[Three vertebral reduction and fixation for revision of lumbar spondylolisthesis]. OBJECTIVE
 To analyze the surgical failure of lumbar spondylolisthesis and investigate the clinical effect of three vertebral reduction and fixation in revision of lumbar spondylolisthesis.


 The clinical data of 19 patients underwent revision to lumbar spondylolisthesis was retrospectively analyzed between January 2009 and December 2012.  Reduction loss of olisthy segment had in 6 cases, internal fixation loosening or breakage had in 5 cases, slippage aggravating had in 8 cases.  Clinical symptoms including lower back pain, unilateral or bilateral lower extremity pain and numbness, etc.  Revision surgery was performed with three vertebral pedicle screw internal fixation and posterior decompression, reduction, and posterolateral bone graft between vertebral body.  For the first time after surgery pedicle screw loosening or fracture of vertebral body, to switch thick or long pedicle screws implanted into again, or with bone cement perfusion and implanted with pedicle.  The condition of intervertebral fusion and clinical effect were respectively assessed by X-ray films and JOA score.


 No pedicle screws loosening and breakage were found and no reduction loss vertebral body.  JOA score were statistically analyzed between preoperative and postoperative at 6 months, in 3 cases with degree I, the score respectively was 13.33 ± 1.53 and 26.33 ± 0.58; in 7 cases with degree II, the score respectively was 12.85 ± 2.19 and 26.29 ± 2.21; in 9 cases with degree III, the score respectively was 12.21 ± 2.73 and 26.44 ± 1.81; there was statistical significance between preoperative and postoperative at 6 months, the improvement rate of JOA was (78.06 ± 3.90)%.


 CONCLUSION
 For the patients with lumbar spondylolisthesis, the reason of primary surgical failure mainly concerned with internal fixation loosening and breakage, and bone graft no-fusion.  Revision surgery using three vertebral pedicle screw internal fixation, can get rigid fixation, complete decompression, bone graft fusion, combined with the guidance of the postoperative functional exercise for patients, can obtain satisfactory therapeutic effects.
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