| Objective :In this study,we construct three-dimensional models of levator ani muscle before and after surgery in patients with pelvic organ prolapse(POP)by magnetic resonance imaging(MRI),and initially explore the changes of three-dimensional imaging characteristics of levator ani before and after surgery in patients with pop,so as to establish a theoretical basis for evaluating the efficacy of surgery for pop repair using three-dimensional models of levator ani magnetic resonance.Methods: Images of pelvic floor tissue before and after surgery in patients with pop were acquired with Ge 3.0 magnetic resonance(GE 3.0 750 W),3D T2 space axial sequence,and ultimately included 7 patients who showed clear pelvic floor tissue before and after surgery,The raw MR data were imported in DICOM(digital imaging and communications in medicine,digital imaging and communications standards in medicine)format into mimics21.0 3D reconstruction software to construct a 3D model of the levator ani muscle of the patient,to observe the shape of the levator ani hiatus and the shape of the iliocostalis muscle before surgery and the 3D model of the levator ani muscle of the patient,and to measure the width and angle of the bilateral levator ani muscle and the plate angle of the levator ani muscle using the constructed 3D model Nine morphological parameters,including bilateral pubic symphysis distance and transverse diameter of the levator ani cleft,were statistically analyzed to determine whether there were differences in the width and angle of the bilateral appendicular tail muscles,the angle of the levator ani plate,bilateral pubic symphysis distance and the long and transverse diameter of the levator ani cleft between preoperative and postoperative three-dimensional models.Results:(1)Successfully constructed three-dimensional models of levator ani muscle in 7 patients with POP before and after surgery.(2)There was no significant difference in the morphology of levator ani muscle hiatus and iliococcygeal muscle between the postoperative group and the preoperative group(P>0.05).(3)The paired sample t-test results of the distance between the pubic symphysis of the right levator ani muscle,the maximum transverse diameter of the levator ani muscle fissure,and the angle of the levator ani muscle plate were(t=2.737,P=0.034),(t=2.960,P=0.025),and(t=2.485,P=0.048),respectively,P<0.05,with a statistically significant difference.Conclusions:(1)Based on MRI images,a three-dimensional model of the levator ani muscle in patients with POP before and after surgery can be constructed through post-processing software,enabling a more intuitive observation of morphological changes in the levator ani muscle between the two groups from a morphological perspective.(2)By observing the changes in the three-dimensional model of the levator ani muscle reconstructed before and after surgery(the shape of the levator ani muscle hiatus and the shape of the iliococcygeal muscle),it was found that there was no significant difference between before and after surgery,indicating that the three-dimensional model of the levator ani muscle did not change significantly after surgical treatment in POP patients.(3)After surgical treatment,the right of the levator syrnphysis gap,the maximum levator hiatus width,and levator plate angle of the same patient decreased compared to the previous period(P<0.05).Comparing the trend of POP leading to the increase in the distance between the pubic symphysis of the levator ani muscle,the levator ani muscle hiatus,and the levator ani muscle plate,indirectly indicates that the change trend of the above parameters is reasonable.Therefore,the above data has the potential to be used as an indicator for evaluating surgical efficacy.Objective :Based on the constructed three-dimensional model of POP patients before and after surgery,this study simulates the displacement and stress distribution of levator ani muscle before and after surgery under three load modes with the help of finite element analysis method,and preliminarily discusses the changes of levator ani muscle before and after surgery in biomechanical aspects of POP patients,laying a theoretical foundation for evaluating the effect of POP repair surgery with the finite element model of levator ani muscle from the perspective of biomechanics..Methods: The three-dimensional models of levator ani muscle before and after surgery were built by the Mimics21.0 medical image three-dimensional reconstruction software and 3-Matic graphic optimization software.The finite element analysis method was used to generate the finite element models of levator ani muscle before and after surgery,and the average intra-abdominal pressure(0.5 kpa,4.5 kpa,5.0 kpa)was applied to simulate the changes of levator ani muscle under three conditions(rest,moderate,intense tension)The displacement of levator ani muscle,Von Mises stress distribution nephogram,and the displacement of levator ani muscle,Von Mises stress distribution characteristics and maximum displacement,Von Mises stress location before and after the operation were observed.Results:(1)Based on the pre and post operative three-dimensional models of the levator ani muscle,the pre and post operative finite element models of 7 patients were successfully constructed.(2)In 7 patients under different loads,the maximum displacement before surgery occurred at the same location as the maximum displacement and maximum stress after surgery,both located at the pubic attachment points of the bilateral levator ani muscle.(3)After surgical treatment in patients with POP,the maximum displacement of the levator ani muscle was significantly reduced when a load of 0.5,4.5,and 5.0 kpa was applied to the levator ani muscle after surgery(P<0.05);Similarly,when a load of 4.5 kpa was applied to the levator ani muscle after surgery,the maximum stress value of the levator ani muscle significantly decreased compared to before surgery(P<0.05).(4)When the loading load is 4.5 kpa,the maximum stress cutoff value of the levator ani muscle is 0.0085,the Yoden index is 0.571,the AUC is 0.816,the diagnostic sensitivity is 0.714,and the specificity is0.857.Conclusions:(1)Based on a preoperative and postoperative three-dimensional model of a POP patient and optimized processing,the finite element model of the levator ani muscle was successfully established for 7 patients through ANSYS software post-processing.(2)In patients with POP before and after surgery,the maximum stress of the levator ani muscle appears at the bilateral pubic bone attachment,which is different from the location of the maximum stress of the levator ani muscle(the caudal bone attachment of the levator ani muscle)reported in the above literature in healthy adult women,indicating that the maximum stress has changed,and the change is not significant in the early postoperative period compared to the preoperative period.(3)After surgical treatment for POP patients,the maximum displacement and stress location of the levator ani muscle did not significantly change compared to preoperative,but the measured parameters of the maximum displacement and maximum stress decreased compared to preoperative,indicating that the finite element method has the potential to evaluate the efficacy and prognosis of POP surgery for the biomechanical study of the levator ani muscle in POP patients.(4)When the maximum stress(kpa)of the levator ani muscle at 4.5 kpa(moderate tension)is 0.0085 as the optimal threshold value,the diagnostic efficacy of biomechanical changes in the pelvic floor levator ani muscle in patients with POP before and after surgery is the best. |
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