The commonly taught Schneider technique uses a straight anteroposterior approach to the joint. A 3.5-inch (8.9-cm), 22-gauge needle is directed vertically at the junction of the middle and lower thirds of the glenohumeral joint under fluoroscopic guidance. A recent study determined that the anterior stabilizing structures of the glenohumeral joint are often traversed by the needle when this technique is used, which may cause distortion of the healthy anatomic structures. We think the approach described below is easier and better.
In 85% of our patients, some of them obese, a 1.5-inch (3.8-cm) 22-gauge needle needle was used successfully to enter the glenohumeral joint. This short needle is easier to manipulate than a 3.5-inch (8.9-cm) needle. A shorter needle can be used when entering the shoulder joint through the rotator cuff interval because the joint is more superficial in this location as compared with more inferiorly.
Patients were positioned supinely on a fluoroscopy table with the arm in external rotation (palm of the hand up) to avoid the long head of the biceps tendon or, if this position was too painful for the patient, in neutral rotation (palm of the hand against the thigh). With the X-ray tube perpendicular to the table, the skin was marked over the upper medial quadrant of the humeral head close to the articular joint line.
Radiograph shows initial position of humeral head during arthrography of left shoulder. Humeral head is positioned in external rotation. Pointer indicates site of needle entry at medial upper quadrant of humeral head.
22-gauge needle introduced into glenohumeral joint under intermittent fluoroscopy at level of rotator cuff interval. Needle is advanced until it contacts humeral head.
Radiograph shows intraarticular injection of contrast material. Short extension tubing was attached to 1.5-inch (3.8-cm), 22-gauge needle, and contrast material was injected under fluoroscopy. Contrast material flows freely away from needle tip. Distribution of contrast material toward joint line and subscapularis recess confirms intraarticular injection.
Diagram of rotator cuff interval shows left shoulder in external rotation. Rotator cuff interval (asterisk) lies between supraspinatus (SUP) muscle and subscapularis (SUB) muscle. Long head of biceps tendon (arrow) courses in bicipital groove and is displaced laterally away from target site for needle.
Drawing shows patient in prone position for posterior approach to fluoroscopically guided arthrography of shoulder.
Image obtained during fluoroscopy shows glenohumeral joint is viewed tangentially, and needle (arrow) is advanced parallel to X-ray beam onto inferomedial quadrant of humeral head within boundary of anatomic neck (interrupted line).
Axial T1-weighted fat-saturated image after intraarticular injection shows attachment of posterior capsule and increased latitude available for needle placement (arrow).
Tailoring the site of injection according to the suspected pattern of instability (posterior approach for anterior instability and vice versa) avoids injury to anterior stabilizing structures under investigation
The injection of contrast material using the posterior approach to the shoulder is particularly useful in patients suspected of having anterior instability because the approach avoids the potential for interpretive difficulties, a consequence of anterior extracapsular contrast extravasation, and decreases the apprehension of the patient during needle placement.