Scoliosis is abnormal curvature of the spine. The severity of the condition is measured in degrees, as viewed from back to front with an X-ray film. In cases up to 25 degrees, doctors monitor the scoliosis for progression, but do not treat it actively. Between 25 to 40 degrees, the standard of care is bracing. For children younger than 10 years with this severity of scoliosis, however, the effectiveness of bracing has been called into question.
As a result, a new intervention has been developed: fusion-less surgery, in which the spine is tethered rather than irreversibly fused with spinal fusion surgery. Tethering the spine may be more effective than bracing it, and avoiding spinal fusion allows for continued growth in very young children and more normal function of the spine, as the vertebrae can move.
Vertebral body stapling is the only tethering procedure performed on patients in the United States. In the procedure, staples are inserted across growth plates of the vertebrae. The staples are applied to the convex (longer) side of the curve, which is growing faster than the concave side. By tethering the faster growing plates, the spine may be guided to stop curving while still being allowed to grow, or even to grow straighter.
X-ray of a child with scoliosis, taken
before vertebral body stapling.
X-ray of the same child, taken shortly
after the procedure.
Stapling across growth plates to modulate the growth of children's bones was introduced in the 1940s, in particular at the knee to treat knock knees and bow legs. When this technique was first used on the spine in the 1950s, it did not meet with the same success, in part because the staple design did not anticipate that the scoliotic spine is mechanically more challenging, and the staples backed out of the bone.
The staples used today are made of NiTiNOL, a shape-changing or memory metal alloy made of nickel and titanium that was originally developed by the U.S. Navy. The prongs of each staple are straight when kept on ice in the operating room. As they warm to body temperature after insertion into the spine, the prongs curve so that the staples assume a "C" shape and clamp securely to the body of each vertebra. This prevents them from backing out of the bone.
UCSF began performing vertebral body stapling only after studying it in the laboratory. Dr. Mohammad Diab and his colleagues completed the only biomechanical spinal study of the procedure before he was willing to offer the procedure to patients. Currently, UCSF is the only hospital in the Western U.S. to perform this procedure.
Our program focuses on children less than 10 years old with a curvature greater than 30 degrees. These children are at the greatest risk for progression that will eventually require spine fusion, regardless of bracing. Our early experience has shown excellent success in controlling scoliotic curves, with no significant complications.
Vertebral body stapling is indicated for children less than 10 years old with scoliotic curves greater than 30 degrees.
Diab and his staff will take a medical history and perform a physical examination of your child in the Pediatric Orthopedic Clinic. They will obtain X-rays of the spine to measure the degree of curvature and to determine the part of the spine on which to operate. They will also obtain an MRI to evaluate the nerves of the spine, including the spinal cord, as nerve tissue is invisible to X-rays.
Diab has found that both children and parents benefit from connections with other patients, as they can provide excellent support for each other. If you wish, our staff will connect you with patients who have already undergone the procedure.
Your child will be admitted to the hospital on the day of the operation. The operation takes about six hours and is performed under general anesthesia.
During the procedure, your child will lie on his or her side. The vertebral bodies (which are at the front of the spine) are accessed through an incision in the side of the chest, going between ribs, or in the side of the flank, going behind the abdominal organs. The staples are inserted with the assistance of an X-ray machine in the operating room.
We will monitor nerve function throughout the procedure with electrodes placed on the head and the lower limbs. Your child will leave the operating room with a chest tube as well as intravenous and urinary catheters.
After the operation, your child will be admitted to the children's ward. The day after surgery, your child will get out of bed with the assistance of a physiotherapist. While in the hospital, your child will be fitted for a custom spine brace, which is worn for six weeks after the operation.
Your child will be discharged home three or four days after the operation. Before discharge, the incision will be checked and redressed, and all tubes and catheters removed. Your child will return home with the brace and pain medications.
You may plan on your child returning to school one month after the operation. A follow-up visit should be scheduled six weeks after the operation, when X-rays will be taken and the brace removed. After this, your child may return to full and unrestricted activity.
Diab will follow your child throughout growth until maturity, to look for any change in the scoliosis. Barring any issues, the staples do not need to be removed. Your child will not notice them in any way and the spine will remain mobile, with no long-term adverse effects from these implants.
Reviewed by health care specialists at UCSF Benioff Children's Hospital.