Revision Surgery After Vertebral Body Tethering (VBT) Failure or Anterior Scoliosis Correction (ASC) Failure

Dr. Zeeshan Sardar, MD, MSc, F.R.C.S.C
Co-Chief of Spinal Deformity Surgery • Director, Quality & Patient Safety • Medical Director, Spine Unit
Och Spine Hospital at NewYork-Presbyterian / Columbia University • New York, NY

Vertebral body tethering was approved by the FDA in 2019 as a growth-modulation alternative to posterior spinal fusion for selected patients with adolescent idiopathic scoliosis. Its appeal was genuine: a motion-preserving, fusionless approach that used the patient’s remaining skeletal growth to gradually correct the curve, without permanently locking the spine into a fixed position. For carefully selected patients, it works. For others — because of biology, curve pattern, implant mechanics, or the unpredictability of growth — it does not.

The first VBT procedures in the United States were performed in 2019 and 2020. Those patients are now young adults, 5 to 6 years out from surgery, reaching the follow-up window where the outcomes of this relatively new technology are becoming clear in the real world. Some are doing well. Others are facing the difficult news that their tether has broken, their curve has progressed, or their correction has failed — and that a second surgery may be necessary.

This page is written for those patients and their families. It explains what VBT failure looks like, what revision options exist, and what evaluation at a high-volume deformity center involves.

HOW VBT WORKS — AND WHY IT CAN FAIL

VBT is an anterior thoracoscopic procedure in which screws are placed into the vertebral bodies on the convex (outer) side of the scoliosis curve, and a flexible cord — the tether — is tensioned across them. The tension compresses the convex side of the spine, slowing growth there, while the concave side continues to grow relatively unimpeded. Over time, with continued skeletal growth, this differential growth is intended to progressively correct the curve. The procedure preserves motion at all treated levels, which is its principal advantage over posterior spinal fusion.

VBT’s dependence on continued skeletal growth is both its mechanism and its limitation. If a patient has less growth remaining than anticipated at the time of surgery, the growth-modulation effect is incomplete. If growth is asymmetric or unpredictable, the correction can go beyond what was intended — overcorrection, which produces its own problems. If the tether breaks — a recognized mechanical event — the corrective tension is suddenly lost, and the curve may resume its natural trajectory, or may behave differently depending on what growth remains and at what stage the breakage occurred.

PATTERNS OF VBT FAILURE

Tether Breakage

The tether is a flexible cord under sustained mechanical tension. It can break — at the cord itself, at a screw-cord junction, or at multiple points along the construct. Tether breakage is one of the most common mechanical events in VBT and is well-documented in published series. What happens after tether breakage depends critically on when it occurs:

  • Breakage after adequate correction and near skeletal maturity — in this scenario, the tether has done its job. The curve is corrected, growth is nearly complete, and the breakage is a mechanical event that does not meaningfully affect the outcome. Many published cases of tether breakage fall into this category and do not require revision surgery.
  • Breakage before adequate correction or with significant growth remaining — in this scenario, the corrective mechanism is lost prematurely. The curve may progress, particularly if the patient still has meaningful growth ahead. This is the pattern that most commonly leads to revision surgery.
  • Multiple-point breakage or complete construct failure — more extensive mechanical failure that typically requires earlier and more comprehensive revision planning.

Curve Progression Despite Intact Tether

Some patients experience inadequate correction or curve progression even when the tether remains structurally intact. This reflects the biological unpredictability of growth modulation: the curve does not correct as expected, either because insufficient growth remained at the time of surgery or because the growth response was not what the model predicted. These patients often have a structurally sound VBT construct on imaging but a clinical outcome that requires revision consideration.

Overcorrection

Overcorrection occurs when the growth modulation effect exceeds what was intended — the curve corrects past neutral and crosses to the opposite side, creating a new curve in the opposite direction from the original deformity. Overcorrection can produce significant trunk imbalance, shoulder asymmetry, and pain. The coronal imbalance from overcorrection may be cosmetically and functionally disabling and can require surgical intervention to address.

Undercorrection and Residual Deformity

Not all VBT failures are dramatic. Some patients reach skeletal maturity with a curve that is improved but still above the range that would have been considered acceptable — a 40° residual curve where a curve under 30° was the goal, for example. These patients may be stable and asymptomatic, or they may have a curve that continues to progress slowly in adulthood. Evaluation of the residual deformity in the context of skeletal maturity, symptoms, and rate of progression determines whether additional treatment is needed.

