When you think of limb lengthening devices, you will be tempted to have devices that can make your limbs longer by slowly separating your limbs a certain amount each day. Depending on the technology developing in these devices, there has been a great evolution over time. There are fundamental differences between external and internal lengthening devices in terms of criteria such as lengthening capacity, price, complications and device construction.

1. Device Structure

Limb lengthening devices are generally divided into two as external and internal devices. External fixator is a surgical method in which the rods are screwed to the bone and removed from the body and attached to a stabilizing structure outside the body. The structure that provides lengthening and fixation is outside the extremity. The internal method is motorized nails that are attached to the inside of your long bones with screws. Advanced internal nails feature a remote controlled system that is placed outside your limb and lengthens the nail.

2. Lengthening Capacity

Internal motorized nails usually have an elongation capacity of 8-9 cm. In external devices, this figure may be slightly higher. However, the amount of limb lengthening generally depends on your lengthening process, not the device. Security should always be a priority. Complications that may develop during your lengthening process and the tolerance of your soft tissues against the lengthening will determine the maximum lengthening amount you will reach. Since the complications and pain level of internal devices are low, patients who are applied this method usually reach a higher level of lengthening.

3. Complications

In terms of complications, internal devices have a great advantage over external devices. External devices provide connection to the inside of the body by piercing the muscles and bone from the outside. This increases the risk of infection. Attention should be paid to the hygiene and dressing of the entry points into the body. There is no such risk in the internal method.

Since external devices are outside the body and large, they cause difficulties in the patient’s daily activities and movements such as walking, in-bed transfer, exercise. Although the size and weight of these external devices have decreased over time, this difficulty continues when compared to internal devices.

Movement and exercise limitation seen in external devices can result in muscle shortness, joint contracture, decreased ROM and walking difficulty. This can affect your lengthening capacity and quality.

When evaluated in terms of pain, it was observed that people who were applied external devices had more pain. The pain criterion should not be considered alone, because pain affects a person’s psychology, sleep quality, motivation and exercise capacity. Pain is of great importance to the quality of the lengthening process.

Since internal devices are placed in the bone, there is no risk of infection and does not cause limitation of movement. Pain is much less than the external method. It is clear that internal devices have a great advantage in terms of complications.

4. Price

The price of internal nails is much higher than external devices. This is because internal motorized nails are high-tech products. Internal nails developed to reduce complications and increase patient comfort brought the disadvantage of high prices.