Lateral Approach to the Proximal Humerus
Lateral Approach to the Proximal Humerus
The lateral approach provides limited access to the head and surgical neck of the humerus. It is not a classically extensile approach, because it is limited distally by the traverse of the axillary nerve running on the deep surface of the deltoid muscle. Distal extension is however possible by utilizing a separate deltoid split distal to the nerve (see minimally invasive approach to proximal humerus). It can be extended usefully in a proximal direction to reveal the entire length of the supraspinatus muscle. Its use in fracture surgery is reserved for fractures of the surgical neck and tuberosities of the humerus. Most distal fractures are best approached through the anterior approach to the shoulder (see page 7, Fig. 1-8) or the minimally invasive lateral approach to the proximal humerus (see page 14, Fig. 1-41).
The uses of the lateral approach include the following:
-
Open reduction and internal fixation of displaced fractures of the greater tuberosity of the humerus
-
Open reduction and internal fixation of humeral neck fractures
-
Insertion of intramedullary nails into the humerus
-
Removal of calcific deposits from the subacromial bursa
-
Repair of the supraspinatus tendon
-
Repair of the rotator cuff
Position of the Patient
Place the patient in a supine position with the affected arm at the edge of the table. Elevate the head of the table to reduce venous pressure and operative bleeding (Fig. 1-35). A sandbag should be placed under the patient’s shoulder. Ensure that adequate intraoperative imaging can be obtained before prepping and draping the patient.
Landmarks and Incision
Landmarks
The acromion is rectangular. Its bony dorsum and lateral border are easy to palpate on the outer aspect of the shoulder.
 |
Figure 1-35 Position of the patient on the operating table for the lateral approach to the shoulder. Elevate the table to 45 degrees. Place a sandbag under the shoulder to lift it off the operating table.
 |
 |
Figure 1-36 Make a 5-cm longitudinal incision from the tip of the acromion down the lateral aspect of the arm.
The lateral side of the proximal humerus is also easily palpable.
Incision
Make a 5-cm longitudinal incision from the tip of the acromion down the lateral aspect of the arm (Fig. 1-36).
Internervous Plane
There is no true internervous plane; the lateral approach involves splitting
the deltoid muscle.
Superficial Surgical Dissection
Split the multipennate deltoid muscle in the line of its fibers from the acromion downward for 5 cm. This may involve sharp as well as blunt dissection. Insert a suture at the inferior apex of the split to help prevent it from extending accidentally, with consequent axillary nerve damage, as the exposure is worked on (Figs. 1-37 and 1-38).
Deep Surgical Dissection
The lateral aspect of the upper humerus and its attached rotator cuff lie directly under the deltoid muscle and the subacromial bursa (Fig. 1-39). In fractures of the neck of the humerus, the bare ends of bone usually appear at this point without further dissection.
Small tears of the supraspinatus muscle also can be reached through this approach. Most defects in the supraspinatus muscle are large, however. Some surgical procedures require that the whole supraspinatus be mobilized so that the muscle can be advanced and the tendon repaired (Fig. 1-40).
 |
 |
Figure 1-37 Split the deltoid muscle in line with its fibers and insert a stay suture at the inferior apex of the split to prevent it from extending distally and causing axillary nerve damage.
 |
 |
Figure 1-38 Expose the subdeltoid portion of the subacromial bursa by retracting the deltoid muscle anteriorly and posteriorly.
 |
 |
Figure 1-39 Incise the bursa to reveal the insertion of the supraspinatus tendon into the greater tuberosity.
Dang
Nerves
The axillary nerve leaves the posterior wall of the axilla by penetrating the quadrangular space. Then it winds around the humerus with the posterior circumflex humeral artery (see Figs. 1-37 and 1-52). The nerve enters the deltoid muscle posteriorly from its deep surface, about 5 to 7 cm
below the tip of the acromion. From that point, its fibers spread anteriorly. Because of the nerve’s course, the dissection cannot be extended farther in an inferior direction without denervating that portion of the deltoid muscle that is located anterior to the muscle split.
How to Enlarge the Approach
Extensile Measures
Proximal Extension. Extend the incision superiorly and medially across the acromion and parallel to the upper margin of the spine of the scapula, about 1 cm above it along the lateral two-thirds of the scapular spine.33
Incise the trapezius muscle parallel to the spine of the scapula and about 1 cm above it. Retract the muscle superiorly to reveal the supraspinatus and its fascial covering.
Incise the fascia overlying the supraspinatus in the line of the skin incision to expose the muscle.
Split the acromion in the line of the skin incision, using an osteotome. Retract the two parts of the acromion with a self-retaining retractor.
The entire length of the supraspinatus, from its origin in the supraspinous fossa to its insertion onto the greater tuberosity of the humerus, now is exposed (see Figs. 1-40 and 1-52). Take great care to reconstruct the divided acromion during closure.
 |
 |
 |
Figure 1-40 To expose the entire supraspinatus muscle, cut the acromion and split the trapezius muscle to reveal the underlying supraspinatus muscle belly and tendon. The entire muscle can be advanced and the tendon repaired.