ANTEROLATERAL APPROACH TO HUMERUS
- What are the indications for the anterolateral approach to the humerus?
The main indication is for the ORIF of middle-third and distal-third diaphyseal humerus fractures. Unlike the anterior approach, it can be extended both proxi- mally and distally.
Other indications include exploration of the radial nerve, humeral osteotomies and tumour biopsies/resections.
- What is the internervous plane utilised by this approach?
There is no true internervous plane. This approach uses an intermuscular plane as both the lateral third of brachialis and brachioradialis muscles are supplied by the radial nerve.
- How would you position the patient?
Supine with the arm abducted to 60 degrees on an arm board.
- Where would you base your incision?
I would make a curved longitudinal incision over the lateral border of the biceps, starting about 10 cm proximal to the elbow crease and ending just proximal to it.
- Talk me through the superficial dissection.
After making my skin incision (as above) I would identify and retract the cephalic vein and divide the deep fascia of the arm in line with the incision to identify the lateral border of the biceps.
The lateral cutaneous nerve of forearm (LCNF) crosses from medial to lateral under the fascia. Approximately 5 cm proximal to the elbow crease, it emerges from between the biceps and brachialis as the continuation of the musculocutaneous nerve. It should be retracted with the biceps.
- What about the deep dissection?
Retract biceps medially along with the LCNF to identify the interval between bra- chioradialis and brachialis. Incise the deep fascia in line with the intermuscular septum between brachioradialis and brachialis and develop the intermuscular plane to find the radial nerve. The radial nerve is most readily identified distally between these two muscles. Mobilise and protect the nerve and trace it back up the lateral humerus to where it pierces the lateral intermuscular septum. Brachialis is then stripped with a periosteal elevator and retracted medially to expose the anterior shaft of the distal humerus.
- What are the dangers of this approach?
Radial nerve
Lateral cutaneous nerve of forearm
- How would you extend this approach?
This extensile approach can be extended proximally or distally.
Proximally, the plane between brachialis medially and the lateral head of the tri- ceps posterolaterally can be utilised. Posterior dissection may injure the radial nerve in the spiral groove and therefore any dissection should be subperiosteal.
Distally, the anterolateral approach can be extended into the anterior approach to the elbow/proximal forearm by developing the same internervous plane at the elbow and, in the proximal forearm, between brachioradialis (radial nerve) and pronator teres (median nerve).
- When would you use the anterolateral approach over the anterior approach?
The anterior approach cannot be extended distally, nor does it allow for exploration of the radial nerve. Therefore, the anterolateral approach is used over the anterior approach where there is any requirement for distal extension down the humeral shaft or the radial nerve requires exploration.