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Managing spina bifida in primary care

08 Apr 2021

Dr Jeremy Lin, a consultant at the Division of Paediatric Neurology, Khoo Teck Puat – National University Children’s Medical Institute, National University Hospital, Singapore, provides Roshini Claire Anthony with an in-depth look on spina bifida and explains the crucial role played by the primary care physician in managing this condition. 

 

Introduction

Spina bifida is an array of congenital malformations in which the spinal column (vertebral column) is split (bifid), often with spinal cord involvement, as a result of failed closure or formation of the embryonic neural tube. It is the most common and complex central nervous system malformation in humans.

The estimated global incidence of spina bifida is 0.5 per 1,000 live births, varying substantially across populations, in patterns that follow nutritional, geographic, and ethnic factors. In the UK, the population prevalence of spina bifida is 7.8–8.4 per 10,000 males and 9.0–9.4 per 10,000 females.

Studies in Asia, such as one done in Malaysia, have shown a lower occurrence of spina bifida than that of the UK but differences may be related to variations in ascertainment methods. The exact incidence of spina bifida in Singapore is unknown as there are no available registries.

 

Types of spina bifida

There are two main forms or classifications of spina bifida. The first is spina bifida aperta (SBA) or open spina bifida (skin defect with exposed neural tissue). The classic example is myelomeningocele, where spinal cord elements protrude out from the posterior vertebral defect into a meningeal sac. Myelomeningoceles constitute >98 percent of open spina bifida cases. The second type is spina bifida occulta (SBO) or closed spina bifida (intact skin). This group consists of a large spectrum of pathological variants including isolated missing vertebral arches, meningocele (meninges protrusion but covered by skin), lipomeningocele/lipomyelomeningocele (abnormal fat collection), and dermal sinus tract. The main clinical concern in SBO is the involvement of the spinal cord, nerves, and the development of tethered cord syndrome (TCS).

Both forms of spina bifida demand different approaches in their acute management after birth but have similar principles in the initial evaluation, investigations, and need for long-term multidisciplinary management and follow-up.

 

Risk factors

Spina bifida has multiple causes (genes and environment). The genetic component is the cause in about 60–70 percent of cases. Observational studies have shown a threefold incidence of spina bifida in consanguineous marriages, as well as a higher incidence in monozygotic twins. Established environmental factors include maternal reduced folate intake, anticonvulsant therapy (eg, anti-epileptic drugs sodium valproate and carbamazepine), diabetes mellitus, and obesity.

Folic acid deficiency (and elevated homocysteine) is undoubtedly the best-known risk factor for spina bifida with a definite benefit demonstrated with periconception maternal supplementation (0.4 mg/day from 3 months preconception until the end of the first trimester). The decision to fortify staple foods with folic acid in many countries and the subsequent reduction in the incidence of spina bifida is often heralded as a modern public health success.

Individuals who have one child with spina bifida will have a three- to fivefold increased risk for a second affected child and these mothers should take 10 times the usual dose of folate to reduce this risk (4 mg/day from 3 months preconception until the end of the first trimester).

 

Preventing spina bifida

Maternal periconceptional folic acid supplementation with the doses mentioned above is one of the main open spina bifida prevention strategies. Women with pre-existing diabetes must have their condition well-controlled prior to conception. They should also avoid other risk factors including obesity and teratogenic drugs such as sodium valproate and carbamazepine while pregnant. Pregnant women should receive routine antenatal foetal anomaly ultrasound so that severe conditions can be diagnosed early and the decision whether to continue the pregnancy can be made.

 

Diagnosing spina bifida

SBA is often easily diagnosed due to antenatal diagnosis with routine second trimester anomaly ultrasound scanning, which has high sensitivity and specificity. The ultrasound can examine the foetal spine from late in the first trimester onwards and is the principal and most accurate mode of prenatal diagnosis. Foetal MRI is now increasingly employed to provide further details of the foetal central nervous system but is still technically difficult and used only in tertiary centres. Clinical diagnosis at birth is often straightforward with the presence of midline anomaly in the thoracolumbar or lumbosacral region, where the contents can be delineated by further imaging. MRI of the whole spine and brain is usually the preferred modality.

In contrast, SBO is less commonly diagnosed antenatally. The condition varies widely and ranges from asymptomatic to severe. The age of presentation usually ranges from postnatal to 14 years (mean age of 2 years). Younger children usually present with cutaneous signs while older children present with back and lower limb pain and neurological symptoms. Cutaneous signs usually involve a sacral lesion typically that of a dimple. Features of the dimple that increase the likelihood of an underlying SBO include:

·       Association with other cutaneous markers: Hypertrichosis, capillary hemangioma, subcutaneous mass (eg, lipoma), caudal appendage, etc.

