ADVERTISEMENT

New Limb-Lengthening Tech May Reduce Complications for Sufferers of Crippling Deformities [Slide Show]

A move to lengthen limbs internally rather than via an external scaffold could reduce the effects of painful treatments, especially among younger patients



Dr. John Herzenberg

More In This Article

Screaming woke Lanz Ellingsworth. The piercing cries were loud, they were shrill — and they were coming from his daughter's bedroom.

At 8:30 p.m., Ellingsworth and his wife had tucked their youngest, Lindsay, in for the night. They read her a bedtime story, kissed her on both cheeks and crept out of the room. Six hours later, their little girl was a mass of quivering agony.

In the middle of the night Lindsay had shifted slightly in her sleep. The abnormally brittle femur in her left leg splintered into multiple pieces. She woke from her dreams and plunged into a living nightmare.

"When I woke up that night, what I kept repeating was that 'somebody hit me with a sledgehammer,' Lindsay says. "That's how it felt. Somebody literally smashed my leg with something. And I just screamed."

Lindsay, a tiny, freckled eight-year-old, was used to pain. She was born with a congenital limb deformity called "underdeveloped femur condition," in which one leg is shorter than the other by more than two centimeters. Up to 100,000 people are diagnosed with limb-length disorders in the U.S. each year, according to Bart Balkman, vice president of Ellipse Technologies, an Irvine, Calif.–based orthopedics company.

Left untreated, the condition can result in chronic pain, loss of mobility, degenerative arthritis and debilitating scoliosis, an abnormal and painful curvature of the spine that typically progresses throughout one's lifetime. At birth or shortly thereafter parents whose children have a severe discrepancy (estimates range from a two- to three-centimeter or more differential) must make a decision—amputate the shorter limb or commit to a lengthening regimen to equalize them.

"Can you ever imagine having a child and loving that child and being told that part of your child's leg had to be amputated?" says David Hootnick an orthopedic surgeon in Onondaga County, N.Y., who studies congenital abnormalities. "Can you imagine the emotional stress you'd have to go through?"

Limb-lengthening technology has progressed significantly from the early 1950s when a handful of doctors first began the practice. Gavriil Ilizarov invented the external fixator in Russia, a device he modeled after a horse harness. Now, about 100 surgeons in the U.S. perform limb-lengthening procedures, and a new internal approach offers patients expanded mobility and promises fewer complications. The device, called "Precice," received U.S. Food and Drug Administration approval for consumer use but is still relatively unknown within the greater medical community.

[View a slideshow of the Precice technology.]

By far the most common procedure for children with leg discrepancies—and the one used in Lindsay's surgery—is an external "fixator." Surgeons break a patient's bone in half and pull it apart, allowing the body's natural healing capabilities to fill in the gap with new bone, thereby lengthening the limb.

John Blanco, a specialist in pediatric orthopedics and scoliosis at the Hospital for Special Surgery in New York City, has been performing the operation for years. With the patient under a general anesthetic, Blanco drills screws into the top and the bottom of the afflicted bone. The screws are fastened into a metal frame that will stabilize the leg during and subsequent to the procedure. After cutting a small incision in the leg, Blanco takes a hammer and breaks the bone in two. It's a dull sound, he says, like hitting wood—more of a thwack than a snap. The finished product resembles an Erector Set construction covering the leg.

By manually twisting the screws on either end of the fixator, discrete pieces of bone are pulled apart to lengthen legs an average of 1.25 centimeters per day. The body regenerates bone, filling the gap in a matter of hours.

"You gradually stretch out the healing bone sort of like salt water taffy," Blanco says.

Once the desired length has been achieved, Blanco removes the fixator. Months of physical therapy follow. Patients going through any limb-lengthening procedure relearn how to bend their knees, rotate their ankles, walk and swim. If all goes well, the limbs are equal in length and the range of motion is average. Unlucky patients can suffer complications such as multiple fractures, scarring, an off-kilter gait and arthritis as well as hip knee and disc pain.

About 500 limb-lengthening surgeries are performed each year at Sinai Hospital in Baltimore. Doctors there have partnered with Ellipse Technologies to promote the new internal limb-lengthening method. External fixators are invasive, and guarantee postoperative weight loss, inflammation, oozing pustules, and reduced mobility along with the above-mentioned problems. In the best cases a patient treated conventionally can expect to have at least two complications, such as Lindsay's fractured bone, says Debbie Stanitski, an emeritus professor at the Medical University of South Carolina Children’s Hospital.

