The goals of scoliosis surgery are threefold:
- Straighten the spine as much as possible in a safe manner
- Balance the torso and pelvic areas
- Maintain the correction long term
It takes a two-part process to accomplish these goals:
- Fusing (joining together) the vertebrae along the curve
- Supporting these fused bones with instrumentation (steel rods, hooks, and other devices) attached to the spine
Many surgical variations use different instruments, procedures, and surgical approaches to treat scoliosis. All of the operations require meticulous skill. In most cases, success depends less on the type of operation than on the skill and experience of the surgeon.
The cause of scoliosis often determines the type of procedure. Other determinants include the location of the curve (thoracic, thoracolumbar, or lumbar); single, double, or triple curves, and any rotation that may be present; and how large the curve is.
Parents of patients or adult patients should not be shy. They should always ask the surgeon and hospital about their experience with the specific procedures being considered.
Idiopathic Scoliosis. Surgery is usually recommended for the following children and adolescents with idiopathic scoliosis:
- All young people whose skeletons have matured, and who have a curve greater than 45 degrees.
- Growing children whose curve has gone beyond 40 degrees. (There is still some debate, however, about whether all children with curves of 40 degrees should have surgery.)
Neuromuscular Scoliosis (such as meningomyelocele and cerebral palsy).Surgery is done when curving has progressed to 40 degrees or more in patients younger than 15 years old. However, this patient group is considered to be at increased surgical risk, particularly those patients with feeding problems, malnourishment, or respiratory difficulties due to the scoliosis. They also have an increased risk of bleeding complications.
Congenital Scoliosis. These children are at a higher risk of neurological injury when having surgery. However, chances for success are higher when surgery is performed at a younger age.
Adult Scoliosis. Due to the increased chance of complications, health care providers are more reluctant to do surgery on this patient group.
Procedures will differ depending on whether a child has idiopathic scoliosis, or scoliosis due to muscle and nerve disorders (such as muscular dystrophy or cerebral palsy). In the latter cases, children also need a team approach to reduce their risks for serious complications. Average hospital stay is 4-5 days, with 4-6 weeks of recovery time. About 3-10% of surgical patients will require additional surgery within 10 years.
Before the operation, a doctor conducts a complete physical examination to determine leg lengths, muscle strength, lung function, and any postural abnormalities. The patient receives training in deep breathing and effective coughing to avoid lung congestion after the operation. The patient should also receive training in turning over in bed in a single movement (called log-rolling), before the operation. Psychological intervention, using cognitive-behavioral methods that help young patients cope, may be very helpful in reducing anxiety and pain after surgery.
Patients are encouraged to donate their own blood before the operation, for use in possible transfusions. The patient should have no sunburn, rashes, or sores on the back before the operation. These conditions could increase the risk for infection.
Most scoliosis operations involve fusing the vertebrae. The instruments and devices used to support the fusion vary, however.
In the fusion procedure, the surgeon will:
- Raise flaps to expose the backs of the vertebrae that lie along the curve.
- Remove the bony outgrowths along the vertebrae that allow the spine to twist and bend.
- Lay matchstick-sized bone grafts vertically across the exposed surface of each vertebra, being careful that they touch adjoining vertebrae.
- Fold the flaps back to their original position, covering the bone grafts.
- These grafts will regenerate, grow into the bone, and fuse the vertebrae together.
Graft Materials. A surgeon takes bone grafts from the patient's hip, ribs, spine, or other bones (these grafts are called autografts). This is the best quality bone. However, because autografts are taken directly from the scoliosis patient, the operation is longer, and the patient has more pain afterward. Researchers are investigating allografts, bone grafts taken from another living person or a cadaver. This would reduce the pain and duration of the operation. Allografts, however, pose an increased risk for infection from the donor.
Newer graft materials that are being used include a biologically-manufactured human bone protein instead of bone grafts. RhBMP-2 (INFUSE Bone Graft) contains a bone morphogenetic protein (BMP) that helps the body grow its own bone.
Healing. The healed fusions harden in a straightened position to prevent further curvature, leaving the rest of the spine flexible. It takes about 3 months for the vertebrae to fuse substantially, although 1 - 2 years are required before fusion is complete. Fusion stops growth in the spine, but most growth occurs in the long bones of the body (such as in the legs), anyway. Patients will most likely gain height from both growth in the legs and from the straighter spine.
