Children's Hospital Los Angeles recently became the first pediatric hospital on the West Coast to implant an innovative new system of spring-based rods in children with early onset scoliosis (EOS).
The Spring Distraction System (SDS), developed by Cresco Spine, requires fewer surgeries and adjustments than traditional treatments and has been in use in Europe for roughly a decade. It received clearance from the U.S. Food and Drug Administration (FDA) in January, and CHLA is one of the first children's hospitals in the nation to offer it.
CHLA spine surgeons Lindsay Andras, MD, and Tyler Tetreault, MD, have implanted the system in two patients so far. They were trained in the procedure earlier this year by René Castelein, MD, PhD, who originally co-developed the SDS with Moyo Kruyt, MD, PhD, in the Netherlands.
I was fortunate to go to the Netherlands with the Scoliosis Research Society in 2024 to see the SDS in use, and I was really impressed with the results I saw there. Ever since then, I was hopeful for bringing that implant system here."
Dr. Lindsay Andras, Director, Children's Spine Center and Associate Chief of the Jackie and Gene Autry Orthopedic Center, CHLA
Limitations among existing spinal distraction options
The SDS is different from standard methods of spinal distraction, a scoliosis treatment strategy that uses stretching forces to gradually straighten a curved spine while allowing children to continue growing. These standard methods include traditional rods and magnetically lengthening growing rods, both of which are surgically implanted into a patient's back.
Because young children are still growing, spinal fusion surgery is not a viable option for young children with early onset scoliosis. Spinal distraction treatments have long been the best approach, but both traditional and magnetically lengthening growing rods have limitations. Traditional rods require additional surgeries every six months as a child grows, until they are old enough for a definitive spinal fusion-a high number of repetitive procedures.
Magnetically lengthening growing rods, which can be lengthened using external magnets instead of surgery, address this issue. However, these rods need to be magnetically lengthened every few months, meaning frequent clinic visits for families. The magnets in the rods are also not effective for patients with higher levels of subcutaneous fat, and they can obscure MRI imaging. "Some kids who have had prior tumors or other issues that need to be scanned are not candidates for magnetic rods," Dr. Andras says.
Additionally, traditional and magnetically lengthening growing rods both have specific sections that need to remain straight when implanted, which doesn't work for certain spinal curves.
Traditional and magnetically lengthening growing rods share another significant drawback as well. "The major downside is that you stretch the spine out and hold it in place, motionless, for years," Dr. Tetrault says. "Over time, the spine can become really stiff, which is called autofusion, and this becomes an issue when you eventually go in to definitively correct the curve with spinal fusion. You have to get some flexibility back into the spine to get a good correction."
A new spinal distraction system with more flexibility
The spring rod system avoids these issues. Once surgically implanted, the springs in the rods continually apply the force needed to stretch the spine, while also compressing and expanding as the patient moves.
"There's a little bit of micro motion that's always happening, which has been shown to reduce the risk of developing autofusion," Dr. Tetrault says.
Unlike traditional rods, spring rods don't need to be surgically lengthened every few months because the springs allow them to naturally expand as the patient grows. Surgery may be required after a few years to re-tension the springs, but this is a small procedure.
The spring rods can also be contoured to match the shape of the patient's spine, fitting a wider range of spinal curves than the other rod options. In fact, the spring rod system was first developed by Dr. Castelein to treat a child with a spinal deformity for which traditional or magnetically lengthening growing rods would not have worked.
Looking ahead to additional SDS surgeries
The spring rod system is currently only available in one size in the U.S. "In the Netherlands, they have different sizes to suit different patients, but in the U.S., we don't yet have approval for all of those," Dr. Andras says. "So for really thin kids, the SDS available in the U.S. right now is not a good option. But for a normal weight child, this option has a lot of benefits." Dr. Andras is hopeful that more sizes will be available in the U.S. in the future.
Since the spring rod system has been used in Europe for about 10 years, doctors already have supportive data showing its long-term effectiveness. This meant Drs. Tetreault and Andras could move forward with confidence once they were trained in implanting the rods. "I've got a few other patients who would be really good candidates for this system, so we will likely do more of these procedures soon," Dr. Tetreault says.
"This is a significant improvement over past treatments," Dr. Andras adds, "both in terms of the outcomes and how it impacts the day-to-day lives of families."
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