**2. Types of spina bifida**

Spina bifida or spinal dysraphism is a wide spectrum of clinical and imaging findings concerning incomplete fusion of the midline neural and bony structures during early embryogenesis. Spina bifida can be devided into closed and open forms (**Table 1**).

**Closed spinal dysraphism** (spina bifida occulta or ocult spinal dysraphism) is the most common type. This group of dysraphisms refers to broad spectrum of skin-covered congenital defects caused by non-union or failure to fuse of the neural tube. Clinical manifestation can range from asymptomatic simple non-union of vertebral arch taht is usually diagnosed as an incidental finding on imaging and causes no symptoms to more severe forms with progressive neurological deterioration. Closed spinal dysraphism can bez present with or without subcutaneous mass.

To closed spina bifida without subcutaneous mass belong: tethered spinal cord, dermal sinus, diastematomyelia and spinal lipoma. Closed spinal dysraphism with subcutaneous mass are: lipomyelomeningocele, lipomyelocele, terminal myelocystocele, meningocele, non-terminal myelocystocele.

**Tethered spinal cord** characterized by abnormal attachment of spinal cord to surrounding structures causes traction of spinal cord during growth and its ischaemisation leading to progressive motor deficit, urological and ortopedical complications [2].

**Dermal sinus** is a median or paramedian epithelial duct causing persistent communication connecting spinal cord with skin. It is a consequence of incomplete separation of the ectoderm from the neural crest. It is usually visible during aspection as a small pit in lumbosacral area often connected with hpertrichosis or hyperpigmentation. The duct can terminate in the soft tissue overlying spinal canal, in epidural space and, in most of the cases, directly on conus medullaris, cauda equina or fillum terminale. Newborn can display neurological deficit or can


**29**

*Management of Pediatric Patients with Spina Bifida DOI: http://dx.doi.org/10.5772/intechopen.97237*

arachnoid space [3].

and double dural sac into two types:

atic. Type II has both hemicords in a single dural sac [3].

during life because adipocytes can increase in size easily.

Spinal lipoma can be present in 3 forms:

spinal cord with subsequent symptoms [5].

terminates in a cyst [3].

**3. Epidemiology**

extending caudally in asymmetrical position [3].

develop neuroinfection. Because of direct communication between skin surface and spinal canal germ can easily spread and cause meningitis or intraspinal abscess. Ultrasonography is a useful accessible first-line imaging that can show the length of the sinus. Subsequently, MR imaging is necessary. In differential diagnosis is necessary to diffentiate from sacro-coccygeal sinus that is located lower in sacral or coccygeal region and usually terminates in fascia and does not extend into sub-

**Diastematomyelia** is also known as split cord malformation and it is a longitudinal split. It is mostly located between L1 and L3, less frequently between Th7 and Th12. This defect is devided according to a presence of dividing septum and single

Type I has common midline septum or spur, double dural sac and is symptom-

**Filum terminale fibrolipoma** – filum terminale above 2 mm thick, hyperechoic

**Lipomyelomeningocele** and **lipomyelocele** belong to closed spinal dysraphisms that present as fat-containing subcutaneous mass beginning above gluteal cleft and

**Myelocystocele** is a closed spinal dysraphism with dilatation of central canal of spinal cord that protrudes dorsally into the subcutaneous tissue. Spinal cord

**Meningocele** is protrusion of meninges through a defect in vertebral column. There is a visible sac fiiled with fluid on the back but without involvement of spinal

**Open spinal dysraphisms** are developmental anomalies that are not covered by skin and are caused by unclosure of the neural tube during primary neurulation. They are mostly diagnosed during antenatal screening by ultrasonography and are also visible during newborn physical examination. To open spinal dysraphisms belong: myelocele, myelomeningocele, hemimyelomeningocele and hemimyelocele. **Myelomeningocele** is the most common and most severe type of spina bifida occuring mostly in middle or lower back (but also more cranially) forming a sac on infant's back that contains open dural layer and improperly formed spinal cord or nerve radixes. Nerve structures are extruded into the fluid-filled sac – this is called

Incidence of spina bifida varies worldwide between 1 to 10 per 1000 births [6] and between 0,17 to 6,4 per 1000 live births for myelomeningocele [7] but has differences in geogrefical regions with higher rates in less developed countries. In Europe it is around 4500 pregnancies a year that are affected by neural tube defect. Over 90% of more serious spina bifida cases is diagnosed before 22nd gestational

**Intradural lipoma** – usually lying along midline with completely formed and propriately closed dural sac. In lumbosacral region causes often tethered cord syndrome and in cervical and thoracic regions lipoma usually causes compresion of

on ultrasonography, often connected with tethered cord syndrome [3].

cord. There is usually minimal or none neurological impairment.

spina bifida cystica. Vertebral arches are dorsaly incomplete.

**Spinal lipoma** is caused by premature separation of the ectoderm from the neural crest causing mesenchymal cells to get stick within the spinal canal. Lipoma can be extradural or intradural or their combination. Lipoma is made of adipous tissue but also contain menigeal and neural cells [4]. These lesions can expand later

#### **Table 1.** *Types of spinal dysraphisms [3].*

*Management of Pediatric Patients with Spina Bifida DOI: http://dx.doi.org/10.5772/intechopen.97237*

*Spina Bifida and Craniosynostosis - New Perspectives and Clinical Applications*

tocele, meningocele, non-terminal myelocystocele.

