrepancies in the current literature and emphasizing on the need for a consensus. Quantitative Imaging in Medicine and Surgery 2020;10(3):549.
- Vissarionov SV, Krutelev NA, Snischuk VP, et al. Diagnosis and treatment of diastematomyelia in children: a perspective cohort study. Spinal Cord Series and Cases 2018;4(1):1-6.
- Kumar R, Chandra A. Terminal myelocystocele. The Indian Journal of Pediatrics 2002;69(12):1083-1086.
- Pang D, Zovickian J, Lee JY, Moes GS, Wang K-C. Terminal myelocystocele: surgical observations and theory of embryogenesis. Neurosurgery 2012;70(6):1383-1405.
- Wilmshurst JM, Kelly R, Borzyskowski M. Presentation and outcome of sacral agenesis: 20 years’ experience. Developmental medicine and child neurology 1999;41(12):806-812.
- Liptak GS, El Samra A. Optimizing health care for children with spina bifida. Developmental disabilities research reviews 2010;16(1):66-75.
- Association SB. Guidelines for the care of people with spina bifida. 2018. Available from: https.
- Dicianno BE, Kurowski BG, Yang JMJ, et al. Rehabilitation and medical management of the adult with spina bifida. American journal of physical medicine & rehabilitation 2008;87(12):1027-1050.
- Hoffman HJ, Taecholarn C, Hendrick EB, Humphreys RP. Management of lipomyelomeningoceles: experience at the Hospital for Sick Children, Toronto. Journal of neurosurgery 1985;62(1):1-8.
- Medina LS, Crone K, Kuntz KM. Newborns with suspected occult spinal dysraphism: a cost-effectiveness analysis of diagnostic strategies. Pediatrics 2001;108(6):e101-e101.
- Huang S-L, He X-J, Wang K-Z, Lan B-S. Diastematomyelia: a 35-year experience. Spine 2013;38(6):E344-E349.
- Patil PS, Gupta A, Kothari PL, et al. Immediate and long-term outcome analysis of lipomeningomyelocele repair in asymptomatic infants in a tertiary care center. Journal of Pediatric Neurosciences 2016;11(2):99.
- Milani HJF, Barreto EQdS, Chau LH, et al. Prenatal diagnosis of closed spina bifida: multicenter case series and review of the literature. The Journal of Maternal-Fetal & Neonatal Medicine 2020;33(5):736-742.
- Micu R, Chicea AL, Bratu DG, Nita P, Nemeti G, Chicea R. Ultrasound and magnetic resonance imaging in the prenatal diagnosis of open spina bifida. Medical ultrasonography 2018;20(2):221-227.
- Börcek AÖ, Aslan A, Uçar M. Do we need to scan the whole neuraxis for coexistent abnormalities in children with surgically treated occult spinal dysraphism? ANZ journal of surgery 2019;89(7-8):914-918.
Original Version of the Topic
Matthew McLaughlin, MD. Other Spinal Dysraphism. 9/22/2015
Ashlee Bolger, MD, MEd
Nothing to Disclose
Caitlin Chicoine, MD
Nothing to Disclose
Matthew McLaughlin, MD, MS
National Institute of Health (NICHD), Grant, Principal Investigator
Mary McMahon, MD
Nothing to Disclose