1.
Brief History
2. Change of Concepts
3. Lengtheners and Innovation
The first case of leg-lengthening was performed by Prof. G. A Ilizarov in 1972, for a dwarf on both low limbs. The first report on the principals and applications of distraction osteogenesis techniques was by Prof. Codivilla of Italy, in 1905. In a paper published in American Journal of Surgery, Codivilla has summarised distraction osteogenesis techniques into three steps, first, osteotomy, then lengthening by gradual traction, and followed by a bone consolidation phase. Cadivilla's paper was the first publication defining distraction osteogenesis techniques in English literatures. All the subsequent reports and studies on distraction osteogenesis or leg-lengthening techniques are all based on Cadivilla's principles. Since 1980s, some orthopaedic surgeons in China and aboard had performed leg-lengthening surgery for the treatment of dwarf patients, to increase height for these patients, and have achieved fairly good clinical outcome. We have performed our first case of leg-lengthening using Ilizarov technique in 1980, for a young man from Taiwan.
2.
Change of concepts
Leg-lengthening surgery was first performed for treating orthopaedic conditions
on affected limbs only, it was then adopted for treating dwarf on both
low limbs with relative normal anatomy. Ilizarov was the first who had
carefully studied the leg-lengthening techniques, mechanisms and its potential
clinical applications in many aspects of orthopaedics including leg-lengthening.
Based on the findings of Ilizarov and many others, Dr. He-Tao Xia has
put forward a theory of induced tissue and bone regeneration, and reconstruction
of limb function naturally . According to this theory, Dr. Xia has redefined
the leg-lengthening surgery by using combined external and internal fixation
techniques, he has refined the external fixator to allow dynamics and
synchronism during lengthening, this is now termed as Xia's concept on
leg-lengthening.
3.
Lengtheners and innovation
Lengtheners used for leg-lengthening surgery varied and have been constantly
refined. At present, there are about more than 10 different kinds of commercial
lengthener on the international market, and many more self-designed or
self-made ones in use in many hospitals across the world. Since 1990s,
the advancement of tissue regeneration (tissue engineering) theories and
the development of material and engineering sciences have promoted some
revolutionary changes in the designs of external fixators. There are three
new breakthroughs in the lengtheners: dynamic lengthener; external fixator
combined with intramedullary nail system and fully implantable lengthener.
These three lengtheners will lead the leg-lengthening field for a considerable
time to come, while the traditional Ilizarov circular or Orthfix unilateral
external fixators will still hold their value, especially for the treatment
of complex limb discrepancy. The following are some common lengtheners:
3. 1. Circular bone lengthener: designed by Ilizarov. Circular frames are connected by thin wires at multiple panels. Advantages: good mechanical stability, traction forces distributed evenly through tissues; good for mechanical line correction; patients can walk on it and do functional exercises. Shortcomings: limited lengthening range; long duration of wearing bulky frames; many pin hole scars; difficult to operate, and some complications associated with bone-lengthening are common.
Figure 1. Circular frame used in our institute.
3. 2. Unilateral external lengthener: Wagner and Bastsiani have designed similar unilateral lengtheners. Most commonly used are Orthofix unilateral lengtheners. Unilateral lengtheners are fixed to the bone with 4-6 pins (5-6 mm in diameter). Advantages: easy to assemble; few pin hole scars, usually used in paediatric patients. Disadvantages: limited lengthening range; long duration of treatment; bigger scars; pin hole infections are common; difficult to control axial mechanical line and complications associated with bone-lengthening are common.
Figure 2. Orthofix unilateral external lengthener was in use
3.3. Combined external and internal bone lengthening system: First reported by Xia and Pile in 1997. In our institute, this system can be used in combination with the dynamic lengthener. Advantages: Intramedullary nails can be locked once the lengthening is achieved, and the external fixators can be removed early; shorter treatment duration; reduced pin numbers and sizes; greatly reduced complications (see more under Xia's leg-lengthening techniques).
3.4. Fully implantable intermedullary lengthener: This was designed by Dr. Baumgart (Germany), which has completed changed the concepts of leg-lengthening by external lengtheners. Advantages: convinces; no bulky external lengthener needed; no pinhole scars. Disadvantages: lack of practical values at present; limited lengthening range; only can be used in patients taller than 160cm; concerns of mechanical and electronic breakdowns; very expensive (approx. 100,000 - 300,000 euros). We had used this lengthener on 1 patient in 2000, when the tibiae were lengthened to 3.5 cm, the lengthener at the right tibia was broken down, hence we had to change to external lengthener to complete the treatment.
Fig. 3. A patient underwent leg-lengthening treatment on both tibiae in our institute in 2000.
3.5. Dynamic synchronism lengthener in combination with internal bone lengthening system: This was invented by Dr. Xia , which is considered a breakthrough of leg-lengthening technique. This technique combines the advantages of dynamic synchronism lengthener (external lengthener) and internal intramedullay laocking nail system. This system can be used to lengthen patients with bone and joint deformities with almost 0% complication rate (see more details under Xia's leg-lengthening techniques).
These above mentioned lengtheners have advantages and disadvantages, and are used commonly in China and aboard. The dynamic synchronism lengthener in combination with internal bone lengthening system is only used in our institute and a few collaborative units in China, and this system is patented.
In addition, there are other forms of lengtheners in use, such as semi-circular lengthener, bilateral lengthener and others. Those devices are not recommended and used in our institute as they have some mechanical defects for leg lengthening surgery and may cause undesirable complications.
Prof Hetao Xia
