What is Kyphosis? At What Degree is the Kyphosis Angle Considered Abnormal?
Kyphosis refers to the outward curve of the spine when viewed from the side. Normally, this curve ranges between 20-40 degrees. When the kyphosis angle exceeds 40 degrees, it is called hyperkyphosis, meaning increased kyphosis, which is considered abnormal.
How Many Types of Kyphosis Are There?
Kyphosis can be categorized into structural and non-structural kyphosis. Structural kyphosis is less flexible and includes kyphosis accompanied by pathologies in the bone and soft tissue that cannot be easily corrected. Non-structural kyphosis, such as postural kyphosis, is more flexible and can be corrected with physical therapy and muscle strengthening and stretching exercises.
What is the Most Common Structural Kyphosis in Society?
Structural kyphosis can result from congenital (congenital) adhesions at the front of the vertebral body leading to halted growth at the anterior body, abnormal vertebral shaping, fractures due to osteoporosis, or vertebral slippage. The most commonly observed type, however, is Scheuermann's kyphosis.
How is the Radiological Diagnosis of Scheuermann's Kyphosis Made?
In this type of kyphosis, a lateral spine X-ray showing wedging of at least three consecutive vertebrae with more than 5 degrees each is diagnostic. This may be accompanied by irregularities in the upper vertebrae and Schmorl's nodes.
What Are the Symptoms of Kyphosis?
Patients frequently experience cosmetic concerns, back and lower back pain. Neurological deficits are rare and typically occur in advanced congenital cases. Curvatures exceeding 80 degrees may lead to impaired respiratory function.
Kyphosis Treatment
- Non-Surgical Treatments
For children who have not completed their growth, curves between 50-80 degrees or curves over 45 degrees accompanied by structural deformities such as vertebral wedging and Schmorl's nodes are treated with braces and physical therapy.
There are different types of braces available. Commonly used braces include Boston, Milwaukee, and Gschwend braces, as well as hyperextension (Jewett) braces. For effectiveness, the brace should be worn for at least 16 hours daily.
Physical therapy aims to strengthen the back and abdominal muscles while relaxing the chest pectoral muscles and hamstring muscles in the thighs.
- Surgical Treatments
Surgery is generally considered for curvatures over 80 degrees. Cosmetic concerns and persistent back and lower back pain are the main reasons for surgery.
Surgery typically involves inserting screws through the posterior approach (from the back) and correcting the curve using two rigid metal rods. In cases of rigid curves, bone-cutting procedures called osteotomies may be performed to release the curve. The goal of surgery is to achieve an average correction of about 50%. Excessive correction can increase the risk of developing complications such as transitional kyphosis. In these surgeries, it is essential to use a neuromonitoring system to monitor the passage of signals through the spinal cord during the operation.
What Are the Risks Associated with Kyphosis Surgery and Its Aftermath?
Like all spinal deformity surgeries, kyphosis surgery carries the risk of neurological deficit, i.e., paralysis. However, this risk is very low in experienced hands. If signal loss occurs during excessive correction, the surgeon can be alerted, allowing them to reduce the correction to prevent such complications. The most common complication post-surgery is the development of a forward tilt immediately above the topmost screw, known as proximal junctional kyphosis, occurring in about 10% of cases. This risk can be minimized by adhering to proper surgical techniques. Other potential complications include early-stage infections and long-term non-union.