Department of Orthopaedic Surgery, Higashiosaka City Medical Center, 3-4-5 Nishi-iwata Higashiosaka City, Osaka 5788588, Japan.
Department of Orthopaedic Surgery, Nara Medical University, 840 Shijo-cho Kashihara City, Nara 6348522, Japan.
Spine J. 2023 Dec;23(12):1928-1934. doi: 10.1016/j.spinee.2023.07.009. Epub 2023 Jul 20.
Lumbosacral fusion supplemented with sacropelvic fusion has recently been increasingly employed for correcting spinal deformity and is associated with lower incidence of pseudarthrosis and implant failure. To date, few studies have evaluated anatomical parameters and technical feasibility between different entry points for S2 alar-iliac screws.
To compare anatomical parameters and technical feasibility of two entry points for the S2 alar-iliac screw (S2AIS) in a Japanese cohort using three-dimensional (3D) computed tomography (CT).
STUDY DESIGN/SETTING: Retrospective cohort study.
Fifteen men and 15 women aged 50-79 years who underwent pelvic CT at our hospital in 2013.
Screw length, lateral angulation, caudal angulation, angle range, distance from the entry point to the sacroiliac joint, distance from the S2AIS to the acetabular roof, distance from the S2AIS to the sciatic notch, and insertion difficulty.
We used 30 pelvic CT images (15 men and 15 women). We selected two entry points from previous studies: one was 1 mm distal and 1 mm lateral to the S1 dorsal foramen (A group) and the other was the midpoint between the S1 and S2 dorsal foramen (B group). We resliced the plane in which the pelvis was sectioned obliquely from these entry points to the anterior inferior iliac spine in the sagittal plane. We placed the shortest and longest virtual S2AISs bilaterally in this plane using a 4-mm margin. We measured screw length, lateral angulation, caudal angulation, angle range, distance from the entry point to the sacroiliac joint, distance from the S2AIS to the acetabular roof, distance from the S2AIS to the sciatic notch, and insertion difficulty. These measurements were compared between Groups A and B.
In group A, the angle in the sagittal plane was significantly smaller and the distance from the entry point to the sciatic notch was significantly longer than in group B. Group B demonstrated a significantly longer screw length, longer distance from the entry point to the sacroiliac joint, and longer distance from the entry point to the acetabular roof than group A. The rate of insertion difficulty of S2AIS was much higher in group A.
Insertion of S2AIS from the midpoint between the S1 and S2 dorsal foramen compared with the entry at distal and lateral to S1 foramen enables insertion of longer screws with low insertion difficulty.
腰骶融合联合骶髂融合最近越来越多地用于矫正脊柱畸形，并且与假关节和植入物失败的发生率较低有关。迄今为止，很少有研究评估不同 S2 骼骨螺钉入点的解剖参数和技术可行性。
使用三维（3D）计算机断层扫描（CT）比较 S2 骼骨螺钉（S2AIS）在日本队列中的两种入点的解剖参数和技术可行性。
研究设计/设置：回顾性队列研究。
2013 年在我院接受骨盆 CT 检查的 15 名男性和 15 名女性，年龄 50-79 岁。
螺钉长度、外侧成角、尾侧成角、角度范围、从入点到骶髂关节的距离、从 S2AIS 到髋臼顶的距离、从 S2AIS 到坐骨切迹的距离和插入难度。
我们使用了 30 个骨盆 CT 图像（15 名男性和 15 名女性）。我们从以前的研究中选择了两个入点：一个位于 S1 背侧孔外侧 1mm 处（A 组），另一个位于 S1 和 S2 背侧孔之间的中点（B 组）。我们从这些入点斜切骨盆的平面在矢状面上重新切片到前下髂棘。我们在这个平面上双侧放置最短和最长的虚拟 S2AIS，使用 4mm 的边界。我们测量了螺钉长度、外侧成角、尾侧成角、角度范围、从入点到骶髂关节的距离、从 S2AIS 到髋臼顶的距离、从 S2AIS 到坐骨切迹的距离和插入难度。比较了 A 组和 B 组之间的这些测量值。
在 A 组中，矢状面角度明显较小，从入点到坐骨切迹的距离明显较长。B 组的螺钉长度、从入点到骶髂关节的距离和从入点到髋臼顶的距离均明显长于 A 组。A 组 S2AIS 插入困难的发生率明显较高。
与 S1 背侧孔外侧和背侧孔相比，S1 和 S2 背侧孔之间的中点插入 S2AIS 可插入更长的螺钉，且插入难度较低。
