Anterolateral Approach to the Humerus

Anterolateral Approach to the Humerus exposes the distal fourth of the humerus. Its major advantage over the brachialis-splitting anterior approach is that it can be extended both distally and proximally. It’s used for:

1. Open reduction and internal fixation of humeral shaft fractures.
2. Radial nerve exploration in the distal part of the arm.

• The patient is placed supine with arm on arm board, abducted 45-60 degrees.

Landmarks:

• Biceps brachii muscle.
• The flexion crease of the elbow.

Incision:

• Make a curved incision over the lateral border of the biceps centered over the fracture site.

There is No Internervous plane for the Anterolateral Approach to the Humerus:

• The interval is between:
  1. The brachialis muscle (musculocutaneous nerve and radial nerve).
  2. Brachioradialis muscle (radial nerve).

• Identify the lateral border of the biceps muscle and retract it medially,
• Ensure that the lateral antebrachial cutaneous nerve is retracted with the biceps muscle,
• This reveals the brachialis and brachioradialis muscles lying underneath.

• Incise the fascia overlying these muscles and develop the intermuscular plane,
• The radial nerve lies between the brachialis and brachioradialis muscles :
  • The nerve is generally easiest to find in the distal arm, just proximal to the elbow.
  • This must be traced proximally until it pierces the lateral intermuscular septum and be carefully protected.
• The brachialis and biceps muscles are retracted medially and the brachioradialis muscle laterally.
• Subperiosteal elevation of the brachialis reveals the humeral shaft underneath.

Proximal Extension of anterolateral approach to the humerus:

• • The incision can be extended proximally  by developing the plane between the brachialis medially and the lateral head of the triceps posterolaterally.
  • Stripping brachialis from the front of the anterior aspect of the humerus exposes the bone.

Distal Extension of anterolateral approach to the humerus:

• • The anterolateral approach may be extended into an anterior approach to the elbow by continuing the skin incision distally and developing a plane between the brachioradialis muscle (which is
    supplied by the radial nerve) and the pronator teres muscle (which is supplied by the median nerve).
  • Care should be taken to avoid the lateral cutaneous nerve of the forearm (the continuation of the musculocutaneous nerve), which emerges along the lateral side of the biceps tendon.

The structures at risk during Anterolateral Approach to the Humerus include:

1. Lateral cutaneous nerve of the forearm:
   • This terminal branch of the musculocutaneous nerve is injured at the distal end of the incision as it exits the biceps laterally.
2. Radial nerve:
   • Must be identified before any incision is made into the brachialis muscle or before periosteal elevation of the brachialis off the humerus occurs.

• Surgical Exposures in Orthopaedics book - 4th Edition
• Campbel's Operative Orthopaedics book 12th