A Surgical Technique Of Plate And Screw Insertion At Pelvic Brim In The Modified Stoppa Approach

Backgroud: It was difficult to treat the pelvic and acetabular fractures due to the complicated anatomical structures of pelvis and acetabulum and various patterns of fracture.The emergence of modified stoppa approach that could adequately expose quadrilateral surface and pelvic brim,made the surgical approach of pelvic and acetabular simple.It has been widely used clinically for relatively less invasion.However,the acetabular surface could not be exposed in the modified stoppa approach,causing a blind screws insertion introoperatively.The intra-articular screw placement in modified stoppa approach may result in serious consequence.Objective: The objective of this study was to introduce a surgical technique of plate and screw insertion at pelvic brim in the modified stoppa approach by measuring the danger zone for treating pelvic and acetabular fractures with plate and screws along pelvic brim in the modified stoppa approach and by determining the pitch-row of the straight pelvic reconstruction plate in a clinical practice.Methods: The different producers' straight pelvic reconstruction plates were acquired to measure the pitch-row of the plates and the safe length of the plates after screw insertion.50 cases of normal adults anteroposterior radiographs of the pelvis were analyzed,the hips were divided into two groups of the left and right side.With pubic tubercle to point A,a vertical line through the inferior acetabulum crossing to pelvic brim was marked with point B,a horizontal line through the superior of acetabulum crossing to pelvic brim was marked with point C,sacroiliac joint peak around the pelvis to point D,and the distances of AB,BC and CD were measured by computer.Combined with the clinical operation feasibility and preventing the intra-articular screw placement,the direction for nailing was as follows the proximal of acetabulum is extending to long body axis vertically or away from the direction of the acetabulum,and the distal of acetabulum is extending to bone surface or away from the direction of the acetabulum vertically.Results: The pitch-row of the commonly used straight pelvic reconstruction plates(Smithnephew,Trauson,Wego,Irene)were 12 mm,and that of Synthes was 13 mm.The safe length of the plates(Smithnephew,Trauson,Wego,Irene)after emptying three holes screw insertion was 43 mm,and that of Synthes' was 47 mm.The pubic ramus district(right side:49.32±1.24mm;left side: 49.07±0.95mm)and the near sacroiliac joint zone right side :49.32±1.24mm;left side: 49.07±0.95mm)were safe zone for screw insertion,the danger zone for screw placement along pelvic brim in right side was(40.30±0.90)mm,and that in left side was(40.40±0.78)mm.There was no statistical significance between two sides.Comparing the pelvis with the pitch-row of the plates and the safe length of the plates after screw insertion,it was safe to empty three holes to insert screws in the danger zone and that was safer for Synthes' plate.The pubic ramus district was safe for screw insertion of a 4 holes plate,that was suggested 3 holes for Synthes' plate,and the near sacroiliac joint region was safe for screw insertion of a 3-4 holes plate..Conclusion: In conclusion,it should according to different fracture lines to insert plates,and it is safe to empty three holes to insert screws in the danger zone when inserting screws around acetabulum in modified stoppa approach,This technique has an important clinical significance in guidance for inserting screws and plates during operation.