Precice technology claims to be far less painful and much easier to manage than an external fixator. The newer mechanism relies on rare earth magnets made of an alloy of neodymium iron and boron as well as revolving screw gears to extend a fixator rod that is inserted inside the bone. Doctors direct the gearbox magnetically via a handheld controller, and manipulations occur entirely within the bone, thus minimizing the risk of infection because there are no open wounds. So far, Sinai Hospital has implanted the internal fixator in 31 patients and the initial results look promising. This approach has been much safer than external limb-lengthening methods, reducing the complication rate by 75 percent, says John Herzenberg, director of the International Center for Limb Lengthening at Sinai.

A tough decision

When the Ellingsworths elected to put Lindsay through limb-lengthening surgery, they were aware of the consequences. What they didn't bargain for was how agonizing it would be to watch their little girl suffer through the external fixation process.

Surgically lengthened limbs are never as strong as they were prior to treatment. In Lindsay's case her femur was unable to take the weight of her body and snapped as a result. In order to keep her bone from fracturing again, Lindsay needed the stability of the external fixator's metal frame, which had been removed prematurely. According to the doctor, one of her parents would have to reattach the frame to the screws in her leg—leftovers from an earlier surgery.

Using an Allen wrench, Ellingsworth cinched the fixator's steel bar to screws already deep within Lindsay's bone. For an hour the terrified father tinkered with the brace while Lindsay's mother held her close. Latch the wrench. Dry her tears. Twist the wrench. Listen to her screams. Repeat. When it was over, Ellingsworth embraced his child tightly and wished he could take some of the burden off her small shoulders. Lindsay was only eight years old, and this was just the first surgery with many to follow. Legs can only stretch about 12.7 centimeters at a time so patients must come in for multiple operations.

"They'll spend the rest of their life being lengthened," says Doreen DiPasquale, a reconstructive orthopedic surgeon at Sharp Memorial Hospital in San Diego, Calif. "That's not fair to the kid...It's a quality-of-life issue."       

There aren't any specific rules governing the limb-lengthening practice because each one is so unique, leaving the number and duration of the procedures up to individual doctors. This leads to a host of unnecessary operations, Hootnick says. Surgeons are apt to do what they do best—operate. Oftentimes, safer options like amputation are overlooked, especially with advancements in prosthetic limbs. Parents, pressured by social standards and desperate to keep their children "normal," don't question the medical advice.

Are prosthetics the better alternative?

For those who have achondroplasia—the most common form of dwarfism—limb lengthening isn’t much of a decision. Without the procedure, little people run the risk of having their spinal vertebrates fuse as they age. The result is severe scoliosis that confines them to a wheelchair.

Still, Hootnick thinks most limb lengthenings are not justified. It's a doctor's responsibility to do no harm, but this procedure causes nothing but harm, he says. Surgeons need to take more responsibility for pushing people down this path, he adds.

"We physicians are able to guide patients in the direction that we think things should go, simply because people seldom have any knowledge of what we're talking about," Hootnick says. "You can't understand the complexities of an operation—you've never had one."

Looking back, Hootnick says amputating Lindsay's shorter leg and fitting her with a prosthetic would have saved the Ellingsworth family a lot of heartache and their daughter a lot of pain. Now 25 years old, Lindsay recently underwent her 11th limb discrepancy–related surgery. She spent most of her teenage years in and out of the hospital, bound by wires from the external fixator. Now she owns a house in upstate New York and works as an emergency medical technician. Her leg problem is always something of a burden, due to the complications from arthritis.

Still, Ellingsworth says he made the right choice, despite his daughter's suffering. Lindsay isn't so sure. She often wonders what it would have been like to have a childhood free of surgery and chronic pain.

"Sometimes I wish I was the one with the prosthetic leg," she says. "There's always that could have been, but I guess with this choice, I'll never know."

Rights & Permissions
Share this Article:

Comments

You must sign in or register as a ScientificAmerican.com member to submit a comment.
Scientific American Back To School

Back to School Sale!

12 Digital Issues + 4 Years of Archive Access just $19.99

Order Now >

X

Email this Article

X