A non-union refers to a failed spinal fusion (pseudoarthrosis) in which the segments of vertebral bone do not merge over the disc space. Spinal fusion can take up to two years for union to take place consummately and the rate of improvement depends on the health of the bones, recovery of nerve compression, and conditioning of spinal muscles.
Internal and external bone growth stimulator devices can be applied at or near the fusion site to help the fusion. Nonunion rates are higher for patients who have had prior surgery, patients who smoke or are obese, patients who have multiple level spine fusion surgery, and for patients who have been treated with radiation for cancer.
