External non-invasive bone stimulator provides stimulation through electrical and/or magnetic fields to promote osteogenesis to facilitate the healing of nonunion fractures and lumbar spinal fusions. The stimulation may be delivered through capacitive coupling ('CC) with electrodes placed directly over the treatment site, or through pulsed electromagnetic fields (PEMF) with treatment coils placed into a brace or over a cast at the treatment site. It is intended for use for the treatment of established nonunion fractures acquired secondary to trauma and as an adjunct to the treatment of lumbar spinal fusion surgery for one or two levels.