Development of the vertebrae begins at 4–6 weeks of gestation. This is when the mesenchymal mold is formed which is the model for the framework for the secondary cartilaginous and osseous development of the vertebrae (Dewald et al. 2003). Subsequent chondrification and ossification follow this mold. The neural axis is developing at the same time, which explains why children with vertebral anomalies may potentially have neural anomalies as well. The embryologic insult resulting in the vertebral anomaly is unknown, and there has been no clear-cut genetic etiology of congenital scoliosis to date. In animal models, it has been demonstrated that deformities have been linked with maternal hypoxia at the critical time of gestation (Devlin 2012). There have also been associations with maternal diabetes, ingestion of antiepileptic drugs during pregnancy, and maternal exposure to toxins (Hedequist and Emans 2007).

Congenital vertebral anomalies are rare. The prevalence rate of congenital scoliosis is approximately 1 in 1,000 live births (Hedequist and Emans 2007). Isolated anomalies (hemivertebra) are sporadic with no familial or genetic tendencies. However, there is a 5–10% risk of similar lesions in siblings or subsequent generations, as well as an increased risk of neural tube defects when there are complex anomalies in multiple locations (Dewald et al. 2003).

Organ systems that are developing during the same gestational period as the spine may also be at risk for developing malformations. There are some common malformations that are associated with congenital spinal anomalies, including intraspinal abnormalities. Neural axis abnormalities, such as tethered cord, spinal stenosis, diastematomyelia (split cord), diplomyelia (complete or incomplete doubling of the spinal cord), and syringomyelia (fluid-filled space within the spinal cord), are present in up to 38% of patients with congenital vertebral anomalies. Clinical findings of posterior midline skin lesions like hairy patches or dimples, foot deformity (especially unilateral), muscle weakness, or spasticity may be a red flag as to an underlying intraspinal anomaly. Other anomalies associated with vertebral abnormalities are vertebral anomalies at another level, urinary tract structural abnormalities, cranial nerve palsy, upper extremity hypoplasia, clubfoot, dislocated hip, and congenital cardiac disease. Specifically, the vertebral malformation most often associated with an abnormality of the neural axis is a unilateral unsegmented bar and a same-level contralateral hemivertebra. It has been estimated that approximately 50% of this population have an associated neural axis abnormality (Devlin 2012). These may often be occult anomalies such as a tethered cord, intradural lipoma, syringomyelia, or diastematomyelia, which is the most common (Dewald et al. 2003). The clinical signs and radiographic findings of these spinal cord anomalies are discussed in the physical assessment and imaging sections of this chapter.

As high as 35% of children with a congenital spine deformity may also have a congenital anomaly of the neural axis or a spinal dysraphism. Some of the forms of spinal dysraphism include spina bifida (spina bifida occulta, meningocele, and myelomeningocele), diastematomyelia, and tethered cord (Hedequist and Emans 2007). The symptoms of spinal dysraphisms are difficult to generalize as they are quite varied depending on the type and severity of the malformation. A thorough past medical history with focus on the physical exam should be obtained, keeping in mind the correlation of the congenital spine deformity and other congenital anomalies. Detailed questions should be directed as to the child’s neurologic status. Age-appropriate questions related to development history, toilet training, bed wetting, changes in bowel or bladder habits, and complaints of lower extremity pain, numbness, or weakness are all of great importance in the evaluation of the child’s neurologic status. A complete evaluation of the patient should include a comprehensive exam of the patient as well as a close evaluation of the spine itself with a thorough neurologic exam.

