Pushing the Envelope 

Orthopaedics Offers Breakthrough Ways to Keep Kids Moving

If James McCarthy, MD, is working outside of his comfort zone, you sure can’t tell. He became director of the Division of Orthopaedic Surgery last summer. He leads a team of talented orthopaedic surgeons, each doing breakthrough work. And he is overseeing plans to launch major services this year.

It is a lot to tackle for this self-described introvert who was initially drawn to a more solitary profession as a mechanical engineer.

“Engineering lends itself to my skills,” says McCarthy. “Medicine was just the opposite. It required a lot of interaction and people skills, which I never felt I had.”

He went into medicine anyway and proved himself wrong.

“It was a big change but I really enjoyed it. It forced me to be more rounded. It’s one of the things I love about what I’m doing right now. It forces me to do things that I’m not always comfortable doing.”

New motion lab in the works

Those things include planning a new motion analysis laboratory to open this summer. The lab will allow Cincinnati Children’s to dramatically improve the care of children with neuromuscular disorders.

McCarthy’s particular interest is in kids with cerebral palsy (CP). He hopes the motion analysis facility will help orthopaedists perform fewer surgeries on these kids, with better results.

“Historically, these children have orthopaedic surgeries several times throughout their lives,” he says. “There was actually something called the ‘birthday phenomenon,’ where every year they would get something done.”

McCarthy and his team want to change that. He is working with the Division of Physical Medicine and Rehabilitation and physiatrist Jilda Vargus-Adams, MD, who
specializes in the care of children with CP at Cincinnati Children’s.

“Motion analysis data can inform decisions about medical, therapeutic and surgical interventions for children with CP,” Vargus-Adams says. “The lab will provide information about the mechanics of walking in a manner that cannot be seen with the eyes.”

Plotting movement

The analysis gives doctors kinematic data, showing where a child’s joints are over periods of time, and what the forces and moments of power are at the specific joints, McCarthy explains. It can also tell which muscles are firing, and when.

Doctors can then sort out whether a child is compensating or if there is a true abnormality that needs correcting. If a child’s walking improves on its own over time, doctors can hold off on intervention.

“If, on the other hand, they’ve plateaued or they’re getting worse, we might operate,” says McCarthy. Following surgery, periodic motion analyses will give doctors a better idea of whether their interventions have been effective.

“Ultimately, it can keep children from having multiple surgeries and improve the quality of care we give them.”

Casting light on early onset scoliosis

A low-tech method used by orthopaedic surgeon Peter Sturm, MD, just might revolutionize the care of very young children with severe scoliosis.

Sturm arrived at Cincinnati Children’s just a few months ago to serve as co-director of the Crawford Spine Center. He specializes in using a casting technique for very young children with early onset scoliosis. The technique uses a lightweight plaster cast to guide the spine out of its curve during the years when children are growing most rapidly. The goal is to avoid surgery altogether – or at the very least, to postpone it until the child reaches adolescence.

Surgery not ideal

While traditional scoliosis surgery works to fix scoliosis in older kids whose trunks have finished growing, Sturm says, it is not ideal for younger children.

“When an adolescent needs surgery, we straighten out the curve and fuse the spine, and he does very well,” Sturm says. “But if we fuse a 3-year-old, the spine isn’t going to grow any more over the area where we fuse it. Therefore the chest isn’t going to grow either, and that’s the big concern.”

A chest that does not grow results in poor lung function, a major complication for these very young children. Casting appears to control the progression of scoliosis while allowing the child to continue growing, so lungs develop normally.

Sturm learned the casting technique from British orthopaedic surgeon Min H. Mehta, MD, who pioneered it. In his previous role as chief of staff at Shriners Hospital for Children in Chicago, Sturm had as many as 30 children at any given time actively wearing casts to correct their scoliosis. Although braces can also be used on these young children, they are cumbersome and not always effective. Sturm is a co-investigator on a multi-center study of casting versus bracing for these children and favors the casting technique.

“I’m pretty convinced that bracing doesn’t work and casting does,” he says.

Staying ahead of the curve

A plastic case about 2 inches square holds what could be the next big thing in scoliosis surgery.

The case carries four small titanium brackets with screws, similar to a bracket you might use to repair a wobbly shelf. Except in this case, surgeons hope it will repair children’s off-kilter spines.

The brackets were the invention of orthopaedic surgeon Eric Wall, MD, and biomechanics researcher Donita Bylski-Austrow, PhD. Wall had performed countless scoliosis surgeries on young people. Under the tutelage of Alvin Crawford, MD, he researched what has become the gold standard of scoliosis surgery, the thoracoscopic approach.

A better way?

Thoracoscopy approaches the spine from the front of the body. It uses a series of smaller incisions along the rib cage into which surgeons insert the steel rods and screws that hold the spine straight. While it is a dramatic improvement over traditional posterior approaches, it is still a lengthy and complicated surgery. Recovery takes weeks. And the results, while remarkable, have limitations.
Wall believes there has to be a better way.

“The goal was to develop an implant that would correct scoliosis using a patient’s own growth,” he says. “Instead of using big rods to bend the spine into position, the idea was to catch the curves earlier and apply a tiny implant that would control the growth of each vertebral body in the spine curve. That uses the patient’s own growth to power it.”

So the idea for the HemiBridge spine clip was born. Described by Wall as “just a specially designed staple with two screws,” the device was just given FDA approval for phase I
clinical trial and will be used in patients for the first time later this year.

“It’s the only current FDA-approved study of a class 3 pediatric orthopaedic device of any sort,” Wall says. “We’ve now got approval to start using it in humans.”

Guided growth

It’s been a long road – 17 years – getting the clip from idea to reality, says Wall. But the painstaking work of developing a simple device that actually alters growth has been worthwhile. The clip has proven highly successful in preclinical animal models, with significant growth modification seen in just a few months.

The clip will initially be used in children with scoliosis 10 years or older who still have significant growing to do. Initially, the study will involve a small group. Wall believes once the early data show how safe the clips are in humans, the FDA will quickly approve testing the device’s effectiveness in a multicenter study at about 10 children’s hospitals across the nation.

Lessons from sports medicine

Wall got the idea for the bracket from his experience in sports medicine, where he and others often use minimally invasive surgery to fix significant injuries, with excellent results. He believes the same principle could apply to spine straightening.

“In our preclinical model, this surgery often took less than an hour,” he says. “The average hospital stay would probably be reduced from five days to three almost from the start. And I think as we gain skill in this, and confidence, it could become an outpatient surgery.”