Ahead Of The CurveTM

The Tether™ – Vertebral Body Tethering System is a non-fusion spinal device intended for treatment of idiopathic scoliosis. Anchors and vertebral body screws are placed laterally from a thoracoscopic or thoracotomy approach into the vertebral body on the convex side of a spinal deformity.  

A SULENE® polyethylene terephthalate (PET) tensioning cord is secured to the vertebral body screws with set screws to connect the levels of the construct. The device provides a lateral tension band across the convex side of the spine that, on insertion and tensioning, partially corrects the curvature, and subsequently can arrest or correct the deformity through modulation of remaining spinal growth. In addition, the subject system includes instrumentation for insertion, manipulation, and removal of the implants. 

System Features

The Tether™ - Vertebral Body Tethering System is different from the other surgical treatments for scoliosis — e.g. spinal fusion — because the spine is still able to bend and flex, rather than being fixed in place with the stiff metal rods needed for spinal fusion.

  • There may be smaller incisions required (less scarring).
Tether with Spine and Ribs
  • Designed to allow for motion at the levels treated.
  • There may be less muscle and soft tissue disruption.
The Tether System

Clinical Results

Zimmer Biomet Spine conducted a single-center, non-randomized, clinical study under Investigational Device Exemption (IDE) application G150001 in fifty-seven (57) subjects. The purpose of this study was to assess the safety and probable benefit of the device in subjects with idiopathic scoliosis. Spinal tethering subjects were retrospectively evaluated for clinical and radiographic outcomes and were then prospectively followed until 30 out of 57 (47.4%) reached skeletal maturity by the time of database lock. All subjects were surgically treated utilizing components of the Dynesys® Top-Loading Spinal System which is cleared for spinal fusion (K133164). The Tether™ - Vertebral Body Tethering System includes similar components, but differs from the Dynesys® System in that screws have a lower profile head. A common primary assessment collected for all subjects was curve magnitude as determined by Cobb angle. Radiographic images were analyzed using a single core laboratory for assessment of coronal Cobb angle, device loosening, and device breakage. AEs were also reported and assessed by each investigator.

Non-Clinical Information

A number of non-clinical tests were conducted on The Tether™ - Vertebral Body Tethering System, including static and dynamic tension bending, static axial grip, creep, stress relaxation and wear testing. All tests passed pre-determined acceptance criteria.


Important Information

Additional Information