Congenital scoliosis (CS) is a side-to-side curvature of the spine that originates from structural defects present at birth. This spinal deformity occurs when the bones of the spine, called vertebrae, do not form or separate properly during the baby’s development in the womb. The issue arises very early, typically within the first six weeks of embryonic development. While the defect is present at birth, the resulting spinal curve may not become visually noticeable until later in childhood as the child grows.
Differentiation from Idiopathic Scoliosis
Congenital scoliosis differs fundamentally from the much more common adolescent idiopathic scoliosis (AIS) in both its cause and timing. AIS accounts for the majority of all scoliosis cases, typically appearing after age 10, and is termed “idiopathic” because the cause is unknown. CS is defined by a known structural defect in the vertebrae, making it a congenital condition present from birth. The CS malformation occurs within the first two months of gestation, permanently altering the shape of spinal bones. Because congenital defects are rigid bony malformations, they often lead to more severe and rapidly progressing curves compared to the typically more flexible curves seen in AIS.
Types of Vertebral Malformations
The specific way a vertebra develops abnormally dictates the progression and severity of the congenital spinal curve. These defects fall into two main categories: failures of formation and failures of segmentation.
Failures of Formation
A failure of formation occurs when only a portion of a vertebra develops, resulting in a wedge-shaped bone called a hemivertebra. Because this malformed vertebra is triangular instead of rectangular, it acts like an extra growth plate on one side of the spine. This imbalance causes the spine to grow at an angle, leading to a progressive curvature that worsens rapidly.
Failures of Segmentation
The second type, a failure of segmentation, happens when two or more adjacent vertebrae fail to separate properly and remain fused together. If this fusion, known as an unsegmented bar, occurs only on one side, it creates a rigid restraint that limits growth on that side. The spine continues to grow normally on the unrestricted side, forcing the spinal column to bend away from the rigid bar, resulting in a severe scoliotic curve. The most challenging cases often involve mixed defects, where a hemivertebra is present on one side and an unsegmented bar on the opposite side.
Identifying the Spinal Curve
The diagnostic process for congenital scoliosis begins with a physical examination. Initial imaging involves full-spine X-rays, which are necessary to visualize the bony defects and measure the exact angle of the curve using the Cobb method. This initial imaging confirms the diagnosis and helps classify the specific type of vertebral malformation present.
A detailed assessment requires advanced imaging, particularly a Magnetic Resonance Imaging (MRI) scan, to evaluate the spinal cord and surrounding soft tissues. This is crucial because a significant percentage of patients with congenital scoliosis also have anomalies of the central nervous system, such as a tethered spinal cord. Screening for associated anomalies in other organ systems is mandatory since the spine, heart, and kidneys develop simultaneously during the early embryonic stage. An abdominal ultrasound and a cardiac echocardiogram are typically performed to check for kidney and heart issues, which frequently co-occur with congenital spinal defects.
Medical Management and Follow-Up
The management of congenital scoliosis is tailored to the specific defect and its potential for progression. For children with small, non-progressing, or balanced curves, the primary approach is observation with regular follow-up visits and X-rays, typically every six to twelve months. This careful monitoring is important during the child’s two major growth phases: the first five years of life and the adolescent growth spurt.
Bracing is generally less effective for congenital scoliosis than for idiopathic scoliosis because the underlying spinal deformity is rigid and structural. However, a brace may be used in select cases to manage secondary curves or to provide support during the early stages of a mild curve.
For curves that are rapidly progressing or already severe, surgical intervention is often necessary, sometimes as early as the first few years of life. Surgical options include spinal fusion, which permanently connects the abnormal vertebrae to prevent further progression, or growth-sparing techniques, such as growing rods. Growing rods are surgically attached to the spine and are periodically lengthened with minor procedures to allow the child’s trunk and lungs to continue growing while the curve is controlled. Follow-up care is lifelong, with continued monitoring recommended even after skeletal maturity.