General patient evaluation should occur throughout the encounter with the child. A full exam should include sitting and standing heights or supine measurements for infants and head circumference. Take note of any alterations in head shape, along with size, shape, and symmetry of the ears and eyes. Assessment of the neck and cervical spine should be noted for range of motion. There are some syndromes, such as Klippel-Feil syndrome, which have congenital cervical fusions thus limiting cervical range of motion. The spine exam itself should focus on trunk and pelvic balance, including the coronal and sagittal planes (Hedequist and Emans 2007). The finding of abnormal kyphosis on physical exam may be postural or congenital and thus should be thoroughly evaluated. Complaints of back pain, muscle fatigue, and stiffness are common in kyphosis. In severe cases, there can be compression of the spinal cord with neurologic symptoms that include weakness, altered sensation, and loss of bowel and bladder control. The chest should be examined for symmetry and deformity. Observation of inspiration, expiration, and the abdominal wall for movement, masses, and hernias may be an indication of a fixed chest wall deformity (Dewald et al. 2003). Lastly, secondary sexual development should be noted with examination of the genitalia and Tanner staging.

Neurologic evaluation can quickly and easily be performed throughout the physical exam. Extremity development, length, and symmetry should be noted, as well as anomalies of the feet. Feet abnormalities may include extra or absent toes, cavus (high arch), or flat feet. Remember that flat feet alone may be a benign common finding in young children. These can be red flags as to underlying neurologic conditions. Congenital deformities of the upper body and extremities such as Sprengel’s deformity (undescended scapula) and syndactyly should also be noted (Fig. 11.2). Further neurologic exam can be performed simply by observing the child walk, run, and move, noting overall general motor function. Testing of reflexes should be carefully performed. Abdominal reflexes should be symmetric. Asymmetric or depressed reflexes can be symptomatic of a spinal dysraphism. Hyperactive reflexes can be indicative of spinal cord compression (Dewald et al. 2003).

Children with congenital scoliosis are also at risk for abnormalities of the cardiac and genitourinary systems. Congenital heart disease may be observed in up to 25% of children with congenital scoliosis and genitourinary anomalies in as many as 20% of these patients (Hedequist and Emans 2007). These abnormalities may be benign and asymptomatic. They are typically detected during a routine screening or preoperative appointment. Alternatively, these anomalies may be severe and have possibly already required treatment. If it is determined through the medical history that these patients have not previously been evaluated for possible cardiac and/or urologic anomalies, they should be referred to a cardiologist or urologist for further screening and evaluation.

When anomalies of the spine are suspected, radiologic study is essential, especially for anomalies of the cervical spine. Early identification may significantly reduce potential major complications (Albright et al. 1999). Plain x-rays are always a recommended and reliable starting point for radiographic evaluation; however, they may give limited information depending on the age of the patient and the type of anomaly present.

Ultrasound, a simple and very useful type of study, can be a good screening tool in neonates and infants when physical findings suggest an underlying dysraphic lesion. Prenatal findings, family history, and other anomalies may also be an indication for an ultrasound (Albright et al. 1999). Normal vertebral growth and ossification can demonstrate many patterns, as well as be difficult to read on plain films due to the many overlying structures. CT scans are often needed to assess congenital anomalies. This is true especially in the cervical spine. Both CT and MR are especially useful in studying the entire spinal cord and the cervical spine. If any anomaly or malformation is suspected, it is important to image the entire spine as multiple spinal anomalies can commonly present. (Albright et al. 1999).

The incidence of intraspinal abnormalities associated with congenital spine anomalies as detected by MRI has become better defined. In a study by Suh, Sarwark, Vora, and Huang in 2001, there was an incidence of intraspinal anomalies in 31% in children with congenital spine anomalies. A screening MRI is indicated in patients with a spinal deformity that is known to be associated with neural axis abnormalities because of its capacity to detect clinically unsuspected dysraphia in asymptomatic patients. Other indications would include patients with a progressive deformity, abnormal reflexes, neurological deficits, or major extremity anomalies (Hedequist and Emans 2007). Angiography may be required if vertebral circulation is a concern. Some of the intraspinal pathologic conditions that may be found in patients with such conditions include congenital spinal stenosis, tethered cord, syrinx, Chiari malformation, diastematomyelia, and spinal cord tumor (Devlin 2012). Again, as clinical manifestations may not be detectable initially, MR imaging of the entire spinal cord and vertebral column from the foramen magnum to the distal sacrum is essential for complete evaluation. The advantages of MR imaging is that it is a technique that avoids invasive procedures and high radiation exposure.

