The Ilizarov Apparatus is a set of external fixators comprising rings, rods and Kirschner's wires. It is different from the conventional external fixators in that it encases the limb as a cylinder-the limb itself being shaped like one and it uses wires instead of pins to fix the bone to the rings.

The Ilizarov Method uses Ilizarov's Principle of DISTRACTION OSTEOGENESIS (osteo=bone, genesis=formation). This refers to the induction of new bone between bone surfaces that are pulled apart in a gradual, controlled manner. The distraction initially gives rise to NEOVASCULARISATION (Neo=new, vascular=relating to blood), which is what actually stimulates new bone formation. In addition, there is simultaneous histogenesis (histo=tissue) of muscles, nerves and skin; in bone diseases (osteomyelitis, fibrous dysplasia, pseudo-arthrosis) this new bone replaces pathological bone with normal bone. This is a revolutionary concept; diseases for which earlier there was no treatment are now successfully treated using the Ilizarov Method.

No skin incision is made as in a conventional operation. Incidents of haemorrhage, tissue trauma and infection are much fewer. The whole procedure is minimally invasive as only wires fix the bones to the rings and there is very little soft tissue damage. The Ilizarov fixator is very versatile; the cylindrical shape of the fixator allows deformities to be corrected simultaneously in 3 dimensions. The patient remains mobile throughout the course of the treatment. Intensive physiotherapy is instituted early; as a consequence, problems of joint stiffness and contractures are rare. Further, the patient's stay in the hospital is considerably reduced.

Called TRANSOSSEOUS OSTEOSYNTHESIS (trans=across). Wires of 1.5 mm diameter are passed percutaneously (through the skin) through bones by means of a drill. The protruding ends of these wires are then fixed to rings with special "wire-fixation" bolts. These rings in turn are connected and fixed to one another by threaded rods. Once it is fixed, the Ilizarov frame affords a stable support to the affected limb. A CORTICOTOMY is then performed; it is an osteotomy (cutting the bone) where the periosteum of the bone is preserved. Adjustments in the rods produce compression or distraction as desired between the bone ends, and simultaneously, deformities are also corrected. The ring fixator is removed at the end of the treatment.