Callus distraction involves cutting a bone and increasing its length by means of an implanted system. This therapy may be useful, for example, in clinically relevant lateral limb differences that result in deformity. There is little risk of infection since fully implanted systems.
What is callus distraction?
Callus distraction is a treatment procedure in orthopedics and oral surgery that artificially lengthens a skeletal bone. Callus distraction is also referred to as callotasis. In addition, the term distraction osteogenesis is widespread. It is a treatment procedure in orthopedics and maxillofacial surgery that artificially lengthens a skeletal bone. The affected bone is cut by the orthopedic surgeon. The two halves of the bone are reattached via conventional external fixation or an extension intramedullary nail. Over a period of several weeks, the severed bone is slowly stretched apart along the previously determined growth axis. The procedure got its name because of the callus. This is fresh bone substance that forms along the growth axis during the procedure. The bone lengthened in this way grows together in its new position once distraction comes to a permanent halt.
Function, effect and goals
In most cases, long tubular bones provide an indication for callus distraction. Through the procedure, orthopedics can correct pathological deformities such as a functionally relevant leg length discrepancy. In addition, callus distraction is used as cosmetic surgery and then has no medical indication. For the first time, Hopkins and Penrose lengthened a bone in an intraoperative manner in 1889. The procedure at that time involved the insertion of bone blocks. About 20 years later, Alessandro Codivilla undertook a purely surgical technique for bone lengthening in the lower extremities. The surgical techniques of the time were associated with a significant complication rate. As expected, complications occurred during the healing phase. Infection represented the most common complications. These infections mainly affected the entry site of the fixator. Surgery-related pain was high at that time. The same was true for irritation of the nerves and surrounding soft tissues. In many cases, the bone could not be sufficiently lengthened at the end. The Russian orthopedist Gawriil Abramovich Ilisarov realized bone lengthening for the first time with a major breakthrough. His applied method was based on bone biology. He recognized the ability of the soft tissues around the bone to regenerate in response to any tensile stress. To apply his procedure, he used an external fixator, also known as an Ilizarov ring fixator. Both the incidence and severity of complications decreased with ach Ilizarov’s technique. Current systems for callus distraction still rely on the renewal ability of the surrounding tissue under tensile loading. Meanwhile, fully implantable systems are available for callus distraction that almost completely eliminate the risk of infection. In the distraction phase, there is no connection whatsoever between the system, the skin and the outside world. This means that only the operation itself can be associated with infection risks, which are mainly concentrated on the implantation of the intramedullary nail. The systems used are equipped with a motor that allows daily distraction of the cut bone by about 1 millimeter after the operation. In addition to the energy supply, the systems are also controlled externally. The patient can thus take care of the distraction himself and is exposed to much less stress than 100 years ago. Physiotherapy is already taking place during the distraction. This physiotherapeutic accompaniment means that faster treatment successes can be expected.
Risks, side effects and dangers
Like any surgery, callus distraction is associated with risks and side effects. In addition to bleeding, general surgical risks include infection, for example. In modern times, infections are rarely found in callus distractions. However, such infections can certainly occur in individual cases, especially during implantation and explantation of the intramedullary nail.The surgery should be performed in an orthopedically oriented center where the doctors are thoroughly familiar with the procedure and any risks of the surgery. In this way, the risk of complications can be minimized. Infections can result in necrosis of the tissue, which in extreme cases can lead to sepsis. To prevent sepsis, the necrotic tissue must usually be removed. In the case of callus distraction, this may be equivalent to amputation of the affected limb. If neither bleeding nor infection occurs during surgery, the risk of subsequent complications is infinitesimal. Pain may occur both postoperatively and during gradual distraction. For this pain, the patient usually receives analgesic medication. Bruising is also conceivable postoperatively. However, these manifestations of the operation recede after one week at the latest. In individual cases, the motor of the system used may be faulty. Although such incidents are not known from the past, all technology can be subject to production errors and thus lose its functionality. If this is the case, the distraction cannot be performed despite the operation. Either the system is replaced by a functional system in a second operation or the bone grows back together as usual. In the healing phase, the position of the bone fragments must be correct above all. If the position of the bone pieces slips, the bone can still grow together, but the patient will suffer from a malposition afterwards. Physiotherapeutic measures should be started as early as possible to exclude atrophy of the muscles.