Patients may walk at a slightly slower pace after fusion, but balance may improve, and sports activities are not restricted after the procedure.
Harrington Procedure. Until 10 years ago, the standard instruments used in fusion procedures were those of the Harrington procedure, first developed in the 1960s. It involves placing one or more steel rods to position the vertebrae for fusion.
The Harrington procedure is very difficult to undergo, particularly for young people, and although the operation can achieve a 50% correction of the curve, studies have reported a 10 - 25% loss in this correction over time. The procedure does not correct the rotation of the spine and, therefore, does not improve an existing rib hump that was caused by the rotation. Complications are fairly common, but the operation does not interfere with normal pregnancies and deliveries later in life.
Cotrel-Dubousset Procedure. The Cotrel-Dubousset procedure corrects not only the curve but also possibly rotation. It does not cause flat back syndrome.
With this procedure, a surgeon cross links parallel rods for better stability in holding the fused vertebrae. Patients often go home in 5 days and may be back in school in 3 weeks.
Other Forms of Instrumentation. Other instrumentation procedures have refined the hardware used in the Harrington and Cotrel-Dubousset operations. They include the Texas Scottish Rite Hospital Luque, and Wisconsin Segmental Spine instrumentations.
Approaching the Spine
Posterior Approach (Through the Back). Many surgeons use a posterior approach for scoliosis, which reaches the surgical area by opening the back of the patient. It has been the gold standard for decades and is generally used with Harrington instrumentation. The posterior approach has advantages and disadvantages:
Anterior Approach (Through the Front). Increasingly, surgeons are using the anterior approach, in which the surgeon performs the operation through the chest wall (called a thoracotomy). With the anterior approach, the surgeon makes an incision in the chest, deflates the lung, and removes a rib in order to reach the spine. This rib can be used during the operation as a strut to support the spine. It also may be repositioned within the patient until it is used for bone grafting during fusion.
The Combined Anterior-Posterior Approach. The combination approach uses an anterior approach first, which allows better correction of the problems. The fusion part of the operation is done with the posterior approach. This is a very long and complex procedure. It appears to be safe, however, and is proving to be useful, even in very young patients, for preventing the crankshaft phenomenon. It also may correct large rigid curves and specific severe curves in the thoracic spine.
Video-Assisted Thoracoscopic Surgery (VATS). The anterior thoracoscopic surgery uses a video-assisted anterior approach and recently-developed spinal instrumentation.
This procedure is complicated, and few surgeons are trained to perform it. The surgery is generally used only for single curves in the upper back, or for patients with a curve in the upper back and a compensating curve in the lower back. Some surgeons are now able to operate on areas below the diaphragm, including the lumbar spine. The patients must still wear a brace for 3 months after surgery. Long-term studies to compare results of VATS to those of standard procedures are needed.
These new treatments have shown some early positive results, but more research will be needed to determine their true value.
Complications of All Procedures
Complication rates are high with any of the procedures, including the standard Harrington method and the newer Cotrel-Dubousset procedure.
Complications for all procedures include allergic reactions to anesthesia and other problems.
Bleeding. Standard procedures increase the risk for major blood loss during the procedure. Patients are encouraged to donate blood before the operation for use in possible transfusions. Children sometimes need more than one transfusion following surgery. Researchers are investigating various methods for reducing the need for transfusions, such as the use of preoperative erythropoietin (rhEPO), which increases production of red blood cells in the bone marrow. Newer endoscopic techniques are reducing the need for transfusions.
Infection. Infection is always a risk with any operation. One study reported changes in the immune system for about 3 weeks after surgery, which indicated a greater risk for infection. Researchers recommended being very vigilant for signs of infection, including those in the pancreas and urinary tract. Doctors also recommend antibiotics, given before and after surgery.
Nerve Damage. Patients often worry about neurological injuries, but the risk is actually very low. In general, nerve injury occurs in 1% of patients, with the risk highest in adults. If neurological damage occurs, it most often causes muscle weakness. Paralysis is very rare and can be prevented using monitoring techniques during the operation. Nearly all monitoring procedures use a so-called wake-up test, in which the patient is brought out of anesthesia during or at the end of the procedure and assessed for sensations to be sure no injury has occurred. One simple method is to wake patients up in the middle of their operations and ask them to wiggle their toes. More sophisticated methods measure the electrical activity of the spinal cord. If the monitor indicates a fall in electrical response and possible injury, the surgeon makes adjustments to avoid further damage to the spinal cord.
