Kyphotic deformity is characterized by an excessive forward rounding of the upper back, often called “hunchback” or “roundback.” While the upper spine naturally curves forward, an abnormal exaggeration of this curvature leads to a visible deformity. This excessive rounding can cause discomfort, stiffness, and in severe instances, impact physical function. Understanding the various factors that contribute to this curvature is essential for effective management.
Understanding Normal vs. Kyphotic Spinal Curvature
The human spine possesses three natural curves that balance the body’s weight and absorb shock. The neck (cervical) and lower back (lumbar) curve inward (lordosis), while the upper-mid back (thoracic spine) naturally curves outward (normal kyphosis).
In a healthy adolescent, the normal range for this thoracic curve measures between 20 and 45 degrees. Doctors quantify this curve using the Cobb angle, determined by drawing lines along the top and bottom vertebrae of the curved section on a lateral X-ray image.
When the measured thoracic curve exceeds the normal range, typically defined as greater than 50 degrees, the condition is termed hyperkyphosis or pathologic kyphosis. This excessive angle disrupts the spine’s normal alignment, shifting the body’s center of gravity forward. This imbalance strains muscles and ligaments, causing the noticeable rounding of the back.
Categorizing the Primary Causes of Kyphotic Deformity
The development of an excessive spinal curve falls into three main categories: postural, structural, and degenerative.
Postural Kyphosis
The most common form, postural kyphosis, results from habitual poor posture, such as slouching. This form is flexible, meaning the spine’s shape can be corrected simply by standing up straight. Postural kyphosis does not involve vertebral abnormalities but is caused by muscle weakness and ligament stretching over time.
Structural Kyphosis
Structural kyphosis involves a fixed deformity where the shape of the bones is altered, making it non-correctable by posture alone. A prominent example is Scheuermann’s kyphosis, which typically appears during the adolescent growth spurt. This condition is defined by the wedging of three or more consecutive thoracic vertebrae. While the cause is not fully understood, it is thought to involve a growth disturbance of the vertebral endplates.
Congenital kyphosis is a structural form present at birth, resulting from a failure of the vertebrae to form or segment correctly during fetal development. This type often progresses as the child grows and may require early intervention. Other structural causes include trauma, such as severe fractures, or systemic diseases like infections or tumors affecting the spine.
Degenerative Kyphosis
Degenerative or age-related kyphosis is frequently observed in older adults. This condition is often linked to osteoporosis, a loss of bone density that leads to vertebral compression fractures. When the front part of a vertebra collapses due to weakened bone, it creates a wedge shape that significantly increases the forward curve. Natural wear and tear, including disc degeneration and muscle atrophy, also contribute to the gradual increase in the kyphotic angle.
Clinical Assessment and Diagnostic Procedures
The identification of kyphotic deformity begins with a physical examination. Patients often report a visible rounding of the upper back, persistent thoracic pain, stiffness, or fatigue. Doctors look for signs such as a forward-tilted head position and uneven shoulder height.
The Adam’s forward bend test helps distinguish between flexible postural kyphosis and fixed structural forms. During this test, the patient bends forward at the waist. If the curve straightens out or significantly reduces, it indicates a flexible, postural issue. If the prominence remains fixed, it suggests a structural abnormality.
If a structural issue is suspected, a standing lateral X-ray is necessary to confirm the diagnosis and measure the curve using the Cobb method. This imaging identifies specific causes, such as vertebral wedging or compression fractures. MRI or CT scans may be ordered if there are signs of neurological involvement, such as weakness or numbness, to assess the spinal cord and nerve roots.
Non-Surgical and Surgical Treatment Pathways
Treatment selection depends on the underlying cause, the severity of the curvature, and the patient’s age. Non-surgical management is the initial approach for most cases, especially postural kyphosis and mild structural curves. Physical therapy is a primary intervention focused on strengthening core and back extensor muscles to improve posture and reduce muscular strain.
For adolescents with Scheuermann’s kyphosis who are still growing, bracing may be recommended to prevent curve progression. Pain is managed with anti-inflammatory medications. These conservative methods aim to manage symptoms and maintain the current curve rather than fully correct the spinal shape.
Surgical intervention is reserved for severe or progressive structural curves, typically those exceeding 70 to 80 degrees, or when the deformity causes neurological deficits or compromises lung function. The most common procedure is spinal fusion, where several vertebrae are permanently joined to stabilize the spine and correct the curvature. For older adults with kyphosis caused by recent compression fractures, kyphoplasty may be performed to restore vertebral height and alleviate pain.