Study On The Optimal Design And Clinical Application Of The Individualized Retrograde Anterior Column Screw Of Acetabulum With The Aid Of Computer

Objective:1 ? To design a set of percutaneous screw placement scheme for patients with acetabular fracture without displacement or slight displacement by using Mimics software.2?To investigate the clinical effect of individualized anterior column design with computer-aided in the treatment of acetabular anterior column fracture without displacement or slight displacement.Methods:1?We used the software of mimics to build a three-dimensional model of patients before operation,to simulate the operation of screw placement,to measure the curvature of the acetabulum anterior column,and to measure the length of the angle of screw placement to guide the clinical operation.Before the operation,the pelvis of patients was scanned with CT to obtain the target data.The data was imported into Mimics software in DICOM format,and the three-dimensional simulation model was established after bilateral femur and five lumbar vertebrae were removed by erasing tools.Take the intersection point M of the body sagittal plane and the inner edge of the superior pubic branch,take the intersection point W of the anterior inferior iliac spine and the upper edge of the acetabulum,make the intersection point N of the sagittal plane and the inner upper edge of the true pelvis through the point W,take the midpoint H of the pubic M,N,draw a circle with the points M,N and H,and calculate the radian.The best insertion point was selected at the mid point of the lateral pubic branch about 3cm away from the talus fold line.A virtual cylinder with a diameter of 6.5mm was created by using the MedCAD module instead of the intraoperative tension screw.In the three-dimensional space,the virtual screw position and direction should be adjusted continuously to ensure that it does not enter the hip joint,does not break through the bone cortex,puts the screw into the acetabulum anterior column,and adjusts the screw to the appropriate fixed length.The diameter of the cylinder was reduced to 0.1mm to obtain the insertion point.The vertical distance from the insertion point to the superior pubic ramus and pubic symphysis was measured.The angle between the screw and the coronal plane,sagittal plane and cross section wascalculated according to the three-dimensional coordinate of the screw.The anterior column of acetabulum was resected by using the resection function of Mimics software,and the shortest distance from screw to bone cortex was measured in each section,among which the shortest distance in all sections was the largest diameter of screw channel.Record the curvature of the acetabulum anterior column,the length of the screw,the insertion point,the direction of the screw,and the data of the maximum diameter.2?The data of individual preoperative measurement were used to guide the operation and analyze the clinical effect.From December 2018 to December 2019,we analyzed the clinical data of 19 cases(4bilateral and 11 unilateral)of acetabulum anterior column fracture without displacement or slight displacement treated by computer-aided individualized anterior column optimal design scheme.Among them,12 cases were male(3 bilateral and 9 unilateral),3 cases were female(1 bilateral and 2 unilateral),aged 25-60 years,average 44.2 years Causes: 6cases of falling from height,9 cases of traffic accident.There were 7 cases with limb fracture,3 cases with spine injury and 2 cases with urethra injury.The time of inserting each acetabulum anterior column screw,times of intraoperative fluoroscopy,time of fracture healing,short-term and long-term complications and Majeed score at the last follow-up were evaluated.Result:1?The three-dimensional reconstruction of Mimics software can restore the anatomy and local details.We can observe the anatomical structure of patients through different angles and sections,and accurately measure the data of acetabulum anterior column radian,anterior column screw insertion point,angle,length,maximum diameter,etc.2?All the patients had a short-term follow-up of more than 5 months.A total of 18 sides of 15 patients were successfully implanted with minimally invasive technique.One patient could not be fixed with bridging plate and screw after multiple attempts to insert the right channel due to the deviation of the osseous channel.The average operative time of each acetabulum anterior column screw was(30.8 ± 4.8)min,the average intraoperative hemorrhage was(6.8 ± 1.8)ml,the average intraoperative fluoroscopy times was(30.8 ± 5.7),and the average fracture healing time was(3.0 ± 0.34)months.Conclusion:1?Mimics software can be used to screen whether patients with acetabular anterior column fracture are suitable for acetabular anterior column screw placement before operation,and calculate the optimal insertion point,angle,length and maximum diameterby simulation.2?The application of Mimics software in the design of the optimal screw path of the anterior column of acetabulum for the patients with acetabulum fracture without displacement or slight displacement has certain guiding significance.