All systems should be thoroughly reviewed and examined. Frequently, a renal and cardiac consultation is a part of an expanded evaluation.

Computed tomography (CT) is not typically used for serial monitoring and observation of scoliosis; however, it is routinely used in preoperative assessment and planning. CT scans are extremely useful in clearly defining the anatomy and identification of previously unrecognized malformations (Hedequist and Emans 2007). There are concerns regarding high radiation exposure during a CT scan. Today, most institutions typically have written protocols for various scans in order to minimize the amount of radiation that children are exposed to during their scans.

Treatment of congenital scoliosis focuses on early recognition, diagnosis, and treatment. Surgical treatment may include early arthrodesis and the routine use of spinal instrumentation for progressive curves. Younger children with congenital deformities may be treated with fusionless surgery by using a growing rod technique. Further discussion of various surgical corrections, fusion, and instrumentation is beyond the scope of the chapter.

All conditions of skeletal dysplasia share a common theme of some systemic defect in skeletal development. The categories of spine-related problems common to many of the skeletal dysplasias are instability, stenosis, and deformity, although they may occur concurrently at different levels of the spine and in different planes. Any type of dysplasia may manifest one or more of these problems with some exceptions. The phenotypic variability seen in genetic diseases makes it difficult to predict specific patterns of problems within the skeletal dysplasia groups (Dewald et al. 2003).

The first issue of instability may be a bony or ligamentous issue and usually occurs at the C1–C2 level. Instability is most common in the mucopolysaccharidoses, spondyloepiphyseal dysplasia, and metatropic dysplasia (Dewald et al. 2003). Baseline flexion and extension films of the cervical spine are always indicated. Also, a clinical exam evaluating spasticity, strength, and coordination should be included. An MRI in neutral, flexion, and extension would be indicated if it is not clear whether cord compression is developing. Stenosis may occur at any level of the spine. It is most commonly found in the patient with achondroplasia (80–90%) (Dewald et al. 2003). Treatment, typically decompression of the affected region, is determined by the extent and location of the neurologic deficit (Fig. 11.3 and Box 11.1).

Larsen syndrome is a heterogeneous, rare genetic disorder occurring in approximately 1 in 100,000 births. It was first recognized as an entity by Larsen in 1950 (Hennekam 2010). It is known to follow an autosomal-dominant or autosomal-recessive mode of inheritance, although sporadic occurrences have also been described in the literature (Becker et al. 2000).

Symptoms and severity in Larsen syndrome may vary greatly, ranging from a lethal form of the disorder to a mild clinical expression where there is an absence of major diagnostic features. Characteristic findings include skeletal and large joint abnormalities with distinctive facial features, cleft palate, hearing loss, and spinal abnormalities. Classic facial features of the syndrome are flattened, hypoplastic midface, a prominent forehead, depressed nasal bridge, and hypertelorism (Becker et al. 2000). Some symptoms are present at birth such as dislocation of large joints, especially the hips, knees, and elbows. Club foot is present in 75% of affected individuals. Spine abnormalities occur in about 84% of those with Larsen syndrome. This includes scoliosis and cervical kyphosis. Cervical kyphosis can occur from subluxation or fusion of the cervical vertebral bodies associated with dysplasia of the vertebral laminae and hypoplasia of the lateral processes of the cervical vertebrae. This is potentially the most life-threatening manifestation due to the impingement of the spinal cord at the apex of the kyphosis (Johnston et al. 1996). Early diagnosis and intervention of cervical kyphosis can help patients avoid potential neurologic deficits.

Loeys-Dietz syndrome (type 1–5), also referred to as LDS or Marfan 2, is a rare genetic disorder. The exact prevalence of LDS is unknown. Its characteristic features of craniofacial, vascular, and musculoskeletal malformations are also common to Marfan syndrome. Although LDS has been called Marfan 2, there are some significant differences between Loeys-Dietz and Marfan syndrome (The Marfan Foundation 2016).

