What are spinal degenerative deformities?
The spine is a column of 24 moveable bones called vertebrae that are connected to one another by ligaments. The bones are separated by discs, which act as shock absorbers and give the spine flexibility. Each vertebra has a three-joint complex with a large disc in the front and two facet joints in the back. This strong, tripod design keeps the bones connected and aligned, one on top of the other, while allowing our spine to bend and twist.
When viewed from the front the spine is perfectly straight, but from the side it has three curves. The curvature enables us to stand upright, absorbs the shock of footsteps, and positions our head naturally over the pelvis and hip. At the neck, or cervical level, the normal spine arches slightly inward toward the jaw in a curvature called lordosis. The spine arches out slightly at the chest level (kyphosis), and it curves inward again (lordosis) at lumbar level, or lower back.
Spinal alignment and curvature can be altered in many ways. They can occur as a result of a birth defect, a child’s growth, aging, injury, or previous spine surgery. The most common type of spinal deformity in adults is degenerative scoliosis.
Scoliosis
Scoliosis is an abnormal side-to-side curvature of the spine. Idiopathic (of unknown cause) scoliosis develops in children and can persist into adulthood. Degenerative scoliosis develops in adults when their facet joints and discs begin to deteriorate. The facet joints give the spine flexibility, enabling us to twist, stretch, or curl up on the couch. When these joints deteriorate, the spine bones can tilt, rotate, and begin to shift to one side.
Scoliosis is not a single disease. It falls along a spectrum, from mild to moderate to severe. Symptoms include:
- Pain or stiffness in the mid-to-lower back
- Numbness or weakness in the legs or feet.
In more severe cases, scoliosis can cause shooting pain down the leg (sciatica), an inability to stand up straight, and an inability to walk more than a short distance. Symptoms of severe, progressive scoliosis are similar to those of stenosis, but with visible spinal imbalance. This imbalance can result in strain on the hips and knees, the inability to walk a straight line, and falls.
Kyphosis
Kyphosis is an abnormal forward rounding (more than 50 degrees of curvature) of the spine. In the upper (thoracic) back, kyphosis is commonly due to osteoporotic compression fractures. It can also occur in the lower (lumbar) spine. Patients with kyphosis have lost their ability to stand up straight. Hunched over while standing, they may become quickly fatigued and have difficulty talking to others or maintaining eye contact. They also may have difficulty lying flat.
Lordosis
Also called swayback, lordosis is a condition in which the spine curves significantly inward at the lower back, giving a backward leaning appearance.
What causes spinal deformities?
As you get older, your bones undergo degenerative changes that are part of the natural aging process. When joints deteriorate, arthritis can develop, and the spinal column can shift sideways. Mild to moderate spinal deformity is common in older adults, but it can also affect adults in their 50s and younger. An estimated 60% of people over age 60 may have mild degenerative scoliosis.
Other conditions that might cause degeneration include:
- Arthritis from degenerative discs and facet joint syndrome, resulting in the loss of normal vertebral alignment.
- Osteoporosis (loss of bone mass) and vertebral compression fractures.
- Previous spine surgery (adjacent level disease). The passage of time after a spine surgery is a leading cause of spinal deformity.
The aging of joints, combined with a fracture at a level above a previous fusion, can also cause a significant deformity. Simply removing material from the spine can cause a problem down the road. It may reduce or eliminate pain in the near term, but symptoms can return later because of instability of the spine. Think of the game, Jenga. When you remove a block from the tower, what goes on globally in the spinal balance and pathology is important.
How is a spinal deformity diagnosed?
Diagnostic tests include a physician examination, x-rays, CT scan, MRI, or myelogram.
- X-rays create images of the bones in your spine and show whether any of them are too close together or whether you have arthritic changes, bone spurs, fractures, or slippage of the vertebrae. Special long-cassette x-rays are taken in standing, flexion, and extension to measure angles and monitor curve progression.
