Posterior approach to the shoulder

The posterior approach to the shoulder (Judet approach) provides access to the posterior and inferior parts of the glenohumeral joint.

The Judet approach can be used for:

1. Fracture-dislocations of the proximal humerus.
2. Glenoid fractures/osteotomy.
3. Removal of loose bodies from the shoulder joint.
4. Irrigation and debridement of septic joints.
5. Scapular neck fractures.
6. Biopsy and removal of tumors.
7. Repairs for recurrent posterior dislocation or subluxation of the shoulder.

Patient Positioning

The best positions for the posterior approach to the shoulder (Judet approach) are:

• Prone position (most commonly used).
• Lateral position.
• Beach chair position.

Landmarks and Incision

Landmarks:

• Acromion.
• The spine of the scapula.

Incision:

The incision is made along the spine of the scapula, extending to the lateral acromial border.

Internervous Plane

The internervous plane for the posterior approach to the shoulder lies between:

• The teres minor muscle, innervated by the axillary nerve.
• The infraspinatus muscle, innervated by the suprascapular nerve.

Superficial Dissection

• Care must be taken with superficial cutaneous vessels, as they can bleed profusely.
• The origin of the deltoid muscle is released from the scapular spine.
• The plane between the deltoid and infraspinatus muscles is identified and developed bluntly. This is usually easiest to find on the lateral part of the incision.
• The deltoid muscle is retracted distally and laterally.

Deep Dissection

• The interval between the infraspinatus muscle (innervated by the suprascapular nerve) and the teres minor muscle (innervated by the axillary nerve) is developed bluntly. This interval can often be difficult to find, but careful dissection is essential.
• Retract the infraspinatus muscle superiorly and the teres minor muscle inferiorly to expose the posterior glenoid and the scapular neck.

Approach Extension

• The posterior approach to the shoulder cannot be extended in a useful way.
• Its primary goal is to provide access to the posterior part of the shoulder joint.

Dangers

Structures at risk during the posterior approach to the shoulder (Judet approach) include:

1. Suprascapular nerve:
   • It runs around the base of the scapular spine (avoid excessive retraction of the infraspinatus).
2. Axillary nerve:
   • It passes through the quadrangular space below the teres minor (stay above the teres minor).
   • It is accompanied by the posterior circumflex humeral artery.

Related Anatomy

The posterior aspect of the shoulder is covered by two muscular sleeves. The posterior part of the deltoid forms the outer muscular sleeve. The inner sleeve consists of two rotator cuff muscles, the infraspinatus and the teres minor.

The Spine of the Scapula

• The spine of the scapula is a thick bony ridge projecting from the back of the scapula. Its base runs almost horizontally, and its free lateral edge curves forward to form the acromion.
• The spine separates the supraspinous fossa from the infraspinous fossa. The trapezius muscle inserts onto its superior surface; a part of the deltoid muscle originates from its inferior border.

Infraspinatus Muscle

• The fibers of the infraspinatus muscle are multipennate; numerous fibrous intramuscular septa provide attachment sites.
• The infraspinatus forms its tendon just before crossing the posterior aspect of the shoulder joint. A small bursa lies between the muscle and the posterior scapular neck, helping the tendon glide freely over the bone.
• The muscle also blends into the capsule of the shoulder joint, mechanically increasing capsular strength.

Teres Minor Muscle

• The teres minor runs alongside the infraspinatus. Unlike the multipennate fibers of the infraspinatus, its fibers run parallel to each other. This difference can be helpful in identifying the interval between the two muscles.
• The axillary nerve enters the muscle at its inferior border. The superior border (the interval between the infraspinatus and teres minor) is therefore the safe side of the muscle and represents a true internervous plane.

Axillary Nerve

• The axillary nerve is a branch of the posterior cord of the brachial plexus. It runs along the posterior wall of the axilla on the surface of the subscapularis, away from the plane used in the anterior approach to the shoulder.
• The nerve then passes through the quadrangular space, where it contacts the surgical neck of the humerus. At this point, it can be easily damaged by surgery, fractures of the surgical neck of the humerus, or anterior dislocation of the shoulder.

Within the quadrangular space, after giving off a branch to the shoulder joint, the axillary nerve divides into two branches:

• The deep branch enters and supplies the deep surface of the deltoid muscle.
• The superficial branch supplies the teres minor muscle and gives off a cutaneous branch to the lateral side of the arm, the superior lateral cutaneous nerve of the arm, which supplies the skin over the deltoid insertion.

Radial Nerve

• The radial nerve, the other major terminal branch of the posterior cord of the brachial plexus, leaves the axilla by passing posteriorly through a triangular space bounded superiorly by the lower border of the teres major, laterally by the humeral shaft, and medially by the long head of the triceps.
• The risk to the radial nerve from this approach is low. It cannot be damaged during the posterior approach to the shoulder unless the correct plane is significantly violated, going not only below the teres minor but also below the teres major.

Circumflex Scapular Vessels

Another triangular space is formed when viewing the inner aspect of the shoulder muscles from behind.

Its boundaries are as follows:

• Superiorly: the inferior border of the teres minor.
• Laterally: the long head of the triceps.
• Inferiorly: the superior border of the teres major.

This triangular space contains the circumflex scapular vessels, which are part of the extremely rich blood supply of the scapula. During elective surgical procedures, dissection between the teres minor and teres major muscles should not be performed, as these vessels can be damaged, causing significant bleeding that is difficult to control.

Because the scapula has such a rich blood supply, scapular fractures are often associated with significant blood loss. The hematoma is contained within the fascia surrounding the scapular muscles and may not be immediately obvious.

When performing a vascular assessment of a polytrauma patient, potential blood loss from a fractured scapula must always be considered.

References

1. Surgical Exposures in Orthopaedics Book - 4th Edition
2. Campbell's Operative Orthopaedics, 12th Edition
3. Fucentese SF, Jost B. Posterior approach to the shoulder. Oper Orthop Traumatol. 2010 May;22(2):188-95. doi: 10.1007/s00064-010-8064-3. PMID: 20711829.