·       Abnormal neurological or orthopaedic findings of lower limbs

·       >1 dimple

·       Dimple diameter >5 mm

·       Location >2.5 cm above anal verge

·       Dimple outside the sacrococcygeal region

Neurological complaints of an underlying closed spina bifida may vary depending on the underlying spinal cord/nerve involvement but usually include neurogenic bladder, bowel, lower limb muscular, and sensory symptoms as well as TCS. TCS occurs when there is attachment of the filum terminale to inelastic structures caudally, resulting in a progressive stretched-induced dysfunction of caudal spinal cord/conus from repeated spine flexion/extension and differential growth of vertebral column. As such there would be progressive motor and sensory dysfunction including:

·       Bladder dysfunction (most common)

·       Gait and motor abnormalities (distal weakness), sensory abnormalities (loss, paraesthesia)

·       Pain in the lumbosacral region, perineum, legs

The most definitive diagnostic tool for SBO is spinal imaging such as ultrasound which can only be utilized in infants up to 6 months of age (due to progressive vertebrae ossification and loss of the sonographic window) and MRI of the spine.

Routine second trimester foetal anomaly ultrasound scanning routinely looks for open spina bifida and has high sensitivity and specificity in diagnosing the condition antenatally. Doctors and nurses also routinely look for sacral lesions such as a sacral dimple during newborn checks after birth.

 

Diagnostic challenges

The diagnosis of SBO remains a challenge in asymptomatic patients. Depending on the underlying spinal cord involvement, patients with SBO are at risk of neurological impairment and future TCS especially as the child undergoes a growth spurt, typically at puberty, where there is further tethering of the spinal cord. In TCS, there is a risk of permanent neurological dysfunction (4.5–10 percent) despite emergent surgical correction.

We need to educate medical providers on screening and picking up sacral lesions (sacral dimples as described above) and referring patients for further assessment. Early assessment in infancy (<6 months) is helpful due to the window of opportunity for a simple, low risk, and inexpensive ultrasound assessment, after which MRI of the spine would be the only option.  

 

Treating spina bifida

SBA is a complex condition with immediate and long-term multisystem issues depending on the level of spinal cord involvement. In general, lower limb, bladder, bowel, and brain functions are primarily affected. The higher the spinal lesion, the more severe the deficits. SBA is also often accompanied by the development of later complications including hydrocephalus, musculoskeletal deformities, infections (soft tissue, bone, and urinary tract), latex allergy, sexual dysfunction, and psychological and social issues. 

SBA is an emergency after birth and should be managed in a tertiary hospital where MRI of the brain and spine and paediatric neurosurgical expertise are available. Neonatal surgical closure of the lesion is considered the standard of care. It is traditionally done within 48 hours of birth to reduce risk of ascending infections and further mechanical damage. The child may also need a ventriculo-peritoneal shunt in the same setting if there is concomitant Arnold-Chiari Type II Malformation (hindbrain herniation with obstructive hydrocephalus which occurs in up to 30 percent of patients).

Earlier intervention involving foetal surgery is now advocated and only in available selected overseas centres with promising results. The main goal for prenatal repair of SBA is to achieve skin closure to prevent further damage of the neural tissue and arrest cerebrospinal fluid leak.

Orthopaedic deformities are treated shortly after birth and require long-term follow-up. Urological complications, including neurogenic bladder, often need further management that includes a combination of clean intermittent catherization, drugs, and surgery. Bowel function often only needs to be managed later in older children with suppositories, laxatives, or antegrade colonic or traditional enemas.

Early and lifelong rehabilitation with a child neurologist or paediatrician and allied health professionals (specialist nurses, physiotherapists, occupational therapists, orthotists, and psychologists) is important to optimize the physical and emotional development and well-being of the child.

Multidisciplinary team management coordinated by a primary care physician/nurse is important to address various issues at different stages in life.

Not all SBO conditions require treatment. For example, isolated defective posterior vertebral arches with normal spinal cord do not need treatment.

Treatment in SBO is considered when there is tethered cord and risks of neurological impairments. Acute TCS should be emergently operated on to release the tethered cord. Unfortunately, there is a risk of permanent neurological dysfunction with TCS (4.5–10 percent) despite emergent surgical correction.

Chronically symptomatic patients with closed spina bifida should also undergo neurosurgical correction (usually spinal cord detethering and excision of intra-spinal lesions).

