| ObjectiveLumbar fusion leads or accelerates ASDeg, and some patients with ASDis mustreceive secondary surgical treatment.Especially the intervertebral discs with preoperativeinitial degenerative changes are more prone to injury and further degeneration, but theresult of surgical treatment ASDis was not satisfactory, so how to prevent ASDis is veryimportant, so far there was no good way to prevent or treat ASDis. In recent years, hybriddynamic stabilization with posterior spinal fusion (Topping-off surgery) is expected tobecome an effective means to solve this problem, dynamic stabilization reserved part of theROM while offloading disc and joint stress load, prevent the degeneration of pathologicalprocess progress. However, controversy exists concerning curative effect and value ofTopping-off surgery.Therefore, the aim of this study was to evaluate the clinical outcomes of hybriddynamic stabilization with posterior spinal fusion (a topping-off surgery),to explore theindications of this surgery.And evaluate the impact on lumbar via compare with single-levelfusion.Finally,evaluate the protective effect of dynamic stabilization on intervertebral discby quantitative analysis of disc signal on MRI.MethodsRetrospectively analysed54degenerative diseases patients with adjacent segmentspreoperative degeneration of fused underwent hybrid Isobar (Isobar group) or K-rod (K-rodgroup) dynamic stabilization, and30lumbar degenerative diseases patients withoutadjacent segments preoperative degeneration underwent single-level fusion (fusion group)in Southwest Hospital between October2008and March2012.Isobar group:17males and 13females with average age48.0years old range from31to65years; K-rod group:13males and11females with average age54.1years old range from25to73years; fusiongroup:13males and17females with average age47.7years old range from18to67years.VAS, ODI were used to evaluate clinical efficiency; ISR and ROM of index level,ROM of global lumbar spine, ROM1, ROM2were measured and used to evaluate thelumbar spine motor function. The incidence of ASDeg, ASDis and the radiologicallyadverse events was compared between3groups. Quantitative analysis of index level disc,first adjacent disc and second adjacent disc signal on MRI by Image J software to evaluatethe effect of dynamic stabilization on index level disc.ReslutsAll patients operations were successful and lumbocrural pain were significantlyrelieved or disappeared. Average radiologically follow-up of group Isobar, group K-rod andgroup fusion for26.6,18.1and19.8months.VAS score of group Isobar decreased frompreoperative6.23±0.82to1.70±0.65at final follow-up(P<0.01),the K-rod group decreasedfrom preoperative5.88±0.90to1.58±0.65at final follow-up(P<0.01)and the fusion groupdecreased from preoperative6.23±0.86to1.73±0.78(P<0.01) at final follow-up(P<0.01);VAS of group K-rod at6month after operation higher than group Isobar(P<0.05),and no nosignificant difference of VAS between3groups at other follow-up time points.ODI of groupIsobar was improved from preoperative55.93%±10.96%to14.47%±3.79%at finalfollow-up(P<0.01),the K-rod group was improved from preoperative54.93%±10.37%to13.33%±8.54%at final follow-up(P<0.01)and the fusion group was improved frompreoperative50.26%+12.01%to14.15%±4.35%at final follow-up(P<0.01); ODI of groupK-rod at6month after operation higher than group Isobar and group fusion(P<0.05),but nosignificant difference of ODI at other follow-up time points between3groups. The ISR ofindex level was no significant difference between preoperation and final follow-up in groupIsobar and group K-rod (P>0.05), and no significant difference at all follow-up time pointsbetween these2groups. The ROM of index level was (2.53±1.04)°,(2.67±1.20)°at finalfollow-up of group Isobar and group K-rod and accounted for36.4%and46.8%ofpreoperative. The ROM of global lumbar spine were no significant difference between3groups at preoperative and final follow-up(P>0.05);ROM1and ROM2of group Isobar and K-rod were significant increased at final follow-up(P<0.05),ROM1of group single-levelfusion was significant increased at final follow-up(P<0.05).The ROM1and ROM2were nosignificant difference between3groups at preoperative and final follow-up(P>0.05).Duringfollow-up,7cases of group Isobar,2cases of K-rod and5cases of group single-level fusionwere observed adjacent segment instability,and no ASDis was observed in3groups, theincidence of ASDeg were no significant difference between3groups(P=0.34). Noprogression of degeneration was observed in the index levels during follow-up period.1patient of group Isobar with2screws loosening and another patient with2screws breakage.8patients of group K-rod with11(11/138,8%)screws loosening;The incidence ofradiologically adverse events of group K-rod was higher than other two groups.17cases of group Isobar and4cases of group K-rod performed postoperative1years-plus MRI, mean follow-up time27.0months,12males and9females, mean age49.3years (range,25-65years).The NSI of index level decreased from preoperative23.5±10.2to19.9±7.3, but there was no significant difference (P=0.11), but the NSI of the first andsecond adjacent disc were significant differences between preoperative and final follow-up(P<0.05).Conclusion1. Hybrid Isobar or K-rod dynamic stabilization with posterior spinal fusion achievedsatisfactory clinical results in early term follow-up, is an alternative choice for patients withadjacent segments preoperative degeneration of fused to avoid a postoperative ASDis.2. Isobar and K-rod dynamic stabilization system can stabilize spine and preserve partmobility of index level, and prevent the disc space height reduction.3. The ROM of adjacent segents were compensatory increased significantly afterhybrid Isobar or K-rod dynamic stabilization with posterior spinal fusion,but no significantdifference compared to single-level fusion, suggesting this Topping-off surgery also existsthe risk of accelerated adjacent segment degeneration, but this risk may not be higher thansingle-level fusion.4. Isobar and K-rod dynamic stabilization can delay or prevent the disc degenerationprogression.5. Hybrid dynamic stabilization with posterior spinal fusion exists the risk of fixation system failure so must select the appropriate indications and exclude the contraindications,and the incidence of K-rod dynamic stabilization screw loosening was significantly higherthan Isobar dynamic stabilization system. |
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