下腰椎单节段经椎间孔腰椎体间融合术后融合器沉降对腰椎矢状面形态的影响

Cage subsidence after monosegmental transforaminal lumbar interbody fusion at the lower lumbar spine: its effect on sagittal alignment

中文关键词:  下腰椎单节段  经椎间孔腰椎体间融合术  融合器沉降  腰椎矢状面形态

英文关键词:Monosegmental  Transforaminal lumbar interbody fusion  Cage subsidence  Lumbar sagittal alignment

中文摘要:

  【摘要】 目的：探讨下腰椎单节段经椎间孔椎体间融合术（transforminal lumbar interbody fusion，TLIF）术后融合器沉降对腰椎矢状面形态的影响。方法：回顾性分析于2015年1月~2017年1月在我院就诊的行L4/5或L5/S1单节段TLIF患者，共有114例患者纳入本研究，其中男31例，女83例，年龄57.0±11.6岁（31~74岁），随访时间29.8±4.3个月。按照手术的节段不同分为L4/5组（65例）和L5/S1组（49例）；根据术后1年CT融合器沉降情况分为沉降组（沉降≥2mm，22例）和未沉降组（沉降<2mm，92例）。在术前、术后3个月以及末次随访站立位全脊柱侧位X线片测量腰椎前凸角（lumbar lordosis，LL）、局部前凸角（segmental lordosis，SL）、椎间隙高度（disc height，DH），分别通过术后3月-术前和末次随访-术后三月差值表示手术重建情况以及随访丢失情况，同时填写Oswestry功能障碍指数（Oswestry disability index，ODI）量表和VAS疼痛评分量表评估生活质量。通过独立样本t检验比较数值变量，同时采用卡方检验对分类变量进行检验，P<0.05有统计学差异。结果：L4/5组和L5/S1组术前、术后3月及末次随访时LL、SL及DH无统计学差异（P>0.05），而L4/5组术后3个月随访时LL（4.8°±1.0° vs 3.2°±0.96°，P<0.001）和SL（2.7°±0.5° vs -0.15°±0.79°，P<0.001）重建明显优于L5/S1组，且在末次随访时的LL（-1.1±1.4 vs -1.7°±1.3°，P<0.05）和SL（-0.53°±0.57° vs -0.84°±0.93°，P<0.05）矫正丢失更小。此外，两组患者DH重建及随访丢失无统计学差异（P>0.05）。纳入本研究患者术后1年融合器沉降发生率为19.3%，L5/S1组沉降率高于L4/5，但无统计学差异（15.4% vs 24.5%，P>0.05）。沉降组年龄高于未沉降组（62.1±10.9岁 vs 55.8±11.7岁，P<0.05）。两组患者术前、术后3个月、末次随访及手术重建LL、SL及DH无统计学差异（P>0.05），而沉降组末次随访LL（-3.5°±1.4° vs -1.1°±0.94°）、SL（-1.11°±0.89° vs -0.33°±0.71°）及DH（-0.98±1.2mm vs -0.39±0.19mm）丢失均显著高于未沉降组（P<0.05）。沉降组年龄与未沉降组之间术前、术后早期及末次随访ODI、VAS腰痛和VAS腿痛无统计学差异（P>0.05）。结论：下腰椎L5/S1单节段TLIF术后1年融合器沉降发生率高于L4/5。融合器沉降导致SL和LL的丢失，但未明显降低患者生活质量。

英文摘要:

  【Abstract】 Objectives: To investigate the effects of cage subsidence after monosegmental transforaminal lumbar interbody fusion(TLIF) at the lower lumbar spine on the sagittal alignment outcomes. Methods: A consecutive cohort of 114 patients(31 males and 83 females) was retrospectively reviewed, who had received monosegmental TLIF at L4/5 or L5/S1 level between January 2015 and January 2017, with an average age of 57.0±11.6 years(31-74 years) and a mean follow-up of 29.8±4.3 months. There were 65 patients receiving TLIF at L4/5 and 49 at L5/S1. They were also classified into the cage subsidence group and the non-subsidence group, with 22 patients in the cage subsidence group and 92 patients in the non-subsidence group, respectively. Lumbar lordosis(LL), segmental lordosis(SL) and disc height(DH) parameters were measured to evaluate the radiographic outcomes. The 3 months after postoperative parameters minus its values in preoperation and the final follow-up values minus the values in 3 months after postoperative represented reconstruction and the loss of follow-up respectively. Oswestry disability index(ODI) and visual analogue scale(VAS) were collected to evaluate the clinical outcomes. The student T test was used to compare continuous variables and chi-squared test for categorical variables(P<0.05 was considered statistically significant). Results: There was no statistical significance in preoperative, postoperative and final follow-up LL, SL or DH between the L4/5 group and the L5/S1 group(P>0.05). However, the reconstruction of LL and SL in the L4/5 group were superior than those in the L5/S1 group(4.8°±1.0° vs 3.2°±0.96°, P<0.001). Also, patients in the L5/S1 group were noted to have more significant loss in LL and SL(2.7°±0.5° vs -0.15°±0.79°, P<0.001). In addition, there was no significant difference in reconstruction or loss of DH between two groups(P>0.05). The incidence of cage subsidence in this study was 19.4%, being a little higher at L5/S1 than L4/5(15.4% vs 24.5%) but without statistical significance(P>0.05). The age in the cage subsidence group was older than the non-subsidence group(P<0.05). There was no statistical significance of reconstructive LL, SL and DH between the cage subsidence group and the non-subsidence group at preoperation, postoperation and the final follow-up(P>0.05). However, the losses of LL, SL and DH in the cage subsidence group were higher than those in the non-subsidence group at the final follow-up(P<0.05), but the patient reported outcomes were not significantly different between two groups with/without cage subsidence before surgery or at each follow-up(P>0.05). Conclusions: About 19.3% of patients experienced cage subsidence after monosegmental TLIF at the lower lumbar spine, slightly more frequently at L5/S1 than L4/5. Cage subsidence had a significant association with correction loss of SL and LL, but it did not affect patient reported outcomes.