Harrington rods were intended to provide a means to reduce the curvature and to provide more stability to a spinal fusion. Before the Harrington rod was invented, scoliosis patients had their spines fused without any instrumentation to support it; such fusions required many months in plaster casts, and large curvatures could progress despite fusion.
The PLIF procedure was first described in 1944 by Briggs and Milligan 1) who used laminectomy bone chips in the disc space as interbody graft. In 1946, Jaslow 2) modified the technique by positioning an excised portion of the spinous process within the intervertebral space. It was not until 1953 when Cloward 3) described his technique, which used impacted blocks of iliac crest autograft that the popularity of PLIF surgery increased. Although technically more difficult than posterolateral fusion techniques (i.e., intertransverse fusion in which bone graft spans between the transverse processes), the PLIF procedure was found to have the advantage of substantially increased fusion rates, often in excess of 85%. Despite the increased fusion rate, this technique was fraught with complications related to blood loss, dural/neural injury, graft extrusion, and arachnoiditis 4).