Anatomical Research Of CMOR Vessels And The Anatomical Measure Of The Screw Safety Zone Around The Acetabulum In The Modified Stoppa Approach

Objective:⑴In order to evaluate the safety of Modified Stoppa Approach for thesurgical treatment of the pelvic ang acetabular fracture, an anatomical study ofCMOR vessels was carried out. CMOR vessels, the anastomotic vessels between theobturator vessels and the external iliac vessels or inferior epigastric vessels located atthe region of the superior ramus of pubis, are probably met in the modified Stoppaapproach.⑵The screw penetrating into the hip joint is a serious complication in theacetabular fracture operation. In order to upgrade the safety of the screw penetratingwhen applying the modified stoppa approach to fix the pelvic acetabular fracture byusing the plate screw along the true pelvic rim, this research incises the transection ofthe parallel pecten pubis, and measures the screw safety zone around the acetabulum.Methods:⑴Twelve human adult cadavers (7males,5females, total24lateralhemipelvises) were dissected in the Anatomy Department of Xiangnan University.The modified Stoppa approach were simulatively applied to observe the presence ofthe CMOR vessels, the anastomotic vessels between the obturator vessels and theexternal iliac vessels or inferior epigastric vessels located at the region of the superiorramus of pubis. Distinguish the anastomotic vessels is the artery or vein. The length,the vessels diameter, and the distance between the symphysis pubis and theilio-pectineal elevation were measured.⑵24dry human adult hip bones were dissected in Anatomy Department ofXiangnan University. After measuring the width of the titanium reconstruction platefrom the Synthes Company, this research used the true pelvic rim(pecten pubis) asthe superior border, and moved the half plate width down by paralleling the superiorborder as the traverse soteotomy line. Then, finished the osteotomy by following the soteotomy line into the internal surface of the true pelvic vertically. When cutting theacetabulum open, the research attached it tightly into the white paper and copied thetransection of the acetabulum in order to measure the screw safety area,relative safetyarea and the danger area around the acetabulum and analyze it by drawing a picture.Results:⑴:Among the24lateral hemipelvises there are21lateral hemipelvises withthe CMOR vessels (14.3%arterial;62.5%venous;28.6%combined), the rate ofoccurance is87.5%. The diameter of the CMOR vessels ranges from1.4mm to3.7mm, and the average is1.9mm. The length of CMOR vessels ranges from24.1mmto40.6mm, and the average is32.1mm. The CMOR vessels are located at54.9mm(ranged from47.8mm to63.8mm) away from the symphysis pubis and20.3mm(ranged from6.2mm to35.0mm) away from the ilio-pectineal elevation.⑵:1. the dangerous zone of the screw around the acetabulum parameter: L5,L9andBD surround area is the dangerous screw penetrating area.The distance from point A(the point of ilio-pectineal elevation) to the point D is the AD, which has the12.58mm±7.94mm.The distance from point A to the point B is the AB, which hasthe9.66mm±8.28mm.The left side AD is the13.34mm±7.62mm, and the right sideAD is the11.82mm±8.50mm. The left side AB is the9.35mm±9.85mm, and the rightside AB is the9.98mm±6.77mm. There is no statistical meaning (P>0.05) of thedifference of each data between the left and right group.2. the relative safe zone ofthe screw around the acetabulum parameter: L7,L5and ED on the outside, L11andBC on the inner side surround triangle area is the relative safe screw penetrating area(each of the outside and inner side has one). The distance from point A to the point Eis the AE, which has the21.10mm±6.09mm.The distance from point A to the point Cis the AC, which has the16.53mm±6.57mm. The left side AE is the20.49mm±6.31mm, and the right side AE is the21.7mm±6.08mm. The left side AC isthe17.16mm±6.90mm, and the right side AC is the15.91mm±6.47mm. There is nostatistical meaning (P>0.05) of the difference of each data between the left and rightgroup.3. The longest length of the safe screw penetrating around acetabulumparameter: the line DG is the longest screw length of the outside safe screwpenetrating around acetabulum, and the line CI is the longest screw length of the inner side safe screw penetrating around acetabulum. The length of DG is38.35mm±6.09mm, and the length of CI is25.28mm±3.60mm. The left side of DG is38.20mm±7.17mm, and the right side of DG is38.70mm±5.10mm.The left side of CIis26.28mm±3.04mm, and the right side of CI is24.27mm±3.95mm.There is nostatistical meaning (P>0.05) of the difference of each data between the left and rightgroup.Conclusion:⑴:The CMOR vessels, with the existence rate of87.5%, consist of theanastomotic branch between the obturator vessels and the external iliac vessels orinferior epigastric vessels, which is found between the ilio-pectineal elevation thatlocated on the surface of the superior ramus of pubis and the symphysis pubis, andwith more variability, the main type is venous branch. The attention should be paid tothe existence of the CMOR vessels when the modified Stoppa approach is used.Stripping under the periosteum is recommended.⑵This research data as the guidance for the safe screw penetrating around theacetabulum, when applying the modified stoppa approach to fix the pelvic acetabularfracture by using the plate screw along the true pelvic rim, and can reduce using X-ray.The screw points around the acetabulum that should be selected in the safe andrelative safe zone, avoid in the dangerous zone.We recommend firstly in safe zone.