WHAT “NOT REQUIRING REVISION” ACTUALLY MEANS

Published literature and some center websites note that tether breakage “oftenly” does not require revision surgery. This is accurate but requires context to be useful to a patient.

Tether breakage that occurs after the correction has been achieved and near or after skeletal maturity does not require revision — the tether has completed its work. But tether breakage that occurs early, before adequate correction, with significant growth remaining, or in a curve that is now progressing on serial X-rays is a different clinical situation. The statement that “many cases don’t need revision” should not be interpreted as reassurance for patients who are experiencing curve progression after tether failure. Those are the cases that do need careful evaluation and, often, intervention.

If you have had a VBT procedure and are being told your tether has broken, the most important question is not simply whether the tether broke — it is what your most recent X-rays show about your curve, and whether it is stable or progressive.

REVISION SURGERY OPTIONS

When VBT failure does require surgical revision, three broad approaches exist. The right choice depends on the specific failure pattern, the patient’s skeletal maturity, the degree of curve, and the anatomy created by the prior VBT procedure.

1. Conversion to Posterior Spinal Fusion

Posterior spinal fusion (PSF) is the most common destination for VBT revision and is typically the approach of choice when skeletal maturity is reached or near, when the curve is significant and symptomatic, or when re-tethering is not technically feasible. PSF after VBT is fundamentally a revision deformity procedure — it is performed in the presence of prior anterior hardware (screws and cord remnants from the VBT), through altered anatomy, and with the goal of achieving correction and long-term stability in a spine that has already been operated on.

This is not a standard first-time posterior spinal fusion. The prior VBT alters the anterior spinal anatomy, the disc spaces, and potentially the vertebral bodies themselves (disc space narrowing and vertebral wedging can occur adjacent to VBT hardware). The surgeon performing PSF after VBT must have experience managing this specific anatomical situation. It requires planning for the existing hardware, assessment of whether anterior column issues need to be addressed before or during the posterior correction, and selection of fusion levels that account for both the current deformity and the prior instrumentation pattern.

The outcome of conversion to PSF after VBT failure is generally good in published series for appropriately selected patients, though the correction achieved may be somewhat less complete than what would have been obtained with primary PSF, reflecting the anatomical changes from the prior anterior procedure.

2. Re-tethering

In selected patients — typically those who still have significant skeletal growth remaining, whose tether broke early, and whose curve has not yet progressed to the range where fusion would be necessary — re-tethering (placement of a new tether, often extending or revising the prior construct) is an option. Re-tethering allows the growth-modulation strategy to continue in patients who genuinely still have growth remaining to harness.

Re-tethering outcomes are less predictable: the prior screw sites must be assessed for bone quality and fixation, the approach is through scarred anterior tissue, and the new tether must be tensioned to achieve the intended correction without the overcorrection risk of a first-time procedure in potentially stiffer anatomy.

3. Observation and Monitoring

For patients whose VBT has produced an imperfect but stable result — modest residual deformity at skeletal maturity, no significant symptoms, no documented progression — careful observation with periodic imaging is an appropriate and often preferred approach. Not every VBT that did not achieve its target correction requires immediate revision. The natural history of the residual curve at skeletal maturity is the relevant question: is it stable, or is it progressing? Serial standing X-rays at appropriate intervals answer this question.

WHY REVISION AFTER VBT IS COMPLEX

Revision after VBT is not a routine procedure, and it should not be treated as one. Several factors make it genuinely more demanding than primary scoliosis surgery:

  • Altered anterior anatomy. The prior thoracoscopic VBT procedure leaves anterior screws, residual cord material, and scar tissue in the thoracic or thoracolumbar cavity. Any subsequent anterior approach must navigate this anatomy. Even posterior procedures must account for the anterior hardware in planning the fusion levels and correction strategy.
  • Disc space changes. VBT applies sustained compressive force to the convex side of each instrumented disc space. Over time, this can produce disc narrowing and vertebral wedging adjacent to the screws — structural changes that affect both the flexibility of the spine and the options for correction at revision.
  • Limited published evidence base. VBT itself is a relatively new procedure. Revision after VBT is newer still, with a small published evidence base. The surgeon performing this revision is working from first principles of spinal deformity reconstruction applied to a specific anatomical situation, rather than from a large body of established revision-specific literature.
  • Emotional complexity. Patients who chose VBT specifically to avoid fusion now face a fusion as their revision option. Processing this — while also evaluating surgical risk and making a second major decision — requires honest, unhurried communication from a surgeon who respects what the patient hoped for and can explain clearly why the path has changed.

