The Tether

The Vertebral Body Tethering System

The Tether – Vertebral Body Tethering System helps treat children with advanced scoliosis. These patients need surgery to stop an increasing idiopathic scoliosis spinal curve. The patient described here has scoliosis with a main 30-65 degrees Cobb angle and whose body will adequately support screw fixation (Radiographic imaging determines this). Also, the Tether provides an alternative solution when bracing gives poor results or the patient can’t use a brace.

The Tether provides another option for a scoliosis patient. The typical procedure that we have mastered uses an approach to fuse vertebras together,  It also implants stiff metal rods along either side of your spine. Doctors carry out this technique to straighten unwanted curves.

Rather than stiff metal rods, the Tether – Vertebral Body Tethering System uses a strong flexible cord.  The cord pulls on the outside of the spinal curve and straightens out the spine.  The system straightens the spine using the patient’s own growth process.  Doctors refer to this process as growth modulation.

The bones or vertebra in a scoliotic spine look like a wedge, tall on one and short on the other.  When the cord gets pulled, it puts pressure on the tall side of the vertebra on the outside of the cure.  This pressure slows down the growth on the tall side so that the short side can grow and catch up.  After surgery, the spine continues to straighten even more over time with the growth of the child.

The Tether Attached to a Spine

The Tether – Vertebral Body Tethering System provides a different approach from the other surgical treatments for scoliosis because the spine can bend and flex, rather than being fused in place with the stiff metal rods needed for spinal fusion.  However, when it comes to the Tether, we only consider children. A child’s growth causes the spinal curve to correct itself over time.

The Tether’s approval stems from a special medical classification called a Humanitarian Use Device.  This means that the FDA approved the device for idiopathic scoliosis in young people who possess scoliosis with a significant amount of growth remaining.  However, note that Tether does not appear to help all cases of scoliosis, it falls under the classification of a humanitarian use device.  Instead, the Tether has been shown to have a probable benefit.  The tether – Vertebral Body Tethering System is the only medical device available that treats scoliosis while a person actively grows and uses their own growth to repair their curve. We strongly suggest that parents talk with our doctors about tethering procedures, and learn from the literature that is available on the procedure, and what outcomes have been like for other patients.

Introduction to Vertebral Body Tethering (VBT)

Vertebral Body Tethering (VBT) is a minimally invasive surgical option designed to treat scoliosis in adolescents and young adults. Unlike traditional spinal fusion, which restricts spinal flexibility, VBT allows for continued growth and mobility. Using a flexible tether, or cord, the system gradually straightens the spine as the patient grows. This treatment is particularly beneficial for individuals who are still in a growth phase, as the VBT technique leverages this natural growth to correct the curvature.

The Purpose and Philosophy Behind VBT

The Tether VBT System was developed to address the limitations of spinal fusion, particularly the permanent loss of flexibility and increased risk of adjacent segment degeneration over time. The philosophy behind VBT is growth modulation: as the patient grows, the tether creates tension on the convex side of the spinal curve, promoting realignment. By correcting the curvature naturally, VBT aims to offer both functional and cosmetic benefits that align with the active lifestyles of young patients.

Advantages of The Tether VBT System

Key benefits of The Tether VBT System include:

• Flexibility preservation: Unlike fusion, VBT allows for a near-normal range of motion.
• Natural curve correction: The spine straightens over time as the patient grows.
• Reduced risk of adjacent segment disease: By avoiding fusion, VBT helps prevent degeneration in segments adjacent to the treated area.
• Improved cosmetic outcomes: For younger patients, VBT offers correction with less impact on growth and body symmetry.

Who is a Candidate for The Tether VBT System?

Ideal candidates for VBT include:

• Adolescents and young adults: Typically, those who are still experiencing growth (often around ages 10-15) are prime candidates, as their spines can continue to adjust post-surgery.
• Curves between 30-60 degrees: VBT is most effective in moderate curves that are flexible and can be corrected through growth modulation.
• Flexible curves: Rigid curves may not respond well to tethering, as flexibility is essential for the tether to achieve correction.
• Progressive scoliosis: Patients whose scoliosis is likely to progress without intervention.

Pre-Surgical Preparation for VBT

To prepare for VBT, patients undergo a series of evaluations to ensure the best possible outcome:

• Medical history review and physical examination: To understand the full scope of the patient’s scoliosis.
• Imaging tests: These include X-rays, MRIs, and CT scans to measure the curve’s flexibility and visualize the spine’s structure.
• Growth assessment: Evaluation of growth plates and skeletal maturity using techniques like bone age studies.
• Lifestyle and physical readiness: Pre-surgical exercises may be recommended to strengthen core muscles, preparing the body for post-surgical recovery.

