The key to this approach is finding the fat between the brachialis and brachioradialis. Once you are deep to the subcutaneous tissue, any fat between muscles is a warning sign that there are nerves or arteries close by. Therefore, if you find the fat between the brachialis and brachioradialis, it will lead you to the radial nerve. Similarly, medial to the biceps tendon, the fat will guide you to the neurovascular structures. Except for radial nerve release, generally speaking, the fat is used as a warning sign of where not to go. The key to protecting the median neurovascular structures is staying lateral to the biceps tendon.
HOW TO TELL IF YOU ARE LOST
The fiber orientation of the muscles will guide you to them. The brachioradialis runs from proximal to the elbow in a straight line toward the radial styloid, whether the elbow is flexed or extended. With the elbow flexed, the tendons of the brachialis and biceps will be at a 60- or 70-degree angle, or perhaps greater, to the fiber direction of the brachioradialis. If you dissect too far proximally along the brachioradialis, you will not see the brachialis muscle well. You should, however, see the fat in the gap between those two muscles and you will come in through the fat.
If you are lost medially, the artery will be closest to the biceps tendon. The median nerve will be medial to that. If you do not see the biceps tendon, then go back proximally until you find muscle and work your way along the muscle distally.
When coming in from the lateral side, if you retract the brachioradialis and radial nerve laterally, the first muscle you see will be the brachialis. It starts slightly more laterally and crosses to insert more medially, and the biceps goes the other direction.
FIGURE 10–1 The skin incision.
FIGURE 10–2 The brachioradialis muscle and the brachialis muscle. Seen between the two is some fat, which is always the warning sign that there may be a nerve or artery close by. Note that the gap between the biceps and brachioradialis is covered by overlying fascia and is not apparent immediately.
FIGURE 10–3 The fascia overlying the brachialis muscle has been split. You can see clearly the fat around the radial nerve and you can see anteriorly the biceps tendon.
FIGURE 10–4 The radial nerve, which has now been identified underneath the brachioradialis muscle and just lateral to the brachialis muscle. The fat that is overlying it has been removed, making the nerve's location more obvious.
FIGURE 10–5 The lacertus fibrosis of the biceps anteriorly. All of the mediail neurovascular structures will be medial to this area.
FIGURE 10–6 The bicipital tuberosity, tracing the tendon down to its insertion on the radius. This is facilitated by rotation of the forearm.
FIGURE 10–7 The medial neurovascular structures encased in their fat just medial to the biceps tendon.
11
POSTEROLATERAL APPROACH
USES
This approach is the lateral equivalent of the approach to the ulnar nerve. The incision stays behind the lateral epicondyle and thus is useful for fractures of the capitellum and for open reductions and internal fixation of the distal humerus and the radial head. The exposure is useful for lateral ligament repairs around the elbow and for contracture releases around the elbow. This approach is a combination of Hoppenfeld's lateral approach to the distal humerus and the posterolateral approach to the radial head. Campbell calls it the lateral and lateral J approach.
ADVANTAGES
This approach gives a good view of the lateral elbow and capitellum area. Also, by staying somewhat posterior, the radial nerve is less at risk.
DISADVANTAGES
It is difficult to visualize the posterior aspect of the humerus for comminuted fractures through this approach. The approach, therefore, is limited to either fractures of the capitellum or two-part supracondylar fractures. The approach is difficult to extend proximally or distally because of the radial nerve.
STRUCTURES AT RISK
The major structure at risk is the radial nerve. The radial nerve wraps around the humerus, and at the junction of the middle and distal thirds of the humerus the nerve is usually posterior. From there, it comes along the lateral border to enter the forearm anteriorly. The radial nerve can be transected if the brachioradialis is stripped off of its humeral origin because the nerve will have to come around the humerus right along the proximal edge of this muscle.
The blood supply to the capitellar fragment can be destroyed if all the soft tissue attaching to that lateral piece is removed. The blood supply to the capitellum is quite precarious and, especially in children, the soft tissue attachments need to be handled gently.
TECHNIQUE
The incision is centered on the lateral epicondyle and 1 cm posterior to it. It is carried as far proximal or distal as necessary. The incision goes through the subcutaneous tissue. The tissue plane between the brachioradialis anteriorly and the triceps posteriorly is developed. The fascia is split starting at the lateral epicondyle and proceeding in that interval along the humerus proximally. It is critical not to carry sharp dissection into or underneath the brachioradialis muscle. The dissection should be done bluntly. When the elbow capsule is identified, it can be opened as in the anconeus approach (see Case 12). Once the posterior aspect of the humerus is identified, the bone can
