SharedClarity, LLC, Phoenix, AZ, USA.
HealthPartners, Minneapolis, MN, USA.
Eur J Orthop Surg Traumatol. 2021 Oct;31(7):1485-1492. doi: 10.1007/s00590-021-02913-5. Epub 2021 Mar 1.
The purpose of this study was to determine the angular tolerance of the S1 and S2 segments to accommodate a transiliosacral screw across both sacroiliac joints.
We hypothesized that the angular tolerance for transiliosacral screw placement would be more constrained than the angular tolerance for iliosacral fixation in pelves where a safe osseous corridor was measured.
The cortical boundaries of the S1 and S2 sacral segments in 433 pelvic CTs were digitally mapped. A straight-line path was placed within each osseous corridor and extended across both SI joints past the outer iliac cortices. The diameter of the path was increased until it breached the cortex, geometrically determining maximum diameter (Dmax). Angular tolerance for screw placement was calculated with trigonometric analysis of the Dmax value of the corridor, and the average distance from the termination of the osseous corridor to the site of percutaneous insertion. Gender, age, and BMI were evaluated as independent predictors using binomial logistic regression.
The transiliosacral angular tolerance for the S1 and S2 osseous corridors was 1.53 ± 0.57 degrees and 1.02 ± 0.33 degrees, respectively. 68.9% of S1 corridors and 81.1% of S2 corridors had a safe zone (corridor diameter ≥ 10 mm) for transiliosacral placement, 48.3% of the pelves had a safe zone for both corridors, while 5.1% had no safe zones. Females had a less frequent Dmax ≥ 10 mm at S1, 52% vs 67% (p = 0.001), and at S2, 64% vs 86% (p < 0.001).
In conclusion, the angular tolerance of 1.53 and 1.03 degrees for the S1 and S2 segments, respectively, creating a narrow interval for safe passage of the trans-iliac and trans-sacral, with approximately 31.1% of patients not having a viable corridor for screw passage. A correlation exist between S1 and S2 corridors with Dmax ≥ 10 mm and the resulting increase in angular tolerance for safe passage of a transilioscral screw.
Level Retrospective Cohort.
本研究旨在确定 S1 和 S2 节段的角度容差，以容纳穿过双侧骶髂关节的经骶髂螺钉。
我们假设，在测量到安全的骨道的骨盆中，经骶髂螺钉放置的角度容差将比经骶髂固定的角度容差更受限制。
对 433 例骨盆 CT 的 S1 和 S2 骶骨段的皮质边界进行了数字映射。在每个骨道内放置一条直线，并穿过两个 SI 关节延伸到髂骨外皮质之外。路径的直径增加，直到它突破皮质，从几何上确定最大直径（Dmax）。通过对骨道 Dmax 值的三角分析和从骨道末端到经皮插入点的平均距离，计算螺钉放置的角度容差。使用二项逻辑回归评估性别、年龄和 BMI 作为独立预测因素。
S1 和 S2 骨道的经骶髂角度容差分别为 1.53±0.57 度和 1.02±0.33 度。68.9%的 S1 骨道和 81.1%的 S2 骨道有安全区（骨道直径≥10mm）用于经骶髂放置，48.3%的骨盆有两个骨道的安全区，而 5.1%的骨盆没有安全区。女性 S1 处的 Dmax≥10mm 的频率较低，为 52%对 67%（p=0.001），S2 处为 64%对 86%（p<0.001）。
总之，S1 和 S2 节段的角度容差分别为 1.53 和 1.03 度，为经髂骨和经骶骨的安全通过创造了一个狭窄的间隔，大约 31.1%的患者没有可行的螺钉通道。S1 和 S2 骨道之间存在 Dmax≥10mm 的相关性，以及由此产生的经骶髂螺钉安全通过的角度容差增加。
证据等级 IV：回顾性队列研究。
