Vertebral Body Tethering (VBT) & Anterior Scoliosis Correction (Scoliosis Tethering)
Is Vertebral Body Tethering (VBT) in patients Risser 0-2, and Anterior Scoliosis Correction (i.e. scoliosis tethering) in patients Risser 3-5, a better way to treat scoliosis than traditional spinal fusion surgery?
The answer is YES, in some cases, for patients with moderate to large curves who still have adolescent growth remaining and continue to experience significant curve progression despite conservative scoliosis treatment approaches.
This innovative, less-invasive surgical procedure can modulate bone growth of the spine during the periods of rapid growth spurts, when adolescent spinal curvatures typically progress.
It can also be utilized for patients with little or no skeletal growth remaining, depending on curve flexibility.
While ScoliSMART Clinics do not perform these procedures, we have developed close working relationships with many of the top orthopedic spine surgeons who do offer VBT* as part of our commitment to providing the right treatment options, to the right patients, at the right time. The ultimate goal is to achieve the best possible results and prevent spinal fusion surgery.
Bone growth modulation (i.e. bracing; VBT) is not a new concept and is based off the Hueter-Volkmann principle, which states that bone under more pressure will grow slower and denser than bone not under stress.
Eventually, the bone on the inside part of the curve will grow slower and denser than the bone on the outside of the curve, creating a wedge deformity.
Bone growth modulation techniques are attempting to influence the secondary reaction to the uneven loading caused by the curve, not the genetic and environmental factors that initiate the scoliosis condition itself.
Vertebral Body Tethering
- Less invasive
- Less surgical hardware
- Curve reduction dependent on curve flexibility
- Less blood loss and risk of infection
- Can be used pre-skeletal maturity
- Spinal Motion sparing
- Long-term complications unknown
Spinal Fusion Surgery
- Highly invasive
- Extensive surgical hardware
- Can achieve significant curve reduction in rigid curves
- Requires self-donated blood transfusions
- Requires growing rods prior for younger patients
- Significant decrease in spinal motion
- Known high long-term complication rates
Scoliosis bracing attempts to hold a curve from progressing, but it will not correct the curve. VBT is very different not only in theory, but also in application. By applying counter loading directly to the spine, bone growth modulation can be controlled. Many experts in the field of conservative scoliosis treatment feel that VBT is far superior to traditional spinal-fusion-based surgeries. For additional information, please see this article.
*Vertebral Body Tethering for scoliosis has been not been approved by the FDA at this time, but has many case studies published in peer reviewed journals. The procedure has been in use for approximately 10 years and has been used on several hundred patients thus far. Long term data and complication rates are no possible at this time.
Vertebral Body Tethering vs. Spinal Fusion Surgery
How Does the Vertebral Body Tethering / Scoliosis Tethering Treatment Work?
Vertebral Body Tethering:
For patients with a significant amount of growth remaining (Risser 0-2), VBT uses growth modulation — restraining one side of the spine to allow growth on the other side — to reverse the abnormal scoliosis growth pattern in the thoracic or lumbar spine.
Titanium pedicle screws are placed on the outside of the vertebrae that are causing the scoliosis; a white polyethylene-terephthalate flexible cord, usually used for fusion, is attached to each of the bone screws in the vertebral bodies of the spine. When the cord is tightened, it compresses the adjacent screws to help straighten the spine. The affected curve(s) show an immediate improvement after surgery, and continued improvement over time as the spine grows.
Also referred to as Anterior Scoliosis Correction
For patients with little or no growth remaining (Risser 3-5, particularly adults), curve flexibility is the primary determination for candidates for scoliosis tethering.
Curve flexibility, which is not fully understood in scoliosis, can be improved through specialized scoliosis rehabilitation programs and/or surgically releasing specific areas of ligaments and discs during the procedure. Some studies suggest the use of manipulation under anesthesia may also hold future benefit for patients that require additional curve flexibility for VBT procedures.
ScoliPATH Model of Treatment
A comprehensive scoliosis treatment approach, like ScoliSMART (and newer, less invasive surgical procedures, like scoliosis tethering), allows for an updated treatment model for idiopathic scoliosis. In this treatment model, observation is replaced with Early Stage Scoliosis Intervention (ESSI), full-time bracing is replaced with aggressive, non-invasive ScoliSMART rehabilitation, and highly invasive spinal fusion is replace with less invasive scoliosis tethering procedures.
What Are the Advantages of Vertebral Body Tethering & Scoliosis Tethering?
Typically, less-invasive surgery will carry fewer risks. In the case of VBT, the spine can continue to grow, therefore most often allowing for correction of the curve. The spine can continue to move and bend, allowing the patient to experience more comfort and freedom of movement.
Being a one-time surgery (for the most part), no bridges are burned; future treatments — if even necessary — are still viable options.
These (and other factors) result in a reduced length of hospital stay, making surgery less inconvenient for both patient and family.
For more information on the advantages of Vertebral Body Tethering/VBT/Anterior Scoliosis Correction/Scoliosis Tethering, please see this additional article.
Potential Risks & Complications of VBT or Scoliosis Tethering
As with all significant spinal surgeries, VBT and scoliosis tethering have inherent risks of infection, nerve damage, and paralysis, which are rare. Over-correction in the thoracic spine and postural collapse (destabilization of the lumbar spine) have been reported in some cases. In rare cases, the tether may break, possibly leading to a destabilization of the spine in that area.
The over-correction complications occur in cases in which the VBT procedure is performed in the early stages of growth (Risser 0-2) and the tether is applied too tightly. Depending on the amount of over-correction and growth remaining, a second surgical procedure may be required to adjust the tension of the tether.
Complications related to postural collapse generally occur in cases in which the translation of the torso/thoracic spine does not sufficiently correct in relation to the lumbar spine below it. A specialized scoliosis rehabilitation program may be necessary to re-stabilize the lumbar spine and reverse the process or halt its progress.
Ligament and disc "releases" (surgically cut) may be utilized to obtain the necessary curve flexibility in scoliosis cases where curve flexibility is poor. The long-term effect of this practice on the stability of the disc, ligament, and overall spine are unknown at this time.
Who Is a Good Candidate for a Vertebral Body Tethering or Scoliosis Tethering Procedure?
As with any healthcare procedure, the risks/benefits ratio must be carefully considered on a case-by-case basis.
Vertebral Body Tethering and Anterior Scoliosis Correction (Scoliosis Tethering) should only be considered as an alternative to scoliosis fusion surgery in patients with a high risk for further scoliosis curve progression.
Cosmetic improvement of the spinal deformity remains the primary indication for the procedure and it often also requires additional surgical procedures, such as rib resections.
As with any surgical procedure, all non-invasive, conservative efforts to treat the condition should be attempted first to reduce the risk of short-term, intermediate, and long-term surgical complications.
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