Superior mesenteric artery syndrome after segmental instrumentation: a biomechanical analysis.

Superior mesenteric artery (SMA) syndrome is a rare complication that occurs after correction of scoliosis. A review of the literature suggests that the incidence of this syndrome may be decreasing, as methods for the correction of scoliosis have improved. We present the first report of SMA syndrome that occurred after segmental 'derotational' instrumentation. Computerized axial tomography was helpful in suggesting the diagnosis of this condition. The risk factors and pathophysiology of SMA syndrome are reviewed with respect to the biomechanical effects of casting and Harrington and segmental instrumentation systems on the spine. Attention to the three-dimensional nature of the scoliotic deformity, particularly in the sagittal plane, may help to predict those at risk for the development of this potentially fatal syndrome.