Lumbosacral instrumentation continues to be challenging due to complex biomechanical force distributions and poor sacral bone quality. Various techniques have therefore been established. The aim of this study was to investigate the outcome of patients treated with S2-alar-iliac (S2AI), S2-alar (S2A), and iliac (I) instrumentation as the most caudal level. Sixty patients underwent one of the 3 techniques between January 2012 and June 2017 (S2AI 18 patients, S2A 20 patients, I 22 patients). Mean age was 70.4 ± 8.5 years. Screw loosening (SL) and sacroiliac joint (SIJ) pain were evaluated during the course at 3-month and maximum follow-up (FU). All patients completed 3-month FU, the mean FU period was 2.5 ± 1.5 years (p = 0.38), and a median of 5 segments was operated on (p = 0.26), respectively. Bone mineral density (BMD), derived opportunistically from computed tomography (CT), did not significantly differ between the groups (p = 0.66), but cages were more frequently implanted in patients of the S2A group (p = 0.04). SL of sacral or iliac screws was more common in patients of the S2A and I groups compared with the S2AI group (S2AI 16.7%, S2A 55.0%, I 27.3% of patients; p = 0.03). SIJ pain was more often improved in the S2AI group not only after 3 months but also at maximum FU (S2AI 61.1%, S2A 25.0%, I 22.7% of patients showing improvement; p = 0.02). Even in shorter or mid-length lumbar or thoracolumbar constructs, S2AI might be considered superior to S2A and I instrumentation due to showing lower incidences of caudal SL and SIJ pain.

由于复杂的生物力学力分布和较差的骶骨质量，腰骶部器械仍然具有挑战性。因此已经建立了各种技术。本研究的目的是调查使用 S2-alar-iliac (S2AI)、S2-alar (S2A) 和髂骨 (I) 器械作为最尾部水平的患者的结果。60 名患者在 2012 年 1 月至 2017 年 6 月期间接受了 3 种技术中的一种（S2AI 18 名患者，S2A 20 名患者，I 22 名患者）。平均年龄为 70.4 ± 8.5 岁。在 3 个月和最大随访 (FU) 的过程中评估螺钉松动 (SL) 和骶髂关节 (SIJ) 疼痛。所有患者均完成 3 个月 FU，平均 FU 时间为 2.5 ± 1.5 年（p  = 0.38），并且中位数为 5 个节段（p = 0.26)，分别。从计算机断层扫描 (CT) 机会主义地得出的骨矿物质密度 (BMD) 在各组之间没有显着差异 ( p  = 0.66)，但 S2A 组患者更频繁地植入骨笼 ( p  = 0.04)。与 S2AI 组相比，S2A 和 I 组患者的骶骨或髂骨螺钉 SL 更常见（S2AI 16.7%，S2A 55.0%，I 27.3% 的患者；p  = 0.03）。S2AI 组的 SIJ 疼痛更常在 3 个月后和最大 FU 时得到改善（S2AI 61.1%，S2A 25.0%，I 22.7% 的患者表现出改善；p = 0.02）。即使在较短或中等长度的腰椎或胸腰椎结构中，S2AI 也可能被认为优于 S2A 和 I 器械，因为其尾部 SL 和 SIJ 疼痛的发生率较低。