The Application And Analysis Of Subcoracoid Impingement Syndrome By MRI

Background The concept of shoulder impingement syndrome was first proposed by Neer,which can occur at any age[4].Then,the Neer divided the impingement syndrome into "export impingement syndrome" and "non export impingement syndrome”.The acromion impingement syndrome causes exit in front of osteophyte formation,excessive tilt,acromion of acromioclavicular joint degeneration,which can cause supraspinatus tendon degeneration and rupture.The normal acromion is flat,slightly curved downward,with the increase of age,the attachment of the coracoacromial ligament calcification.The domestic and foreign scholars believe that hook acromion caused by degeneration,and shoulder impingement syndrome and rotator cuff injury[6].At present,shoulder impingement syndrome were divided into three types: the subacromial impingement,subcoracoid impingement and internal impingement[1].According to the different pathogenesis,it can be divided into primary and secondary impingement[32].The bone structure or related soft tissue degeneration caused subacromial space or coracohumeral distance decreasing.As a result,the rotator cuff exist mechanical extrusion between acromion and coracoacromial arch.The impingement called the primary impingement.In the long term engaged in the throwing sports crowd,such as water polo,shot and swimming athletes.In the long term,the joint is in the extreme external abduction and rotation position,that lead to the joint capsule and the support ligament relaxation,as a result,causes the joint instability.Instability in different directions can lead to different types of impingement modes.For example,in an anterior instability mode,anterior humeral head in the course of displacement increase can cause subcoracoid impingement syndrome[39].The impingement syndrome secondary to joint instability is called secondary impingement syndrome.Goldthwait first described coracoid impingement in the anterior aspect of the shoulder which lead to shoulder pain in 1909.it is important for clinicians to be familiar with the diagnostic process involving a detailed medical history of the patient,a thorough clinical examination and appropriate imaging.MRI is the most effective imaging method for the diagnosis of shoulder impingement syndrome.With the deepening understanding of this disease,the diagnosis and treatment have been the topic of debate.A large number of foreign research[16,27,29]using specific indicators such as CH or CI to to provide more imaging evidence for this disease.The purpose of this study is to use MRI,review the validation and analysis relationship between the CH,CI index and coracoid impigement syndrome.The purpose is to comprehend that the changes of CH and CI is an important cause of subcoracoid impingement,then caused the rotator cuff and long head of biceps tendon and soft tissue structure damage,and in order to provide better service for surgeon.Objective Application by MRI to measure coracoidhumeral distance(CH)and coracoid index(CI)of subcoracoid impingement syndrome patients,Retrospective analysis CH and CI have significant difference or not when compared with normal shoulder joints.Methods choose 30 cases diagnosed with subcoracoid impingement syndrome before operation and final clarify by arthroscopic surgery patients ' MRI as case group,28 cases of normal shoulder MRI as the control group.Measuring the minimum distance between the lesser tuberosity of humerus and coracoid process (relerred to as CH)and coracoid process over a plane of the glenoid(CI)distance.Results The average CH value and the standard deviation of case group are(6.81±1.42)mm.In normal group,the CH value is(10.17±1.19)mm.The average CI value and the standard deviation of case group are(14.77±4.88)mm.In normal group,the CI value is(9.92±2.27)mm.The CH and CI values of the case group and the normal group are significantly different(P<0.001).Conclusion Coracoid impingement in patients with CH compared to the normal distance is narrow,and the coracoid index increased significantly.MRI is one of the important methods for the diagnosis of subcoracoid impingement,and the use of MRI CH and CI distance measurement can provide important clues for the diagnosis and treatment of disease.