| Objective:The MIMICS software was used to reconstruct the 3D model of the pelvis and blood vessels,simulate the retrograde placement of 6.5mm diameter and 85 mm length posterior acetabular column screws,and measure the safe distance,angle and area between the retrograde tension screws of the posterior acetabular column and its surrounding related blood vessels and articular surfaces to provide a theoretical basis for the safe clinical placement of retrograde screws of the posterior acetabular column.Methods:Complete pelvic image data were randomly collected from February 2020 to December 2022 from 68 healthy adults with 136 hemipelvises in our CT room,34 cases of each sex,all aged 18-65 years,mean(38.96±8.48)years,excluding fractures,lesions,anatomical abnormalities,deformities and poorly visualized cases,and the collected CTA data were imported in DICOM format into The collected CTA data were imported into Mimicsl9.0(Materialise`s interactive medical image control system)software for digital processing and reconstruction of 3D models of the pelvis and peripheral vessels.A line is made from the most prominent points of the bony landmarks of the anterior superior iliac spine and the posterior superior iliac spine,and a plumb line is made along the midpoint of this line.The line through this midpoint towards the centre of the sciatic tuberosity is the screw channel,and the point where the bone has just been breached is the point of entry.A virtual screw is placed in a virtual space on the computer to measure the shortest distance between the entry point and the peripheral artery,the shortest distance betweenthe screw body and the peripheral artery,the shortest distance between the exit point and the peripheral artery,the shortest distance between the screw and the articular surface and the maximum safe offset angle of the screw.Statistical software was applied to analyse the measurement data,compare the differences in each measurement across gender and left and right sides,and explore their clinical significance.Results:When the posterior acetabular column was located in the nail placement position in this article,the shortest distances from the point of entry of the screws in the posterior column to the superior gluteal,external iliac and obturator arteries were(22.72±7.36)mm,(46.86±5.12)mm and(37.60±8.03)mm for males and(21.17±7.98)mm,(33.31±4.35)mm and(29.09±5.41)mm for females,respectively.The shortest distance between the body of the screw and the closed artery was(16.19±3.48)mm and(10.81±1.82)mm for both men and women with paralleling nail placement.In males,the shortest distances from the point of proximal screw emergence to the inferior gluteal and internal pubic arteries were(19.58±3.48)mm and(23.51±5.40)mm,respectively;in females,the shortest distances from the point of proximal screw emergence to the inferior gluteal and internal pubic arteries were(16.53±3.20)mm and(17.06±5.91)mm,respectively.The minimum distance of the screw from the articular surface for paralleling the nail was(7.44±1.63)mm and(5.72±1.46)mm for both men and women.The maximum permissible excursion angles for screw injury to the inferior gluteal artery,internal pubic artery,and articular surface were(21.99±5.55)?,(21.94±4.33)?,(12.62±2.43)?in men and(15.60±3.49)?,(19.72±4.57)?,(13.48±2.98)?in women.There was no statistically significant difference in the angle of the superior gluteal artery and articular surface between the male and female sexes,and the rest of the data were statistically significant;all data were statistically insignificantly different between left and right.Conclusion:1.Pre-operative reconstruction of the pelvis and surrounding vasculature using Mimics and simulated nail placement provided a rigorous anatomical basis and safety assurance for the minimally invasive and precise placement of nails in the posterior acetabular column.2.For paralleling the posterior acetabular column,for men: the screw should be ≥0.58 cm from the articular surface and the screw should be ≤10.19?offset from the intended position;for women: the screw should be ≥0.42 cm from the articular surface and the screw should be ≤10.50?from the intended position. |
PDF Full Text Request