From the Guidelines
Congenital scoliosis is associated with three main vertebral types: failure of formation, failure of segmentation, and mixed defects, which can lead to significant morbidity and mortality if left untreated or improperly managed, ultimately affecting the patient's quality of life. These vertebral anomalies develop during the first trimester of pregnancy (between the 4th and 8th weeks of gestation) due to abnormal vertebral formation 1. The severity and progression of congenital scoliosis depend on the type, location, and number of vertebral anomalies, with unilateral unsegmented bars combined with contralateral hemivertebrae typically causing the most severe and progressive curves.
Vertebral Types
- Failure of formation defects include hemivertebrae, which are wedge-shaped vertebrae that develop on only one side of the spine, causing the spine to curve 1.
- Failure of segmentation defects occur when vertebrae fail to separate properly during development, resulting in unilateral unsegmented bars (fusion of vertebrae on one side) or block vertebrae (complete fusion of adjacent vertebrae) 1.
- Mixed defects involve combinations of both formation and segmentation failures in the same patient.
Clinical Significance
The diagnosis and classification of congenital scoliosis are crucial for determining the appropriate treatment and predicting the risk of curve progression 1. Radiographs and MRI are essential imaging modalities for evaluating congenital scoliosis, with radiographs providing information on the type and severity of the vertebral anomaly and MRI helping to identify underlying neural axis abnormalities.
Key Considerations
- The presence of underlying neural axis abnormalities, such as tethered cord or syringohydromyelia, can affect the treatment plan and outcome of patients with congenital scoliosis 1.
- Early detection and treatment of congenital scoliosis can help prevent significant morbidity and mortality, and improve the patient's quality of life.
From the Research
Vertebral Types Associated with Congenital Scoliosis
The vertebral types associated with congenital scoliosis can be classified into several categories, including:
- Failures of formation, such as hemivertebrae 2, 3
- Failures of segmentation, such as unilateral unsegmented bars 4, 3
- Combined types, which involve both formation and segmentation failures 3
Hemivertebrae
Hemivertebrae can be further divided into three types:
- Non-segmented
- Semi-segmented
- Fully-segmented 2 Fully-segmented hemivertebrae are most likely to progress and cause deformation 2
Unilateral Unsegmented Bars
Unilateral unsegmented bars with contralateral hemivertebrae are associated with a high risk of progression and severe deformation 4 This type of congenital scoliosis is considered to be one of the most rapidly progressive and severely deforming types 4
Other Vertebral Anomalies
Other vertebral anomalies, such as spinal dysraphy, fusion of the ribs, and heart defects, can also be associated with congenital scoliosis 3 These anomalies can affect the prognosis and treatment of congenital scoliosis 3
Classification and Prognosis
The type of malformation determines the prognosis of congenital scoliosis 3 The risk of progression varies depending on the type of vertebral anomaly, with some types being more likely to progress than others 3