Low-power electromagnetic stimulation of osteotomized rabbit fibulae. A randomized, blinded study

The purpose of this study was to determine whether low-power-consuming symmetrical-waveform electromagnetic stimuli could increase the stiffness of fracture sites in a rabbit fibular-osteotomy model. Both active and placebo devices were used in a blinded study protocol. Dose-response studies of pulse amplitude and pulse width were performed by continuous application (twenty- four hours a day) of repetitive (fifteen-hertz), bursted (five-millisecond- long) symmetrical, rectangular electromagnetic stimulus waveforms. The power consumed by these stimuli is approximately one-fifth that consumed by the pulsing electromagnetic field devices that are in current clinical use. Significant increase of callus bending stiffness was produced by pulse widths of five to seven microseconds and pulse amplitudes of fifty to 100 millivolts. CLINICAL AND RELEVANCE: The large consumption of electrical power that is demanded by the specific waveform parameters of the pulsing electromagnetic fields used clinically necessitates an increase in the size, weight, and complexity of the devices, which in turn requires increased patient compliance and imposes an added management problem for the physician. Noncompliance on the part of the patient often causes loss of prescribed treatment time, and the possibility of therapeutic success is thereby diminished. The ideal stimulation device would be totally cast-incorporated; it would require no intervention on the part of the patient or physician, thereby ensuring delivery of the intended therapeutic dosage of electromagnetic stimulation; and its simplicity would facilitate the conduct of double-blind clinical-efficacy studies. The development of such a device requires the development of new specific parameters for electromagnetic stimuli that consume significantly less electrical power than do the current pulsing electromagnetic fields. Because the rabbit model used in the present study has previously been predictive of clinical success in the application of capacitively coupled stimulation for the treatment of fracture non- unions, it is expected that these specific signals have the potential to be clinically effective in the treatment of non-unions.