Bone lengthening is required when a specific bone fails to grow at a sufficient or normal rate, resulting in a significant difference in limb length compared to the opposite side. This condition can be congenital or developmental, often caused by infections, traumatic injuries, or other factors affecting bone growth.
When the limb (and its bones) are shorter to a degree that hinders proper function, we consider the benefits of bone lengthening against the risks associated with the procedure. Small discrepancies in limb length, for example in the arms, might not be problematic, and minor differences in leg length can be balanced during growth by slowing down the growth of the unaffected limb.
Until recently, external fixators were used for bone lengthening. These are external systems attached to the limb, containing pins or wires that penetrate the soft tissue to reach the bone, securing it externally. The bone is cut in a specific location, where it is relatively easy to extend, and after a few days, the limb is gradually stretched using the external frame. This creates a gap between the cut bone segments, which is gradually filled with new bone tissue.
Currently, we have an internal magnetic lengthening nail for bone lengthening. It is a nail that is entirely located inside the bone. There are models available for children and adults, suitable for lengthening the thigh, shinbone, and arm. It is operated by an external magnetic system (controlled by the patient daily). The possible lengthening achieved is up to 5-8 centimeters, depending on the model. The insertion of the nail is performed with a minor incision and guided by X-ray fluoroscopy. The nail extends both the bone and the surrounding tissues.
Approximately ten days after the surgery to insert the nail, the lengthening phase begins. The patient operates the nail using an external magnetic device, following the instructions provided by the surgeon. The external system automatically extends the nail. The main advantages of this method compared to older external systems are that there is no external device attached to the limb, the activation is electronic and straightforward, and the nail remains within the limb, preventing the risk of breakage in the lengthening area. Hospitalization is usually short, and the patient can move freely after the surgery.
Once the required lengthening is completed, the system stops operating. The nail stabilizes the newly formed bone, which is still relatively soft at this stage. After a few months, the bone consolidates, and the nail is no longer needed. It can be removed in a subsequent surgical procedure, but this is not necessary if it is not causing any discomfort. The nail is typically made of titanium, similar to other orthopedic implants, and its presence within the bone poses no significant risk.
Patients in need of limb lengthening will receive detailed explanations about this option. It is important to note that this treatment is not suitable for everyone and should be carefully considered based on individual circumstances.