Lateral approach to the shoulder

The lateral approach to the shoulder (also known as the deltoid split approach or transdeltoid lateral approach) provides limited access to the humeral head and the surgical neck of the humerus.

The lateral approach to the shoulder is used for:

1. Open reduction and internal fixation (ORIF) of proximal humerus fractures.
2. Open reduction and internal fixation of displaced fractures of the greater tubercle of the humerus.
3. Removal of calcium deposits from the subacromial bursa.
4. Supraspinatus tendon repair.
5. Rotator cuff repair.
6. Debridement of the subacromial space.

In a comparative study of the lateral deltoid-split approach versus the deltopectoral approach for treating proximal humerus fractures, the lateral deltoid-split approach provided superior reduction of the humeral head and tuberosity fragments.

Patient Positioning

• The lateral approach to the shoulder is performed with the patient in the supine position. A bump or roll is placed under the spine or the ipsilateral scapula.
• Raising the head of the table helps reduce venous pressure in the surgical field.
• Alternatively, a "beach chair" positioning adapter may be used, depending on the surgeon's preference.
• The operative arm should be positioned at the edge of the table to allow optimal manipulation of the extremity.

Landmarks and Incision

• Landmarks:
  • The acromion bone.
• Incision:
  • A 5 cm longitudinal incision is made from the tip of the acromion, extending down the outer side of the arm.

Internervous Plane

There is no true internervous plane in the lateral approach to the shoulder, as the deltoid muscle is split along its fibers.

Superficial Dissection

• The deltoid muscle is split in line with its fibers, with the split extending no more than 5 cm distal to the lateral edge of the acromion to protect the axillary nerve.
• A stay suture is placed at the lower tip of the split to prevent it from extending further.

Deep Dissection

• The subacromial bursa lies directly beneath the deltoid muscle and can be removed to expose the underlying rotator cuff insertion and the proximal humerus.

Approach Extension

The lateral approach to the shoulder is not a classic extensile approach, as it is limited distally by the course of the axillary nerve across the deep surface of the deltoid muscle.

Proximal Extension:

• Extend the incision upward and medially over the acromion, parallel to the superior border of the scapular spine, approximately 1 cm above it, along the lateral two-thirds of the spine.
• Incise the trapezius muscle and retract it upward.
• Incise the fascia over the supraspinatus muscle.
• Split the acromion in line with the skin incision using an osteotome (the acromion will be reconstructed during closure).

Distal Extension:

Distal extension is possible by creating a separate deltoid split distal to the axillary nerve.

Dangers

During the lateral approach to the shoulder, the following structures are at risk:

Axillary Nerve:

• Exits the posterior aspect of the axilla by passing through the quadrangular space (bordered by the teres minor, teres major, long head of the triceps, and the medial border of the humerus).
• It wraps around the humerus anteriorly and laterally to enter and innervate the deltoid muscle on its deep surface.
• At this point, it runs 5–7 cm transversely from posterior to anterior relative to the edge of the acromion.
• The split cannot be extended further distally due to the risk of denervating the anterior deltoid.
• If distal extension is required (most commonly for fractures), a second, separate incision must be made distally to create a safe "second window."

References

1. Korkmaz MF, Erdem MN, Karakaplan M, Görmeli G, Selçuk EB, MarŸ Z, Karataş T. Comparison of lateral deltoid splitting and deltopectoral approaches in the treatment of proximal humerus fractures. Ulus Travma Emergency Surgery Journal. 2015 Mar;21(2):113-8. Turkish. doi: 10.5505/tjtes.2015.74150. PMID: 25904272.
2. Book: "Surgical Exposures in Orthopaedics" – 4th Edition.
3. Campbell's Operative Orthopaedics, 12th Edition.