Prophylactic detethering of tethered cords in patients with spina bifida who are asymptomatic remains controversial as not all patients may eventually develop symptoms or TCS. However, it is widely believed that the risks of the surgery in modern settings outweigh that of the risk of permanent neurological dysfunction with TCS.

 

How successful is treatment?

SBA: Surgical repair is often effective to prevent further neurological damage and complications such as hydrocephalus. However, there is often residual permanent neurological deficits. This is because of the 2-hit hypothesis much described in the literature. Firstly, the neural tube did not form normally. Secondly, the exposed tissue has been subjected to physical and chemical perturbation in-utero. Management of the residual neurological deficits is essentially symptomatic and aimed at preventing complications, and maximizing the patient’s function and quality of life (QoL).

SBO: Emergent detethering of TCS carries the risk of permanent neurological dysfunction. Prophylactic detethering is often deemed as effective as emergent detethering although there are no definite means to measure this as not all patients will eventually develop TCS. The surgery also carries the risk of cord re-tethering with post-surgical fibrosis. 

 

Treatment challenges

SBA: Management is symptomatic and not curative. SBA is a lifelong condition that affects multiple systems including the urological, musculoskeletal, and central nervous system, as well as bowels, at different stages of life. In addition, individuals with spina bifida are often cognitively intact and as a result, face emotional and psychological difficulties dealing with the many medical and physical challenges. A coordinated, lifelong multidisciplinary approach with healthcare professionals with the necessary expertise is critical to maximize the patient’s health, function, and QoL. This journey requires high patient and family commitment, and financial and healthcare resources.

SBO: Closed spina bifida remains a diagnostic challenge with scarce evidence and guidelines on the management of these conditions. More research is needed to provide evidence-based management practices of closed spina bifida and TCS.

 

Long-term complications

The long-term complications of open spina bifida are as follows:

·       Neurological weakness and sensory disturbances of lower limbs and trunk, depending on the level of the spinal lesion

·       Mobility issues

·       Obstructive hydrocephalus from Chiari Type II malformation and development of syrinx or syringomyelia (fluid in the spinal cord with resultant neurological deficits)

·       Musculoskeletal deformities of lower limbs and spine including non-healing ulcers or pressure sores

·       Neurogenic bladder with resultant hydronephrosis and renal injury

·       Bowel issues including constipation and incontinence

·       Chronic infections from ulcers and sores with soft tissue/bone involvement (osteomyelitis)

·       Precocious puberty (due to hydrocephalus)

·       Obesity and metabolic syndrome (tendency for increased fat mass after age 4 years)

·       Sleep-related breathing disorders including obstructive sleep apnoea (due to high spinal cord lesions, Chiari malformations, obesity)

·       Sexual dysfunction

·       Emotional and psychological issues including bullying, adjustment disorders, depression, etc

·       Latex allergy (very common due to early and repeated exposure to latex)

Unfortunately, many of these conditions currently need specialist/specialist nurses or allied health inputs and management. However, we often see patients with spina bifida who do not receive the necessary multidisciplinary specialist care due to various reasons. Thus, the general practitioner (GP) plays a very important role as the primary physician with a good overview of the potential complications and helps manage the issues when appropriate.

 

The role of the GP

GP interventions start from prevention in terms of periconceptional care (eg, folate supplementation and diabetes control) to reduce the risk of spina bifida. The GP can also help diagnose cases of SBO through detection of sacral lesions or in patients presenting with lower limb and/or bladder/bowel symptoms. In the event of antenatal diagnosis of spina bifida, the GP’s role may begin before birth as families that have a pre-existing relationship with the GP may turn to him/her for guidance and information.

After birth, the GP will be the primary care provider to the child, attending to acute illnesses and routine development, and the care continues through to adult healthcare. The GP usually has first contact with the family, whether for routine or acute care. The care of the individual with spina bifida requires the GP to be able to recognize and treat issues unrelated to spina bifida (eg, gastrointestinal or respiratory tract infections) and also identify and rapidly refer patients for conditions such as headaches or new-onset weakness that might indicate serious problems (eg, ventricular shunt malfunction). This ability requires knowledge about spina bifida and optimal communication.

The GP is fully capable of taking on the critical role of the primary physician, helping to coordinate multidisciplinary care for the patient. Acute or routine visits are opportunities for the GP to assess the potential issues that may affect the patient with spina bifida. The GP can help coordinate and refer the patient to the appropriate specialty and resource as needed.

The GP remains an important source of advice and support to the patient and family. The psychosocial and emotional consequences of spina bifida on the patient, siblings, and family should be part of the overall care of the child with spina bifida. A family-centred approach to care and anticipation of potential problems will help identify and address stressors early.

