When is this procedure indicated?
Limb lengthening surgery is indicated in patients with school-age achondroplasic dwarfism. There are no treatment alternatives. In order to obtain good results, it is essential a total compliance by the patient and the family, which must be adequately informed of the risks and benefits associated with the intervention.
How is it performed?
Limb lengthening surgery consists of interrupting the bone by osteotomy, which is a fracture made with the use of a saw and osteotomes, and placing a device, called an external fixator, which is anchored upstream and downstream of the osteotomy itself. There are several types of external fixator: axial, circular/Ilizarov, and hexapodal.
For the first stage of the lengthening path, which involves the tibiae bilaterally, we use a circular external fixator, formed by circular rings fixed by metal chips in proximal and distal positions with respect to the osteotomy. The rings are connected to each other by threaded rods parallel to each other that allow the progressive distancing of the two abutments.
The axial fixator has a simpler structure, formed by a single metal bar, it is the fixator of choice in femoral lengthening. Both fixation systems (circular and axial) can be used for humeral lengthening. Hexapodal fixators are preferred in cases with rotational defects.
In any case, the lengthening system is simple and intuitive and the patient generally has no difficulty in managing it independently.
In the days of post-operative stay, the patient is monitored through blood tests and detection parameters. Pain relief and antibiotic therapy is set, the latter until the third postoperative day to prevent early infections.
Physiotherapy is started with postural transitions and initial step re-education with the help of a walker. On the II-III post-operative day, the first medication is performed with sterile gauze and disinfectant. Prior to discharge, the patient is instructed on how to perform the dressings and the stretching system. This is usually done at a rate of 1 mm per day.
Patients are then monitored by regular clinical and radiographic follow-ups to evaluate and, if necessary, correct the progress of lengthening, which usually ends with the removal of the fixator after about 8-12 months.
As with all surgical procedures, the lengthening procedure is associated with some early complications. Those observed most frequently are:
- Postoperative anemia, which is more frequent in femoral lengthening procedures and is associated with major blood loss;
- Peripheral vascular nerve deficits;
- Superficial infections;
- DVT especially in operations involving the lower limbs;
In the long term, complications may occur due to failure/partial consolidation of the bone callus (pseudoarthrosis) including recurrent dysmetria, instability, and spontaneous fractures, with the possibility of having to undergo further surgery.