Pseudarthrosis of the spine.

Pseudarthrosis remains the leading cause of failed spinal fusions. The common causes of this complication are inadequate surgical technique, excessive stresses across the fusion site, insufficient internal or external stabilization, and unrecognized metabolic abnormalities. Many radiologic techniques have been used to diagnose pseudarthrosis in the spine. Nonetheless, the diagnosis of a nonunion as well as the ability to correlate the nonunion with the patient's clinical symptoms remains a challenge. In treating a symptomatic pseudarthrosis, the surgeon should first attempt to identify those factors that contributed to the development of a nonunion. The approach can then either be exploration of the fusion mass with regrafting of the pseudarthrosis or extending a fusion to locations within the abnormal segment of spinal motion.