Late neurological complications of Harrington-rod instrumentation.

From our patients who had idiopathic scoliosis, we identified a subset of eighteen in whom Harrington rods were used for fixation down to the fifth lumbar vertebra. In five of these patients, low-back pain, sciatica, and other neurological problems developed at two to thirty-two months after arthrodesis. These complications were caused by migration of the caudad hook into the spinal canal. The migration was probably caused by a combination of lumbosacral lordosis and mobility of the fifth lumbar vertebra (the most caudad mobile segment) on the segment below, resulting in weakening of the lamina of the fifth lumbar vertebra. After removal of the hardware, all patients had improvement of the lumbosacral and radicular pain as well as resolution of the neurological abnormalities.