后路腰椎融合术椎间笼架沉降的相关因素

Factors associated with cage subsidence in posterior lumbar interbody fusion

摘要:

[目的] 探讨后路腰椎间融合术 （posterior lumbar interbody fusion, PLIF） 术后融合器沉降的相关因素。[方法] 2018 年 1 月—3 月行 L_4/5单节段 PLIF 手术 91 例患者纳入本研究，观察术后融合器沉降的发生情况，采用单因素比较和多元逻辑回归分析探索融合器沉降发生的相关因素。[结果] 至末次随访，发生融合器沉降 21 例 （23.1%），未发生融合器沉降 70 例 （76.9%）。沉降组合并骨质疏松患者比例显著高于未沉降组 [是/否, (9/12) vs (10/60), P=0.005]。两组手术时间、切口长度、术中失血量差异均无统计学意义（P＞0.05），但沉降组的终板损伤率显著高于未沉降组 [是/否, (3/18) vs (1/69), P=0.012]。术前影像方面， 沉降组腰大肌 rCSA [(1.5±0.4) vs (1.7±0.5), P=0.038]、椎旁肌 CSA [(4 530.3±776.6) mm² vs (5 000.5±912.8) mm² , P=0.035] 、椎旁肌 rC- SA[(3.0±0.7) vs (3.9±0.8), P＜0.001]、椎旁肌 rFCSA [(2.3±0.6) vs (2.9±0.7), P＜0.001] 均显著小于未沉降组，但沉降组椎体 CSA 显著大于未沉降组 [(1 547.8±309.9) mm² vs (1321.2±296.0) mm² , P=0.003]。术后影像方面，沉降组 PI-LL [(11.7±7.0)° vs (6.4±9.6)°, P= 0.022]、即刻 SL 角 [(6.0±3.3)° vs (3.0±3.4)°, P＜0.001]、即刻椎间隙高度 [(2.9±1.3) mm vs (1.9±1.0) mm, P＜0.001] 显著大于未沉降组。 前者椎间骨融合时间显著晚于后者 [(6.7±1.8) 个月 vs (5.2±1.4) 个月, P＜0.001]。二元多因素逻辑回归显示，骨质疏松（OR=5.967, P=0.030）、术后即刻椎间隙高度（OR=2.296, P=0.013）、即刻 SL（OR=1.256, P=0.041）是融合器沉降的危险因素。而椎旁肌 rFC- SA（OR=0.525, P=0.048）是融合器沉降的保护因素。[结论] 骨质疏松、矫正椎间隙高度过大、SL 矫正角度过大、术前椎旁肌 rFCSA 过小是 PLIF 术后发生融合器沉降的危险因素。

Abstract:

[Objective] To search the factors related to cage subsidence after posterior lumbar interbody fusion (PLIF). [Methods] A total of 91 patients who underwent L_4/5 single-segment PLIF from January to March 2018 were included in this study to observe whether cage subsidence (CS) happened after surgery. Univariate comparison and multiple logistic regression analysis were used to explore the related factors of the cage subsidence. [Results] Up to the last follow-up, 21 cases (23.1%) had CS, while the remaining 70 cases (76.9%) were of nonCS. The CS group proved significantly higher proportion of osteoporosis than the non-CS group [yes/no, (9/12) vs (10/60), P=0.005]. There were no statistically significant differences in operation time, incision length and intraoperative blood loss between the two groups (P＞0.05), but the CS group had significantly higher intraoperative endplate injury rate than the non-CS [yes/no, (3/18) vs (1/69), P=0.012]. In terms of preoperative imaging, the CS group was significantly less than the non-CS group regarding psoas major muscle rCSA [(1.5±0.4) vs (1.7±0.5), P=0.038], paravertebral muscle CSA [(4 530.3±776.6) mm² vs (5 000.5±912.8) mm² , P=0.035], paravertebral muscle rCSA [(3.0±0.7) vs (3.9± 0.8), P＜0.001], paravertebral muscle rFCSA [(2.3±0.6) vs (2.9±0.7), P＜0.001], but the former was significantly greater than the latter in vertebral body CSA [(1 547.8±309.9) mm² vs (1 321.2±296.0) mm² , P=0.003]. In term of postoperative imaging, the CS group was significantly greater than the non-CS group in PI-LL [(11.7±7.0)° vs (6.4±9.6)°, P=0.022], segmental lordosis (SL) [(6.0±3.3)° vs (3.0±3.4)°, P＜0.001], intervertebral space height [(2.9±1.3) mm vs (1.9±1.0) mm, P＜0.001]. In addition, the former got intervertebral fusion significantly later than the latter [(6.7±1.8) months vs (5.2±1.4) months, P＜0.001]. As consequence of binary multifactor logistic regression, the osteoporosis (OR= 5.967, P=0.030), greater postoperative intervertebral space height (OR=2.296, P=0.013), and greater SL (OR=1.256, P=0.041) were the risk factors, while greater paravertebral muscle rFCSA (OR=0.525, P=0.048) was the protective factor for CS. [Conclusion] Osteoporosis, excessively corrected intervertebral space height, excessively corrected SL, and smaller preoperative paravertebral muscle rFCSA are risk factors for CS after PLIF.