Surgical Techniques

Here are the steps in the Tether procedure to correct scoliosis:

• The surgeon makes a small incision in the back.
• The surgeon carefully separates the muscles and nerves to expose the spine.
• The surgeon identifies the location of the curve in the spine.
• The surgeon attaches the tether to the spine at the location of the curve.
• The surgeon tightens the tether to gradually correct the curve over time.
• The surgeon closes the incision.

Risks and Complications Associated with VBT

While VBT offers many benefits, potential risks include:

• Nerve damage: Rare, but a potential risk in any spinal surgery.
• Pulmonary complications: Due to thoracoscopic surgery near the lungs.
• Tether breakage: Though infrequent, it can necessitate additional surgery.
• Overcorrection or insufficient correction: The procedure may lead to an overcorrection if growth surpasses expectations, or insufficient correction if the tether loosens.

Recovery Process After VBT Surgery

Recovery typically involves:

• Hospital stay: Most patients stay 3-5 days post-surgery.
• Initial recovery: Light activity is encouraged after about 2-4 weeks, with a gradual return to normal activities over the following months.
• Physical therapy: Essential to restore strength, flexibility, and function.
• Long-term follow-up: Regular imaging and appointments ensure the tether is functioning as expected and that the spine is progressing toward full correction.

Limitations and Considerations of VBT

The Tether is not suitable for all patients. Limitations include:

• Growth-dependent effectiveness: Older teens and adults who are past their growth phase may not benefit from VBT.
• Curve rigidity: VBT is best suited for curves that are flexible and modifiable through growth.
• Potential for repeat surgery: Some patients may need additional surgery if the tether loosens or breaks.

Outcomes and Success Rates of VBT

Studies indicate:

• Significant curve correction: Many patients experience a curve reduction of 50% or more.
• High satisfaction rates: Most patients report satisfaction with both functional and cosmetic outcomes.
• Comparison with fusion: Data suggests comparable or superior outcomes in flexibility and long-term function.

Challenges and Revisions with VBT

Some patients may experience:

• Tether breakage: A possible issue that may require a revision.
• Under-correction or over-correction: A few cases may need additional adjustments if the initial correction was insufficient or if growth continues beyond expectations.

Comparison of VBT with Spinal Fusion Surgery

When compared to fusion:

• Preservation of flexibility: VBT is less restrictive.
• Faster recovery: VBT patients tend to return to normal activities sooner.
• Better for growing patients: Fusion is typically a last resort, especially for young, growing patients.

VBT in Practice: Case Studies and Patient Experiences

Numerous patients report positive experiences with VBT:

• Improved self-confidence and body image
• Greater satisfaction in physical activities
• Success stories from patients who have avoided fusion and enjoyed active lifestyles

Future of VBT and Advancements in Scoliosis Treatment

Research into:

• Enhanced tether materials: More durable tethers are under development.
• Robotic-assisted techniques: Increasing accuracy and minimizing risks.

Choosing a Surgeon and Facility for VBT

Factors to consider include:

• Specialist’s experience: Look for a specialist with extensive VBT expertise.
• Facility reputation: High success rates in spine care are essential.
• Patient-centered care: A surgeon who values individualized care.

Potential Benefits of the Tether

When compared with traditional straightening of the spine using screws, rods, and spinal fusion, the Tether has the following observations.

• The Tether – Vertebral Body Tethering System allows for motion at the levels treated
• The procedure requires smaller incisions with less scarring
• The Tether could cause muscle and soft tissue disruption

The Use of the Tether

Studies show a likely benefit with less invasive surgery for scoliosis surgery with the Tether™ – Vertebral Body Tethering System, however, with all surgeries, complications are possible and parents should discuss those with their doctor.

Why Should Parents Bring their Children with Scoliosis to the Southwest Scoliosis and Spine Institute?

The Southwest Scoliosis and Spine Institute is a medical practice that specializes in the treating children with scoliosis. As such, their surgeons are experts in the Tether procedure, a surgical technique used to treat certain types of scoliosis. Also, the website provides valuable information about the Tether procedure and the benefits it can offer to patients.

If you are considering bringing your child to the Southwest Scoliosis and Spine Institute for treatment with offices in Dallas, Plano, and Frisco, Texas, it is important to do your own research and gather information about the practice and its surgeons. You may want to look at online reviews and ratings from other patients who have received treatment at the institute. It’s smart to schedule a consultation with one of our surgeons to discuss your child’s condition and treatment options.

It is important to remember that every patient and every case of scoliosis is unique. While the Tether procedure may be an appropriate treatment option for some children with scoliosis, it may not be the best option for every child. Your child’s treatment plan should be individualized to their specific needs and circumstances. It is important to work with a medical team that you trust and feel comfortable with, and who can provide you with the information and guidance you need to make informed decisions about your child’s care. We urge you to call us and make an appointment.

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National Institute of Health: The Tether