From time to time, the National Scoliosis Foundation receives letters from parents about kyphosis. To find out more about this spinal deformity, our Medical Update editor, Nancy Schommer, interviewed Dr. Howard King, Clinical Associate Professor of Orthopaedic surgery, University of Washington, and Northwest Spine and Pediatric Orthopaedic Surgeons Seattle, Washington. What follows are excerpts from that interview.

Q: Dr. King, how do you define the spinal deformity known as kyphosis?
A: Let me begin by saying that everyone has a little bit of round back (kyphosis) and a little bit of swayback (lordosis). As a spinal deformity, however, kyphosis is defined as an abnormal increase in the sagittal plane curvature. If you look at a person from the side and see more " roundback " than is considered normal, it's possible that the person has some type of kyphosis.

Q: What are the measurements of normal vs. abnormal kyphosis?
A: The degree of normal kyphosis is usually considered to be between 20 and 40 degrees. Once the curvature approaches 45 to 50 degrees or more, we'd consider that abnormal.

Q: Where along the spine does abnormal kyphosis occur?
A: It can occur anywhere-in the cervical area, the thoracic area, or the lumbar area, but most often we see it in the thoracic or chest area which is naturally rounded to begin with.

Q: Is kyphosis as common as scoliosis?
A: Not at all. The incidence of scoliosis is roughly 2 in 100, whereas the incidence of kyphosis is approximately 1 in 1,000.

Q: Tell us about a variation on normal kyphotic development that you see in your practice.
A: Quite often, we see adolescents with "postural roundback," which is confused with abnormal kyphosis. 'I'm sure your readers have seen teenagers slouching or hunched over. They have poor posture, but no deformity; when you ask them to stand straight, they're able to straighten up, and if you take an x-ray, you see that their spines are perfectly normal. Sometimes, postural exercises can help, but eventually, most postural roundbacks straighten by themselves as the individual matures.

Q: What about some of the abnormal cases of kyphosis that you're currently seeing?
A: One of them is called Scheuermann's Disease, a deformity which can be differentiated from postural roundback by clinical examination and x-rays. Whereas the postural roundback patient generally has a flexible spine and normal vertebral development, a patient with Scheuermann's will have structural problems, including vertebral wedging (instead of being rectangular, the affected vertebrae are trapezoid-shaped); disk space narrowing; and irregularity of the end plates of the vertebrae. As a result of these and other problems, patients with Scheuermann's cannot stand up straight.

Q: Is pain associated with Scheuermann's Disease?
A: A fair number of youngsters come in with pain. We presume that the pain is caused by micro-fractures of those wedged vertebrae.

Q: Do scientists know what causes Scheuermann's?
A: The etiology is unknown, but studies suggest a variety of etiologies that include mechanical, familial, hereditary, developmental, traumatic and metabolic theories.

Q: What are your objectives for treatment of Scheuermann's?
A: Treatment is usually based on these objectives: (1) Relief of pain; (2) avoidance of recurring pain; (3) improvement in deformity; and (4) maintenance of that improvement.

Q: Tell us about the various treatments for Scheuermann's.
A: In children with pain and deformities between 60 and 80 degrees, Milwaukee-type bracing can be helpful. Bracing tends to work better on curves that are under 80 degrees-in many cases, up to 50% correction can be obtained. Surgical treatment is rarely indicated, although persistent pain and a progressive deformity are reasonable indications for surgery. When surgery is indicated, we usually combine an anterior and posterior approach and do both procedures on the same. The type of hardware used would determine whether or not the patient would need to wear a post-surgical brace.

Q: What other types of abnormal kyphosis are you seeing?
A: Congenital kyphosis is usually caused by some structural defect-for example, the anterior (front) part of the spine may not have formed properly. The deformity may be severe, and neurological problems may result. Early posterior fusion can be done in children under five with a kyphosis of less than 50 degrees. If the patient is older than five, or has a curve over 50 degrees, we would perform a combined anterior and posterior surgery. We usually recommend that patients with congenital kyphosis have a pre-operative MRI scan that would help us detect spinal cord problems.

We're also seeing patients with "post laminectomy kyphosis," a condition sometimes caused when surgery is per- formed to remove a tumor of the spinal cord. In surgery, figaments and other structures are removed, which causes the loss of one's posterior 'tether'-think of it as a guy wire that keeps your spine upright. Without that tether, the spine starts to bend and kyphosis can result. We can reconstruct the spine with surgical treatment, but we're trying to avoid the problem in the first place by educating neurosurgeons and oncologist and rehabilitation people to watch for these deformities.

Q: We sometimes receive letters from individuals about "dowager's hump," a deformity that causes the patient to be hunched over. Is that a type of kyphosis, what causes it, and what can be done about it?
A: Yes, we do consider this kyphosis. We're seeing it more and more in senior citizens who develop osteoporosis (loss of bone density) and as result, their spines start to collapse. These problems are generally treated medically with calcium vitamin D and other medications. Pain can on occasion be reduced by brace treatment. Surgery can be performed in severe cases with collapse of the spinal column and where neurologic compromise has occurred. Because the bone density is decreased, this surgery is complex and the results are variable. The best course of action is prevention. Young women need to be on a regular exercise program, and should get at least 1,200 mgs. of elemental calcium per day-either through diet or with supplements. When women begin menopause, they should continue with an exercise program, and be on appropriate hormone replacement therapy under the supervision of their doctor. Cigarettes and caffeinated beverages are best avoided.