This is a retrospective study analyzing 76 patients treated by decompression, pedicle screw instrumentatin and fusion for spondylolytic spondylolisthesis with symptomatic spinal stenosis.

This is to verify the advantages of adding posterior lumbar interbody fusion (PLIF) to the usual posterolateral fusion (PLF) with pedicle screw instrumentation.

Stabilization after decompression of spondylolytic spondy- lolisthsis is difficult due to insufficiency of fusion base, gap between the bases and incompetent anterior disc support. PLIF offers anterior support, reduction and a broad fusion base.

Forty patients were treated with PLF and 36 were treated with additional PLIF. They were compared for union, reductin of the deformity and clinical results.

The patients were followed up for more than 2 years (mean: 4.6 years). Nonunion was observed in 3 PLF cases (7.5%) and none in PLIF. Reduction of slippage was 28.3% in PLF and 41.6% in PLIF (p<0.05). In PLF group, 8 patients (20%) had recurrence of deformity with loss of reduction more than 50%. Hardware failures occurred in 2 with PLF. There was no major neurologic complications in both groups. Both groups had a few difference in the satisfactory results, but some difference in the excellent result by Kirkaldy-Willis criteria. Excellent result was 45% in PLF and 75% in PLIF.

Addition of PLIF to PLF following a complete decompression and pedicle screw flxation is a recommendable procedure for the treatment of spondylolytic spondylolisthesis with spinal stenosis.