Clinical Study And Finite Element Analysis Of Unlocking Reduction And Minimally Invasive Internal Fixation Technique In The Treatment Of Pelvic Fractures

Objective: The traditional open reduction and internal fixation technique has many drawbacks in the treatment of unstable pelvic fractures.Although the unlocking reduction and minimally invasive internal fixation technique can improve these drawbacks and obtain better clinical efficacy,most of the previous literatures on this technique are small sample cases,and lack multi-angle and comprehensive analysis of this technique.In this paper,through retrospective analysis of a large number of cases previously treated with these two techniques in our group and finite element analysis of the stability of internal fixation methods in the unlocking reduction and minimally invasive internal fixation technique,the clinical efficacy of this technique was evaluated from different perspectives.These results of the analysis provide a reference for clinicians applying this technique,thus they can further improve the clinical efficacy of unstable pelvic fractures.Methods: Retrospective study and finite element analysis were performed in this paper.Firstly,a large number of cases of unstable pelvic fractures(Department of Trauma Surgery,Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology)treated with the unlocking reduction and minimally invasive internal fixation technique and the traditional open reduction and internal fixation technique were reviewed.The characteristics of the two techniques were compared.The perspectives of preoperative,intraoperative,postoperative,and recovery were evaluated comprehensively.Then the advantages of the unlocking reduction and minimally invasive internal fixation technique were analyzed.Secondly,the application of the unlocking reduction and minimally invasive internal fixation technique in cases outside the indication range were reviewed,to explore whether this technique can still obtain satisfactory clinical efficacy in bilateral unstable AO/OTA type C2 and C3 pelvic fractures.Also,the experience and skills of this technique were elaborated.Thirdly,the case data of this technique in the treatment of unstable pelvic fractures were reviewed,and the related factors affecting closed reduction failure,reduction quality,and ineffective fixation were analyzed.Finally,according to the problem of ineffective internal fixation in this technique,the stability analysis of finite elements was performed on the common internal fixation methods.Results: Chapter 1,the interval from injury to surgery(P=0.046),operation time(P<0.01),intraoperative blood loss(P<0.01),the total length of the surgical incision(P<0.01),wound complications(P=0.03),and the application rate of this technique in sacral plexus injury cases requiring decompression(P=0.03)were significantly lower in the unlocking reduction and minimally internal fixation technique group than those in the traditional open reduction and internal fixation technique group.For the two groups,the application rate of the unlocking reduction and minimally invasive internal fixation technique in AO/OTA type C1 and C3 pelvic fractures is significantly higher and lower,respectively(P=0.03).Chapter 2,the unlocking reduction and minimally invasive internal fixation technique was used to treat AO/OTA type C2 and C3 pelvic fractures;19 of 25 patients(76%)completed the operation with this technique;the results of 19 patients showed that the operation time was 129.8±20.6 min,intraoperative blood loss was 53.7±52.4 m L,fluoroscopy times were 35.4±11.3 times,and the total length of surgical incision was 11.4±3.5 cm.According to Matta scoring criteria: excellent in 15 cases,good in 3 cases,and fair in 1 case;the excellent and good rate was 94.7%.One patient developed symptoms of lateral femoral cutaneous nerve injury after surgery.At the last follow-up,the efficacy was evaluated according to Majeed scoring criteria: excellent in 18 cases and good in 1 case,with an excellent and good rate of 100%.Chapter 3,AO/OTA type C3 pelvic fracture(P=0.04),osteoporosis(P=0.02),and L5/S1 facet joint interlocking(P=0.04)were risk factors leading to closed reduction failure;the interval from injury to surgery was <21 days as a protective factor for excellent reduction quality(P<0.01);lumbopelvic triangular osteosynthesis,two transiliac-transsacral screws fixation,or one transiliac-transsacral screw combined with two iliosacral screws were protective factors to avoid ineffective internal fixation in AO/OTA type C1 pelvic fractures(P=0.03).Chapter 4,the results of finite element analysis showed that the anterior pelvic ring was fixed with INFIX,the posterior ring was fixed with S1 and S2 two-level transiliactranssacral screws or S1 two-iliosacral screws combined with S2 transiliac-transsacral screw in reducing the relative displacement of the fracture line and enhancing the vertical stiffness of the pelvis were superior to other internal fixation methods in different AO/OTA type C1.3 pelvic fracture internal fixation models.Conclusion: The unlocking reduction and minimally internal fixation technique and the traditional open reduction and internal fixation technique in the treatment of unstable pelvic fractures both can obtain satisfactory clinical results.However,the unlocking reduction and minimally internal fixation technique has less trauma and fewer wound complications,without worrying about the second hit of trauma caused by open reduction and internal fixation,and it advances the time window for definitive treatment of pelvic fractures.The unlocking reduction and minimally internal fixation technique can also treat most AO/OTA type C2 and C3 pelvic fractures and achieve satisfactory clinical efficacy,but for some AO/OTA type C3 pelvic fractures that require simultaneous nerve decompression or closed reduction difficulties,the traditional open reduction and internal fixation technique is still required.In the application of the unlocking reduction and minimally internal fixation technique,surgery should be performed within 3 weeks as far as possible to obtain a satisfactory quality of reduction.When combined with factors of L5/S1 facet joint locking,osteoporosis,and AO/OTA type C3 pelvic fractures,preparation for conversion to open surgery is required.During the operation,AO/OTA type C1 pelvic fracture can be fixed by S1 and S2 two-level sacral transiliac-transsacral screws or S1 two-iliosacral screws combined with S2 transiliac-transsacral screw,which can obtain stronger pelvic stability.