This is a brief overview of information related to FDA's approval to market this product. See the links below to the Summary of Safety and Probable Benefit (SSPB) and product labeling for more complete information on this product, its indications for use, and the basis for FDA's approval.
Product Name: The Tether™ - Vertebral Body Tethering System
HDE Applicant: Zimmer Biomet Spine, Inc.
Address: 10225 Westmoor Dr. Westminster, CO 80021
Approval Date: August 16, 2019
Approval Letter: Approval Order
What is it? The Tether™ - Vertebral Body Tethering System is a non-fusion spinal device intended to treat idiopathic scoliosis, an abnormal curvature in the spine that occurs without a known cause, in young patients whose bones have not fully matured. The Tether™ - Vertebral Body Tethering System is made up of: anchors, bone screws, cord, and set screws. The anchors, bone screws and set screws are made out of titanium alloys that are commonly used as spine implants. The cord is made of a strong flexible polymer, SULENE® PET (polyethylene-terephthalate).
How does it work? An anchor and bone screw are placed into the patient's spine on the side of the spinal curvature. The cord is secured to the bone screws using set screws. During surgery, the surgeon will apply tension to the cord to partially straighten the patient's spine. After surgery, the cord continues to straighten the spine while the patient continues to grow.
When is it used? The Tether™ - Vertebral Body Tethering System is indicated for skeletally immature patients that require surgical treatment to obtain and maintain correction of progressive idiopathic scoliosis, with a major Cobb angle of 30 to 65 degrees whose osseous structure is dimensionally adequate to accommodate screw fixation, as determined by radiographic imaging. Patients should have failed bracing and/or be intolerant to brace wear.
What will it accomplish? The clinical data suggests The Tether™ - Vertebral Body Tethering System provides probable benefit related to prevention of spinal curve progression and avoidance of spinal fusion, the current standard-of-care treatment. The rate of revisions and reoperations reported for patients treated with The Tether™ - Vertebral Body Tethering System were greater compared to spinal fusion. However, only one (1) out of fifty-seven (57) patients required conversion to a spinal fusion. Patient preference information regarding The Tether™ - Vertebral Body Tethering System was positive.
When should it not be used? The Tether™ - Vertebral Body Tethering System should not be used in patients who:
- Have any type of infection, or have irritated, cut or damaged skin on the back or sides of the ribs and stomach
- Had a previous surgery at the spinal levels where a scoliotic curve exists
- Have bone that is soft or measured to have a T-score (bone density measurement) -1.5 or less
- Are skeletally mature and have no spinal growth remaining
- Have any other medical or surgical condition that would not allow spinal surgery, such as:
- problems with their blood flowing too much or too little,
- allergies to the implant materials, and/or
- an unwillingness or inability to cooperate with instructions from their doctor after surgery.
Additional information (including warnings, precautions, and adverse events):