Developmental Kyphosis

Figure 1. Magnified image of wedged vertebrae in Scheuermann's kyphosis

Hyperkyphosis (forward bend of the thoracic [ribbed] vertebrae beyond normal limits) is classified as either postural or structural in origin.

Postural Kyphosis

Postural kyphosis is flexible and will correct when the patient is asked to stand up straight. Patients with postural kyphosis have no abnormalities in their vertebrae shape.

Structural Kyphosis

Structural kyphosis, known as Scheuermann's kyphosis, is defined as rigid. The front sections of the vertebrae grow slower than the back sections. The abnormal kyphosis is best viewed from the side in the forward-bending position where a sharp, angular abnormal kyphosis is clearly visible.

Instead of normal, rectangular vertebrae with ideal alignment, wedge-shaped vertebrae cause misalignment (Figures 1 and 2). This process occurs during a period of rapid bone growth (usually between the ages of 12 and 15 in males or a few years earlier in females). The kyphotic curve that develops with growth frequently remains mild and requires only periodic x-rays.

Patients often have poor posture and complaints of back pain, which is most common in early teenage years and less so as they approach adulthood. The pain rarely interferes with daily activity or professional careers. The kyphosis is more likely to be painful the apex (most angular section) is in the mid-to-low back instead of the upper back. In severe cases, adolescents may not be able to lie on their back without several pillows under their head.

Figure 2. A) Lateral x-ray of a patient with Scheuermann’s disease. B) Close-up x-ray demonstrating wedge-shaped vertebrae characteristic of Scheuermann’s disease.

Treatment Options

Nonoperative Management

Observation

Observation is typically recommended for:

• Postural hyperkyphosis (rounded back straightens with proper posture)
• Curves that are less than 60° in patients that are growing
• Curves 60° to 80° in patients that are finished growing

X-Rays and Exercise

Standing, long-cassette (scoliosis) x-rays are taken every six months as the child grows. If the child experiences pain, an exercise program is usually recommended.

Figure 3. On the left is a side-view of a patient with Scheuermann's kyphosis. On the right is the same x-ray after he was placed in a hyperextension brace.

Bracing

When the curve is moderately severe (60° to 80°) and the patient is still growing, brace treatment in conjunction with an exercise program may be recommended. The brace fit must be regularly evaluated and adjusted to ensure optimal correction.

• Full-time use of a brace (20 hours/day) is usually required initially until maximum correction has been achieved.
• During the last year of treatment prior to skeletal maturity, part-time brace wear (12 to 14 hours/day) may be proposed.
• Brace wear must be continued for a minimum of 18 months in order to maintain a significant, permanent correction of the curve (Figure 3).

Operative Treatment

Spinal Fusion

If kyphosis has become severe (greater than 80°) and causes frequent back pain, surgical treatment may be recommended. Surgery provides significant correction without the need for postoperative bracing. Pedicle screws, hooks, or sublaminar cables are placed, two per level, and connected with two rods.

Most surgeries are performed from the back; however, some physicians may recommend additional surgery on the front of the spine. Patients are usually able to return to normal daily activities within four to six months following surgery. (Figure 4).

Figure 4. A) Preoperative photo of patient with severe kyphosis secondary to Scheuermann's disease. B) Preoperative x-ray of the same patient. C) Postoperative photos of the same patient one year after surgical correction of the kyphosis. D) Postoperative x-ray of the same patient.

Moderately flexible curves often straighten simply from lying face down during surgery; however, rigid curves may require additional surgical intervention, such as Smith-Peterson osteotomies.

Smith-Peterson Osteotomy

The Smith-Peterson osteotomy involves cutting the bone to improve vertebral alignment; as a result, every spinal segment included in the osteotomy is limited in extension (backward bend) by two sliding facet joints. If these joints are removed and the disc in front is mobile, it is possible to achieve 5° to 10° additional extension, per level. (Figure 5).

Figure 5. A) & B) Front and side x-rays of a person with severe, rigid Scheuermann's kyphosis. C) Illustration of a side view of the spine showing how the facet joints are removed. D) After the facets are removed, the spine can be tilted backward. E) & F) Front and side x-rays after surgery.