The efficacy of direct current electrical stimulation to enhance canine spinal fusions.

A prospective experimental study was devised to examine the effect of direct current electrical stimulation on the healing of lumbar spinal fusions. Twelve mongrel dogs had posterior facet fusion bilaterally at L1-L2 and L4-L5. A direct current electrical stimulator was placed through each facet fusion. One-half of the electrodes were functional, while the remainder served as controls. Two animals were killed at two and four weeks, and four animals were killed at six and 12 weeks, postoperatively. Each facet fusion was evaluated using high-resolution roentgenograms and routine histology. In the two-, four-, and six-week specimens, there was little difference in the roentgenographic or histologic appearance of the control and stimulated fusions. However, by 12 weeks, all eight stimulated facet joints showed roentgenographic and histologic evidence of solid bony fusion, but none of the eight control facet joints demonstrated osseous bridging of the fusion site. The results of this study suggest that direct current electrical stimulation appears to enhance the bony union of facet fusions in the canine lumbar spine.