Nakashima Hiroaki, Kanemura Tokumi, Satake Kotaro, Ito Kenyu, Ishikawa Yoshimoto, Ouchida Jun, Segi Naoki, Yamaguchi Hidetoshi, Imagama Shiro
Department of Orthopedic Surgery, Konan Kosei Hospital, Konan, Japan.
Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Asian Spine J. 2020 Apr;14(2):177-184. doi: 10.31616/asj.2019.0127. Epub 2019 Nov 5.
A retrospective cohort study.
The purpose of this study was to investigate the prevalence and risk factors for S2 alar-iliac (SAI) screw loosening following lumbosacral fixation, with a minimum 2-year follow-up.
Although SAI screws allow surgeons to perform lumbosacral fixation with a low profile and enhanced biomechanical strength, screw loosening following surgery can occur in some cases. However, few studies have investigated the prevalence and risk factors for SAI screw loosening.
This retrospective study included 35 patients (mean age, 72.8±8.0 years; male, 10; female, 25) who underwent lumbosacral fixation using SAI screws with at least 2 years of follow-up. SAI screw loosening and L5-S bony fusion were assessed using computed tomography. The period for which the screws appeared loose and the risk factors for SAI screw loosening were investigated 2 years after surgery.
A total of 70 SAI screws and 70 S1 pedicle screws were inserted. Loosening was observed 0.5, 1, and 2 years after surgery in 17 (24.3%), 35 (50.0%), and 35 (50.0%) SAI screws, respectively. Bony fusion rate at L5-S was significantly lower in patients with SAI screw loosening than in those without screw loosening (65.0% vs. 93.3%, p =0.048). The score for SAI screw contact with the iliac cortical bone and the bony fusion rate at L5-S were significantly lower in the loosening group than in the non-loosening group (1.8±0.5 vs. 2.2±0.3, p <0.001, respectively). Postoperative pelvic incidence-lumbar lordosis was significantly higher in the loosening group than in the non-loosening group (7.9°±15.4° vs. 0.5°±8.7°, p =0.02, respectively).
SAI screw loosening is closely correlated with pseudoarthrosis at L5-S. Appropriate screw insertion and optimal lumbar lordosis restoration are important to prevent postoperative complications related to SAI screws.
一项回顾性队列研究。
本研究旨在调查腰骶部固定术后S2翼状髂骨（SAI）螺钉松动的发生率及危险因素，并进行至少2年的随访。
尽管SAI螺钉能使外科医生以较低的外形轮廓和增强的生物力学强度进行腰骶部固定，但术后螺钉松动在某些情况下仍可能发生。然而，很少有研究调查SAI螺钉松动的发生率及危险因素。
这项回顾性研究纳入了35例患者（平均年龄72.8±8.0岁；男性10例，女性25例），这些患者接受了使用SAI螺钉的腰骶部固定术，并进行了至少2年的随访。使用计算机断层扫描评估SAI螺钉松动和L5-S椎体融合情况。术后2年调查螺钉出现松动的时间以及SAI螺钉松动的危险因素。
共植入70枚SAI螺钉和70枚S1椎弓根螺钉。术后0.5年、1年和2年分别观察到17枚（24.3%）、35枚（50.0%）和35枚（50.0%）SAI螺钉松动。SAI螺钉松动患者的L5-S椎体融合率显著低于未出现螺钉松动的患者（65.0%对93.3%，p =0.048）。松动组SAI螺钉与髂骨皮质骨的接触评分及L5-S椎体融合率显著低于未松动组（分别为1.8±0.5对2.2±0.3，p <0.001）。松动组术后骨盆倾斜度-腰椎前凸显著高于未松动组（分别为7.9°±15.4°对0.5°±8.7°，p =0.02）。
SAI螺钉松动与L5-S椎体假关节形成密切相关。正确的螺钉植入和最佳的腰椎前凸恢复对于预防与SAI螺钉相关的术后并发症很重要。
