The Study Of Minimal Invasive Bone Tunnel In Pelvic Fracture And Biomechanics Analysis Of Internal Fixation And Relative Clinical Application

Background:The treatment of pelvic fracture has been gradually from open reduction internal fixation to close reduction minimal invasive fixation. The minimal invasive technique has become more and more popular because of smaller incision, fewer soft tissue damage, less blood loss, and quickly rehabilitation. However, satisfied reduction is the base of minimal invasive surgery. It is still a challenge to make a satisfied closed reduction. For the injury of the pelvic ring, anterior ring fixation is also difficulty that surgeon need make screw accurately without damage vessel, nerve, and into the cavity. The surgeon can finished minimal invasive surgery who have more than 5 years experiences in pelvic fracture because of narrow bone tunnel, undeterminable enter point and angle. At the same time, the treatment of posterior ring of pelvic still lack of conclusion because of the biomechanics analysis study of internal fixation in pelvic fracture is still incomplete. The number and biomechanical characteristic of screw has been controversies. This study aim to focus on design and modified the minimal invasive reduction frame and clinical application. Additionally, we study on bone tunnel and the way of fluoroscopy to simplify the procedure of surgery and help surgeon finish the surgery safer, faster and better. Lastly, this study will analysis the treatment and biomechanical fixation in posterior pelvic ring. Make sure the surgeon use the best choice of internal fixation.Object(1) Discuss the design and modified the closed reduction frame for pelvic fractures and clinical results for closed reduction.(2) Discuss the enter point of percutaneous internal fixation techniques in anterior ring of pelvic fracture and the new axial pedicle view of the anterior column for percutaneous fixation.(3) Discuss the treatment and biomechanical of four kinds of percutaneous screw fixation in posterior pelvic ring.Methods(1) We designed and modified closed reduction frame for pelvic fracture and applied it in clinical.(2) We made 3D reconstruction with Mimics software and analysis the enter point of anterior column screw and compare the retrograde way and anterograde way and position and angle of limited screws. After that, we analysis the best intra-operative fluoroscopy and enter point in 3D reconstruction, we simulate the intra-operative fluoroscopy and virtual implantation with cadaver bone. We simplify the procedure of pelvic surgery and standardize the operation.(3) We discuss the treatment of posterior ring fixation and analysis the biomechanical difference from two models in four kinds of fixation.Results(1) By designed and modified the minimal invasive reduction frame. We can nearly closed reduction more complex cases with satisfactory effects. Less open surgery, less blood loss and wider indications for minimal invasive surgery.(2) This study found out that there is a region for anterior column screw enter. The anterograde region is bigger than the retrograde region. The anterograde way is recommended because it is safer to avoid the vessel and reproductive organs. We can use the axial pedicle fluoroscopy view which can easily determine the enter point and angle. The cadaver study testified the feasibility of this method. At clinical, we practiced this method and had a better effect which make the procedure faster, safer and easier.(3) For the posterior ring injury, the SI screw can be the best choice for a better biomechanical stability. For bilateral injury, the long SI screw can have satisfied results too. Through biomechanical study, we found out that single screw fixation can be used in Tile B injury and double screw fixation was recommended in Tile C injury.ConclusionThis study can improve the understanding of close reduction and minimal invasive surgery in pelvic fracture. It supply the best way of implant the anterior column screw and the better fluoroscopy application. The biomechanical screw fixation analysis fulfilling the blank of this field. At last, all of this study will improve the close reduction minimal invasive surgery and technology promotion because it is faster, safer, easier and better outcome.