Engines of Our Ingenuity

No. 1176:
ILIZAROV SURGERY

by John H. Lienhard

Click here for audio of Episode 1176.

Today, we straighten crooked bones. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Dr. John Gugenheim suits me up and leads me into an operating room. The small leg of a 7-year-old boy protrudes from surgical linens on the table. His deformed foot bends at a right angle. All his life he's limped about on the side of that twisted foot.

Until now his deformity might've been altered by conventional surgery, but it couldn't be eliminated. "He's such a sweet boy," says the scrub nurse readying his leg for a new kind of surgery. A technician wheels in carts full of parts -- like a big erector set. Gugenheim finds a 1/16-inch wire, fits it into a drill, and begins.

He drills the pointed wire right through the skin, muscle, and bone of the lower leg. He selects a second wire and drills it through at right angles to the first. He picks up two half rings made of a carbon-fiber composite material --light and strong. It's the same material they use to make stealth bombers, but now we're repairing bodies, not destroying them.

From the rings he fashions a wheel. The wires are its spokes. He tensions them to 240 pounds. Now he repeats the process at the ankle. Then he connects the rings with adjustable rods, parallel to the leg. Soon he has an external cylinder, anchored to the bone.

He calls this exoskeleton an external fixator. Gavariil Ilizarov, a Jewish doctor in Siberia, invented it in 1951. Ilizarov had to work far from Russian seats of power, but his method nevertheless managed to take root in Russia, then Italy. During the mid-80s it reached the rest of Europe and America. It's been widely accepted in the West only since the 1990s.

I recently happened to meet an Azerbaijani émigré -- a petroleum engineer. "Oh yes," he said, "Ilizarov was my mother's relative. We had many open fractures in the oil fields. After Ilizarov surgery, workers walked again, right away." I'd wondered what kind of magic this was. Now I'm finding out.

Gugenheim works steadily for three hours. He follows his own careful, but minimal, sketches taped to the wall. He assembles some 150 parts into a machine that encompasses the whole foot and lower leg. It's equipped with screw adjustments and universal joints.

He'll send the boy home in this device. The parents will move the screws a quarter turn, a few times a day, according to Gugenheim's specifications. Ilizarov found that bone regenerates under tension. This structure will slowly draw the bones out so they can grow into a normal arrangement. The boy will keep limping, but less and less each day. He'll walk normally in six months.

I leave the operating room thinking about the opera, Amahl and the Night Visitors. Lame Amahl, visited by the Magi as they travel to the manger, is miraculously healed. The word Magi comes from the same root as magic -- and I have seen the magic that will make this Amahl walk again.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


This surgery was done on October 25, 1996, by Dr. J. John Gugenheim at the Texas Orthopedic Hospital in Houston, Texas. I did not see the young patient's face, nor did I feel it proper to ask his name. I am grateful to Dr. Gugenheim for instructional commentary during the operation. That commentary revealed the enormous geometric and kinematic complexity of the operation. For more on the Ilizarov method, see articles in Techniques in Orthopedics, Vol. 11, No. 2, 1996. I am also grateful to Mr. Jeffrey A. Russell, President of the Joe W. King Orthopedic Institute, for providing a document titled, "The Ilizarov External Fixator: General Surgical Technique Brochure." (I believe this is a manufacturer's document. I have no bibliographic information for it.)

The following websites show illustrations of the Ilizarov procedure:

http://www.drmendbone.com/ilizarov.htm

http://www.bonejoints.com/


The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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