Ilizarov
Gavril Abramovitch Ilizarov (1921-1992) was a Russian surgeon who was working in Siberia at the end of the Second World War. Overwhelmed with injured soldiers, many of whom had knee contractures in amputated limbs, he developed a system of portable traction using an external fixator frame and rods and hinges that could be gradually adjusted to straighten the knee joint. This fixator was attached not by big bolts as most external fixators were at the time, but by thin wires under tension, that had to be attached to rings around the limb (circular fixator) and became known as the 'Ilizarov Frame'
Fortuitously, he discovered that other effects occurred when tissues were pulled apart; a carefully made fracture could be left a few days to start healing, then the new bone gradually stretched to regain length, a process called 'callus distraction'This technique, along with distraction or compression of non-unions, angular correction with hinges etc. became the mainstay of the 'Ilizarov Technique' which is regularly used with other external fixators such as the Taylor Spatial Frame, or even lengthening internal devices such as the Precice nail.
With any external fixator frame, there is a point where the wire or pin goes through the skin. This is not usually painful, but can get irritated, particularly during adjustments of position of the frame. To avoid these pinsites becoming infected, we use soft sponge dressings held on by clips, and usually teach patients how to change these themselves.
The Ilizarov technique and Ilizarov Frame however allow some very complex limb reconstruction techniques, such as this case of MRSA infected nonunion with bone destruction that had been offered amputation:
With the Ilizarov technique it is possible to cut out the infected area, and bring the ends of bones together (acute shortening). This allows removal of the damaged skin and soft tissues so the open wounds can be closed, and leaves fresh, clean bone ends to heal together under compression by the frame. Unfortunately removing several centimetres of bone would need a lifelong huge shoe raise, so the leg is lengthened by creating a controlled fracture above, which is gradually stretched to restore limb length equality.
This phase of stretching out bone is usually at a rate of 1mm per day, split into 4 increments of a quarter of a millimetre each. Patients do this themselves at home, by adjusting rods or turning nuts ('dice nuts') on the frame with spanners.
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Once out to length, there follows several months of waiting for the bone to mature sufficiently to allow removal of the frame. This period is variable, but at least one month per centimetre gained in children, and longer in adults. It is dramatically slowed by smoking and the anti-inflammatory drugs such as ibuprofen, diclofenac, naproxen and indomethacin, so these are discouraged.
Eventually however the bone is solid enough to allow frame removal, either under another anaesthetic or with Entonox ('gas and air') in the outpatient department.
