烏口突起センタリングジグの改良

Abstract

We developed a drilling instrument (Type 1) for the coracoid process two years ago, and have been performing a modified Boytchev's procedure for patients with recurrent shoulder disloction using this instrument.When we inserted a screw into the coracoid process using the Type 1 instrument, the axis of the screw was directed caudally toward the coracoid process. We have now developed a new drilling instrument for the coracoid process (Type 2) that is able to insert the screw correctly into the center of the coracoid process. We performed a comparative study concerned with direction of the screw for three groups. Group 1: 13 cases had a screw inserted without intstrumentation. Group 2: 14 cases had their screw inserted using the Type 1 instrument. Grupe 3: Five cases had their screw inserted using the Type 2 instrument. Angles of inserted screw toward the coracoid process were compared in each group and were measured in antero-postero views, scapular outlet views and axial views by plain X-ray after the modified Boytchev procedure. The angles of Group 1 revealed a larger deviation than one of Group 1 and Group 2. The angles of Group 2 and Group 3 were less than the one of Group 1 in A-P views and Y-views. Using the improved drilling instrument for the coracoid process (Type 2), a hole can be easily made in the center of the coracoid process.The Type 2 instrument is available for various shoulder operations, for example, Bankart's procedure, capsular shift, Dewar's procedure, Bristow's procedure and total replacement of the shoulder joint.