Loeys-Dietz is an autosomal-dominant connective tissue disorder. It is caused by a mutation in the transforming growth factor-beta receptor 1 or 2 (TGF-BR1 or TGF-BR2) genes (Fuhrhop et al. 2015). Loeys-Dietz syndrome, first described in 2005, is characterized by a triad of aggressive aneurysm formation, bifid uvula or cleft palate, and hypertelorism. Other common physical features in Loeys-Dietz include translucent skin, easy bruising, and craniofacial abnormalities such as craniosynostosis, retrognathia, and malar hypoplasia. Vertebral anomalies and cervical instability also have a high prevalence in Loeys-Dietz syndrome. Cervical instability especially at C2–C3 is associated with C3 vertebral body hypoplasia and C2–C3 kyphosis (Fig. 11.4). Other spine malformations may include scoliosis and spondylolisthesis. Deformity of the extremities including arachnodactyly, talipes equinovarus, and joint hypermobility are also noted. Pectus excavatum or carinatum deformities may also be present (Fuhrhop et al. 2015).

As evidenced by the literature, cervical midline defects are common in Loeys-Dietz syndrome as are vascular abnormalities. With these patients having a high prevalence of cervical instability, there is a very important need for frequent imaging to monitor for progression and subsequent neurologic sequelae from the deformity (Fig. 11.5). Early diagnosis is critical for appropriate and timely intervention (Fuhrhop et al. 2015).

Achondroplasia is an autosomal-dominant genetic disorder affecting endochondral bone formation. It is the most common form of short-limbed dwarfism. The prevalence rate is approximately 1 in 26,000 live births (Wright et al. 2000). The mutation of the gene which is involved in the growth and development of bone results in abnormal stunting of bone formation at the epiphyseal plates (Alman 2002; Shiang et al. 1994). The bones in the face, skull base, spine, hands, feet, and proximal long bones, such as the humerus and femur, are especially affected resulting in characteristic features involving these structures (Fig. 11.8) (Alman 2002; Poseti 1988). Hydrocephalus, upper cervical spinal cord compression, and spinal stenosis are three neurological problems seen in achondroplasts (Park et al. 2003). The spinal manifestations of achondroplasia will be the primary focus of this section.

Abnormal development of the bones of the skull base results in abnormalities of the foramen magnum, posterior fossa, and brain stem. These abnormalities contribute to compression at the cervicomedullary junction. The diameter of the foramen magnum is significantly decreased in achondroplasia leading to compression of the upper cervical spinal cord and distal medulla (Schnuerer et al. 2001). The foramen magnum is also displaced anteriorly resulting in a shallow posterior fossa. As a result, the brainstem is displaced upward and posteriorly, simulating hyperextension of the neck. The compression on the upper cervical spinal cord is exacerbated further because it is often stretched over the edge of the occipital bone (Kokoska et al. 2001; Kopits 1988).

Klippel-Feil syndrome (KFS) was first described in 1912 by Maurice Klippel and Andre Feil (Sullivan and O’Dononghue 2005). This syndrome is a rare congenital disorder that affects the spine as well as many other body systems. This disorder is characterized by “the congenital fusion of any two of the seven cervical vertebrae” (Sullivan and O’Dononghue 2005). The resulting fusion is caused by a failure of the normal division of the cervical somites vertebrae during early fetal development. Patients with Klippel-Feil syndrome present with a triad of symptoms: short neck, low hairline at the back of the head, and restricted mobility of the upper spine (Fig. 11.2).

Mucopolysaccharide disorders (MPS) were first identified in 1917 (website MPS Society). These inherited disorders are errors of metabolism that are progressive in nature and may not become apparent until later in childhood. The disorder may also be referred to as lysosomal storage disorder (LSD). The lysosomal enzyme normally found in each cell is needed to degrade and recycle glycosaminoglycans. If these enzymes are not degraded and recycled, they accumulate within the cells causing the disease process with progressive damage to the body (Vogel et al. 2004). People affected with these disorders either do not produce enough of any one of the 12 identified enzymes that normally degrade and recycle the sugar chains into proteins, or the enzymes do not work correctly to produce the enzyme necessary for degradation.