Scoliosis refers to an abnormal, three-dimensional curvature of the spine that deviates sideways from the body’s central axis. A scoliotic spine forms an “S” or “C” shape and involves a rotation of the vertebrae. Dextroscoliosis is a specific subtype defined by the direction of the curve. The term “dextro” means “right,” indicating that the spine’s curve bends toward the patient’s right side.
Defining Dextroscoliosis and Its Location
Dextroscoliosis is characterized by a curve that is convex, or bowed outward, toward the right side. This directional naming convention distinguishes it from levoscoliosis, where the curvature is directed toward the left side. The direction of the curve is an important feature for classification, but it does not indicate the severity of the spinal deformity.
The curvature can manifest in any part of the spinal column, though it is most frequently observed in the thoracic spine, which is the middle section of the back. When the curve is located here, it is referred to as thoracic dextroscoliosis. If the curve spans both the thoracic and lumbar regions, it is called thoracolumbar dextroscoliosis, and a curve confined to the lower back is lumbar dextroscoliosis.
Thoracic dextroscoliosis may cause a noticeable protrusion of the right ribs due to the rotational component of the spinal deformity. Right-sided curves in the thoracic spine are typical in the most common form of the condition. Conversely, levoscoliosis is considered atypical in the thoracic area and may prompt investigation for underlying neurological causes.
Identifying the Underlying Causes
The etiology, or underlying cause, of dextroscoliosis is varied, but the vast majority of cases fall into a category where the origin is unknown. This is known as Idiopathic Scoliosis, which accounts for about 80% of all diagnosed scoliosis cases. The most prevalent form is Adolescent Idiopathic Scoliosis (AIS), which develops in children between the ages of 10 and 18.
While the specific cause remains elusive, research suggests that genetics and hereditary factors play a significant role in idiopathic cases, as the condition often runs in families. The remaining 20% of cases have a known cause and are classified into other types of scoliosis. These known causes include congenital and neuromuscular factors.
Congenital scoliosis is present at birth, resulting from a malformation of the vertebrae during fetal development, such as a failure to form properly or separate. Neuromuscular scoliosis results from underlying neurological or muscular disorders that impair spinal alignment. Conditions like cerebral palsy, muscular dystrophy, or spinal cord injury can lead to this curvature.
Confirmation Through Diagnosis and Measurement
The diagnostic process begins with a physical examination, often including the Adam’s forward bend test, where the patient bends forward at the waist. This maneuver helps a clinician observe for any asymmetry, such as a rib hump or unevenness in the trunk, which suggests a rotational spinal deformity. If a spinal curve is suspected, standing X-rays are the standard imaging tool used to confirm the diagnosis and quantify the curve’s severity.
The severity of the curvature is determined by the Cobb angle, a standardized measurement taken from X-ray images. It is calculated by drawing lines parallel to the top and bottom endplates of the most tilted vertebrae at the curve’s apex and base. The angle formed where these lines intersect defines the Cobb angle.
A diagnosis of scoliosis is confirmed when the Cobb angle measures 10 degrees or greater. This measurement is crucial for monitoring the condition and guiding treatment decisions. Curves are generally categorized as mild (10 to 24 degrees), moderate (25 to 40 degrees), or severe (40 degrees or more).
Treatment Pathways Based on Severity
Management strategies for dextroscoliosis are directly dependent on the Cobb angle measurement, the patient’s age, and their remaining skeletal growth. For mild curves, typically those measuring less than 25 degrees, the standard approach is observation and regular monitoring. This involves periodic physical exams and X-rays, often every four to six months, to track whether the curve is progressing, especially in growing patients.
If the curve is moderate, generally between 25 and 45 degrees, and the patient is still growing, bracing is usually recommended to prevent further progression of the curve. A common type is the thoracolumbosacral orthosis (TLSO), such as a Boston brace, which is designed to be worn for many hours each day until skeletal maturity is reached. The primary goal of bracing is not to correct the existing curve but to halt its worsening.
Surgical intervention is reserved for severe curves or those that progress rapidly despite bracing, typically when the Cobb angle reaches 45 or 50 degrees in a growing child. The most common procedure is spinal fusion, which uses instrumentation like rods and screws to straighten the spine and fuse the affected vertebrae into a single, solid bone. Surgery aims to correct the deformity, stabilize the spine, and prevent potential complications like compromised respiratory function associated with very large curves.