Sublaminar fixation to stainless steel rectangles was employed in an effort to improve the fusion rate in lumbar and lumbosacral arthrodesis. Thirty-seven patients had spondylolisthesis, and 26 had other causes of pain secondary to lumbar mechanical instability. Of the 63 patients, 53 achieved fusion and 52 had relief of pain. No infections or neurologic complications were encountered. This fusion rate of 84% does not significantly differ from rates obtained with noninstrumented methods, and this construct is no longer used for lumbar fusions.