Ilizarov External Fixator

Written by:  Gregory T. Reveal, MD of Central Indiana Orthopedics

Fine wire fixators are external fixators that use tensioned wires (1-2 millimeters in diameter) passed through bone and attached to a circular frame to hold bone in a stable position for healing. Fine wire fixators have been in use since the Thirties. Difficulties with pin tract infections, joint contractures and component failures, eventually lead surgeons to abandon fine wire fixators. These problems were eventually solved by Gavril Abramovich Ilizarov, a Soviet surgeon. He started his medical career treating casualties during World War II. Like most medical innovations, the development of the Ilizarov external fixator came from necessity. Based in Kurgan, Siberia, short of supplies and treating patients with horrible battle wounds; Ilizarov found available surgical techniques inadequate. He developed a fine wire fixator, an application method and pin care regimen that solved most of the previous problems associated with fine wire fixators. He patented his method in the Soviet Union in 1951 and started the Ilizarov Institute in Kurgan, Siberia. Over the following decades, research performed by Ilizarov and other surgeons lead to solutions to many complex problems in orthopaedics that would have previously been “cured” with amputation. Unfortunately, the cold war prevented the dissemination of knowledge from the Soviet Union. It wasn’t until the early eighties that the method of Ilizarov found its way into Western medicine by way of Italy. Although the technique was appreciated by Western surgeons, the complexity of technique has limited its’ use. Over the past two decades, the fixator and method have been modified to simplify usage. Despite improvements, the difficult management of patients with this fixator has limited the indications for this procedure. Most surgeons agree that the Ilizarov external fixator is ideal for complex lower extremity trauma, correction of bone defects, and management of fracture nonunions (bones that have not healed with standard treatment).

Complex fractures are ideally treated with the Ilizarov. The fixator allows absolute control of the fracture with minimal injury to the soft tissues surrounding the bone. The soft tissue supplies the bone with its blood supply. When the soft tissue is ‘stripped’ off the bone (as occurs with plating), the bone loses some of its ability to heal. This can lead to a nonunion, which is a more difficult problem to solve. Open fractures (where the bone is sticking through the skin) have increased risk of infection, especially if plated, and are ideally treated with this method. Nonunions occur for many different reasons but often result from inadequate stabilization of the bone. Motion at the fracture site will not allow the bone ends to heal together. The Ilizarov fixator rigidly holds the bone, allowing early motion and weightbearing without risk of implant failure or motion at the fracture site.

Bone defects are often the result of a traumatic injury that has a piece of bone missing. When this occurs there are not many options; the limb can be shortened, a bone graft can be used to fill the gap, an amputation can be performed, or the Ilizarov can be used to perform a bone transport procedure. The bone transport was developed by Ilizarov as a way to treat bone defects. A shortened limb is poorly tolerated and often requires a prosthesis (shoe lift). Bone grafts of open fractures or infected nonunions have increased risk of infection. Prosthetics for amputees are expensive to produce and amputations increase the energy required for walking. Bone transport manipulates the biology of bone healing to form new bone in the area of the bone defect. A cut is made in the bone above the defect and the free piece of bone is pulled through the soft tissues at a constant rate to regenerate bone. Large sections of bone can be regenerated in this way, but the procedure is time consuming (fixator is on a month for every centimeter of bone regenerate) and painful. The Ilizarov external fixator is ideally suited for this application. This procedure is only recommended in specific situations and often an amputation may have a patient walking and more functioning sooner.

Nonunions are difficult problems to man-age. In a perfect world all bones would heal, but they don’t. Many factors contribute to the development of a nonunion; poor patient health, inadequate stabilization, and infection are most common. The Ilizarov fixator allows the bone ends to be compressed together at a constant tension facilitating bone healing. The lack of plates or screws at the nonunion site eliminates a bacterial haven and improves the chance of healing the bone in the face of an infection. The fixator can be left on as long as needed to heal the fracture.

The Ilizarov external fixator is a complex device that under the certain circumstances is the ideal solution to complex problems that continue to frustrate orthopaedic surgeons. With careful planning, application, and management; it can often mean the difference between amputation and limb salvage.

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