Pseudoarthrosis. If the fusion fails to heal, pseudoarthrosis, a painful condition in which a false joint develops at the site, may develop. In one study, teenagers who smoked and heavier adolescents (over 154 pounds) who had hyperkyphosis (hunchback) were at higher risk for this complication. The anterior approach may pose a higher risk for pseudoarthrosis. One study reported that pseudoarthrosis may be underdiagnosed, and rates may average 20% after surgery, therefore acting as a major contributor to post-surgery pain.
Disk Degeneration and Low Back Pain. Fusion in the lumbar area produces great stress on the lower back and eventually can cause disk degeneration. Loss of trunk mobility, balance, and muscle strength from surgical treatments can also cause lower back pain and chronic problems in future years. Patients who are surgically treated with fusion techniques lose flexibility. Their back muscles may be weakened if they were injured during surgery. In most cases, however, the consequences are mild to moderate.
Lung Function. Some patients may develop serious lung problems after surgery. These complications are highest in children whose scoliosis is due to neuromuscular problems, such as spina bifida, cerebral palsy, or muscular dystrophy. Lung problems can develop up to 1 week after surgery. Lung function may not become completely normal until 1 - 2 months after surgery.
Other Complications. Other problems can include, but are not limited to, the following:
- Hooks dislodging or a fused vertebra fracturing
- Pancreatitis (inflammation of the pancreas) -- among adolescents, this complication tends to occur more often in those who are older or who have a lower body mass index.
- Intestinal obstruction
Click the icon to see an image of gallstones.
Patients must do breathing and coughing exercises shortly after the procedure and continue them through the recovery process to rid the lungs of congestion. The patient is usually able to sit up the day after the operation. Most patients can move independently within a week. A brace may be necessary, depending on the procedure. With the anterior approach in the upper back, patients may have some trouble with activities involving the arms and hands, such as tying shoes and cutting food. However, occupational therapy using stretching and strengthening exercises, may allow for full resumption of daily activities within 3 months, including dressing, bathing, and grooming.
Some pain always follows these procedures, requiring intravenous administration of strong painkillers right after the operation (endoscopic procedures may require only mild pain relievers). NSAIDs (nonsteroidal anti-inflammatory drugs, such as aspirin, Motrin, and Advil) for pain relief right after fusion may increase the risk for fusion failure. Consult with your doctor before you or your child take any pain medication after surgery.
Patients are often concerned that surgery will stiffen their backs, but most cases of scoliosis affect the upper back, which has only limited movement, so that patients do not notice much difference. It may take a year or more for muscle strength to return. In some cases, the operation cannot completely correct the curve, and one leg may be shorter than the other. Heel lifts may help in this case.
Revision (Salvage) Surgery
Patients may need a corrective procedure called revision or salvage surgery, usually for one of these reasons:
- Failure of the previous procedure
- Curvature progression around the fusion site
- Disk degeneration
- Poor posture alignment
Minimally Invasive Surgery
Growing Rod Technique. This technique is used for very young children in whom bracing has not helped. Instead of doing spinal fusion, doctors surgically insert a rod into the patient's back. The patient will have more surgeries every 6 months to extend the rod so that the spine can continue to grow. Some growing rod techniques use a single rod, while others use two rods. Studies suggest that dual rods are stronger than single rods, which may help provide better spinal stability and correction.
Vertebral Body Stapling and Anterior Spinal Tethering. Surgeons do these procedures using an anterior approach surgery and without fusion. Vertebral body stapling is an experimental technique that may prevent curve progression in some young patients with curves less than 50 degrees. It involves stapling the outer curve of the side of the spine facing the chest, which helps stabilize and reduce progression of the inner curve. The procedure uses a special metal device that is clamp-shaped at body temperature. The device can be straightened when subjected to cold temperatures and inserted into the spine. When warmed up, the staple returns to its clamp shape and supports the spine. While short-term results have been favorable, long-term results are not yet available.