Scheuermann's Kyphosis
The human spine has natural curvatures. In the frontal plane (looking at the patient from behind) the spine should be straight. Kyphosis affects the sagittal plane (looking at the patient from the side view). When looking from the side, the spine has normal curvatures. In the neck (cervical spine) and low back (lumbar spine) there is normally an inward curvature or sway back known as lordosis. In the thoracic spine there is an outward curvature known has kyphosis or hunchback. These curves normally balance out each other so that when the patient stands the spine is balanced with the head straight above the hips when viewed from the side. Standing in this position minimizes the effect of gravity and allows the patient to stand with the best posture and use the least energy when moving or walking [Figure 1].
Figure 1: A drawing and x-ray demonstrating a patient with Scheuermann’s kyphosis.
There are several types of kyphosis. The most common form of kyphosis is due to poor posture. Patients with postural kyphosis can conscientiously correct the curve by standing straight. For these patients, no actual structural abnormality of the spine is present. Patients with postural curves are treated with reassurance that their curvature is unlikely to progress and appropriate posture and spinal alignment are reinforced.
Structural kyphosis refers to an increase in the curvature of the spine that is not related to posture or slouching. Patients with structural kyphosis cannot straighten the spine consciously. The most common type of structural kyphosis is Scheuermann's kyphosis. Scheuermann's kyphosis is most commonly diagnosed between the ages of 12 to 14 years of age (Figure 1).
The thoracic spine should have a gentle rounding of the curve behind the shoulders. Normal thoracic kyphosis ranges from 20° to 40° when viewed from the side. If the curvature grows larger than that, a kyphosis is present [Figure 2].
Figure 2: Scheuermann's disease is diagnosed for patients who have kyphosis in the thoracic spine measuring more than 40°with wedging of three or more vertebrae in a row (the vertebrae are taller at the back than at the front).
The cause of Scheuermann's kyphosis is unknown; however, researchers believe it is related to an interruption in an abnormality in vertebral bone growth and development. This condition tends to run within families. Height and weight may also be contributing factors to the development of Scheuermann's kyphosis, with larger people having a greater risk. Scheuermann's kyphosis is most typically seen and diagnosed during periods of rapid bone growth and is often seen in adolescence during the growth spurt. Most patients first note symptoms such as poor posture or slouching. As the kyphosis progresses pain in the area of the curvature can develop.
Diagnosis is based on physical examination and x-ray evaluation. A full medical history is noted to rule out other potential causes of kyphosis. Evaluation of the spinal alignment, motion, and neurologic function is needed. X-rays are used to evaluate the alignment of the spine and to measure the overall curvature when viewed from the front and back. Patients with Scheuermann's kyphosis have an increase in the thoracic curvature in the spine. Scheuermann's disease is diagnosed for patients who have kyphosis in the thoracic spine measuring more than 40° with wedging of three or more vertebrae in a row (Figure 2). Patients with Scheuermann's kyphosis also commonly have Schmorl's nodes which are small disc herniations through the endplates of the vertebra. These disc herniations are different than herniations that occur into the area where spinal nerves are located [Figure 3].
Figure 3: MRI scan in a patient with Scheuermann’s Kyphosis showing wedging in three consecutive vertebral bones (red arrows).
TREATMENT OPTIONS:
Treatment for Scheuermann's kyphosis depends on the patient's age, as well as the size of the curve and symptoms the patient may be experiencing. Most patients with kyphosis are first treated with a period of observation to see if any increase in the size of the curvature is occurring. During this time physical therapy and exercise programs are used to improve posture and help strengthen the muscles of the spine that hold the spine in extension.
For curves that progress, or more severe cases, a brace may be used to help straighten the spine and try to prevent further curvature of the spine during the remainder of the patient's growing years. Bracing helps take the pressure off the front part of the vertebrae allowing growth in the front of the spine to catch up with the growth in the back of the spine. Brace treatment for kyphosis is only used for patients who are still growing and is not an effective treatment for adult patients. Brace treatment for Scheuermann's kyphosis is similar to bracing for patients with scoliosis, however, the location and type of the brace may vary depending on the location of the kyphosis. For patients who need a brace, a light weight thoracolumbosacral (TLSO) brace or Boston brace is most commonly used. This is a light weight brace that is custom molded to the patient's body. This brace can be worn under clothes and allows patients to participate in most sports and activities [Figure 4].
Figure 4: A TLSO brace is a lightweight plastic brace that is molded to fit a person with a spinal curvature. The goal of a brace is to keep the curve from getting bigger during the years of growth.
OPERATIVE TREATMENTS:
Spine surgery for kyphosis is recommended for patients whose curvatures continue to progress or cause symptoms despite non-operative treatment. Surgery for correction of thoracic kyphosis is usually recommended for curves that have progressed and are larger than 80° to 90° when measured on x-rays. For kyphosis extending into the mid or lower back (thoracolumbar spine) surgery is recommended for curves that are larger than 60° to 70° of kyphosis. Surgery is also an option for patients who have disabling back pain or for patients whose limited kyphosis is leading to some compression of the spinal cord or nerves of the spine. [Case Example Figure 5].
Figure 5: This patient is a 35-year-old man diagnosed with Scheuermann’s kyphosis as a teenager. He noticed a worsening forward curvature of the spine and severe back pain. The patient was treated with posterior kyphosis correction surgery with osteotomies. His x-rays show 87° thoracic kyphosis before surgery, which was corrected to 50° with surgery.
The goal of spinal reconstruction surgery for patients with Scheuermann’s kyphosis is to decrease the patient's pain and to place the spine in a more natural position. Most commonly this surgery is performed through a posterior approach in the back of the spine. During the surgery, spinal implants including rods and screws are placed next to the spine. These implants are used to correct the spinal deformity and stabilize the spine in its new position while those segments of the spine fuse together or mend. These bones ultimately heal into one solid piece leading to spinal stability and preventing further progression. The physicians at Virginia Spine Institute use bone graft harvested from the patient's spine as well as biologic protein to achieve spinal fusion. These techniques make it much more likely that the spine fusion will occur correctly. The physicians at the Virginia Spine Institute do not routinely harvest bone graft from the patient's hip or iliac crest as this leads to increased pain and prolongs recovery time.
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