Abstract Objective: The purpose of this study was to evaluate the surgical technique and outcome of posterior lumbar interbody fusion (PLIF). Materials and Methods: Forty patients who underwent PLIF using the pedicle screw fixation system for Meyerding Grade II spondylolisthesis or more were retrospectively studied. After complete circumferential release, the slipped vertebrae would tend to obtain spontaneous reduction, and with compressive force by pedicle screw fixation, additional reduction could be achieved. The radiological measurements including slippage reduction, disc height, restoration of lumbar lordotic angle and focal segmental angle were analyzed. The clinical outcome was assessed using the visual analog scale (VAS) and low back outcome score (LBOS), and procedure related complications were also analyzed. Results: Slippage percentage was improved from 38.0±12.6% to 9.3±7.8% and lumbar lordotic angle was changed from 43.0±13.8° to 48.2±10.3°. Focal segmental angle improved from 10.1±8.5° to 15.9±6.0°. The mean LBOS and mean pain score were also improved significantly. Complications included one case of medial penetration of pedicle border and two cases of transient radiculopathy. However, there were no signs of neurological aggravation or fusion failure during the follow-up period. Conclusion: PLIF using the Pedicle screw fixation following complete circumferential release can be safe and effective treatment for even moderate to severe grade spondylolisthesis

Key Words: Spondylolisthesis, Fusion, Reduction, PLIF.