For decades, significant scoliosis in a growing child meant one thing: fusion. The curve is straightened with rods and screws, and the affected section of spine is permanently locked solid. It works. But that section never bends again.
Vertebral body tethering (VBT) offers a genuinely different approach — and for the right child, it is transformative.
How VBT actually works
Screws are placed along the outer (convex) side of the curve — the side that has grown too long. A strong, flexible cord is attached to those screws and tensioned. That tension gently slows growth on the long side, while the shorter, inner side of the curve continues to grow normally.
Over the following months and years, the child's own growth gradually straightens the spine. The surgeon is not forcing the spine straight — they are steering how it grows.
The critical consequence: nothing is fused. The discs are left intact and the spine keeps bending and twisting.
Why "it still bends" matters so much
Ask any teenager what worries them about scoliosis surgery, and it is rarely the scar. It is: will I still be able to play, dance, bend, do sport?
After a long fusion, the answer is qualified. The spine is straight and stable, but that segment is rigid, and the levels above and below take up the extra movement — which over decades may wear them out faster (adjacent-segment degeneration).
After VBT, the spine retains its flexibility. For an active child, a dancer, a young athlete, that is not a cosmetic detail. It is the whole point.
Who is actually a candidate
VBT is not for every child, and any surgeon who says otherwise is overselling it. Broadly, a good candidate has:
- Significant remaining growth. This is the non-negotiable one. VBT works by using growth. In a child who has finished growing, there is nothing left to steer, and the operation cannot work. This is why timing matters more here than in almost any other spinal procedure.
- A curve in the range that is too large for bracing but not yet extreme
- A flexible curve — it should correct substantially on bending X-rays
- A suitable curve pattern and location
- Good bone quality and no underlying condition that would compromise fixation
Determining this requires X-rays including bending films, an assessment of skeletal maturity, and an honest conversation about timing.
The honest part: what can go wrong
This is where most articles go quiet. They shouldn't.
VBT is a newer procedure than fusion, and the published results reflect that. Across the literature:
- The tether can break. Cord breakage is reported in a substantial minority of cases. Sometimes it happens after correction is already achieved and causes no problem at all. Sometimes it means the correction is lost.
- Overcorrection. If growth continues after the curve has been fully corrected, the spine can be pulled past straight, into a curve the other way. This may require a further procedure to release the tether.
- Undercorrection. If there is less growth remaining than expected, the curve may not straighten enough.
- Reoperation. Unplanned further surgery is meaningfully more common than after fusion.
- Some patients ultimately convert to a fusion anyway.
Set against that, fusion is the more predictable operation. It reliably delivers a straight, stable spine — at the cost of permanent stiffness in the fused segment.
How to think about the choice
This is the real trade-off, stated plainly: VBT offers a flexible spine with a higher chance of needing further surgery. Fusion offers a more predictable result at the cost of permanent rigidity.
Neither is simply "better". Which is right depends on your child's curve, their remaining growth, how active they are, and your family's appetite for that trade-off — after being told the real numbers, not a sales pitch.
What is not acceptable is being offered only one option because that is the only one the surgeon performs.
Concerned about back or neck pain? Dr. M.D.S. Sasidharan offers endoscopic, minimally invasive and non-fusion spine care at Iswarya Hospital, OMR, Chennai. Book a consultation to find out whether you can avoid surgery altogether.
Frequently Asked Questions
Who is eligible for vertebral body tethering (VBT)?
The essential requirement is significant remaining growth, because VBT works by steering the spine's growth. Beyond that, the curve should be flexible (correcting substantially on bending X-rays), of a suitable size and pattern, with good bone quality. A child who has finished growing cannot benefit from VBT.
Will my child still be able to play sport and bend after VBT?
That is the central advantage of VBT — no part of the spine is fused, so it retains its flexibility. Most children return to sport and full activity after recovery. This is precisely why it is attractive for active children, dancers and young athletes, for whom a long fusion means permanent stiffness.
What happens if the tether breaks?
Cord breakage occurs in a significant minority of cases. If it happens after correction has already been achieved, it may cause no problem at all. If it happens earlier, correction can be lost and further surgery may be needed. Unplanned reoperation is more common after VBT than after fusion — this should be discussed honestly before you consent.