BACKGROUND Nonfusion fixation is an effective way to treat lumbar degeneration. In the present study, we analyzed the clinical effects and radiographic outcomes of the Isobar TTL system used to treat two-segment lumbar degenerative disease. METHOD Forty-one patients diagnosed with two-segment lumbar degenerative disease underwent surgical implantation of the Isobar TTL dynamic stabilization system (n = 20) or a rigid system (n = 21) from January 2013 to June 2017. The mean follow-up time was 23.6 (range 15-37) months. Clinical results were evaluated with the Oswestry Disability Index (ODI), modified Macnab criteria, and the visual analog score (VAS). Radiographic evaluations included the height of the intervertebral space and the range of motion (ROM) of the treated and adjacent segments. The intervertebral disc signal was classified using the modified Pfirrmann grading system and the University of California at Los Angeles (UCLA) system. RESULTS The clinical results, including the ODI and VAS, showed that there was significant improvement in the two groups after implantation and that the difference between the two groups was not significant. In addition, the clinical efficacy indicated by the modified Macnab criteria for the two groups was similar. Radiological outcomes included the height of the intervertebral space, lumbar mobility, and intervertebral disc signal. The height of the intervertebral space of the upper adjacent segment L2/3 in the rigid group was significantly lower than that in the Isobar TTL group at the last follow-up. Furthermore, the number of ROMs of the fixed-segment L3/4 in the Isobar TTL group was significantly less than that before implantation, suggesting that the fixed-segment ROMs in the Isobar TTL group were limited. In addition, the ROM of the upper adjacent segment L2/3 in the last follow-up of the rigid group increased significantly, while that of the Isobar TTL group did not change after implantation. Finally, the incidence of adjacent-segment degeneration (ASD) was significantly greater in the rigid group than in the Isobar TTL group according to the UCLA system. CONCLUSION The Isobar TTL system can be clinically effective for treating two-segment lumbar degenerative disease. Compared with rigid fixation, the Isobar TTL system yielded better radiographic outcomes and maintained the mobility of the treated segments with less impact on the proximal adjacent segment.

中文翻译：

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Isobar TTL系统对两节段腰椎退行性疾病的临床效果和影像学结果分析：一项回顾性研究。

背景技术非融合固定术是治疗腰椎变性的有效方法。在本研究中，我们分析了用于治疗两节段腰椎退行性疾病的Isobar TTL系统的临床效果和影像学结果。方法2013年1月至2017年6月，对41例诊断为两段腰椎退行性疾病的患者进行了Isobar TTL动态稳定系统（n = 20）或刚性系统（n = 21）的手术植入。平均随访时间是23.6（范围15-37）个月。使用Oswestry残疾指数（ODI），改良的Macnab标准和视觉模拟评分（VAS）对临床结果进行评估。射线照相评估包括椎间隙的高度以及治疗段和邻近段的运动范围（ROM）。使用改良的Pfirrmann分级系统和加利福尼亚大学洛杉矶分校（UCLA）系统对椎间盘信号进行分类。结果包括ODI和VAS在内的临床结果表明，两组在植入后都有明显改善，并且两组之间的差异不显着。此外，修改后的Macnab标准对两组的临床疗效相似。放射学结果包括椎间隙的高度，腰椎活动度和椎间盘信号。在最后一次随访中，刚性组的上相邻节段L2 / 3的椎间隙高度显着低于Isobar TTL组。此外，Isobar TTL组中固定段L3 / 4的ROM数量明显少于植入前的数量，这表明Isobar TTL组中固定段ROM的数量有限。此外，在刚植入组的最后一次随访中，上相邻节段L2 / 3的ROM显着增加，而Isobar TTL组的ROM在植入后没有变化。最后，根据UCLA系统，刚性组的邻段变性（ASD）的发生率明显高于Isobar TTL组。结论Isobar TTL系统可有效治疗两节段腰椎退行性疾病。与刚性固定相比，