Mike Prindle of Baltimore, Ohio (pictured) used to walk 8 miles a day on his mail route and drive a golf ball 150 yards with his 5 iron. But 2 years ago, he was diagnosed with chondrosarcoma – a tumor deep inside his pelvis – and doctors had to cut off his left leg, part of his spine, and the left half of his hip.
“I did ask the doctors, if you could save my right leg, please, please, at all costs, at least save my right leg,” Prindle says. “And they did.”
It took 37 hours of surgery and hundreds of healthcare professionals. Michael Miller of Ohio State University Medical Center kept the bones of Prindle’s amputated leg alive and repositioned them in the pelvis and spine, meticulously cutting and reattaching blood vessels and veins.
“We knew we were going to take his lower leg and amputate it. But the bones and the blood supply to the lower leg were not involved with the tumor,” says Joel Mayerson of Ohio State’s James Cancer Hospital. “So we decided to make use of those bones.”
About 6 inches of femur (thighbone) became pelvic support, and about 4 inches of fibula (outer shinbone) reinforces the lower spine.
With the left half of his pelvis gone, doctors placed the thigh bone from Mike’s amputated leg between the bottom of his spine and the front of his pelvis. Then, they took one of his shin bones and, using screws and titanium rods, fastened it to Mike’s spine to stabilize it. The hope was, by using his own, living bones, they would fuse together, maintain blood supply, and grow in their new position as if they belonged there.
Indeed they fused quickly after the surgery since there was still blood supply going to these bones, promoting quick bone healing.
Other surgeons have used cadaver bone in the pelvis, but both it and metal implants have significant limitations, Mayerson says, because they aren’t strong enough to withstand the long-term pressure of walking.
Before surgery, doctors fashioned a titanium scaffolding to bolster the strength of Prindle’s lower spine and spent several hours creating a model (pictured) of the support structure to make sure it would work.
With his bones fused together – saving his hip and spine – doctors fitted Prindle with an artificial leg that uses computers in the hip and knee joints to teach him how to walk.
“It learns how he walks from the time his artificial foot strikes the ground, until the toe lifts off with his next step,” Mayerson explains. “The computer actually decreases the amount of energy that he has to spend to move the prosthesis and allows him to move easier.”
Prindle is one of only a few Americans walking on this two-part prosthesis. “You learn the leg a little bit at first, then the leg adjusts and starts learning from the patient too,” he says. “So, it’s a two-way process that we’re learning to work together.” Cancer-free, Prindle walks with almost no assistance at all.
The work was published last month in the Journal of Neuroscience: Spine.
Images: Ohio State University