Exploring Anterior Vertebral Body Tethering for Idiopathic Scoliosis: How Well Does the Tether Hold Up?

Exploring the durability of Anterior Vertebral Body Tethering (VBT) for scoliosis, a recent study reveals a 27% tether breakage rate within two years. While VBT preserves spinal mobility and offers a less invasive alternative to fusion, challenges like breakage and curve correction variability remain. Despite these concerns, most patients report significant improvements. Is VBT the future of scoliosis treatment, or do non-surgical methods like ScolioLife offer a better solution?

Introduction

Scoliosis, particularly adolescent idiopathic scoliosis (AIS), poses a significant challenge in orthopedic care. Traditional spinal fusion surgery, while effective in halting curve progression, often results in reduced spinal flexibility and long recovery periods. Anterior Vertebral Body Tethering (VBT) has emerged as an innovative alternative, promising a minimally invasive solution that preserves spinal mobility. By tethering the spine with a flexible cord, VBT allows for continued growth and correction, especially in young patients. However, questions about the durability of the tether and its long-term efficacy remain central to its broader acceptance. A recent study sheds light on these concerns, examining tether breakage (TB) rates and their impact on clinical outcomes in the largest cohort of VBT patients treated by a single surgeon.

Study Overview and Objectives

The study focused on patients with AIS who underwent VBT, aiming to evaluate the procedure’s effectiveness and durability. The inclusion criteria required participants to have:- A major Cobb angle ≤75°.- Undergone VBT using single- or double-cord tethers.- Completed a minimum of two years of follow-up.

Key objectives included determining the rate of tether breakage (TB), identifying factors contributing to breakage, and assessing the impact of TB on curve correction and patient-reported outcomes. Measurements such as Cobb angle reduction and Scoliosis Research Society-22 (SRS-22) scores were used to evaluate success.

Key Findings

1. Tether Breakage Rates
   By the two-year follow-up, 27% of patients experienced TB, primarily affecting major curves (70%) compared to minor curves. Additionally, thoracolumbar tethers were significantly more prone to breakage (75%) than thoracic tethers. Surprisingly, the study found that the use of double cords did not reduce TB rates in thoracolumbar curves, with similar breakage rates observed between single (32%) and double cords (30%).
    

2. Impact on Curve Correction
   Patients with tether breakage in major curves demonstrated a slightly lower rate of curve correction compared to those without breakage. On average:
    

   • With TB: Major curves improved from 48° to 24° (50% correction).
   • Without TB: Major curves improved from 53° to 21° (60% correction).

   
   Although the difference was statistically significant (p=0.02), the clinical relevance remains debatable. Both groups achieved meaningful reductions in curvature, suggesting that TB may result in minor setbacks rather than significant failures.

    

3. Reoperation Rates
   Reoperation was required in 3% of patients. Among these cases:
    

   • One patient experienced foraminal encroachment caused by a screw tip.
   • Another required surgery due to curve progression associated with TB.

   
   These findings underscore the importance of careful surgical planning, including accurate screw placement and monitoring for tether integrity.
    

4. Patient-Reported Outcomes

   The study also examined patient-reported outcomes using the SRS-22 score, which evaluates domains such as function, pain, and mental health. Despite TB, patients reported overall satisfaction and improved quality of life. This highlights that, even with imperfections, VBT can deliver significant benefits.

Key Takeaways

The study revealed several important insights into the performance and challenges of VBT:

• Durability Concerns: A TB rate of 27% within two years highlights the need for improvements in tether materials and surgical techniques. Ensuring the longevity of tethers is crucial for maximizing VBT’s long-term effectiveness.
• Higher Risk in Thoracolumbar Curves: Thoracolumbar tethers are more prone to breakage, requiring surgeons to approach these cases with added precision and consideration of risk factors.
• Limitations of Double Cords: The expectation that double cords would provide added durability was not supported by the data, indicating that simply increasing tether quantity may not be the solution
• Minor Loss of Correction: While TB can lead to slightly lower correction rates, the clinical impact appears modest. Most patients still experience meaningful improvements in spinal alignment and overall function.

Clinical Implications

VBT offers a promising alternative to spinal fusion, particularly for young patients with growth potential. Its ability to preserve spinal mobility and support ongoing correction makes it an attractive option. However, the high TB rate and associated risks underscore the importance of:

• Patient Selection: Identifying suitable candidates based on curve severity, location, and growth potential is key.
• Follow-Up Care: Regular monitoring is critical to detect TB early and address complications promptly.
• Material Innovation: Developing stronger, more flexible tether materials could significantly enhance VBT outcomes.

These considerations highlight that, while VBT shows great promise, it is not without challenges. Collaborative efforts among researchers, surgeons, and medical device manufacturers are essential to refine the procedure and improve its reliability.

Conclusion: Linking Back to Holistic Scoliosis Care

The findings of this study emphasize that VBT, while innovative, has its limitations, particularly concerning tether durability. However, for many patients, the benefits of a less invasive approach and retained spinal flexibility outweigh the risks. The procedure represents a significant step forward in scoliosis care, offering an alternative to fusion that aligns with modern priorities of preserving function and quality of life.

For those considering scoliosis treatment, it’s important to remember that surgery isn’t always the first or best option. Non-surgical treatments, like those offered at ScolioLife – Scoliosis & Spine Correction Clinic, provide effective alternatives to manage and reduce spinal curvature without invasive procedures. From advanced bracing solutions to personalized exercise programs, we help patients achieve long-term improvements in their spinal health.