Bone Growth Stimulator

Facts about the Bone Growth Stimulator

A bone growth stimulator is a machine that uses either electronic stimulation or ultrasound to heal broken bones. A bone growth stimulator is only used when a bone dos not heal for a very long period of time--usually it is given a minimum period of nine months to heal naturally. Although the FDA approved ultrasound bone growth stimulation back in 1996, the treatments are still very expensive and there is still much debate about when the treatment should be chosen.

A bone growth stimulator can be used on just about any bone but it is most effective on very long bones, such as the tibia. It is used most often on spinal fusions, which are very difficult to heal. The one occasion in which the stimulator cannot work is if there is a gap that is too big between the two ends of the broken bone. The electronic stimulation can be either invasive or non-invasive depending on whether or not it is applied from inside the body or outside of the body, respectively. It is up to the doctor as to which form of stimulation is going to be the most effective.

Invasive electronic stimulation can use a device that is entirely implantable. One of the great benefits of an implanted bone growth stimulator is that it can run all the time, twenty-four hours a day, and this can produce the fastest healing of the broken bone. A semi-implanted device is also able to run twenty-four hours a day but the patient can control the device.

When a bone growth stimulator is implanted, the patient will go to the hospital to have the procedure performed under either local or general anesthesia.  An incision will be made above the broken bone and a cathode will be placed inside the bone. A wire will lead to the source of power and a small anode. A battery pack will serve as the source of the power and the pack is implanted in a muscle near the broken bone. The body’s own electrical current is what closes the circuit. Then the incision is closed and the bone growth stimulator will run 24/7 until removed.

With a partially implanted device the cathode pins are inserted on the edge of each fractured bone. The two wires run out of the surface of the skin and are attached to a power source and the anode. In this case, because of the skin opening, it is the wires that complete the circuit. Usually the cast holds the wires and battery pack snugly so that they cannot move.

In addition to an implanted or semi-implanted bone growth stimulator, a non-invasive option is also available. In this case, external electromagnetic coils are set on each of the sides of the fractured bone and a cuff or strap will hold them in the right position. The two coils pulsate back and forth across the electromagnetic field that has been created between the two coils. The stimulator is usually set to run for periods every day from one to ten hours. The patient is totally in charge of turning the device on and off.

The newest type of bone growth stimulator uses ultrasound, but even though it is technically not that new, there still has not been many studies done on this fracture treatment option. A small ultrasound device is used, which generates low intensity pulses of sound over the area right above the broken bone. Usually, only half an hour a day is required for ultrasound stimulation.

Any time one of these bone growth stimulators is used, the patient is not allowed to place any weight on the bone. That means limited mobility if the broken bone is in either of the legs. The devices need to be in place and running for several months before the fracture is healed.
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