This article compares the postoperative course of 40 patients who had Harrington instrumentation with 40 patients who had Harrington instrumentation and inter spinous process segmental instrumentation of unstable thoracolumbar fractures and reviews the findings. The two groups of patients were otherwise homogeneous, and average operative time, total blood loss, and days to oral intake were similar for both groups of patients. On average, however, patients undergoing interspinous pro cess segmental instrumentation were out of bed sooner (4.5 versus 7.7 days, P < O.OOOl), discharged sooner (32 versus 38 days, P < 0.079), and brace-free earlier (2.1 versus 5.9 months, P < 0,001) and had fewer fixation related complications than did patients undergoing Har rington instrumentation alone. Comparison of average hospital costs documented a savings of $5,160 for the typical patient undergoing interspinous process seg mental instrumentation.