Surgical intervention is the greatest fear of parents and patients suffering from the scoliosis condition and should always be a last resort after all non-conservative approaches have been exhausted. Recently, a robust interest in fusionless scoliosis surgery has encouraged progress in the development of a variety of new surgical approaches, innovation, and devices.
The Origins of Anterior Scoliosis Correction
Vertebral Body Stapling (VBS)
The ASC procedure began with the development of spinal growth modulation surgical procedures in the early 2000s. These initial efforts were vertebral body stapling (VBS) procedures being utilized with early stage growth cases with progressive scoliosis in an attempt to modulate asymmetrical spinal growth. The vertebral body staples provided compression on the outside part of the curve. Many cases did have positive outcomes during periods of remaining growth, the procedure was discontinued for a variety of reasons:
- Limited window patients could benefit from the procedure
- Difficulty stabilizing spinal curves during remaining growth
- Over-correction complications
Although, the vertebral body staples are expected to become available again incoming years for patients with small curves desiring an internal brace, as opposed to wearing an external brace for an extended period of time.
Vertebral Body Tethering (VBT)
Gradually, the concept of using a single cord/tether to “tie” all of the segments of the curve together and achieve a similar clinical goal as vertebral body stapling was explored and began in 2011. This was used primarily in the thoracic spine to provide a more definite and predictable post-surgical outcome during remaining growth. This “combo” approach using VBS and VBT also allowed surgeons to begin treating patients with double curves (“S” shaped scoliosis curves) with non-fusion scoliosis surgery procedures. Soon, the advantages of using a cord/tether instead of staples had become clear and the VBS procedures were discontinued entirely.
While the more powerful and versatile vertebral body tether over vertebral body staples, it was still very limited to young patients who had very flexible spines and significant growth remaining. The Federal Food & Drug Association (FDA) approved “The Tether – Vertebral Body Tethering System” by Zimmer-Biomet in mid 2019. It is the first approval order for a humanitarian-use device in spinal pediatrics within the last 15 years.
Anterior Scoliosis Correction (ASC)
In order to make non-fusion scoliosis surgery available to a larger group of patients, new and innovative surgical techniques have been developed that allow for patients with little or no growth remaining and/or rigid spinal curves an opportunity to be candidates for a less invasive fusionless surgery option. This can include skeletally maturing, skeletally mature, and even adults with scoliosis. The procedures of VBT or ASC do not need FDA approval themselves. It is the implant device that the company markets that needs approval.
Advantages of ASC vs. VBT include:
- Significantly larger range of curve size (40 degrees to 100+ degrees)
- More aggressive de-rotational 3D correction
- Any curve flexibility
- No additional growth remaining requirement
Can the ScoliSMART BootCamp Program Help Improve the Odds of You or Your Child Becoming a Candidate for Anterior Scoliosis Correction?
It may be hard to believe, but the topic of curve flexibility and rigidity is still relatively poorly understood and under researched in the scoliosis condition.
It is known that curve stiffness is correlated with patient age and curve size, but is not necessarily proportional in any given case with any given patient — leaving a huge amount of variability.
While the FDA guidelines for VBT in adolescent patients requires curve flexibility of less than 30 degrees at the apex of the curve, this requirement is not necessary for ASC, but is generally accepted as a general rule of thumb — and contributes greatly to maximizing outcomes for skeletally mature and adult patients with scoliosis who undergo the Anterior Scoliosis Correction procedure.
Scoliosis is widely known and accepted as a 3-dimensional spinal deformity that is primarily “driven” by spinal rotation, resulting in a “coil down” effect. This is similar to the “curve” produced by a rubber band when twisted from the top and bottom (see picture).
The “torsion” created by the “coil down effect” seen as a spinal curvature on x-ray (stemming from the spinal rotation) may be the primary reason for increasing curve rigidity in larger curves.
One peer-reviewed and published case study, in particular, showed a combination of Manipulation Under Anesthesia (MUA) and the ScoliSMART exercises protocols had an encouragingly positive and long-lasting effect on function, range of motion, and curve flexibility.
In addition, anecdotal evidence suggests the ScoliSMART approach for directly targeting, improving, and reducing spinal rotation as a “pre-VBT or ASC preparation program” may be ideal for increasing curve flexibility for patients considering VBT or ASC who do not qualify due to curve rigidity.
Ongoing data collection and evaluation is currently being conducted with the intent of publishing additional clinical data on how specialized scoliosis exercise programs can improve curve flexibility and reduce apex rigidity, enabling more patients to quality for non-fusion scoliosis surgical procedures like ApiFix, Vertebral Body Tethering, and Anterior Scoliosis Correction.