Mendel T, Noser H, Kuervers J, Goehre F, Hofmann G O, Radetzki F
BG-Kliniken Bergmannstrost, Department of Trauma Surgery, Merseburger Strasse 165, 06112 Halle (Saale), Germany; Friedrich Schiller University Jena, Department of Trauma Surgery, Erlanger Allee 101, 07747 Jena, Germany.
Injury. 2013 Dec;44(12):1773-9. doi: 10.1016/j.injury.2013.08.006. Epub 2013 Aug 14.
Sacroiliac (SI) screw fixation for unstable pelvic fractures stands out as the only minimally invasive method among all other ORIF procedures. A strictly transverse screw trajectory is needed for central or bilateral fracture patterns up to a complete iliosacroiliac fixation. However, secure screw insertion is aggravated by a narrow sacroiliac bone stock. This study investigates the influence of a highly variable sacral morphology to the existence of S1 and S2 transverse corridors. The analysis contained in this study is based on 125 CT datasets of intact human pelvises. First, sacral dysplasia was identified using the "lateral sacral triangle" method in a lateral 3-D semi-transparent pelvic view. Second, 3-D corridors for a 7.3mm screw in the upper two sacral levels were visualised using a proprietary IT workflow of custom-made programme scripts based on the Amira(®)-software. Shape-describing measurement variables were calculated as output variables. The results show a significant linear correlation between ratioT and the screw-limiting S1 isthmus height (Pearson coefficient of 0.84). A boundary ratio of 1.5 represented a positive predictive value of 96% for the existence of a transverse S1-corridor for at least one 7.3mm screw. In 100 out of 125 pelvises (80%), a sufficient S1 corridor existed, whereas in 124 specimens (99%), an S2 corridor was found. Statistics revealed significantly larger S1 and S2 corridors in males compared to females (p<0.05). However, no gender-related differences were observed for clinically relevant numbers of up to 3 screws in S1 and 1 screw in S2. The expanse of the S1 corridor is highly influenced by the dimensions of the dysplastic elevated upper sacrum, whereas the S2 corridor is not affected. Hence, in dysplastic pelvises, sacroiliac screw insertion should be recommended into the 2nd sacral segment. Our IT workflow for the automatic computation of 3-D corridors may assist in surgical pre-operative planning. Furthermore, the workflow could be implemented in computer-assisted surgery applications involving pelvic trauma.
骶髂螺钉固定不稳定骨盆骨折是所有切开复位内固定手术中唯一的微创方法。对于中央或双侧骨折类型直至完全髂骶固定，需要严格的横向螺钉轨迹。然而，狭窄的骶髂骨量会加重螺钉安全置入的难度。本研究调查了高度可变的骶骨形态对S1和S2横向通道存在的影响。本研究中的分析基于125例完整人体骨盆的CT数据集。首先，在骨盆侧位三维半透明视图中使用“骶外侧三角”方法识别骶骨发育不良。其次，使用基于Amira（®）软件的定制程序脚本的专有IT工作流程，可视化上两个骶骨水平7.3mm螺钉的三维通道。计算形状描述测量变量作为输出变量。结果显示，ratioT与限制螺钉的S1峡部高度之间存在显著的线性相关性（Pearson系数为0.84）。1.5的边界比值对于至少一枚7.3mm螺钉的横向S1通道存在的阳性预测值为96%。在125例骨盆中的100例（80%）中，存在足够的S1通道，而在124个标本（99%）中，发现了S2通道。统计显示，男性的S1和S2通道明显大于女性（p<0.05）。然而，对于S1中多达3枚螺钉和S2中1枚螺钉的临床相关数量，未观察到性别相关差异。S1通道的范围受发育不良的高位骶骨尺寸的高度影响，而S2通道不受影响。因此，在发育不良的骨盆中，建议将骶髂螺钉置入第二骶骨节段。我们用于自动计算三维通道的IT工作流程可能有助于手术术前规划。此外，该工作流程可应用于涉及骨盆创伤的计算机辅助手术应用中。
