Fourteen patients with degenerative spondylolisthesis and three patients with degenerative scoliosis, all of whom experienced low-back pain, lumbar radiculopathy, and/or intermittent claudication were treated with posterolateral fusion and correction of deformities using a new instrumentation system. This new spinal fixation system combines the advantages of a rod for scoliotic deformities and a plate for sagittal plane disorders. The combination rod-plates can apply multiple forces to facilitate correction of complex deformities as well as enable indirect neurologic decompression. The system allows segmental rigid fixation via transpedicular screws that is limited only to the abnormal vertebral levels to preserve the maximum number of uninvolved lumbar motion segments. The physiologic lumbar lordotic curvature is also preserved. The minimum follow-up period was 1 year. Satisfactory results were obtained in 15 patients (88%). No intraoperative complications occurred. Screw fatigue occurred in two patients at 1-year follow-up examination with no sequelae. The scoliotic and spondylolisthetic deformities were reduced significantly in all patients. This method appears to assist in reducing pathologic motion and deformities that contribute to low-back pain. Compression on neural structures is relieved by thorough decompression and distraction; spinal canal anatomy is also restored.