Subacromial Bursa Injection

Other Names

• Subacromial Bursa Injection
• Subdeltoid Bursa injection
• Subacromial-Subeltoid Bursa Injection

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Illustration of the subacromial bursa anatomy

Background

• This page reviews the subacromial bursa injection, sometimes called the subdeltoid bursa

Key Points

• This is generally considered a very safe injection as there is no major neurovascular structure nearby
• Can be performed with palpation or ultrasound guidance

Anatomy

• Subacromial Bursa
  • Large synovial space that covers the whole rotator cuff like a cap
  • Lies in the subacromial region, between the superior aspect of the supraspinatus tendon, inferior surface of the acromion
  • Function: reduces friction, facilitates movement between the supraspinatus and acromion during abduction
  • Does not communicate with the glenohumeral joint when tendon is intact

Palpation vs Ultrasound Guidance

• One study of palpation guidance found only 49% of injections filled the bursa, 87% infiltrated regional structures
• There are no studies looking at ultrasound guidance or comparing the two techniques

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Bursal fluid is noted in this sagittal plane sonogram

Indications

• Rotator Cuff Tear
• Rotator Cuff Tendonitis
• Calcific Tendinitis of the Rotator Cuff
• Subcoracoid Impingement Syndrome
• Subacromial Bursitis

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Contraindications

• Absolute
  • Anaphylaxis to injectates
  • Overlying cellulitis, skin lesion or systemic infection
  • Septic Bursitis
  • History of Total Shoulder Arthroplasty
• Relative
  • Can be treated with less invasive means
  • Tendon tear or rupture
  • Hyperglycemia or poorly controlled diabetes
  • Lack of symptom improvement with previous injection

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Procedure

Subacromial bursa injection using the posterior approach

a) Scheme and (b) ultrasound image of subacromial bursa injection. The needle (arrows) is inserted within the bursa, filled with hyperechoic material (arrowheads) representing steroid solution. A, acromion; H, humerus; S, supraspinatus tendon.

Normal subacrommial space and bursa in long axis.

Probe position in coronal plane for long-axis, in-plane approach

Ultrasound showing long-axis, in-plane approach with needle in the distended subacromial bursa

Equipment

• Sterile including chloraprep, chlorhexadine, iodine
• Gloves
• Needle: typically 21-25 gauge, 1.5 inch
• Syringe: 5-10 mL
• Gauze
• Ethyl Chloride
• Bandage
• Injectate
  • Local anesthetic
  • Corticosteroid

Palpation Guided: Posterior Approach

• Preferred technique by most physicians
• Patient Position
  • The patient seated, hands placed in the lap with elbows flexed
• Landmarks
  • Palpate the lateral and posterior aspects of the acromion, identifying the posterolateral corner
  • Measure approximately 1 cm below the corner as your point of entry, marking the skin
• Needle Approach
  • Lateral to Medial
  • Insert the needle with needle tip directed towards coracoid process or opposite nipple
• Pearls and Pitfalls
  • If a bony stucture is hit, pull needle out and redirect cranially or caudally
  • Injectate should flow freely

Palpation Guided: Lateral Approach

• Favored by some as it is less likely to inject into the rotator cuff tendon
• Patient Position
  • The patient seated, hands placed in the lap with elbows flexed
• Landmarks
  • Identify lateral edge of the acromion is located, mark midpoint marked
  • Injection point of entry is 1 to 1.5 inches (about 2.5 to 4 cm) below the marked midpoint
  • Angle of entry: parallel the patient's own acromial angle (averaging 50 to 65 degrees)
  • Depth varies between 1.5 inches and 3.5 inches, depending on body habitus.
• Needle Approach
  • Lateral to medial
  • Advanced needle through the subcutaneous tissue, deltoid muscle until the subtle resistance of the deep deltoid fascia is encountered
  • If firm or hard tissue resistance is encountered, withdrawn needle about 0.5 inch, redirected 5 to 10 degrees either up or down
  • May feel "popping" sensation when the subacromial bursa is entered.
  • The injectate should flow freely with little effort placed on the syringe

Pearls and Pitfalls

• • Pearl: apply traction to the flexed elbow to open the subacromial space
  • If high injection pressure is encountered, first try rotating the syringe 180 degrees.

Ultrasound Findings

• General
  • Use high resolution linear array transducer
• Bursa
  • Normally thin, hypoechoic structure approximately 1 mm in thickness
  • Located between subdeltoid fat plane and superficial to the rotator cuff
  • Normal: bursa is collapsed barely visible
  • Bursitis: hypoechoic fluid collection distening the bursal walls
  • Chronic bursopathy: thickened, hypoechoic bursal wall with or without effusion
• Common ultrasound findings
  • Enlargement or distension of the bursa
  • Thickened, filled with soft tissue material
  • Inflamed synovium
  • Hyperemia with power doppler
• Can evaluate dynamically as well

Ultrasound Guided: Long Axis, In Plane

• Patient Position
  • Seated, lateral decubitus or supine
  • Arm resting at side
• Transducer Position
  • Coronal oblique or sagittal plane, optimizing bursal view
  • Identify the subacromial bursa in long axis
• Needle Approach
  • In Plane
  • Lateral to Medial
• Pearls and Pitfalls
  • Normal bursa is thin, nearly impercetible
  • Injectate may flow quickly into the dependent aspect of the bursa
  • avoid piercing the bursa more than once so that steroid does not leak out of the bursa

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Aftercare

• No major restrictions in most cases
• Can augment with ice, NSAIDS

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Complications

• Skin: Subcutaneus fat atrophy, skin atrophy, skin depigmentation
• Painful local reaction
• Infection
• Hyperglycmia
• Tendon, nerve or blood vessel injury

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See Also

• Procedures Main
• Shoulder Pain Main

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