Department of Orthopaedic Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA; and.
Department of Orthopaedic Surgery and Rehabilitation, Queen's Medical Center, Honolulu, HI.
J Orthop Trauma. 2024 Jun 1;38(6):299-305. doi: 10.1097/BOT.0000000000002795.
To estimate the prevalence of suboptimal fluoroscopy of sacral outlet images due to anatomic and equipment dimensions. Pelvic retroversion is hypothesized to mitigate this issue.
In silico simulations using retrospectively collected computed tomography (CT) data from human patients.
Level I trauma center.
Adults with OTA/AO 61 pelvic ring disruptions treated with posterior pelvic fixation between July and December 2021.
C-arm tilt angles required to obtain 3 optimal fluoroscopic sacral outlet images, defined as vectors from pubic symphysis to S2 and parallel to the first and second sacral neural foramina, were calculated from sagittal CT images. A suboptimal view was defined as collision of the C-arm radiation source or image intensifier with the patient/operating table at the required tilt angle simulated using the dimensions of 5 commercial C-arm models and trigonometric calculations. Incidence of suboptimal outlet views and pelvic retroversion necessary to obtain optimal views without collision, which may be obtained by placement of a sacral bump, was determined for each view for all patients and C-arm models.
CT data from 72 adults were used. Collision between patient and C-arm would occur at the optimal tilt angle for 17% of simulations and at least 1 view in 68% of patients. Greater body mass index was associated with greater odds of suboptimal imaging (standard outlet: odds ratio [OR] 0.84, confidence interval [CI] 0.79-0.89, P < 0.001; S1: OR 0.91, CI 0.87-0.97, P = 0.002; S2: OR 0.85, CI 0.80-0.91, P < 0.001). S1 anterior sacral slope was associated with suboptimal S1 outlet views (OR 1.12, Cl 1.07-1.17, P < 0.001). S2 anterior sacral slope was associated with suboptimal standard outlet (OR 1.07, Cl 1.02-1.13, P = 0.004) and S2 outlet (OR 1.16, Cl 1.09-1.23, P < 0.001) views. Retroversion of the pelvis 15-20 degrees made optimal outlet views possible without collision in 95%-99% of all simulations, respectively.
Suboptimal outlet imaging of the sacrum is associated with greater body mass index and sacral slope at S1 and S2. Retroversion of the pelvis by 15-20 degrees with a bump under the distal sacrum may offer a low-tech solution to ensure optimal fluoroscopic imaging for percutaneous fixation of the posterior pelvic ring.
Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.
评估由于解剖和设备尺寸导致骶骨出口图像透视效果不佳的发生率。假设骨盆后倾可以减轻这个问题。
使用回顾性收集的人类患者 CT 数据进行计算机模拟。
一级创伤中心。
2021 年 7 月至 12 月接受后路骨盆固定治疗 OTA/AO 61 型骨盆环破裂的成年人。
从矢状 CT 图像计算获得 3 个最佳透视骶骨出口图像所需的 C 臂倾斜角度，定义为从耻骨联合到 S2 的向量，与第一和第二骶神经孔平行。将在所需倾斜角度下发生 C 臂射线源或影像增强器与患者/手术台碰撞的视图定义为次优视图，使用 5 种商业 C 臂模型和三角计算模拟。对于所有患者和 C 臂模型，确定了每个视图的次优出口视图的发生率和获得无碰撞的最佳视图所需的骨盆后倾角度，这可以通过在骶骨下放置骶骨垫块来实现。
共使用了 72 名成年人的 CT 数据。在 17%的模拟中，在最佳倾斜角度下会发生患者与 C 臂之间的碰撞，而在 68%的患者中至少有一个视图会发生碰撞。更大的体重指数与成像效果不佳的可能性更大相关（标准出口：优势比[OR]0.84，置信区间[CI]0.79-0.89，P < 0.001；S1：OR 0.91，CI 0.87-0.97，P = 0.002；S2：OR 0.85，CI 0.80-0.91，P < 0.001）。S1 前骶骨斜率与 S1 出口视图的次优结果相关（OR 1.12，Cl 1.07-1.17，P < 0.001）。S2 前骶骨斜率与标准出口（OR 1.07，Cl 1.02-1.13，P = 0.004）和 S2 出口（OR 1.16，Cl 1.09-1.23，P < 0.001）视图的次优结果相关。骨盆后倾 15-20 度可使 95%-99%的所有模拟中无碰撞获得最佳出口视图。
骶骨出口成像不佳与更大的体重指数和 S1 和 S2 的骶骨斜率有关。在骶骨远端下放置骶骨垫块，使骨盆后倾 15-20 度，可能是一种确保经皮固定后骨盆环后路透视成像最佳的低技术解决方案。
预后 III 级。有关证据水平的完整描述，请参见作者说明。
