Scoliosis Surgery Techniques
If your child requires surgery for scoliosis, the procedure used will be selected according to the characteristics of the symptoms and the primary syndrome. The procedure chosen will be based upon your child's specific case. With any of the surgical options, maximizing nutrition and medical status prior to surgery are critical to minimize complications.
In Situ Spinal Fusion
This procedure fuses together vertebrae to stop progression of scoliotic curves.
- In situ fusion means that the curve will be fused "where it is" with little or no correction of the spine. The goal is to address the curvature early, before it becomes severe (e.g., a child with a 40°curve that has a poor prognosis).
- It is performed from the back (posteriorly), through the chest (anteriorly), or through a combined approach.
- 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—which replaces the spine joints—that will form the fusion mass, or one solid piece of bone.
- When instrumentation is not used, usually in young children, the child may need to wear a brace, or be placed in a cast, following the operation. In general, in situ fusion is a safer procedure than those that provide more correction in the curvature of the spine.
Aimed at stopping abnormal growth on one side of the spine with the hope that continued growth on the other side will correct the curve over time.
- Every curve has a concave and convex side. 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.
- In young children, this procedure can be challenging and unpredictable. This procedure is typically done for patients with congenital curves (where the bones are not normally formed).
An indication for young children with scoliosis with abnormally shaped vertebrae (triangular vs. rectangular) in their spine who have a “trunk lean” or a progressive curve.
- In a resection, hemivertebra(e) may be removed from the front, back, or both parts of the spine, depending on the child's situation.
- Once a 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, including bleeding and neurologic injury, but good spinal correction is often achieved.
Spine and Rib-Based Growing-Rod Operation
Uses a spine-based or a rib-based system (i.e., VEPTR) where the curve is spanned by 1 or 2 rods under the skin to avoid damaging the growth tissues of the spine.
Rods are attached to the spine or ribs above and below the curve with hooks or screws at either end of the rod. Limited fusion is performed at each of the hook/screw foundation sites.
- The curve can usually be corrected by 50% at the time of the first operation.
- After the rods are implanted, patients are prescribed a special brace to wear for several months.
- The child then returns every 6 months to have the rods "lengthened" until the spine is closer to maturity. This procedure is typically performed on an outpatient basis with the implants being made through a small incision. These frequent surgeries, mostly through the same incision site, can cause infection in the skin tissue susceptible and other skin problems.
- 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 dislodgment, rod breakage/fractures). Newer techniques are more promising as treatment with growing rods remains a long therapy for the child.
- Doesn't interfere with normal spinal growth and may even have a potential for growth stimulation beyond the expected growth rate.
Figure. Growing rods are a spine-based system where the curve is spanned by one or two rods under the skin to avoid damaging the growth tissues of the spine. The rods are attached to the spine above and below the curve with hooks or screws at either end of the rod.
Magnetically Controlled Growing Rod (MCGR) Procedure
The idea of non-invasive multiple lengthening without the need for anesthesia and open surgery is appealing given the direct relationship between high complications and repeated surgeries.
- These devises allow for lengthening to be performed in the doctor's office.
- They are composed of an implantable rod, an external remote controller (ERC) and accessories. The titanium rod includes a telescopic actuator portion that holds a small internal magnet. Rotation of the magnet remotely by use of the ERC causes the rod to be lengthened or shortened. The rod is implanted and secured using standard fixation components, such as hooks and/or pedicle screws as anchors.
- Magnet driven rods are now being used for select patients and preliminary results have shown to be able to reduce morbidities, cost, and decrease stress for patients and parents.
- They have been implanted in cases of both idiopathic and neuromuscular scoliosis.
- Unlike distraction techniques (growing rods), repeated surgeries are not required.
- The Luque trolley uses wires to allow the spine to grow in the desired direction as the wires slide along contoured rods.
- In the Shilla technique initial correction is achieved by instrumentation and fusion at the apex, or most deformed portion of the spine. Specially designed screws are placed at the ends of the curve and slide along the contoured rods guiding the direction of the spine as it grows. Patients who have undergone the Shilla technique are usually placed in a special brace for 3 months after the surgery.
Compression-Based Growth-Friendly Surgery
Intended to produce relative growth inhibition on the convex side of the curve.
- This technique can be used in children who are still growing, have a progressive curvature that measures less than 35º, and who are able to tolerate open or endoscopic exposure of the spine.
- By placing special vertebral body staples or tethers on the convex side of the curve, growth is inhibited on that side. The idea is that the scoliosis may then correct through more growth on the concave side of the curve.
Anterior Spinal Fusion with Instrumentation
May be performed in addition to the posterior approach, depending on the surgeon's determination of how much growth may remain for the patient.
- Performed through an incision in the patient's side or rib cage, or through small incisions between the ribs, aided by a camera (thoracoscopic fusion).
- Mitigates the "crankshaft phenomenon”, which is curve progression that can occur after posterior (rear) fusion due to continued growth of the vertebrae. (Curves sometimes continue to grow by rotating around the original surgical fusion.)
- Typically performed around the same time (shortly before or after) as the definitive posterior operation.
- The decision to undergo the additional (anterior) surgery required to prevent crankshaft curve progression is dependent on the age of the child at the time surgery is selected.
Posterior Spinal Fusion with Instrumentation
Performed to stop curvature of the spine and achieve permanent correction. The procedure provides permanent stabilization in the corrected position by removing the joints between the vertebrae to be fused.
- All the vertebrae involved in the curve are prepared and bone graft (either from the pelvis, ribs, or from the bone bank) is placed in each space resulting from joint removal.
- Over time (4 to 6 months), the graft adheres to the vertebral bone, and the operated portion of the spine heals into a solid block of bone which cannot bend, thus eliminating further progression of the curve.
- Typically, in a child who has reached an appropriate age for definitive fusion, instrumentation will also be placed when the fusion is performed. The instrumentation rigidly “fixes” the spine internally through rods being attached to screws, hooks and wires (“anchors”) at multiple sites along the curve so that the corrected position is carefully preserved while the fusion is completed over a 4- to 6-month period.
- Depending on the flexibility of the curve and any preceding treatment (such as traction), there may even be additional correction of the curve achieved by the application of the instrumentation.
- Often the patient does not need a cast or brace if the internal instrumentation is felt to be adequate at the time of surgery.