Surgical Treatment for the Low Grade Lumbar Isthmic Spondylolisthesis: Comparison between Posterolateral Fusion and Posterior Lumbar Interbody Fusion

Song, Kyung Jin; Kim, Sung Jin

Abstract

STUDY DESIGN AND OBJECTS: This is a retrospective study designed to compare the surgical treatment results between postero-lateral fusion(PLF) and posterior lumbar interbody fusion(PLIF) with pedicle screw fixation for the low grade lumbar isthmic spondylolisthesis with neurologic deficit.
MATERIALS AND METHODS
Forty-one patients were operated from 1990 to 1996, but 9 patients were lost to follow-up, and we analyzed 32 patients with an average 38 months(range:24-65 months) follow-up. Twenty-one patients were operated by pos-terolateral fusion(group A) and 11 patients were operated by posterior lumbar interbody fusion(group B). Age ranged from 18 to 69 years with an average of 44.1 years old. The mean duration of symptom was 26.4 months. Slip angle, percentage of slippage, bone union and complications were considered as an assessment criteria. For the functional results we used Kim's functional evaluation scale. We used two-way ANOVA and chi -square test for the statistical analysis.
RESULTS
The average preoperative slip angle was 6.8degree, postoperative 9.6degreeand last follow-up was 6.9degreein group A and the changes were -0.3degree, 3.6degreeand 1.9degreerespectively in group B. In percentage of slippage, mean pre-operative value was 22.1%, post-operative 19.3% and last follow up was 20.7% in group A. And the changes were 25%, 8.2%, and 8.3% in group B respectively. In bone union, definitive solid union was obtained in 19 cases (90.4%) of group A, and in 10 cases(91%) of group B. Satisfactory functional outcome were obtained in 85.7% of group A and 90.9% of group B according to the Kim's evaluation criteria. There were no significant statistical difference in the changes of slip angle, status of bone union, complications and functional out-come(P>0.05) between group A and group B. But posterior lumbar interbody fuison was superior in the ability and maintenance of reduction compared with posterolateral fusion(p=0.020).. SUMMARY: Both posterolateral fusion and posterior lumbar interbody fusion with Gill procedure and pedicle screw fixation could be reliable surgical treatment option for the maintenance of reduction, higher fusion rate and satisfactory fuctional out-come in the symptomatic low grade lumbar isthmic spondylolisthesis with neurologic deficit.