What is limb lengthening?
The BETZ INSTITUTE® defines limb lengthening as the art of increasing one's height with an eye toward a more aesthetically pleasing and/or functional end result. During a limb lengthening surgery, the bone is carefully cut. Afterwards, the resulting two halves of the bone are slowly pulled apart - either by use of an intramedullary telescopic nail or an external fixator. The decision about which method and device is used is made in accordance with the diagnosis and the patient's initial situation. After the desired body height is reached, the bone knits itself together until the bone is capable of bearing weight again.
Definition of limb lengthening and limb lengthening surgery
Limb-lengthening follows the biological principle of distraction osteogenesis, also known as callus distraction, in which bone tissue grows in a gap between two artificially created halves. This surgical principle is used for the correction of bone anomalies, as well as for the lengthening of bones (for example in a height lengthening surgery).
The process of limb lengthening is divided into two phases:
Distraction phase: During the limb lengthening surgery, the bone that will be lengthened is surgically divided into two segments. After the arm or leg lengthening surgery has been performed, the segments are slowly and continuously pulled apart along the longitudinal axis. In the resulting gap between the two segments, new bone made from the body's own bone tissue is formed.
Consolidation phase: Once the desired correction or length is obtained, the healing in the bone's gap begins. During distraction osteogenesis, not only the bone, but the surrounding soft tissue (muscles, ligaments, and nerves) is stretched and, therefore, continuously lengthened to the same degree. Limb-lengthening can be carried out in the thigh (femur), lower leg (tibia) and the upper arm (humerus), either with external or intramedullary systems.
A short history of limb lengthening surgery – how were arm and leg lengthening surgery developed?
The process of distraction osteogensis has been known since the mid-19th century, but it's practical use was more recently discovered by the Azeri-Siberian Dr. Gavriil Ilizarov (1921-1992). He established a limb lengthening surgery using the circular fixator, in which the leg or the arm is perforated by thin wires and surrounded by metal rings, which are connected to each other by spindles, joints, and bars. The treatment began with the cutting of the bone that would be lengthened with a bone chisel from the outside.
Then the circular fixator was attached to both bone ends via heavy-gauge wires called either "pins" or Kirschner wires, which perforated the skin and muscles. The rings were connected to each other with threaded rods attached through adjustable nuts. With the help of the nuts, the rings are pulled apart, so the gap in the bone expands. While a distraction rate of 1 mm per day is maintained, the new bone tissue is built.
The biggest disadvantages of the external Illizarov fixator are the limited movement abilities, the significant pain, and the risks of infection as well as nerve- and tissue trauma. Modern variations of arm or leg lengthening surgery have been developed to avoid these risks.
Limb lengthening surgery today
For almost 3 decades, Dr. Betz has been using a minimally invasive operation technique for limb-lengthening (mostly performing leg lengthening surgery). During the limb lengthening surgery the bone is cut from the inside and, afterward, stabilized with a telescopic nail. It is thus prepared for the continuous daily lengthening. This state-of-the-art method has many advantages compared to the external fixator. The patients are generally much more mobile after the arm or leg lengthening surgery and thus more capable of doing any kind of physiotherapy.
Furthermore, there is a much smaller risk for infections and nerve- and tissue trauma. Another advantage of this limb lengthening surgery method is the significant reduction in pain. Because Dr. Betz performs the operation by using only very small cuts (0.3 - 1 cm/0.12 - 0.4 inch) this results in very small, almost invisible scars.
Lengthening of both thigh bones with an intramedullary telescopic nail
Distraction phase with newly built bone (pink)
Consolidation phase with solidification of the soft new bone into hard normal bone
1 week after surgery: Very small cuts (0.3 - 1 cm/0.12 - 0.4 inch) results in very small, almost invisible scars
The Circular Fixator is the classic Illisariv-Fixator with a wide indication spectrum. It is mostly used for the lengthening of the lower leg. At the Betz Institute, it is only used in open growth plates or in very rare exceptional indications. We usually prefer internal lengthening methods.
The Monolateral Distractor can be used for upper leg- and lower leg-lengthenings. Compared with the Circular Fixator, the comfort is slightly better, but the biomechanical characteristics are inferior.
LON (Lengthening Over Nail)
LON is the name for the combination of an external and an internal procedure. A solid nail, like a trauma nail, stabilizes the bone from the inside, while the expanding function is carried out by an external fixator. At the end of the lengthening, the lengthened distance is maintained by static blocking. Afterwards, the external fixator is removed. This method combines the risks of external and internal methods and, furthermore, in our opinion, has no economic advantages at this point in time.
The lengthening of the Albizzia® Nail works by using a rotation mechanism, which generates a characteristic click with every activation. The Albizzia® Nail had a high weight bearing, as well as a huge lengthening distance capacity. The production of the Albizzia® was stopped in 2010 by the manufacturer DePuy/Johnson & Johnson due to economic reasons. We used the Albizzia® Nail successfully in approximately 1,000 cases of cosmetic limb-lengthening procedures. Over the years, it was extensively modified and optimized by Dr. Betz. As a result, the BETZBONE® Nail now exceeds the Albizzia® Nail in weight bearing and lengthening distance capacity.
Fitbone® is the name of the electro-mechanical telescopic nail, which was invented by Dr. Betz. The Fitbone® has an electro-mechanical motor. The energy is transferred from an external sender via a high frequency to an internal receiver beneath the skin. Besides the fact that the Fitbone's® lengthening distance capacity is insufficient compared to what is usually desired for cosmetic indications, the Fitbone cannot bear the full weight of the patient's body. Thus, in the event of bilateral lengthening, the patients have to be immobilized in a wheelchair for the whole treatment time.
The Precice® Nail has a similar functional principle as the Fitbone®. Its lengthening and weight-bearing capacities are similar to the Fitbone® as well and, thus, in our opinion, the Precice Nail is inadequate for cosmetic limb-lengthening.
Regarding the capacities of weight-bearing and lengthening distance, the ISKD® Nail is similar to the Fitbone® and the Precice® Nail, but despite its ingenious functional principle, the nail is even more difficult to steer and control than the Fitbone® and the Precice® Nail.