Fix Quantify Topographical Anatomy Research Of Acetabular Posterior Column Lag Screw Together With Plate Techniques And Ilium

Background:The treatment of pelvic trauma have made great progress in recent years, open reduction and internal fixation (ORIF) have become an important therapeutic tool of pelvic fractures and acetabular fractures, sometimes serious complication occurred during internal fixation of the fractured fragment, such as screw penetrating the joint surface, injurying important blood vessel and nerve. So it is basis and key of preventing blood vessel and nerve from accidental injury to comprehend the depth of all parts of pelvis, the distance of important blood vessel and nerve to bone wall, and their projection on pelvis surface.Some doctors overseas have reported the lag screw placement in the posterior column one after another, but the entry point, the angle of inclination and mean length of the lag screw is different, the technique is lack of unity, screw penetrationof the acetabulum, important blood vessel and nerve injury may take place. So the key of minimizing the complication above-mentioned is to choose the optimal entry point, angle of inclination and length of the lag screw through quantitative anatomic study. The quantitative anatomic documents about posterior column lag screw are few at present, and definition of entry point is too tedious and inconvenience.There is no report of the depth of the whole pelvis at present, so we establish a coordinate system on the outer and inner table of the pelvis respectively, measure the depth of all points of the coordinate system, draw contour lines, and fill in different color between different contour lines respectively, thus it form several regions of different depth. Apart from the projection of external iliac a. v., obturator a. v. n., sacroiliac joint, lateral sacral mass and S2 pedicle, there is no report of the projection of other important structures of pelvic on the outer table of the posterior ilium,Objectives:The aim of this project includes two aspects. 1. to study the entry point, the angle of inclination and the mean length of lag screw in acetabular anterior column lag screw technique and acetabular anterior column plate technique. 2. to draw the topographic map of the inner and outer table of pelvis.Methods:In the study of part 2, 10 cadaveric adult antiseptic specimens were prepared. Determine superior and inferior acetabular margin, and the serial cross-sections of the acetabular posterior column, Section posterior column with a fine-toothed hand saw, form cross-sections A, B, C, D, E ,F and G.. We draw the contour lines of the cross-sections above.Acetabular posterior column lag screw techniques: In single screw technique, we define the penetrating point of the Kire-wire on the surface of the iliac fossa as point O, draw vertical line from point O to the linea terminalis of pelvis at point P,the linea terminalis of pelvis intersect the auricular surface at point Q, then measure the length of OP and PQ, and measure the length from point O to cross-section G. In double screw technique, we define the penetrating point of the Kire-wire as point 01 and point 02 respectively, draw vertica line from point 01 and 02 to the linea terminalis of pelvis at point PI and P2, then measure the length of O1P1,O2P2 and P1Q,P2Q, and measure the length from point 01 and 02 to cross-section G respectively,Acetabular posterior column plate technique: Draw the contour line of B,C D cross-setions, then a distance measuring 0.5 cm from and parallel to the bony acetabular medial boundary was determined and also marked on each cross-section, positions were then marked at equidistances of each cross-section on posterior surface of the posterior column on each cross-section. These points represented proposed entry points for cortical screw placement. The line connecting each of entry points with the most medial projection tangent of the parallel lines relative to each entry point was established, The angulation created by this line with respect to the quadrilateral plate is the safe angle of screw entry, the distance of entry point and the penetrate point on quadrilateral plate is t...