WHAT A REVISION EVALUATION INVOLVES

An evaluation for revision after VBT failure typically includes:

  • Full-length standing X-rays in the current state — to measure the residual deformity and compare against serial prior imaging to determine the rate and direction of any progression since the VBT or tether failure
  • CT scan to assess the VBT hardware in detail — screw positions, cord status, vertebral body changes adjacent to instrumentation, and the anatomy available for any planned revision construct
  • MRI to assess disc integrity, any neural element compression, and cord signal — particularly important if neurological symptoms are present
  • Skeletal maturity assessment — whether growth is complete or ongoing
  • Review of prior operative records and imaging from the VBT procedure and subsequent follow-up, to understand the original strategy, what was achieved, and what has changed

FREQUENTLY ASKED QUESTIONS

My tether broke. Does that automatically mean I need surgery?

No. The key question is not whether the tether broke but what your most recent X-rays show. If the tether broke after adequate correction was achieved, near or after skeletal maturity, and the curve is stable, revision surgery may not be needed. If the tether broke early, your curve is progressing, or you still have significant growth remaining, then evaluation for revision is important. Do not wait for symptoms to worsen before getting updated imaging.

If I need revision surgery, will it be a fusion? I had VBT specifically to avoid that.

For most patients who need revision after VBT failure, posterior spinal fusion is the most reliable and appropriate path. This is genuinely difficult news for patients who chose VBT to avoid fusion — and that disappointment deserves to be acknowledged. At skeletal maturity or near it, the growth-modulation approach that VBT depends on is no longer available, and fusion is the procedure that provides reliable, durable correction. Re-tethering remains an option for a subset of patients who are willing to undertake the risk of failure again, but it is not the right path for everyone.

My curve went too far the other way. What does that mean?

Overcorrection — where the growth modulation corrects the curve past neutral and into the opposite direction — produces trunk imbalance, shoulder asymmetry, and sometimes pain. It is one of the more challenging VBT failure patterns because it represents a deformity in the opposite direction from the original one. Evaluation should include current standing X-rays to document the degree and direction of coronal imbalance. Surgical options depend on the severity and whether any additional growth remains.

Can I see a specialist at Columbia who didn’t do my original VBT?

Yes. Dr. Sardar evaluates patients for VBT revision regardless of where the original procedure was performed. Bringing your original operative report, all postoperative X-rays, and any CT or MRI imaging allows the most complete evaluation at a first visit. Telemedicine consultations are available for patients who need to evaluate options before travelling to New York.

Should I get a second opinion before proceeding with revision?

Yes. Revision after VBT failure is technically complex, the evidence base for specific approaches is still evolving, and the right answer varies significantly by patient. A second opinion from a high-volume deformity surgeon who has experience with revision after VBT is appropriate before committing to any revision approach.

What if I was told I don’t need surgery right now but my curve keeps getting worse?

Documented progression on serial X-rays — not just a single set of images — is the evidence base for revision decisions. If your curve has been progressing consistently across multiple imaging timepoints, that is a different clinical picture from a curve that has been stable since tether failure. Bring all your serial imaging to any revision consultation, not just the most recent study.

RELATED CONDITIONS & PROCEDURES

About Dr. Zeeshan Sardar
Dr. Sardar is Co-Chief of Spinal Deformity Surgery at NewYork-Presbyterian / Columbia University and evaluates patients with VBT failure for revision surgery options. He does not perform VBT and has no stake in the original procedure — his evaluation focuses solely on what the current imaging and clinical picture indicate for the patient in front of him. To schedule a consultation or request a second opinion, call 212-932-5187 or visit the contact page. Telemedicine consultations available in NY, NJ, CT, FL, PA, MO, CA, and TX.

This page is for educational purposes only and does not constitute individualized medical advice. Please consult a qualified spine specialist to discuss your specific situation.

Reviewed by Dr. Zeeshan Sardar, MD, MSc, F.R.C.S.C — Last reviewed: August 2026.