The effect of electromagnetic pulsing on posterior lumbar spinal fusions in dogs. 
This study evaluated the effect of pulsed electromagnetic fields (PEMF) on the healing of lumbar spinal fusions.  Bilateral posterior facet fusions were performed at L1-2 and L4-5 in 24 adult mongrel dogs.  After surgery, eight animals were stimulated with a pulse burst type signal (PEMF) for 30 minutes a day, and eight animals were stimulated with the same PEMF for 60 minutes a day.  The remaining eight animals received no active PEMF stimulation and served as controls.  Four animals from each group were euthanatized at 6 and 12 weeks, and the facet fusions were evaluated using high resolution radiographs and routine histology.  No statistical difference in the radiographic or histologic appearance of the fusion mass could be detected between the stimulated and control groups at either 6 or 12 weeks.  The results of this study suggest that PEMF stimulation had no effect on the healing of the primary posterior spinal fusions in this controlled experimental canine model.