Congenital Scoliosis
Surgery
An operation is sometimes necessary to address spinal deformity in the young child, and the decision to do these procedures is based on many factors. If the child's curve has shown progression despite bracing or casting, something will need to be done. The dilemma faced by the surgeon is how to stop the progression of a curve without adversely affecting future growth. Sometimes this is unavoidable, as most operations work by stopping abnormal spinal growth in a procedure called spinal fusion.
In Situ Spinal Fusion
Spinal fusion is a procedure performed to stop growth of the spine. It can be done from the back (posterior) or through the chest (anterior). The joints of the spine are removed, and a bone graft is placed; when the bone heals there will be a fusion mass, or one solid piece of bone. The goal is for the many vertebrae of the spine to become one segment and stop growing crooked. In situ fusion means that the curve will be fused "where it is" with little or no correction of the spine. Sometimes instrumentation (rods, hooks, and screws) may be placed to help straighten the spine slightly and act as an internal brace for the bone graft that will form the fusion mass. When implants are not used, usually in young children, the child may need to wear a brace following the operation.
The goal of an in situ spinal fusion is to address the problem early, before it becomes a serious deformity. For example, if a pediatric spine surgeon sees a child with a 40° curve that has a poor prognosis (high chance to progress), he/she may elect to perform a limited spinal fusion to prevent the curve from getting any bigger. It is generally a safer procedure than those that correct the curvature of the spine. The results of a procedure to correct the curve at a young age can be unpredictable, as continued growth of the spine in other areas can cause the curve to progress or rotate (twist around).
Hemi-epiphysiodesis
This surgical procedure is aimed at stopping abnormal growth on one side of the spine with the hope that continued growth on the other side will result in correction of the curve over time. Every curve has a concave and convex side. (need image here) If the growth centers are removed and spinal fusion is performed on the convex side, the concave side might continue to grow, possibly improving the curve. As noted, these procedures can be unpredictable in young children with abnormal vertebrae in their back.
Hemivertebra Resection
Some young children with scoliosis may have abnormally shaped vertebrae in their back that causes the curve. Normal vertebrae are shaped like rectangles. A hemivertebra is shaped like a triangle. (Figure 3) When this hemivertebra is located at the bottom of the spine it can tilt the base of the spine and cause the child lean to one side. In other parts of the spine, depending on the number of hemivertebrae present, severe deformity can develop. Depending on your child's situation, this hemivertebra may be removed from the front, back, or both parts of the spine. Once the hemivertebra is removed the vertebrae above and below it are fused together, often with instrumentation. Most children will wear a brace or cast after the operation until the spine heals. This operation has inherent risks involved, including bleeding and neurologic injury, but good spinal correction is often achieved.
Figure 3. Three-dimension CT scan of the spine showing a hemivertebra (partially formed vertebra).
Growing Rods
Most operations that address spinal deformity in the young child work by stopping growth. This may have unfavorable effects on growth of the thorax, lung development, and size of the trunk. The theory of the growing rod operation is to allow for continued controlled growth of the spine. This is done through the back of the spine. In general, the curve is spanned by one or two rods under the skin to avoid damaging the growth tissues of the spine. The rods are then attached to the spine above and below the curve with hooks or screws. The curve can usually be corrected by fifty percent at the time of the first operation. The child then returns every six months to have the rods "lengthened" approximately one centimeter to keep up with the child's growth. This is usually an outpatient procedure performed through a small incision. Most children will have to wear a brace to protect the instrumentation. When the child becomes older and the spine has grown, the doctor will remove the instrumentation and perform a formal spinal fusion operation. In the past, this procedure had a very high complication rate, most of which were related to the instrumentation (hook dislodgement, rod breakage). Newer techniques are more promising but treatment with growing rods remains a long, difficult therapy for the child.
VEPTR Expansion Thoracoplasty for Thoracic Insufficiency Syndrome
Vertical Expandable Prosthetic Titanium Rib (VEPTR) expansion thoracoplasty was recently approved by the Food and Drug Administration for treatment of thoracic insufficiency syndrome in skeletally immature patients. Thoracic insufficiency syndrome (TIS) is usually associated with uncommon three-dimensional deformities of both the spine and rib cage. Several types of VEPTR based expansion thoracoplasties operations can be used for different types of deformities to gain chest volume for growth of the underlying lungs while indirectly correcting the scoliosis without spine fusion. VEPTR surgery is extensive, devices are placed under the scapula (shoulder blade) and are attached to the ribs near the neck and continue down to either the spine, or the ribs near the waist, this helps to stabilize the surgically expanded chest wall constriction (expansion thoracoplasty). To accommodate later growth, the devices are expanded twice a year in outpatient surgery through small incisions. Currently, there are a limited number of institutions offering VEPTR surgery. Your child's spine surgeon can advise whether your child's condition is appropriate for VEPTR treatment and provide referral information, if needed. Some centers are using the VEPTR device as a means to straighten the spine indirectly via the ribs and chest wall.