Anterior Vertebral Body Tethering (AVBT) Using Zimmer Biomet Tether System or Dynesys System Components to Treat Pediatric Scoliosis

Prospective Pilot Study of Anterior Vertebral Body Tethering Using Zimmer Biomet Tether System or Dynesys System Components to Treat Pediatric Scoliosis

The Researchers want to assess the short-term safety of Anterior Vertebral Body Tethering (AVBT) in skeletally immature subjects with moderate to severe scoliosis and compare them with a fusion cohort.

Study Overview

• Status: Enrolling by invitation
• Conditions: Scoliosis
• Intervention / Treatment: Device: AVBT using Dynesys System Components; Procedure: Spine fusion

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Minnesota
    • Rochester, Minnesota, United States, 55905
      • Mayo Clinic

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 10 years to 16 years (Child)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Male & female, age 10 years to 16 years.
2. Scoliosis curve between 40-70 degrees.
3. At least 1 year of growth remaining measured by Sanders bone age 4 or less or Risser stage 2 or less.
4. Adolescent idiopathic scoliosis.
5. Lenke 1, 2, 3C, 5 (thoracic, thoracolumbar, or thoracic and lumbar).
6. Parents must be able to understand the study and sign the consent document. Assent will be obtained and documented as age appropriate.
7. Patients and parents must be able to comply with study procedures and visits, including 3-month, 1-year, and 2-year follow-up visits.

Exclusion Criteria:

1. Congenital, neuromuscular or syndromic scoliosis.
2. Underlying neuromuscular disease.
3. Pregnancy.
4. Nonflexible curves (bending films show residual curve greater than 40 degrees).
5. Prior surgery for scoliosis treatment.
6. Patients with active systemic infection.
7. Known, reported allergies to titanium, PET, or PCU. Known, reported substance abuse, including alcohol.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Pediatric Scoliosis Patients; Tether group	Device: AVBT using Dynesys System Components; Zimmer Biomet Tether System and Dynesys System components are intended to treat scoliosis in skeletally immature children.
Active Comparator: Pediatric Scoliosis Control Patients; Fusion (control) group	Procedure: Spine fusion; Children with scoliosis undergoing fusion surgery will form the control arm

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Revision spine surgery within 2 years of index procedure	yes/no parameter, was revision surgery performed within 2 years of index procedure	2 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Major cobb angle curve progression greater than 10 degrees and curve magnitude < 50 degrees at latest f/u after 1st erect postop film (Tether arm)	yes/no parameter, did major Cobb angle worsen by 10 degrees and curve magnitude < 50 degrees at latest f/u after 1st erect postop film	1 year
Curve progression no greater than 10 degrees at latest f/u after 1st erect postop film (Fusion arm)	yes/no parameter, did major Cobb angle worsen by 10 degrees at latest f/u after 1st erect postop film	1 year
Curve flexibility over instrumented vertebra > 5 degrees	Flexibility films will be obtained in patients postoperatively to assess flexibility	At least 1 year postoperatively
Spinal disc health utilizing MRI	Spinal disc health will be assessed in Tether patients post-operatively using an MRI in conjunction with the Pfirrmann classification (scored I to V, where I indicated normal and V indicated the worst degeneration).	At least 1 year postoperatively

Collaborators and Investigators

• Sponsor: Mayo Clinic
• Investigators: Principal Investigator: A. Noelle Larson, MD, Mayo Clinic

Publications and helpful links

General Publications

• Mathew SE, Hargiss JB, Milbrandt TA, Stans AA, Shaughnessy WJ, Larson AN. Vertebral body tethering compared to posterior spinal fusion for skeletally immature adolescent idiopathic scoliosis patients: preliminary results from a matched case-control study. Spine Deform. 2022 Sep;10(5):1123-1131. doi: 10.1007/s43390-022-00519-3. Epub 2022 May 24.

Helpful Links

• Mayo Clinic Clinical Trials

Study record dates

Study Major Dates

• Study Start (Actual): April 25, 2018
• Primary Completion (Estimated): May 1, 2026
• Study Completion (Estimated): May 1, 2026

Study Registration Dates

• First Submitted: April 3, 2018
• First Submitted That Met QC Criteria: April 16, 2018
• First Posted (Actual): April 24, 2018

Study Record Updates

• Last Update Posted (Actual): June 11, 2025
• Last Update Submitted That Met QC Criteria: June 9, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Bone Diseases; Musculoskeletal Diseases; Spinal Diseases; Spinal Curvatures; Scoliosis
• Other Study ID Numbers: 17-007801

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No