Department of Orthopaedics, Southwest Hospital, Army Medical University, Chongqing, China.
Orthop Surg. 2023 Dec;15(12):3193-3201. doi: 10.1111/os.13898. Epub 2023 Oct 24.
Cage subsidence is a common morbidity after oblique lumbar interbody fusion (OLIF), with risk of compromising clinical and radiographic outcomes. The study aims to describe an innovative reverse lumbar pedicle screw (RLPS) technique in OLIF and compare its effect on restricting cage subsidence with classical lateral fixation (LF) in radiological and clinical evaluation.
Consecutive patients having undergone single-level OLIF-LF/RLPS from 2018 to 2020 were retrospectively reviewed. In OLIF-RLPS, the upper entry point was determined at the intersection between one horizontal line (1 cm above inferior endplate) and one vertical line (dissecting anterior and middle thirds of the vertebra) while the inferior entry point between one horizontal line (5 mm below superior endplate) and the same vertical line. Trajectories were from vertebrae reverse into contralateral pedicle. Radiological evaluation included disc height (DH) and segmental lordosis (SL); cage subsidence was evaluated by DH loss. Clinical assessment included visual analogue scale (VAS) and Oswestry disability index (ODI). Student t or Mann-Whitney U test was used for continuous variation according to normality analysis while Chi-square test for category variation.
A total of 29 patients had been enrolled in the study including 14 cases in the RLPS group and 15 cases in the LF group. The DH in the OLIF-RLPS group had increased from the preoperative 9.07 ± 1.73 mm to 13.73 ± 1.83 mm postoperatively, without significant difference compared with the OLIF-LF group during the perioperative, but decreased to 12.53 ± 1.74 mm in 3 months and maintained at 12.00 ± 1.45 mm in 12 months, significantly higher than the OLIF-LF group (p < 0.05). At the last follow-up, 7.1% (1/14) cases in the OLIF-RLPS group had shown subsidence of grade I, significantly less than 46.7% (7/15) cases in the OLIF-LF group. Pain and disability had improved similarly in two groups, without significant difference detected between two groups at the last follow-up.
RLPS technique with modified entry points and prolonged trajectory could effectively restrict cage subsidence in OLIF postoperatively compared with traditional lateral fixation.
腰椎间融合术后（OLIF） cage 沉降是一种常见的并发症，可能会影响临床和影像学结果。本研究旨在描述一种 OLIF 中新型的反向腰椎椎弓根螺钉（RLPS）技术，并比较其在限制 cage 沉降方面与经典的侧方固定（LF）的效果。
回顾性分析 2018 年至 2020 年期间接受单节段 OLIF-LF/RLPS 治疗的连续患者。在 OLIF-RLPS 中，上入口点位于一条水平线（距下终板 1cm 上方）和一条垂直线（解剖椎体前 1/3 和中 1/3）的交点处，而下入口点位于一条水平线（距上终板 5mm 下方）和同一条垂直线之间。轨迹从椎体反向进入对侧椎弓根。影像学评估包括椎间盘高度（DH）和节段前凸（SL）；通过 DH 丢失评估 cage 沉降。临床评估包括视觉模拟评分（VAS）和 Oswestry 残疾指数（ODI）。根据正态性分析，连续变量采用 Student t 或 Mann-Whitney U 检验，分类变量采用卡方检验。
共纳入 29 例患者，其中 RLPS 组 14 例，LF 组 15 例。OLIF-RLPS 组的 DH 从术前的 9.07±1.73mm 增加到术后的 13.73±1.83mm，与 OLIF-LF 组在围手术期相比无显著差异，但在 3 个月时降至 12.53±1.74mm，在 12 个月时保持在 12.00±1.45mm，明显高于 OLIF-LF 组（p<0.05）。末次随访时，OLIF-RLPS 组 7.1%（1/14）例出现 I 级沉降，明显少于 OLIF-LF 组的 46.7%（7/15）例。两组患者的疼痛和残疾均得到改善，末次随访时两组间无显著差异。
与传统的侧方固定相比，改良入点和延长轨迹的 RLPS 技术可有效限制 OLIF 术后 cage 沉降。
