Vertical expandable prosthetic titanium rib (VEPTR) for SMA

Overview
The vertical expandable prosthetic titanium rib (VEPTR) is an invasive breathing support device approved by the U.S. Food & Drug Administration (FDA) to treat children with thoracic insufficiency syndrome (TIS) - severe deformities of the chest, spine and ribs that prevent normal breathing and lung growth.

Children with spinal muscular atrophy (SMA) have a higher incidence of TIS, as a result of scoliosis and rib cage distortion. Those with SMA type 1 and 2 are 60 to 90 percent more likely to develop scoliosis, a curvature of the spine that can be caused by SMA.

The VEPTR device is a curved metal rod that’s surgically attached to a child’s ribs, spine, or pelvis in a vertical position using hooks. It helps straighten the spine and separate ribs so lungs can grow and expand as the child grows. The device also stabilizes the diaphragm, the main muscle used in breathing. Length of the VEPTR can be expanded or contracted as the child grows.

What does it involve?
During surgery, doctors attach and adjust the VEPTR through a small incision in a child’s body. In some cases, more than one VEPTR device may be used, to create space in the chest for the lungs to develop.

VEPTR expansion surgery is needed every six to eight months until the child reaches skeletal maturity (between 10 and 16 years old). These adjustments, done through small incisions in the back, allow continued growth and correction of spine and chest-wall deformities.

A ventilator may be used for a few days after surgery to help the child breathe – or if respiratory complications develop. If problems arise with the chest or spine, surgery to implant more VEPTR parts may be needed, typically three months after the first procedure. A newer version of the device, which can expand with magnets rather than through surgery, may be used on some children.

Intended outcome
Long-term outcomes for children undergoing VEPTR surgery are generally good. The quality and length of life for children with SMA and TIS outweighs the risk associated with implanting a VEPTR.

VEPTR treatment decreases the need for general breathing support with ventilators. When skeletal maturity is reached, spinal fusion surgery is typically recommended to make the spine-and-chest-wall-correction permanent.

If the child has missing or fused ribs, doctors recommend keeping the VEPTR device indefinitely, to ensure the chest wall remains open, lung volume is maximized, and internal organs are protected.

Results
Results of a multicenter study showed that the VEPTR device was safe and effective in helping children with severe scoliosis and chest wall deformities. More studies are needed to completely evaluate long-term outcomes.

Constraints
Any surgery carries risks including blood clots, blood loss, infection, breathing problems, reactions to medication, and heart attack or stroke during the surgery. Risks associated with surgery of the chest include pain, bleeding, infection, heart or lung problems, and pneumonia.

Device-associated risks include breakage of the device during surgery or dislodgement with activity, causing damage to lungs, heart, or large blood vessels in the chest area. Possible risk to the spinal cord could result in temporary or permanent paralysis. Skin and muscle that has been stretched to cover the VEPTR device could break open or become infected. There’s a possibility that the child's body could reject the device.

A VEPTR should not be used if the child has poor bone strength in areas where the device would be attached, missing ribs near the device implantation site, diaphragm problems, or insufficient soft tissue to cover the VEPTR. The device is not recommended for children under six months of age, children whose skeletons have reached mature size (age 14 for girls; age 16 for boys), or those with other medical conditions.

For more details, visit:
1. Vertical Expandable Prosthetic Titanium Rib (VEPTR) - Children's Hospital of Philadelphia
2. Diagnosis and management of spinal muscular atrophy 一 Neuromuscular Disorders
3. Vertical Expandable Prosthetic Titanium Rib (VEPTR) - FDA
4. Vertical Expandable Prosthetic Titanium Rib (VEPTR) - Seattle Children's Hospital