Synonyms in a broader sense
- Extension nail
- Callus distraction
- Posttraumatic leg shortening
- Leg extension
- Extension nail
- Leg length difference
The name ISKD
The name ISKD nail is an acronym:ISKD = Intramedullary Skeletal Kinetic DistractorThe therapy of unilateral leg shortening using ISKD nails presented a major surgical challenge both tibially (on the shin side) and femorally (on the thigh side). Bony distraction (lengthening) was until the beginning of the 1990s only possible with external fixators (see picture below). External fixators are metallic frames that support the bone from the outside during lengthening.
These fixators are particularly problematic due to Furthermore, bulky fixators considerably restrict the quality of life. For this reason, alternatives were sought. In the context of the development of so-called intramedullary osteosyntheses (e.g. nailing in the hollow area of the tubular bone), the application also became possible in the area of callus distraction (bone extension).
An intramedullary osteosynthesis is a (bone) nail that is pushed through the tubular bone and splints the bone from within. One of the most advanced developments in this field is the ISKD nail.
- So-called PIN infections (infections in the area where the metal leaves the bone and skin)
- Loss of correction (change in the result when the external fixator is removed again)
- Insufficient callus formation (lack of bone healing) and
- Refractures (new fractures)
Indication
A need for a leg extension can be caused by various reasons. Reasons for a unilateral leg extension can be
- Congenital leg shortening
- Posttraumatic (accident-related) leg shortening
Lengthening a bone by several centimeters cannot be done in one step. The reason for this is that the bones end up touching each other in order to achieve reunion.
To solve this problem, the ISKD nail uses the so-called callus distraction. This is a slow but continuous lengthening of the bone. By into the slow extension of the bone, in an area that is cut during the operation.
Through into the continuous lengthening, into the fracture healing the lengthened section can constantly regenerate. The ISKD nail is an implant that can be implanted in the tubular bone of the tibia and femur. The extension nail is designed in such a way that two nail sections that can be moved into each other can extend each other.
The distraction (extension) is triggered by the ratchet principle; through 3° alternating (mutual) rotation the nail is extended by a fraction of a millimeter. 160 rotations result in 1 mm distraction (daily desired lengthening goal). Lengthening is controlled by a magnet attached to the lower end of the inner rod of the nail and measured five times a day on an external monitor.
The ISKD nail will continue to lengthen until the desired lengthening goal is achieved. The extension is given to the nail. This means that the maximum extension of the ISKD nail is set before the implantation, and if the nail has extended to the maximum, it cannot be extended any further.
The disadvantage of this procedure is that after implantation of the extension nail, the nail will lengthen to the specified extension target and no further influence can be exerted on it. Good results are achieved in a lengthening range of three to five cm. The maximum achievable extension range with this ISKD nail is 8 cm.
However, since tendons, nerves and muscles also have to stretch, considerable problems arise with increasing lengthening. When can the procedure of the ISKD – nail not be used?
- Open growth joints
- Insufficient internal diameter of the medullary canal bone
- Lack of patient cooperation
- Cooking soft tissue infections
- Atrophic pseudarthroses (non-healing bone fractures)
- Pronounced deformities