External fixator

Definition

The term ‘external fixator’ is used to describe a surgical procedure to treat bone fractures or other bone diseases. Normally, fractures can be treated with a plaster cast or surgically with screws and plates, depending on their severity. The external fixator is usually used when the soft tissues surrounding the bone are so injured that surgery with the classic methods of reconstruction is not possible.

The application of an external fixator is also an established treatment method in emergency situations and for patients with many injuries. With the technique of the external fixator screws are inserted into the affected bone fragments. In contrast to the usual surgical methods, however, the inserted screws protrude from the body and are connected with a metal bar. In this way, fixation and healing of the bone fragments can be achieved without excessive damage to the soft tissue surrounding the bone.

Indications

The installation of an external fixator may be necessary for a number of different diseases and injuries. It is most often performed after severe bone fractures where the soft tissue surrounding the bone has been severely damaged. By fixing the bones from the outside, the damaged soft tissue as well as the damaged bones can heal optimally.

The external fixator is used particularly frequently for fractures of the cervical spine. Another indication is the so-called callus distraction. Here, bone is surgically penetrated in a targeted manner and the ends are pulled apart with the external fixator to stimulate the tissue to form a “callus“, the scar tissue of the bone, which later hardens into a firmer material and thus lengthens the bone.

This method can be used to correct differences in leg length, for example. To remedy the symptoms of certain diseases, it can be useful to stiffen a joint artificially with an external fixator. In severe osteoarthritis, for example, bone can be connected via the joint in between to stiffen it permanently.

How does the external fixator work?

An external fixator is used to create a connection between two bones or bone fragments via a metallic bar. To achieve this, screws are inserted into the affected bones. These screws protrude from the skin above.

In order to be able to connect the screws, and thus the bone fragments, in a stable manner, so-called clamps must be attached to the screws, to which the metal bar can be attached. This bar can temporarily support or replace the bone in the case of bone fractures if the bone is no longer able to guarantee sufficient stability due to a fracture. Soft-tissue injuries are also spared, in contrast to the conventional treatment options for bone injuries, which is why the external fixator is the optimal solution for extreme bone fractures with soft-tissue injuries.