Ilizarov surgery, developed by Gabriel Ilizarov, a Russian Orthopaedic Surgeon, in 1951, is the oldest and most common method of distraction osteogenesis.
The Ilizarov method makes use of a circular external fixator to steady bony parts. The system comprises a sequence of external rings which are linked to one another through different kinds of ring connectors. Tensioned wires and half pins are transfixed to the bone and are also attached to the external rings, thereby stabilising the entire bone.
Because of the circumferential nature of the device, the Ilizarov external fixator provides superior mechanical strength and stability, resisting shear and rotational forces. In fact, the method not only allows for early weight-bearing in lower extremity applications, but weight bearing actually promotes healing and is therefore encouraged throughout treatment.
The Ilizarov technique offers many advantages over other treatments, including:
- Minimal soft tissue dissection required
- Bone regeneration potential
- Tremendous versatility
- Ability to stabilise small bone fragments with thin tensioned wires
In addition to strength and stability, the Ilizarov apparatus is designed to permit rings to change position relative to one another. Because the rings are attached to bone segments via wires and half pins, moving the rings has the effect of moving bone segments. The ability to precisely control the movement of bone segments is unique to the Ilizarov method and allows the orthopaedic surgeon to compress, distract and lengthen various portions of a bone throughout treatment.
The Ilizarov technique is particularly useful for the treatment of complex problems, including:
The Ilizarov method can be used in various modes, including:
- Differential Compression or Distraction
- Bone Transport
Compression is a useful treatment method for certain types of slow healing fractures
(delayed unions) and fracture non-union.
Slow gradual compression of bone segments is generally applied at the rate of ¼ to the ½ millimetre per day by moving the rings closer together (by tightening the ring connectors). The compressive force generated leads to rapid healing in certain types of cases.
Certain types of non-union respond well to distraction. Slow gradual distraction of bone segments is generally applied at the rate of ½ to ¾ millimetres per day by moving the rings progressively apart (by distracting the ring connectors). Although it may seem counter-intuitive, the mechanical force transmitted during the process of distraction (pulling the bone segments apart) results in improved local vascularity and rapid healing in certain types of non-unions.
The Ilizarov method can be used to lengthen a foreshortened bone. In order to accomplish this, the Ilizarov fixator is applied to the extremity and the bone is broken between rings using a variety of specialised techniques.
The controlled breaking of the bone
is known as an “osteotomy” or “corticotomy”. After waiting for about a week, lengthening begins at a rate of ¾ to 1 millimetre.
After waiting for about a week, lengthening begins at a rate of ¾ to 1 millimetre per day. Slow gradual lengthening is accomplished by moving the rings progressively apart (by distracting the ring connectors). Bone forms in the distraction site by a process known as distraction osteogenesis.
Bone transport is a technique that allows the orthopaedic surgeon
to regenerate bony tissue within the patient’s extremity. This regeneration is typically used to fill a gap of missing bone due to trauma