What is vertebral body tethering (VBT)?

Vertebral body tethering (also called VBT or spinal tethering) is a surgical treatment for children with idiopathic scoliosis that was approved by the FDA in 2019. During the VBT procedure, surgeons place screws on the the side of the spinal curve that curves out. A rope-like device, called a tether, is then secured along the side of the vertebrae.

The tether is pulled taut — partially correcting the deformity when implanted — and then the device guides the child’s future growth. As the child grows taller, the bones of the spine grow into a straighter alignment as a response to the tension.

Because vertebral body tethering uses the child’s own growth as the driving force to treat scoliosis, candidates for the procedure must still be growing. Most often, it is appropriate for children aged 8-15.

CHOP has been on the forefront of this technology since it first became available, receiving approval from the FDA to conduct a trial on vertebral tethering prior to the FDA approving a device nationally.

Is vertebral body tethering right for my child?

For your child to be considered for vertebral body tethering at Children’s Hospital of Philadelphia (CHOP), they will need to meet certain criteria, including:

• Have spinal curves that measure 35 to 65 degrees
• Be diagnosed with idiopathic scoliosis i.e. scoliosis not related to other genetic conditions, neurological diseases, malformations, or injury
• Be at least 8 years old, and generally younger than 16
• Have significant bone growth left (as measured by physicians)
• Would otherwise need a spinal fusion surgery

If you would like to find out if vertebral tethering may be an option for your child, contact us to set up an appointment to see one of our doctors.

Evaluation for VBT

During your child’s evaluation at Children’s Hospital of Philadelphia, a board-certified pediatric spine surgeon will take your child’s medical history and perform a physical examination of your child. Imaging tests will be performed of the spine to measure the degree of curvature, part of the spine affected, and how best to proceed with surgery.

Along with X-rays (which show bone placement) and EOS imaging (which shows your child’s spine in weight-bearing position), an MRI may also be needed to evaluate the nerves of the spine and spinal cord. Nerve tissue does not appear on X-rays and may be abnormal in a small percent of children with scoliosis.

X-rays of the hand will also help doctors determine if your child has enough growth left for vertebral body tethering to help correct their spinal curves. If your child has reached skeletal maturity, another treatment will be recommended.

How is the VBT procedure performed?

Pre-op visit

Before your child’s vertebral body tethering surgery, he/she must have an MRI of the entire spine to ensure there is no unusual condition within the spinal cord that is causing the scoliosis.

Your child will also undergo a pulmonary function test/pulmonary visit to be sure their lungs are healthy. Routine blood tests, including a type and cross, are also performed.

Special bending X-rays as well as standing X-rays are done at the pre-op visit prior to surgery. Your child will also be evaluated by an anesthesiologist at this visit prior to surgery.

On the morning of your child’s surgery, you will arrive at the hospital and your child will be admitted. You can stay with your child in the pre-op area until they are ready to go to the operating room.

Your child’s operation will be performed under general anesthesia and will usually take four to five hours.

During vertebral body tethering surgery

Vertebral body tethering surgery is performed by an orthopedic surgeon and general surgeon. The procedure is considered minimally invasive and blood loss is low.

After your child is administered general anesthesia, surgeons will access their spine through small incisions in the side of the chest.

Surgeons then use a fiber-optic video camera to help place titanium screws into the convex side of the vertebrae. This helps to slow growth on that side, allowing the convex side of the curvature to catch up with time.

A flexible cable made of synthetic polymer — called a tether — connects the screws and is secured along the side of your child’s vertebrae. The tether is pulled taut and then guides your child’s future growth.

As your child grows taller, the tether pulls their spine straighter, gradually correcting the deformity. This is why it’s so important for your child to still be growing for this procedure to work effectively. The cable resists stretching in the direction of convex growth, but allows motion in all other directions.

After the surgery, there are normally five or six small incisions on one side of your child’s body. These can be concealed when your child’s arm is by their side.

What are the risks of VBT?

One of the most serious potential complications of the vertebral body tethering procedure is the risk of a collapsed lung (pneumothorax or hemothorax). Since the implants are inserted via access through the chest, and the lungs must be deflated during surgery, this is the area that is most carefully monitored during the post-operative period. Most often the lung remains re-inflated after surgery on its own, but in rare cases, a chest tube may need to be re-inserted to help re-inflate the lung.

