The subacromial space is limited by the humeral head below, the acromion process of the scapula and the coracoacromial ligament above, and indirectly by the acromioclavicular joint. It contains the tendons of supraspinatus and infraspinatus muscles, as well as the subacromial bursa. Under normal physiological conditions, the structures in this space do not undergo excessive compression, and the subacromial bursa allows for proper tendon glide beneath the acromion and acromioclavicular joint.
Subacromial impingement occurs when this space becomes narrowed, for example, due to improper positioning of the humeral head, degenerative changes in the acromioclavicular joint, abnormal structure of the acromion process, or inflammation of the subacromial bursa.
This is most commonly associated with overuse of this area, resulting from excessive use of the shoulder joint above the level of the head or imbalances in muscle strength, which increase the compression of the humeral head on the acromion process. Continuous irritation leads to inflammatory tissue hypertrophy.
Symptoms of subacromial impingement syndrome
A characteristic symptom of subacromial impingement is painful movement of flexion and abduction in the shoulder joint within the range of 60 degrees to 120 degrees, as well as at 180 degrees.
Pain is localized on the anterior and lateral surface of the joint around the acromion process and the humeral head. It often radiates to the elbow joint along the lateral and anterior surface of the arm. It occurs during sleep and lying on the affected shoulder. It intensifies during everyday activities that require lifting the arm.
Clinical examination is crucial for making a diagnosis, in which the doctor palpates the pain in the joint and the painful range of motion.
Routine additional tests include X-ray and ultrasound of the shoulder joint. Ultrasound examination assesses the structures in the subacromial space: the tendons of the rotator cuff, their function in dynamic examination, and inflammation of the bursa.
In some cases, magnetic resonance imaging may also be performed.
Treatment of subacromial impingement syndrome
Depending on the cause, conservative or surgical treatment is used.
Conservative methods involve rehabilitation, which aims to lower the humeral head and improve muscle balance, resulting in relief of the subacromial space. Exercises are supplemented with pharmacological treatment using pain and anti-inflammatory medications.
Intra-articular injections of corticosteroids under ultrasound guidance are also used.
Surgical treatment of subacromial impingement is used in cases of massive inflammation and hypertrophy of the subacromial bursa in order to remove it, address the surface of the acromion process, or treat degenerative changes in the acromioclavicular joint.
It is important to note that chronic compression of the tissues in the subacromial space, especially the tendons, can lead to damage. Therefore, magnetic resonance imaging is recommended to assess any tendon injuries.
This type of surgery is a minimally invasive, arthroscopic procedure performed under general anesthesia using several small incisions. If no tendon repairs are required, the procedure takes about 90 minutes. After surgery, immobilization in a sling is used for 1-2 weeks. Rehabilitation begins a few days after the operation.
In MIRAI, the shoulder area is handled by:
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