Newswise — New data from patients across North America casts doubt on the efficacy of vertebral body tethering for scoliosis.
Led by Lindsey Andrus, M.D., associate director and director of the Spine Program at the Jackie and Jean Autry Orthopedic Center at Children’s Hospital Los Angeles, the study found that 92% of patients who underwent tethered surgery experienced additional postoperative reduction. I know you haven’t experienced it. Major Cobb Angle (a measure of the curvature of the spine).
Dr. Andras presented the results at the 16th Congress.th International Conference on Early-Onset Scoliosis and Growing Spine in Rome, November.
“There was a lot of excitement about tethering, but unfortunately the press was a little ahead of the science,” she says. “These findings shed light on the fact that we are still in the learning phase of this procedure.”
Vertebral body tethering (VBT) is a new surgical option for adolescent idiopathic scoliosis. Approved by the Food and Drug Administration (FDA) in 2019, VBT uses a system of metal anchors and flexible cords called tethers to straighten your spine.
Initial tethering surgery achieves significant curve correction, but the idea is that tethering causes additional gradual correction as the child grows. and some suggest that this “induced growth” is minimal.
However, these studies focused on overall averages rather than individual outcomes. “We know the averages don’t tell the whole story,” says Dr. Andras. “The goal of our study was to be more granular, to see exactly how much the curve changes after the initial placement of the tether.”
To do this, she looked at data from the Pediatric Spine Research Group, an international consortium of Pediatric Research Centers. Data included 113 of her children and adolescents who received tethering for idiopathic scoliosis at facilities in the United States and Canada.
The team then tracked changes in each patient’s major Cobb angle from the first standing radiograph after tethering surgery to the final follow-up visit 2–4 years later.
At a final follow-up, the study found:
- In 50% of patients, the major Cobb angle was unchanged compared to the first standing radiograph after surgery. The curve wasn’t fixed further as planned, but it didn’t get any worse.
- 40% of patients had a curve worsening of 5 degrees or more.
- Only 8% (9 patients total) showed an additional curve reduction of 5 degrees or more. However, two of her patients were actually overcorrected and required her second surgery to release the tether.
Some orthopedic surgeons argue that it is too late to have VBT when the patient does not have sufficient growth potential. The tether is designed to further straighten the spine as the child grows. If this growth does not occur, correction will not occur.
But Dr. Andras says 90% of the patients in her study had VBT while they were still growing, at Risser stage 2 or earlier, at skeletal maturity. Slow growth. )
“Even with this young group, I’m not sure VBT is working,” she says. “Patients may have to be younger.
Another concern: long-term results are unknown. “The data show that most patients still have some curve,” he adds Dr. Andras. “What do these curves do over time? What about 10 years from now? 30 years from now? We don’t know.”
To better understand these effects, she and her team are now investigating what happens to patients with broken tethers. This is common.
The group is investigating whether these patients will eventually undergo reoperation and what happens to those who do not undergo a second surgery. “What we want to see is if the tether breaks, does the curve keep getting worse or does it stabilize at some point?” she says.
These questions, combined with mounting evidence that VBT is not working as consistently as originally hoped, lead Dr. Andras and her team to recommend this procedure in most scoliosis cases. I hesitated.
“We are still working to achieve results on par with VBT, but we still have a long way to go to improve this approach,” she explains.
She says a 2020 study found an average curve of 33 degrees after VBT compared to 16 degrees with spinal fusion. Also, while VBT can theoretically preserve thoracic spine mobility, the range of motion in that area is minimal to begin with.
“It’s important to keep in mind that the majority of children with fusion will return to a very active life that includes participation in elite-level sports,” she says. We hope that we can develop alternatives to spinal fusion, but spinal fusion is currently the definitive procedure to ensure the best outcome for the vast majority of patients.”
