A Focus on Youth Shapes Next-Generation Spinal Surgery

A Focus on Youth Shapes Next-Generation Spinal Surgery

When Michael Kelly, MD Director of scoliosis and spinal deformities at Rady Children’s Hospital, explains how this spine-twisting disease affects adolescents differently from adults, he does so with a blunt example.

“Not many adults ask if they’ll be able to ride a roller coaster again after surgery,” he said. “For adults, spine surgery is mostly about removing pain. For children, it’s about an issue that can be with them for their entire lives.”

The S-shaped curves characteristic of scoliosis develop most frequently during pre-pubescent growth spurts. Most instances of scoliosis are classified as idiopathic—they emerge seemingly out of nowhere, with no underlying spine or neuromuscular causes. For these reasons, pediatric research centers such as the Spine Center at Rady Children’s are emerging as powerhouses for the treatment and understanding of spinal disorders.

“Before I came to Rady Children’s, I was getting pulled in every direction,” recalled Kelly, who joined after completing two spine fellowships at Washington University in St. Louis. “Being able to focus on children instead of a diverse patient mix is beneficial from a research perspective. And having the chance to work with Rady Children’s surgeon-in-chief Peter Newton, MD who’s contributed so much to this field and has such intuitive, emotional intelligence—it was an opportunity I couldn’t pass up.”

With Kelly on board, the Rady Children’s Spine Center is looking to build on its record of patient-centered innovation. But the center also aims to advance the fundamental understanding of scoliosis. In partnership with genomic specialists, the team investigates the genetic basis behind the condition’s development and the immunological factors that may govern patients’ recovery from corrective surgery.

RESTORING BALANCE

Newton has pioneered data-driven techniques to improve scoliosis treatments for over 25 years at Rady Children’s. He notes that the most common method in severe curvature cases is to perform spinal fusion, which transforms twisted vertebrae into a solid block of bone with bone grafts and implants like rods and screws.

“We’ve become exceptional at correcting scoliosis using fusion technology, but it’s highly dependent on the surgeon’s understanding of three-dimensional deformities,” said Newton.

“You need experience to execute these technically challenging operations, and from knowing Mike Kelly’s performance as a surgeon and researcher, this was the person I wanted to join our team.”

With more than 150 peer-reviewed articles on spine surgeries, Kelly’s research focuses on classifying and interpreting the biomechanical issues surrounding spinal surgery.

“We’re putting metal in and ‘gluing’ these bones together that are supposed to move; it’s one of the most biologically abnormal things we could do,” explained Kelly. “If you fuse a shoulder, fuse an elbow—every orthopedic physician knows what angle to lock in the bones, even if it’s quite rare. But very few surgeons think about where spinal bones should be fused, and these are done thousands of times a year.”

GETTING A GRIP ON SCOLIOSIS

Newton is renowned for developing spinal growth tethering surgery, an innovative strategy to straighten the spine without resorting to bone fusion. In this procedure, flexible polyethylene cords are implanted along the side of the spinal column to influence growth, eventually straightening the spine as the patient grows.

Through innovative technology, Newton and his team track the three-dimensional shape of the tethered vertebra over two to three years of growth. Newton emphasizes that the success of the tethering approach depends on finding patients with enough capacity to modulate growth. “Right now, our ability to find the perfect patient is modest at best,” he said. “If you put the tether in too late after the growth spurt, not much happens. And even then, how much you correct initially with the cord, how much additional pressure you need over time—that varies based on the patient curve size and remaining growth. We’ve had some spectacular outcomes with tethering, especially in a 15-year-old patient named Sophie Allison.”

SOPHIE’S STORY

Sophie, a healthy and active 15-year-old, was referred to Rady Children’s for an evaluation of scoliosis. Upon examination, it was found that she had a substantial shift of her trunk to the right side, with a large right thoracic rib prominence. While her neurological examination was normal, there were features of her curvature that made the doctor suspicious of an underlying neurological cause for her scoliosis. “She had an unusually large degree of thoracic roundback, or kyphosis, which is not typical of adolescent idiopathic scoliosis (AIS),” Newton noted.

An MRI scan of her spine revealed a large fluid-filled cyst on her spinal cord, along with a condition called Chiari malformation. With the cause of the cyst determined, Sophie was referred to a neurosurgical colleague, David Gonda, MD, who performed a surgery to relieve pressure on the area where the skull and the neck meet.

Once Sophie had recovered from her Chiari decompression surgery, Newton corrected her scoliosis. This involved using a technique called posterior instrumentation and fusion from T2-L3, connecting the vertebrae from the second thoracic (T2) to the third lumbar (L3) using metal rods. The rods were shaped differently on the right and left sides to fix the rotational and bending issues in Sophie's spine. The screws were carefully positioned and adjusted to correct the deformity. Throughout the surgery, the doctors monitored Sophie's nerves to ensure they were not being affected by the spinal problem seen on the MRI—fortunately, there were no complications.

Following the surgery, Sophie followed a pain regimen and was discharged shortly after. Over the following six months, Sophie returned to her usual activities. Now, two and a half years after her surgery, Sophie lives with scoliosis in the rearview mirror.

HIDDEN IN THE GENES

Using tiny bits of bone and muscle left over from spinal surgeries, Newton and his team work with colleagues at the Rady Children’s Institute for Genomic Medicine to uncover genetic markers that may indicate scoliosis in cases like Sophie’s. He favors the theory that the mechanisms controlling bone growth become out of sync in patients with idiopathic scoliosis, creating curves and twists to accommodate extra spine length.

“Once the spine rotates a little bit off to the side, that vertebra is not in the area where it’s getting its normal weight bearing, and it starts a cycle of asymmetric growth with wedged vertebral shape that gets worse and worse,” Newton explained. “With tethering, we can reverse that cycle; that’s what makes it such an elegant solution.”

Along with expanding knowledge of the genetic underpinnings of scoliosis, Kelly foresees a continuing focus on patient-centered innovations at Rady Children’s. Already experienced in analytic data techniques to determine risks and track reported outcomes, he plans to tackle two key issues: immunology to improve patient self-healing and the expansion of artificial intelligence algorithms to guide surgeons.

“If we can come up with an AI system that can analyze these deformities and design the surgery so that you’re getting the same treatment whether you’re in San Diego, or Idaho, or Tunisia—that’s what we need,” said Kelly. “That’s the democratization of spine surgery, and that will make the treatment and outcomes of our patients infinitely better.”

Learn more about Rady Children's Hospital's innovations in healthcare at rchsd.org