Intra-articular echo-endoscopy during shoulder arthroscopy: an anatomical feasibility study

BACKGROUND: The development of an ultrasound probe that can be used through an arthroscopic portal would provide direct access to the deep tissues of the shoulder. These structures are sometimes barely seen with an external ultrasound system and are also difficult to analyze under arthroscopy. Therefore, this intraoperative imaging technique could refine the diagnosis and surgical procedure and as a result provide more adequate therapy. The main objective of the study was to evaluate the feasibility of using an echo-endoscope to produce images during shoulder arthroscopy without causing secondary lesions. The secondary objective was to detect rotator cuff tears, calcific tendonitis, chondropathies, acromioclavicular arthropathy and labral tears. METHODS: We used 6 shoulders of 3 anatomic subjects. The endo-ultrasound system used was the M15 probe developed by the society Cartimage Medical SAS® . The eleven structure of interest included in the principal objective of the study were: the tendon of the long head of the biceps, the glenoid and humeral cartilage surface, the gleno humeral ligament, the labrum, the rotator cuff tendon on their acromial and articular surfaces and the acromioclavicular joint. We noticed all lesions induced by the probe and we measured the acquisition time for the ultrasound images. The validation of the principles and secondary objectives were assessed by independent observer during the manipulations which were realized by one unique shoulder surgeon specialized in arthroscopic surgery. RESULTS: We were able to produce ultrasound images of 68% of all the structures of interest. The inability to acquire certain images was partially due to the fact that the subjects were elderly (average age 90 years) and therefore, the structures of interest were no longer present. The secondary objective was partially fulfilled with the detection of complete tears of the supraspinatus tendon in 3 shoulders. We were also able to produce images of partial tears in the intra-tendinous cleavage. Intra-tendinous calcifications were explored in 1 shoulder. Humeral or glenoid chondropathy was identified in all the shoulders examined. Finally, no ultrasound-induced injuries were noted in any of the 6 shoulders in the study. The image acquisition time with the echo-endoscope was no more than 20 minutes for each shoulder, with an average time of 10 min 15 sec for shoulders with complete tissue evaluation. CONCLUSION: The echo-endoscope was easy and safe to use to acquire ultrasound images of the different glenohumeral or subacromial structures during shoulder arthroscopy. These results open the way for further explorations with the echo-endoscope.