Lastly, the GP can provide lifelong care to the patient from childhood through to adulthood. This is unlike specialist care which begins with paediatric specialists or allied health professionals and transitions to adult specialists. GPs are important in the lifelong continuum of care to these chronic patients. 

 

Summary of typical primary care interventions by GPs for patients with spina bifida

Foetuses (prenatal)

Pre-conceptional advice and folate supplementation (0.4 mg/day for low risk and 4 mg/day for high risk) to reduce the risks of spina bifida

Counsel families in planning and decision-making, provide information on spina bifida

Options and assistance with family choices

Discuss post-natal planning and treatment

Family support

Newborns

Newborn screening/diagnosis of sacral lesions and dimples (SBO) with appropriate referrals

Advice for avoidance of latex to prevent allergy

Complete avoidance of latex (gloves, adhesive bandages, etc) in those with proven allergy

Family support

Referral to multidisciplinary spina bifida teams as necessary

Primary follow-up

Infants

Provide early and frequent follow-up

Monitor hydrocephalus (head size and neurological examination)

Provide routine and diagnostic-specific primary care

Educate and support family and siblings

Discuss recurrence risk and prevention

Refer to early-intervention programmes

Communicate and coordinate with the spina bifida team

Toddlers

Preventive and well-child care

Developmental monitoring

Mobility

Growth and weight management

Preschool-aged children

Transition from early-intervention programme to preschool programme

Ambulation and mobility

Bowel and bladder programme

Social inclusion

School-aged children

Identify and characterize learning abilities

Ensure appropriate school-based services

Monitor secondary conditions including latex allergy

Encourage physical activity, friends, and household responsibilities

Plan for educational transition

Encourage independent self-care and toileting

Preteens

Advocate for physical activity, recreation, and community inclusion

Monitor progress in school

Address bullying and safety

Monitor growth and puberty

Encourage independence and self-advocacy

Develop and maintain friendships

Teens

Continue transition and transfer process to adult care, activities, and social participation

Educate on spina bifida and self-care

Provide anticipatory guidance regarding sexuality and reproduction

Encourage independence in healthcare decision-making

Monitor growth and vital signs (blood pressure)

Encourage physical activity

Manage weight and nutrition

Encourage cardiopulmonary health and fitness

Young adults

Provide resources for specialty care: Neurosurgery, orthopaedics, urology, etc

Monitor weight and physical fitness

Monitor education and employment

Help build and maintain friendships and social support groups

Monitor for deterioration and late-onset complications

 

Adapted from Providing A Primary Care Medical Home for Children and Youth with Spina Bifida. [Pediatrics 2011;128:e1645-e1657]

 

The role of the caregiver

Caregivers must be educated on spina bifida and have a good overview of the issues that may affect their child at different stages of their life to act as their advocates in the absence of coordinated multidisciplinary care. They need the commitment to ensure their child receives lifelong multidisciplinary care. Early physical, cognitive, and emotional interventions are essential to prevent future complications and to help develop a child who is functional and emotionally resilient.

Caregivers must also learn to take care of themselves in this chronic care journey and seek emotional support as necessary – such as with support groups – to reduce caregiver stress and burnout. 

 

Practice guidelines and management tools

BMJ Best Practice. Spina bifida and neural tube defects.  

https://bestpractice.bmj.com/topics/en-gb/1161

Spina Bifida Association. Guidelines for the Care of People with Spina Bifida. 4th Edition.

https://www.spinabifidaassociation.org/resource/guidelines/

Centers for Disease Control and Prevention. Clinical Care Guidance for Spina Bifida.

https://www.cdc.gov/ncbddd/spinabifida/clinical-care-guidance.html

Providing A Primary Care Medical Home for Children and Youth with Spina Bifida. [Pediatrics 2011;128:e1645-e1657]

 

Conclusion

Spina bifida is the most common complex congenital birth defect associated with long-term survival and morbidity. GPs play an important role in the prevention of spina bifida by providing appropriate periconception maternal care, including control of diabetes during pregnancy. Patients with SBO face multiple medical and psychosocial issues. Knowledge of these issues will allow GPs to be effective primary care providers to patients and their families in terms of their acute medical issues and underlying spina bifida condition. A patient- and family-centred approach to coordinated and multidisciplinary care and anticipation of potential problems is important. The main care goal should be to maximize the overall health, functioning, and QoL of individuals with spina bifida throughout their lives.

Dr Jeremy Lin

Dr Jeremy Lin
 

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