Last Updated on December 16, 2023
Congenital kyphosis is the presence of kyphotic deformity or hump in the spine due to congenital vertebral anomalies.
Kyphosis is an exaggerated forward spine bend. It is called congenital kyphosis when the child is born with it.
The vertebral defect which usually occurs in the first six to eight weeks of embryonic life causes the spine to develop a sharp forward angulation as it grows.
It is more common in girls than boys
Congenital kyphosis (especially without scoliosis) is rare. Those with mild curves may not progress or cause pain. In severe cases (surve >40 degrees), it can worsen without treatment and result in pain, stiffness, and neurological deficit (loss of movement and loss of sensations in the region below the level of kyphosis).
Types of Congenital Kyphosis
Three types of congenital have been described. In fact, as per mechanisms, there are only two types. The third one is a mix of the other two types.
Type 1 (failure of formation)
Type 1 congenital kyphosis is the failure of the development of the vertebral body. The deformity is visible at birth and often worsens with growth. As the name suggests, there is failure of one or more vertebral bodies to form properly. The failure of the formation can result in a range of deformities from kyphosis [anterior defect] to kyphoscoliosis [anterolateral defect with a posterior corner hemivertebra].
Various types of failure of formation are
- Posterolateral quadrant vertebrae
- Posterior hemivertebrae
- Butterfly (sagittal cleft) vertebrae
- Anterior or anterolateral wedged vertebrae
It often appears as a bump or lump on the infant’s spine. This type carries the worse prognosis and deformity tends to worsen and can result in various sequelae or complications if not treated.
- Paraplegia
- Overlying soft tissue breakdown
- Visceral compression
- Effect on lung function
Type 1 is the most common type of deformity occurring in about 65 percent of cases. This type occurs more commonly in the thoracic spine and at the thoracolumbar junction.
Defects of the formation may involve only a single level, but multiple defects are possible. Kyphoses in the upper thoracic spine are more likely to be associated with neurological problems.
About one-fourth of the type I deformities have associated neurological deficits.
Type 2 (Failure of segmentation)
It results in the segmented bony bar as two or more vertebrae fail to separate or form normal discs. It is more common in the thoracic spine followed by the lumbar spine. It has a slightly better prognosis.
The congenital kyphosis due to failure of segmentation is slightly rounded. It has a lesser rate of progression and neurological deficit is not common.
Type 2 is often diagnosed late as often at walking age.
Type 3 (Mix)
A combination of 1 and 2 can occur but is quite rare.
Associated Conditions
- Lower limb abnormalities
- Heart abnormalities
- Kidney abnormalities
- Congenital scoliosis
- Intraspinal malformations
Natural Progression of Congenital Kyphosis
The rate of progression is lesser in cases with failure of separation. The more severe the anterior defects, the more progressive the deformity. Kyphosis from the failure of formation is progressive and, if left untreated, can lead to paraplegia.
Paraplegia is often seen more common during the adolescent growth spurt when a rapid increase occurs in untreated kyphosis. Apart from this, a minor trauma may result in a neurological deficit.
Paraplegia is more common with kyphosis in the upper thoracic area.
Symptoms and Signs
These symptoms and signs vary depending on the severity of the congenital kyphosis. The deformity itself is the major complaint. However, in case the condition is not treated, other symptoms may occur too. Progressive symptoms are noted only with severe, progressing curves.
Most of the symptoms are
- Deformity or back hump: Visible early in type 1 but late in type 2
- Pain & Stiffness: Seen later when a child is upright. Can worsen if untreated.
- Muscle fatigue: Easy tiredness is a common symptom
When the condition is not treated and it worsens, the following symptoms may occur
- Neurological Symptoms
- sensory and motor
- Loss of bladder bowel control in very late cases
- Cardiac & Lung Issue
- Occur as space for chest is compressed
- Chest pain, breathlessness
- Heart/Lung failure
The deformity may be detected before birth on a prenatal ultrasound examination.
Imaging
High-quality, anteroposterior, and lateral radiographs are the basic imaging studies and help to
- Look for the type of deformity present
- The rigidity of the kyphosis [Flexion, extension, and lateral flexion views]
- Measurement of angles to assess the severity of the curve
Computed tomography with three-dimensional reconstructions helps to identify the amount of vertebral body involvement and estimates the possible progression. Significant incidences of intraspinal abnormalities in these patients warrant MRI studies. MRI can also help to identify compression caused by kyphosis.
Cardiac evaluation and renal ultrasonography should be done in these patients to look for visceral abnormalities.
Treatment of Congenital Kyphosis
Nonoperative treatment in these patients is ineffective.
The operative procedure depends on the type and severity of deformity, age, and presence of neurological symptoms.
It has been the convention to do posterior fusion in patients younger than 5 years of age and less than 5o degrees of the curve. Older children with a higher degree of curve require both anterior and posterior surgery.
Recently, however, with newer techniques like the pedicle subtraction osteotomy, posterior vertebral column resection, or vertebral column decancellation, the posterior approach is becoming the preferred approach. Newer implants like pedicle screws have also aided in this.
However, an anterior approach may be required if the curve is too severe and the patient requires anterior decompression.
Complications
- Pseudarthrosis – Failure of fusion
- Progression of kyphosis
- Paralysis
- Low Back Pain
The first two complications can be minimized by performing anterior and posterior fusions for deformities > 50 degrees.
The risk of paralysis can be lessened by not attempting maximum correction at the time of instrumentation.
References
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Rocos B, Lebel DE, Zeller R. Congenital Kyphosis: Progressive Correction With an Instrumented Posterior Epiphysiodesis: A Preliminary Report. J Pediatr Orthop. 2021 Mar 1;41(3):133-137. [link]
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Winter RB. Congenital kyphosis. Clin Orthop Relat Res. 1977 Oct;(128):26-32.
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Kim YJ, Otsuka NY, Flynn JM, Hall JE, Emans JB, Hresko MT. Surgical treatment of congenital kyphosis. Spine (Phila Pa 1976). 2001 Oct 15;26(20):2251-7. [Link]
