Vertebral Body Tethering (VBT)

What it is and why we do it

Vertebral body tethering is a way to treat scoliosis in a child who still has meaningful growing to do, without fusing the spine. Screws are placed in the side of each vertebra along the curve, and a strong, flexible cord (the tether) is attached to them and tightened. The tightened cord partly straightens the curve in the operating room. Then the child's own growth does the rest: the tethered side of each bone grows a little less and the open side grows a little more, so the spine straightens further over the following months and years. This is called growth modulation. Because nothing is fused, the spine keeps bending and twisting.

I offer tethering for idiopathic scoliosis in a growing child with a curve of roughly 30 to 65 degrees that is still flexible, when bracing has not worked or cannot be tolerated. The amount of growth left is the single most important factor. A hand X-ray tells me where your child is on the growth clock. Too much growth left and the curve can overcorrect; too little and the tether cannot do its work. Larger, stiff curves, curves with a lot of kyphosis, and most non-idiopathic curves are better treated with fusion.

The device

I offer tethering with the REFLECT Scoliosis Correction System, made by Globus Medical. It was authorized by the FDA in May 2023 under the Humanitarian Device Exemption pathway, for skeletally immature patients with progressive idiopathic scoliosis and a major curve of 30 to 65 degrees who have failed or cannot tolerate bracing. "Humanitarian" means the device treats a condition that affects a small number of people each year, and that the FDA has found it safe and probably beneficial, while long-term effectiveness is still being studied. Under this pathway the device's effectiveness has not been demonstrated to the standard required for fully approved devices, and a hospital must have its own review board's approval in place to use it. A study following patients for five years after surgery is under way. The other tethering system approved in the United States, The Tether, was authorized in 2019 under the same pathway, and the two work the same way.

What happens during surgery

Your child lies on their side under general anesthesia. Through a few small incisions between the ribs, using a camera (thoracoscopy), I place a screw in the side of each vertebra in the curve, then pass the cord and tighten it one level at a time while watching the correction on X-ray. For curves that reach into the low back, one of the incisions is a little longer so I can reach the lumbar spine. Nerve monitoring runs throughout. The surgery takes about four to five hours. A small chest tube drains the lung space for a day or two.

Recovery

Most children walk the day after surgery and go home in two to four days. Pain is managed with a plan that limits opioids. School usually restarts in one to three weeks. Sports wait until the six-week visit, after which most children return to everything they did before, including contact sports and gymnastics, with no brace. The curve keeps changing as your child grows, so I check X-rays every few months at first and then every six months until growth is finished.

The hybrid option: thoracic fusion with a lumbar tether

Some children have two structural curves, one in the chest and one in the low back. Fusing both means a long fusion down to the lower lumbar spine, which takes away motion where the spine needs it most for bending and sports. Tethering both curves preserves motion but gives a less predictable correction of the thoracic curve.

A hybrid construct takes the strengths of each: I fuse the thoracic curve from the back, where fusion gives a reliable, lasting correction, and I tether the lumbar curve through a small incision in the flank, which corrects it while leaving the lumbar discs free to move. The tether overlaps the bottom of the fusion so there is no gap between the two. Both parts are done in one operation.

Hybrid surgery suits a growing child whose lumbar curve is still flexible, bending to half its size or less on side-bending X-rays, and whose family values keeping the low back mobile. It was developed and reported by the team at Shriners Children's Philadelphia, where I trained, and the early results show both curves corrected to around 20 to 25 degrees. A 2026 comparison with long fusion found that hybrid patients kept more lumbar flexibility and trunk strength, at the cost of the tether's own risks: about one in four tethers broke, most without symptoms, and a small number of patients needed a second surgery. The evidence is early, with follow-up of two to three years, and I will tell you that plainly when we decide together.

What to expect over the years

Tethering trades the certainty of fusion for motion and growth, and families should know the trade honestly:

• Correction continues with growth. In published series, curves of about 48 degrees on average improved to about 22 degrees over two or more years.
• Overcorrection happens in about one child in ten, when the spine keeps straightening past neutral. It is more likely in the youngest patients, which is why timing matters. It is treated by loosening or cutting the cord in a small procedure.
• The cord can break. Breakage is common after the second year and is usually silent. Many broken cords never need anything done, because the correction gained during growth stays. Some lead to a second surgery.
• About one child in ten needs a second operation of some kind, and fewer than one in ten is converted to a fusion.
• The lung space, the diaphragm, and the large vessels are near the screws, and the nerves to the leg run past the lumbar levels. Nerve monitoring and careful placement protect them. Serious injury is rare.

The science: for the curious

Bone growth plates grow less under compression and more under tension. A curved spine loads its own growth plates unevenly, which is why a curve in a growing child tends to worsen. A tether on the outer side of the curve reverses that: it compresses the side that was growing too much and unloads the side that was growing too little. Fusion stops the problem by stopping growth and motion; tethering steers growth instead. That is why the amount of growth remaining is everything, and why the results depend on choosing the right child at the right time.

Learn more

Scoliosis Research Society, Emerging technologies (vertebral body tethering): srs.org (opens in a new tab)

Globus Medical, REFLECT Scoliosis Correction System: globusmedical.com (opens in a new tab)

U.S. Food and Drug Administration, REFLECT Scoliosis Correction System (H210002): fda.gov (opens in a new tab)

Watch

How the REFLECT tether works

This handout is general education about this procedure and does not replace the specific plan, risks, and consent discussion we have together for your child. Your own situation may differ: if anything here does not match what we talked about, what we talked about wins, so please ask me.