Spina bifida or spinal dysraphism is a wide spectrum of clinical and imaging findings concerning incomplete fusion of the midline neural and bony structures during early embryogenesis. Spina bifida can be devided into closed and open forms

**Closed spinal dysraphism** (spina bifida occulta or ocult spinal dysraphism) is the most common type. This group of dysraphisms refers to broad spectrum of skin-covered congenital defects caused by non-union or failure to fuse of the neural tube. Clinical manifestation can range from asymptomatic simple non-union of vertebral arch taht is usually diagnosed as an incidental finding on imaging and causes no symptoms to more severe forms with progressive neurological deterioration. Closed spinal dysraphism can bez present with or without subcutaneous mass. To closed spina bifida without subcutaneous mass belong: tethered spinal cord, dermal sinus, diastematomyelia and spinal lipoma. Closed spinal dysraphism with subcutaneous mass are: lipomyelomeningocele, lipomyelocele, terminal myelocys-

**Tethered spinal cord** characterized by abnormal attachment of spinal cord to surrounding structures causes traction of spinal cord during growth and its ischaemisation leading to progressive motor deficit, urological and ortopedical

**Dermal sinus** is a median or paramedian epithelial duct causing persistent communication connecting spinal cord with skin. It is a consequence of incomplete separation of the ectoderm from the neural crest. It is usually visible during aspection as a small pit in lumbosacral area often connected with hpertrichosis or hyperpigmentation. The duct can terminate in the soft tissue overlying spinal canal, in epidural space and, in most of the cases, directly on conus medullaris, cauda equina or fillum terminale. Newborn can display neurological deficit or can

**2. Types of spina bifida**

(**Table 1**).

complications [2].

Dermal sinus Diastematomyelia Spinal lipoma

Lipomyelocele

Meningocele

Myelocele

Myelomeningocele

Hemimyelomeningicele Hemimyelocele

*Types of spinal dysraphisms [3].*

**Closed spinal dysraphism (CSD) CSD with subcutaneous mass** Tethered cord syndrome

**CSD without subcutaneous mass**

Lipomyelomeningocele

Terminal myelocystocele

Nonterminal myelocystocele **Open spinal dysraphism (OSD)**

**28**

**Table 1.**

develop neuroinfection. Because of direct communication between skin surface and spinal canal germ can easily spread and cause meningitis or intraspinal abscess. Ultrasonography is a useful accessible first-line imaging that can show the length of the sinus. Subsequently, MR imaging is necessary. In differential diagnosis is necessary to diffentiate from sacro-coccygeal sinus that is located lower in sacral or coccygeal region and usually terminates in fascia and does not extend into subarachnoid space [3].

**Diastematomyelia** is also known as split cord malformation and it is a longitudinal split. It is mostly located between L1 and L3, less frequently between Th7 and Th12. This defect is devided according to a presence of dividing septum and single and double dural sac into two types:

Type I has common midline septum or spur, double dural sac and is symptomatic. Type II has both hemicords in a single dural sac [3].

**Spinal lipoma** is caused by premature separation of the ectoderm from the neural crest causing mesenchymal cells to get stick within the spinal canal. Lipoma can be extradural or intradural or their combination. Lipoma is made of adipous tissue but also contain menigeal and neural cells [4]. These lesions can expand later during life because adipocytes can increase in size easily.

Spinal lipoma can be present in 3 forms:

**Filum terminale fibrolipoma** – filum terminale above 2 mm thick, hyperechoic on ultrasonography, often connected with tethered cord syndrome [3].

**Intradural lipoma** – usually lying along midline with completely formed and propriately closed dural sac. In lumbosacral region causes often tethered cord syndrome and in cervical and thoracic regions lipoma usually causes compresion of spinal cord with subsequent symptoms [5].

**Lipomyelomeningocele** and **lipomyelocele** belong to closed spinal dysraphisms that present as fat-containing subcutaneous mass beginning above gluteal cleft and extending caudally in asymmetrical position [3].

**Myelocystocele** is a closed spinal dysraphism with dilatation of central canal of spinal cord that protrudes dorsally into the subcutaneous tissue. Spinal cord terminates in a cyst [3].

**Meningocele** is protrusion of meninges through a defect in vertebral column. There is a visible sac fiiled with fluid on the back but without involvement of spinal cord. There is usually minimal or none neurological impairment.

**Open spinal dysraphisms** are developmental anomalies that are not covered by skin and are caused by unclosure of the neural tube during primary neurulation. They are mostly diagnosed during antenatal screening by ultrasonography and are also visible during newborn physical examination. To open spinal dysraphisms belong: myelocele, myelomeningocele, hemimyelomeningocele and hemimyelocele.

**Myelomeningocele** is the most common and most severe type of spina bifida occuring mostly in middle or lower back (but also more cranially) forming a sac on infant's back that contains open dural layer and improperly formed spinal cord or nerve radixes. Nerve structures are extruded into the fluid-filled sac – this is called spina bifida cystica. Vertebral arches are dorsaly incomplete.

### **3. Epidemiology**

Incidence of spina bifida varies worldwide between 1 to 10 per 1000 births [6] and between 0,17 to 6,4 per 1000 live births for myelomeningocele [7] but has differences in geogrefical regions with higher rates in less developed countries. In Europe it is around 4500 pregnancies a year that are affected by neural tube defect. Over 90% of more serious spina bifida cases is diagnosed before 22nd gestational

week [8]. Overall prevalence of spina bifida is lower in countries with mandatory folic acid fortification of grain products opposite to countries with voluntary or no fortification [9, 10]. More affected are females and whites and Hispanics.
