A few years ago, I underwent a surgical procedure called a Spinal Fusion. Afterwards a special medical device was prescribed to assist with the fusion process. This device is called a Combined Magnetic Field Bone Growth Stimulator.


The little kid in me has been eager to see the inner workings of this device. It was only a matter of time before it would be taken apart.


Here are some photos of what was found inside.




Device Description


The SpinaLogic® bone growth stimulator (DJO, Vista, CA) consists of a three-dimensional patient interface contoured to follow the curvature of the lumbar spine, a control box containing the electronics, and a battery pack . The device is used for 30 consecutive minutes a day until fusion occurs as determined by the treating physician. The patient interface consists of a single transducer coil to generate the magnetic field and a magnetoresistive element to provide feedback as to the magnitude of the earth’s magnetic field which ranges from 25 to 65 microTesla (μT). The coil is constructed using 504 turns of 30-gauge copper magnetic wire.


When the specified current is applied to the coil, it generates an extremely low-frequency and extremely low-intensity magnetic field that has both alternating and direct current (AC and DC) components, labelled a combined magnetic field (CMF). Specifically, the field oscillates sinusoidally at a frequency of 76.6 Hertz with an AC component of 40.0 ± 8.0 μT, peak to peak, and a DC component of 20.0 ± 2.0 μT.


The source for this information.