Safety Outcomes of Vertebral Body Tethering Technique


The objectives of this study is to assess whether the intervention (Anterior Vertebral Tethering) is a safe and efficacious method of anterior approach surgery for spinal deformity in pediatric scoliosis.

Full Title of Study: “Safety and Efficacy of a Vertebral Body Tethering Technique for Pediatric Idiopathic Scoliosis”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: N/A
    • Intervention Model: Single Group Assignment
    • Primary Purpose: Treatment
    • Masking: None (Open Label)
  • Study Primary Completion Date: September 1, 2025

Detailed Description

Scoliosis is a condition where the spine is deformed by a curvature in the coronal plane. It is generally associated with a twisting (axial plane) deformity as well.

Curves between 10 and 25 degrees are considered mild. Curves between 25- and 50 degrees are classified as moderate. Curves greater than 50 degrees are termed severe. The current standard of care for moderate Adolescent Idiopathic Scoliosis(AIS) in patients with remaining growth is to utilize a thoracolumbosacral orthosis (TLSO brace) to prevent progression of deformity. The scientific evidence has supported the efficacy of this intervention in avoiding progression of the Cobb angle to 50 degrees or more.

If treated with a TLSO brace, many idiopathic scoliosis patients would conceivably be subjected to years of brace wear and the cost and psychological factors inherent therein. Additional downsides of brace treatment include the potentially negative psychosocial impact of wearing an external sign of deformity during adolescence, a key period of emotional development. Prior research has identified negative psychosocial effects related to wearing a brace in children.

Recent evidence has suggested that certain curve patterns will likely progress to 50 degrees or more, despite treatment with a TLSO brace. Sanders, et al. demonstrated a correlation of Cobb angle (greater than 35 degrees) and skeletal maturity (bone age 4 or less) to the risk of progression to 50 degrees or more, despite TLSO bracing. The evidence supports that the current practice of TLSO bracing is not an effective treatment to avoid progression to 50 degrees in these patients. It is on this population (thoracic Cobb angle greater than 35 degrees, bone age of 4 or less) that we intend to test the safety and efficacy of Anterior Vertebral Body Tethering to avoid curve progression to more than 50 degrees.


  • Device: Anterior body tether (ABT)
    • To insert the ABT in patients to correct AIS.

Arms, Groups and Cohorts

  • Experimental: Anterior Vertebral Tethering
    • Anterior Vertebral Tether Vertebral body tethering done through anterior spine surgery under anesthesia.

Clinical Trial Outcome Measures

Primary Measures

  • Number of adverse events after the procedure
    • Time Frame: 2 years after the surgery
    • We will look for any changes in neurological status, tether failure, implant reoperation, overcorrection and wound infections. Adverse events will be summarized by their severity and frequency and reported to IRB and Data Safety board on timely bases. The PI will determine if these events are related to the device.

Secondary Measures

  • Cobb angle in degrees
    • Time Frame: Cobb angle will be measured prior to surgery, at 6 moths, 1 year and 2 years past surgery.
    • The difference be between pre and post-operative Cobb angle measurements.

Participating in This Clinical Trial

Inclusion Criteria

1. Males or females age 8 to 16 years old at time of enrollment (inclusive)

2. Diagnosis of idiopathic scoliosis

3. Sanders bone age of less than or equal to 4

4. Thoracic curve of greater than or equal to 35 degrees and less than or equal to 60 degrees

5. Lumbar curve less than 35 degrees

6. Patient has already been identified for and recommended to have surgical intervention

7. Spina bifida occulta is permitted

8. Spondylolysis or Spondylolisthesis is permitted, as long as it is non-operative, the subject has not had any previous surgery for this, and no surgery is planned in the future

Exclusion Criteria

1. Pregnancy (current)

2. Prior spinal or chest surgery

3. MRI abnormalities (including syrinx greater than 4mm, Chiari malformation, or tethered cord)

4. Neuromuscular, thoracogenic, cardiogenic scoliosis, or any other non-idiopathic scoliosis

5. Associated syndrome, including Marfan syndrome or neurofibromatosis

6. Sanders bone age greater than 4

7. Thoracic curve less than 35 degrees or greater than 60 degrees

8. Lumbar curve greater than or equal to 35 degrees

9. Unable or unwilling to firmly commit to returning for required follow-up visits

10. Investigator judgement that the subject/family may not be a candidate for the intervention

Gender Eligibility: All

Minimum Age: 8 Years

Maximum Age: 16 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Nemours Children’s Clinic
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Suken Shah, MD, Principal Investigator, Nemours-AIDHC
  • Overall Contact(s)
    • Petya Yorgova, MS, 3026515920,

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