Comparison And Analysis Of Mid-and-Long-Term Clinical Effect Between The K-rod Non-fusion Operation And PLIF For The Treatment Of The L4/5 Segment Lumbar Disc Herniation

OBJECTIVE:The purpose of this study was to explore the clinical outcomes and the role in delaying the degeneration of adjacent segments of the non-fusion surgery assisted by the K-rod system through the evaluation of the clinical efficacy of single-level lumbar disc herniation treated with posterior lumbar interbody fusion(PLIF)and non-fusion with K-rod system.METHODS:This retrospective analysis included 22 patients with lumbar disc herniation(L4-5)who underwent with the K-rod lumbar dynamic stabilization system(n=13)or PLIF(n=19)from December 2010 to December 2012.The follow-up time was more than five years.The clinical evaluation indexs included Oswestry disability index(ODI),visual analog scale score(VAS),and the Japanese Orthopaedic Association scores(JOA).The imaging evaluation indexs included adjacent segmental intervertebral height,intervertebral mobility(ROM),incidence of lumbar instability,The lordotic angle of lumbar spine(LL),pelvic parameters,Pfirrmann grading,MODIC grading,and UCLA system grading.RESULTS:Before the operation,there were no significant difference in ODI,VAS and JOA score between the two groups.At the last follow-up,we observed the differences happened at the last follow-up between groups(P<0.05).The ODI,VAS and JOA score at the last follow-up were significantly improved(P<0.05).There was a significant difference in ODI improvement rates between groups(P<0.05),but no difference in JOA improvement rates(P<0.05).There were differences in operation time and the bleeding volume between the K-ROD group and PLIF group.There were no significant difference in the intervertebral height and ROM between the two groups before operation(P>0.05).There was no significant difference in the intervertebral height and ROM at the last follow-up compare to the preoperation,but we observed the differences in in the intervertebral height and ROM between the two groups at the last follw-up.The incidence of lumbar instability was 7.7% in the K-rod group which was significantly less than that in the PLIF group(38.9%,P<0.05).In terms of spine-pelvic parameters,compared with the preoperation,there were no significant differences in pelvic index(PI),pelvic tilt angle(PT),sacral slope(SS),lumbar lordosis angle(LL)at the last follow-up in K-ROD,but the differences happened in PLIF group.The general trend of PLIF group was that the SS and LL were smaller and PT was larger at the last follow-up,compared to the preoperation.There were significant differences in PT,SS,LL between the K-rod group and the PLIF group at last follow-up.The incidence of adjacent segment degeneration in the PLIF group was 55.6%,which is significantly higher than in the K-ROD group(15.4%,P<0.05).There was a significant difference between the groups.In the Pfirrmann grade,the incidence was 55.6% in the PLIF group and 15.4% in the K-rod group.In the MODIC grade,it was 22.2% in the PLIF group and 3.8% in the K-rod group.In the UCLA grade,it was 27.8% in the PLIF group and 3.8% in K-rod group.The incidence of loss of intervertebral height exceeded 20% was 16.7% in the PLIF group and 3.8% in the K-rod group.There were significant differences in Pfirrmann grade,MODIC grade,UCLA grade,and the incidence of loss of intervertebral height exceeded 20% between the groups(P<0.05).Conclusion:In the study,we found that the K-rod system can limit abnormal activities and retain the normal activity of the surgical segment,can restore the spinal balance.Compare to PLIF,the posterior lumbar non-fusion surgery assisted with the K-ROD system had many advantages,such as less operation-time,less traumatic,less bleeding,and faster recovery.In a addition,the K-rod non-fusion surgery produced better clinical outcome in the treatment of L4/5 lumbar disc herniation than PLIF.In this study,the role in delaying adjacent segements was confirmed though the intervertebral height,ROM,lumbar instability,spine-pelvic parameters,Pfirrmann grading,MODIC grading,and UCLA grading after lumbar surgery.It had provided the basis to make the selection of treatment strategies for the lumbar degenerative disease.