目的:使用浅表标志准确识别和避免后颅窝内的关键解剖结构对于减少手术并发症至关重要。我们的研究集中在乳突缺口(TMN)的顶部作为颅骨的外部标志,旨在协助初始毛刺孔的战略放置。在这项研究中,我们提出了一种预测横窦(TS)路径的方法,并探讨了横乙状窦交界处与TMN之间的关系。
方法:在尸体标本中对大脑进行解剖解剖后,我们从颅骨内表面对10个成年头骨(20面)进行了颅内钻孔。在颅骨后外侧表面建立了坐标系以辅助分析。使用自流平激光水平仪,我们设置了一条水平的法兰克福线(X轴),并确定了一条穿过TMN的垂直垂直线作为Y轴。为了确定TS的过程,我们沿着法兰克福线将两个下刻点之间的线段分成六个等距点。
结果:在左右两侧的横向乙状窦交界处(TSSJ)的下中央点之间没有观察到显着差异。下位点位于6.6mm的中位数(Q1:3.7mm,Q3:9.4毫米)背侧,中位数为19.2毫米(Q1:16.1毫米,Q3:23.2毫米)从TMN开始。TS的上边缘位于6.4mm(5.7;12.7)的距离处,10.3毫米(8.8;12.3),及右侧13.8毫米(11.9;16.3),和4.9毫米(4.1;7.9),8.6mm(7.6;13.0),和12.8毫米(11.7;17.5)在1/4的法兰克福水平面的左侧,½,和¾线点,分别。底部边缘定位在0.6mm(-2.7;2.0)的距离处,2.1mm(-0.8;3.8),右侧为4.8毫米(2.4;6.7),和1.1毫米(-3.4;2.4),2.0mm(0.2;4.8),和3.9mm(3.7;5.3)在这些相应的点的左侧。与左侧相比,右侧TS的上边缘在1/4线点(p值=0.027)处与法兰克福水平面的距离在统计上更远。窦中心的汇合处被确定为与小齿轮的中值距离为7.8mm(4.5;8.3),下点为1.5mm(0.1;3.0)。在所有被检查的身体中(n=10),与小齿轮相关的汇合处始终位于右侧4.7毫米(3.3;5.6)。值得注意的是,发现右横窦直径的中位数(中位数=9.3mm)明显大于左横窦(中位数=7.0),具有统计学意义的p值为0.048。
结论:关于TSSJ的外部鉴定和TS过程的文献各不相同。在我们努力提供描述的过程中,我们利用TMN作为定位TSSJ的可靠地标。为了描绘TS从鼻窦汇合处退出后的轨迹,我们使用了法兰克福水平面。这些发现可以通过使用外部颅骨标志来识别后颅窝内的颅内结构来帮助外科医生。特别是当图像引导装置不可用或补充神经导航系统时。
OBJECTIVE: Accurately identifying and avoiding crucial anatomical structures within the posterior cranial fossa using superficial landmarks is essential for reducing surgical complications. Our study focuses on the top of the mastoid notch (TMN) as an external landmark of the cranium, aiming to assist in the strategic placement of the initial burr hole. In this study, we present a method for predicting the path of the transverse sinus (TS) and explore the relationship between the junction of the transverse-sigmoid sinus and the TMN.
METHODS: Following anatomical dissections of the brain in cadaveric specimens, we conducted intracranial drilling from the inside surface of the cranium on 10 adult skulls (20 sides). A coordinate system was established on the posterolateral surface of the skull to assist the analysis. Using a self-leveling laser level, we set up a horizontal Frankfurt line (X-axis) and identified a vertical perpendicular line passing through the TMN to serve as the Y-axis. To identify the course of the TS, we divided the segment between the two inferomedial points into six equidistant points along the Frankfurt line.
RESULTS: No significant difference was observed between the inferomedial points of the transverse-sigmoid sinus junction (TSSJ) on the left and right sides. The inferomedial point was positioned at a median of 6.6 mm (Q1: 3.7 mm, Q3: 9.4 mm) dorsally and at a median of 19.2 mm (Q1: 16.1 mm, Q3: 23.2 mm) cranially from the TMN. The upper edge of the TS was located at distances of 6.4 mm (5.7; 12.7), 10.3 mm (8.8; 12.3), and 13.8 mm (11.9; 16.3) on the right, and 4.9 mm (4.1; 7.9), 8.6 mm (7.6; 13.0), and 12.8 mm (11.7; 17.5) on the left side from the Frankfurt horizontal plane at the ¼, ½, and ¾ line points, respectively. The bottom edge was positioned at distances of 0.6 mm (-2.7; 2.0), 2.1 mm (-0.8; 3.8), and 4.8 mm (2.4; 6.7) on the right, and 1.1 mm (-3.4; 2.4), 2.0 mm (0.2; 4.8), and 3.9 mm (3.7; 5.3) on the left from these respective points. The upper edge of the right TS was found to be statistically more distant from the Frankfurt horizontal plane at the ¼ line point (p-value = 0.027) compared to that on the left side. The confluence of the sinus center was identified as having a median distance of 7.8 mm (4.5; 8.3) and an inferior point of 1.5 mm (0.1; 3.0) cranially to the inion. In all examined bodies (n = 10), the confluens sinuum was consistently 4.7 mm (3.3; 5.6) to the right in relation to the inion. Notably, the median of the right transverse sinus diameter (median = 9.3 mm) was found to be significantly larger than that of the left transverse sinus (median = 7.0), with a statistically significant p-value of 0.048.
CONCLUSIONS: The literature regarding the external identification of the TSSJ and the course of the TS varies. In our efforts to provide a description, we have utilized the TMN as a reliable landmark for locating the TSSJ. To delineate the trajectory of the TS after its exit from the confluence of sinuses, we employed a Frankfurt horizontal plane to the inion. These findings may assist surgeons by using external skull landmarks to identify intracranial structures within the posterior fossa, particularly when image guidance devices are not available or to complement a neuronavigational system.