- Computed Tomography (CT) scan is a noninvasive test that uses an x-ray beam and a computer to make 2-dimensional images of your spine. It may or may not be performed with a dye (contrast agent) injected into your bloodstream. It is useful for viewing changes in bony structures.
- Magnetic Resonance Imaging (MRI) is a noninvasive test that uses a magnetic field and radiofrequency waves to give a detailed view of the soft tissues of your spine. Unlike an x-ray, nerves and discs are clearly visible. It may or may not be performed with a dye (contrast agent) injected into your bloodstream. MRI is useful in evaluating soft-tissue damage to the ligaments and discs, and assessing spinal cord injury.
- Myelogram is a specialized X-ray where contrast dye is injected into the spinal canal. A fluoroscope then records the images formed by the dye. Myelograms can show a nerve being pinched by a disc, bony overgrowth or stenosis. The dye gives a picture of the spinal canal, spinal cord, and nerves in detail. A CT scan follows the test.
What are the available treatment options for a spinal deformity?
Treatment for mild to moderate spine deformity in adults is determined by the severity of the symptoms, not the size of the curve. It begins with a trial period of pain management, physical therapy, and nonsurgical options. If pain is caused by inflammation of the facet joints, treatment involves facet joint therapy. If the curvature is mild, the deformity is not treated. If the curvature is severe, complex spinal surgery may be recommended. Barring serious “red flags,” such as a neurologic impairment, conservative care is used for 3 to 6 months before surgery is considered.
Using correct posture and keeping your spine in alignment are the most important things you can do for your back. The lower back (lumbar curve) bear most of your weight, so proper alignment of this section can prevent injury to your vertebrae and discs. You may need to make adjustment to your daily standing, sitting, and sleeping habits. You may also need to learn proper ways to lift and bend. If you smoke or are overweight, you may be able to reduce your symptoms by quitting smoking and/or achieving a healthy weight appropriate for your body frame.
Because good bone density reduces the risk of fractures in aging adults, you may be asked to undergo a bone-density scan to determine the strength of your bones. If osteoporosis is detected, your risk of a fracture to your spine is increased because your bones have weakened and become more brittle. Your doctor may prescribe a medication that slows bone loss.
Exercise and strengthening exercises are key elements to your treatment and should become part of your life-long fitness. Physical therapists can instruct you on proper lifting and walking techniques, and they will work with you to strengthen your back, leg, and stomach muscles. They will also encourage you to stretch and increase the flexibility of your spine and legs. Check with your doctor before you begin any new exercise program and be sure to see a physical therapist who specializes in spine rehabilitation.
Over-the-counter and prescription medications can help you cope with back pain.
Wearing a brace is often used for childhood scoliosis, but it will not straighten the adult spine. A brace may help reduce pain in the short-term, but it also will allow the muscles to get weaker, eventually leading to more back pain.
When is surgery considered for a spinal deformity?
Surgical options vary depending on the level of severity of the symptoms, the number of levels affected, and the type of deformity. A combination of different fusion and instrumentation techniques are used to treat the patient’s specific condition.
- Decompression: If the scoliosis is mild and is causing a pinched nerve at one level, then only that level is treated with a laminectomy.
- Fusion: A patient suffering from stenosis and scoliosis may require a spinal fusion to restore disc height when a vertebra has collapsed on a nerve. Fusion makes the vertebrae square in relations to each other and restores proper alignment. It involves joining two vertebrae with bone graft, which is held together with hardware that could include plates, rods, pedicle screws, or cages. The goal of the bone graft is to join the vertebrae above and below to form one solid piece of bone.
- Minimally invasive fusion: A lateral lumbar interbody fusion (LLIF) surgery is an option for some patients with scoliosis. The surgeon operates through a tube incision at the waist and avoids cutting the back muscles.
- Spinal reconstruction: Complex deformities and kyphosis often require the cutting of bone (osteotomy) and stabilization with long rods and screws in staged operations.