When an 8-year-old boy was diagnosed with early-onset scoliosis (EOS) due to a spinal cord tumor, he was left with few options to control his deformity while allowing continued growth, in addition to required tumor surveillance. With a 70-degree curvature of his spine, any more progression could impact his heart and lung development as well as his spine growth. After bracing and casting failed to sufficiently control the patient’s deformity, Duke pediatric spine surgeon Anthony A. Catanzano Jr., MD, knew they would need a different solution.
Left untreated, EOS can have severe cardiopulmonary ramifications. At younger ages, it’s critical to use implants that will grow with the patient rather than fusing the spine and limiting their growth and development. “Growing rods constituted a major innovation for EOS treatment,” Catanzano says. “They allow us to correct the deformity while maintaining the capacity for the child to grow and develop during this critical period.”
When they were introduced a decade ago, magnetically activated growing rods improved scoliosis treatment, allowing for rods to be lengthened without the typical invasive surgery to do so. However, these rods do pose some risks such as metal debris during lengthening, leading to metallosis and increased blood levels of metal ions. Additionally, the magnets were limited in their maximum length and strength to counteract the spine’s curvature and growth. For this patient, the magnets would interfere in MRIs, which are critical in the care of his spinal cord tumor.
What innovation did Catanzano use to treat EOS?
After reviewing various options, the patient became the first in the U.S. to receive an innovative implant, the MARVEL growing rod system (Globus Medical, Audubon, PA). Rather than a magnetic driver, MARVEL uses a mechanical lengthening technique with the simple insertion of a driver into a specific portion of the rod. “We make a small incision every six months to lengthen the rod, aiming to match the patient’s growth during that time,” Catanzano says. This incision and lengthening can be done without the need for a complete operating room set-up typical in spine surgeries.
The MARVEL growing rods enable a quick recovery from the initial surgery. “We operated on a Friday, and the patient was home by Sunday morning, bouncing around the house and enjoying being taller,” says Catanzano. “He no longer needs a restrictive external cast or brace.”
After six months, the patient returned for his first rod lengthening, which successfully achieved the intended lengthening goal. Unlike magnetic rods’ external control device, the driver and rod’s direct connection reduces the chance of stall or failure during lengthening. The follow-up procedure took place on a Friday morning, and the patient was home by the afternoon, back to his favorite activities — video games.
“It’s important to note that scoliosis is not just a condition of adolescence,” Catanzano cautions referring providers. “Typically, providers begin to check at 10 or 11, but it should be on the radar much earlier. Using the Adams forward bend test and scoliometer at well-child checks for younger patients can help to catch scoliosis earlier.”
Early detection and referral to a medical center with the full range of treatment options are key to improving scoliosis outcomes. With innovations like these growing rods, Duke stands on the cutting edge of scoliosis treatment. Duke was the first program in North Carolina to offer the EOS low-radiation-dose imaging system (EOS imaging, Paris), and now has four machines at Duke locations in Durham and Wake counties. For children who need repeat imaging as with scoliosis, these lower-dose exams use biplanar radiographs and functional 3D data. “At Duke, our multidisciplinary teams are really committed to treating EOS and other concomitant conditions,” says Catanzano.
