External Fixator Types

External fixators are medical devices used to treat a wide variety of bone and soft tissue problems. External fixators operate by connecting pins to a person's bones and then in turn connecting these pins to an outer scaffolding that surrounds the limb. External fixators are used for limb lengthening and limb reconstruction. They were first introduced in the mid-20th century. External fixators are useful because they are less invasive than internal pins, and they are also better at keeping weak areas fixated. Several major types of external fixators are in wide use.

Unilateral Fixators

• Unilateral frame external fixators, also called monolateral frame external fixators, are so named because they are attached to only one side of the limb to which they are fixated. Unilateral frames allow the fixated limb to remain functional. Unilateral frames come in two major subtypes, monobar fixators and pin-to-bar fixators. Unilateral fixators have greater stability than other types of fixators. This is accomplished with the addition of larger-sized pins on unilateral fixators, positioning the fixators closer to the limb, and placing the pins out of plane with one another. Monobody unilateral external fixators have a thick and rigid design, while pin-to-bar unilateral fixators use multiple lightweight fiber rods to improve rigidity.

Taylor Spatial Frame Fixators

• The Taylor Spatial Frame is one of the primary types of ring external fixators. This frame is made up of rings, connecting rods, and struts. Most Taylor Spatial Frames consist of two rings and six variable length struts. These types of external frames have been used primarily to correct deformities, but in recent years they have been used increasingly for managing fractures.

Ilizarov Fixators

• Ilizarov external fixators work on the same general principle as the Taylor Spatial Frame fixators---it consists of a ring connected to the bone with pins. They are named after their inventor, and they operate based upon his principle of Distraction Osteogenesis. This principle refers to the creation of new bone in between two bone sections that have been pulled apart. These types of external fixators are often used to correct deformities, to increase height, to cure bone infections and to help with severe fractures. Advantages of these types of fixators include that they can be used without actually making an incision in the patient's flesh, the pins are connected to bones by wires and the patient can remain mobile throughout the time they are using the fixator.