Risks of any surgery, vertebral tether surgery included, include bleeding and infection.

In rare cases, it is possible for your child’s spinal curve to over-correct in the opposite direction. Curves that over-correct 10 degrees or more may need an additional surgery for correction. If this occurs to your child, they will return to the operating room for a surgery to remove or loosen the vertebral body tether to provide less tension.

Your CHOP doctor will review all of the potential risks in person to help you decide whether to participate in our study.

Vertebral tethering surgery is only performed at CHOP as part of our study.

What to expect after surgery

After surgery, your child will be sent to either the Pediatric Intensive Care Unit (PICU) or a surgical floor, based on the recommendation of the anesthesia team. You will be reunited with your child as soon as possible.

The day after surgery, your child will get out of bed and walk with the assistance of a nurse or therapist. Your child will receive IV pain medication until they are able to eat and drink, then oral pain medications are used. Many patients will only need Motrin and other non-narcotic medications, though narcotics — such as oxycodone — may be prescribed if needed.

Pulmonary monitoring is crucial after surgery, and your child will be shown exercises to do to help their lungs recover quickly. The chest tube and urinary catheter are usually removed within 48 hours of surgery. Before your child is discharged, the incisions will be checked and redressed, and X-rays will be taken to ensure the implants are stable.

Most patients are allowed to go home two to three days after the procedure.

Recovery after vertebral body tethering

Your child is expected to return home walking, climbing stairs, and be able to do most normal activities. Depending on your child’s recovery and pain, he/she can return to school one to three weeks after surgery. Arrangements can be made with your child’s school so they can keep up with their lessons.

Your child will be sent home with a dressing covering the chest tube site. Three days after the chest tube is removed, the dressing may be removed. If a scab has formed, the area may be left uncovered. If there’s no scab, another bandage should be placed over the area. Your child’s other incisions will have small strips covering them, which will eventually curl up and fall off. If they have not fallen off three weeks after surgery, you may remove them.

Normally no bracing or physical therapy is needed. Your child will be restricted from bending and twisting excessively, as well as gym class and sports, until they are seen by an orthopedic surgeon at their six-week post-operative visit.

Follow-up care after vertebral body tethering surgery

Your child will follow up with his primary care provider three weeks after surgery to ensure the wound is healing properly.

Six weeks post-op, your child will return to Children’s Hospital for an evaluation by a pediatric spine surgeon. During this appointment, your child will have X-rays or other imaging done to assess the spinal alignment and position of the implants.

Most children return to full activity after this visit and are allowed to participate in competitive sports. There are no major restrictions on sports or activities, other than activities that are considered dangerous in general (e.g. sky diving, bungee jumping).

Your child will continue to be assessed every six months for changes in their scoliosis until they finish growing. Children who are growing more rapidly will be X-rayed more frequently to check the status of their curve. Since many patients travel a great distance, it may be possible to obtain X-rays at home and mailed to us in lieu of some of the visits. This can be discussed with your surgeon. The goal is to keep a close watch on the curve while your child is still growing.
In most cases, the implants used in vertebral body tethering do not need to be removed. They will remain in your child’s spine through their lifetime.

Why choose CHOP for VBT surgery?

Our surgeons are among the most experienced surgeons in the country with vertebral body tethering surgery. Children’s Hospital of Philadelphia offers vertebral tethering to qualified candidates as an alternative to traditional scoliosis treatments such as spinal fusion, an open surgery that locks the spine into position and limits the child’s long-term flexibility.

Vertebral body tethering at CHOP is performed by Patrick J. Cahill, MD, one of the nation’s leaders in thoracoscopic fusionless spine surgery, and John M. Flynn, MD, an internationally recognized spine surgeon and chief of CHOP’s Orthopedic Center. Dr. Cahill has performed more than 100 thoracoscopic fusionless spine surgeries — which include vertebral body tethering and vertebral body stapling — during the past decade and was the principal investigator for the first FDA-approved trial of vertebral tethering in the United States. Dr. Flynn is the past president of the Pediatric Orthopedic Society of North America and specializes in pediatric spine surgery.

Families considering vertebral body tethering at CHOP will have access to the Hospital’s multidisciplinary expertise, family-centered care and pediatric orthopedic care that is among the top ranked programs in the nation, according to U.S. News & World Report's Honor Roll of Best Children’s Hospitals.